WO2025019816A1

WO2025019816A1 - Overtube devices and assemblies for elongate surgical tools

Info

Publication number: WO2025019816A1
Application number: PCT/US2024/038839
Authority: WO
Inventors: Mark E. Rentschler; Jeffrey P. Castleberry; Aleksander M. Stefanov
Original assignee: Aspero Medical Inc
Current assignee: Aspero Medical Inc
Priority date: 2023-07-19
Filing date: 2024-07-19
Publication date: 2025-01-23
Anticipated expiration: 2026-01-19

Abstract

An overtube assembly is provided. The overtube assembly includes a primary tubular body defining a primary lumen configured to receive a first elongate medical device and a secondary lumen extending along the primary tubular body configured to receive a second elongate medical device. The primary tubular body has a length extending from a proximal end oriented to receive the first elongate medical device to a distal end. The secondary lumen is coupled along the length of the primary tubular body. When a torque force is applied to the proximal end of the primary tubular body to cause the proximal end of the primary tubular body to rotate by a first rotation amount, the distal end of the primary tubular body responds by rotating a second rotation amount, the second rotation amount lagging behind the first rotation amount by a rotation lag amount less than 90 degrees.

Description

OVERTUBE DEVICES AND ASSEMBLIES FOR ELONGATE SURGICAL TOOLS

Cross-Reference to Related Applications

[0001] This application claims priority to U.S. Provisional Patent Application No. 63/514,407, filed July 19, 2023, the entire contents of which is incorporated herein by reference for all purposes.

Government Funding

[0002] This invention was made with government support under grant number 2129152 awarded by the National Science Foundation. The government has certain rights in the invention.

Technical Field

[0003] Aspects of the present disclosure are directed to overtube assemblies for use in medical procedures and, specifically, to overtube assemblies for use with endoscopic and other elongate surgical tools.

Background

[0004] Surgical procedures within the gastrointestinal (Gl) tract may be difficult to perform due to limited access to the target tissue and/or tortuous removal of target tissue. For example, larger lesions that occur in the colon, rectum, esophagus, and/or stomach may require a highly invasive and cost-intensive surgery for removal followed by a more arduous recovery for a patient that may be left without a fully functional Gl tract.

[0005] Endoscopic procedures involving resection and/or dissection of larger legions within the Gl tract has been a positive medical advancement. However, these procedures, such as endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) procedures, may be time-intensive for the endoscopist and challenging given the instability of the Gl tract during surgery and the surgical tool access limitations.

[0006] Thus, there is a need for improved medical tool access for endoscopic procedures within the Gl tract. Specifically, there is a need for overtube devices and assemblies for elongate surgical tools for use in intraluminal surgery to remove lesions within the Gl tract.

Summary

[0007] In one aspect, an overtube assembly is provided. The overtube assembly is for use with a first elongate medical device and a second elongate medical device within a physiological lumen of a patient. The overtube assembly includes a primary tubular body defining a primary lumen configured to receive the first elongate medical device and a secondary lumen extending along the primary tubular body. The primary tubular body has a length extending from a proximal end oriented to receive the first elongate medical device to a distal end. The secondary lumen is coupled along the length of the primary tubular body. When a torque force is applied to the proximal end of the primary tubular body to cause the proximal end of the primary tubular body to rotate by a first rotation amount, the distal end of the primary tubular body responds by rotating a second rotation amount, the second rotation amount lagging behind the first rotation amount by a rotation lag amount less than 90 degrees.

[0008] In another aspect, an overtube assembly is provided. The overtube assembly is for use with a first elongate medical device and a second elongate medical device within a physiological lumen of a patient. The overtube assembly includes a primary tubular body including a first circumferential outer wall and a primary lumen configured to receive the first elongate medical device and at least one of a fluid tubular body or a secondary tubular body. The primary tubular body has a length extending from a proximal end oriented to receive the first elongate medical device to a distal end. The first circumferential outer wall (5711a-c) includes a first radially inward circumferential surface, a first radially outward circumferential surface, and a first radial wall thickness (T1 + T2 + T3) of between approximately 0.126 mm and approximately 7.75 mm. The first radially inward circumferential surface defines the primary lumen and has a first internal diameter (D3) of between approximately 5.5 mm and approximately 17.5 mm. The first radially outward circumferential surface has a first outer diameter (D2) of between approximately 15 mm and approximately 19 mm. Each of the fluid tubular body and the secondary tubular body extends along, is coupled to, and is helically wrapped about the primary tubular body at a helical pitch of between approximately 1 circumferential wrap per 165 mm and approximately 1 circumferential wrap per 170 mm. The fluid tubular body includes a second radially inward circumferential surface, a second radially outward circumferential surface, and a second radial wall thickness defined between the second radially inward circumferential surface and the second radially outward circumferential surface. The second radially inward circumferential surface defines a fluid-conveying lumen and has a second internal diameter (D4) of between approximately 0.5 mm and approximately 3.25. The second radially outward circumferential surface has a second outer diameter (D5) of between approximately 0.75 mm and approximately 6.5 mm. The secondary tubular body includes a third radially inward circumferential surface, a third radially outward circumferential surface, and a third radial wall thickness defined between the third radially inward circumferential surface and the third radially outward circumferential surface. The third radially inward circumferential surface defines a secondary lumen and has a third internal diameter (D6) of between approximately 1.5 mm and approximately 4 mm. The third radially outward circumferential surface has a third outer diameter (D7) of between approximately 1.75 mm and approximately 7.5 mm, the secondary lumen being configured to receive the second elongate medical device. A distance (R1) between a center of the primary lumen and a center of the fluidconveying lumen is between approximately 3.25 mm and approximately 12.5 mm. A distance (R2) between a center of the primary lumen and a center of the secondary lumen is between approximately 3.5 mm and approximately 13.5 mm.

Brief Description

[0009] The foregoing summary, as well as the following detailed description of preferred embodiments, will be better understood when read in conjunction with the appended drawings. For purposes of illustration, there are shown in the drawings embodiments which are presently preferred. It should be understood, however, that the disclosure is not limited to the precise arrangements and instrumentalities shown.

[0010] FIG. 1 is a perspective view of a device according to one or more embodiments of the present disclosure, the device being used within an operational environment.

[0011] FIG. 2A is a front view of an example environment in which devices and systems according to the present disclosure may be used.

[0012] FIG. 2B is an overtube assembly for use in the environment shown in FIG. 2A.

[0013] FIGS. 3A-3C are perspective views of an overtube assembly according to one or more embodiments of the present disclosure.

[0014] FIGS. 4A and 4B are perspective views of a system including a tool coupled to an overtube assembly according to one or more embodiments of the present disclosure.

[0015] FIG. 5 is an isometric view of an overtube assembly according to one or more embodiments of the present disclosure.

[0016] FIG. 6A is an isometric view of an overtube assembly according to one or more embodiments of the present disclosure.

[0017] FIGS. 6B and 6C are isometric views of the overtube assembly shown in FIG. 6A, the overtube assembly being subjected to rotation or torque. [0018] FIGS. 7A-7D are isometric views of a section of an overtube according to one or more embodiments of the present disclosure.

[0019] FIGS. 8A-8M are cross-sectional views of overtubes with a primary lumen and a secondary tube according to one or more embodiments of the present disclosure.

[0020] FIGS. 9A-9C are isometric views of overtube assemblies including a primary tube and a secondary tube according to one or more embodiments of the present disclosure.

[0021] FIGS. 10A-10F are isometric and end views of overtube assemblies including a primary tube and a secondary tube with a steerable end according to one or more embodiments of the present disclosure.

[0022] FIGS. 11 A-11 E isometric and side views of overtube assemblies including a primary tube and a secondary tube with a steerable end according to one or more embodiments of the present disclosure.

[0023] FIGS. 12A and 12B are isometric views of an overtube assembly including a primary tube and a second tube according to one or more embodiments of the present disclosure.

[0024] FIGS. 13A-13C are isometric views of overtube assemblies including a primary tube and a secondary tube formed integrally with the primary tube according to one or more embodiments of the present disclosure.

[0025] FIGS. 14A and 14B are isometric views of sheathed overtube assemblies according to one or more embodiments of the present disclosure.

[0026] FIGS. 15A and 15B are isometric views of overtube assemblies including a primary tube and a secondary tube formed integrally with the primary tube according to one or more embodiments of the present disclosure.

[0027] FIGS. 16A and 16B are isometric views of helical variations of the overtube assemblies shown in FIGS. 15A and 15B.

[0028] FIG. 17A is a cross-sectional view of an overtube assembly including a primary tube and one secondary tube according to one or more embodiments of the present disclosure.

[0029] FIGS. 17B is a cross-sectional view of an overtube assembly including a primary tube and a plurality of secondary tubes according to one or more embodiments of the present disclosure. [0030] FIGS. 18A-18C are isometric and cross-sectional views of overtube assemblies including including a primary tube and a plurality of secondary tubes according to one or more embodiments of the present disclosure.

[0031] FIGS. 19A-19C are isometric and cross-sectional views of overtube assemblies including including a primary tube and a plurality of secondary tubes according to one or more embodiments of the present disclosure.

[0032] FIGS. 20A-20C are isometric and cross-sectional views of overtube assemblies including including a primary tube and a plurality of secondary tubes according to one or more embodiments of the present disclosure.

[0033] FIGS. 21A-21C are isometric views of overtube assemblies with a primary tube and a secondary tube according to one or more embodiments of the present disclosure, the secondary tube with different longitudinal placements.

[0034] FIGS. 22A and 22B are isometric views of overtube assemblies including a primary tube and a secondary tube assembly according to one or more embodiments of the present disclosure.

[0035] FIGS. 23A and 23B are isometric and side views of overtube assemblies including a primary tube and a secondary tube extending along the primary tube according to one or more embodiments of the present disclosure.

[0036] FIGS. 24A and 24B are isometric views of overtube assemblies including a primary tube, a secondary tube, and a balloon according to one or more embodiments of the present disclosure.

[0037] FIGS. 25A and 25B are isometric views of overtube assemblies including a primary tube, a secondary tube, a balloon, and a handle according to one or more embodiments of the present disclosure.

[0038] FIG. 26A is an isometric view of an overtube assembly including a balloon and a handle according to one or more embodiments of the present disclosure, the overtube assembly in a first state with a torque being applied to the handle.

[0039] FIGS. 26B and 26C are isometrics views of the overtube assembly shown in FIG. 26A, the overtube assemblies in subsequent states with the torque being applied to the handle and the balloon.

[0040] FIG. 27 is a partial cross-sectional view of an overtube assembly including a locking mechanism according to one or more embodiments of the present disclosure. [0041] FIGS. 28 and 29 are side and isometric views of overtube assemblies coupled to an elongate tool according to one or more embodiments of the present disclosure.

[0042] FIGS. 30A-30C are isometric views of overtube assemblies including a primary tube, a secondary tube, a balloon, and a handle according to one or more embodiments of the present disclosure, with a tool extending through the secondary tube.

[0043] FIG. 31 is an isometric view of an overtube assembly including two balloons according to one or more embodiments of the present disclosure.

[0044] FIGS. 32A-32C are isometric views of the overtube assembly shown in FIG. 31 in various states of inflation.

[0045] FIGS. 33A and 33B are isometric views of overtube assemblies including a balloon in an alternate placement according to one or more embodiments of the present disclosure.

[0046] FIGS. 34A and 34B are isometric and side views of overtube assemblies including a primary tube, a secondary tube, and a balloon according to one or more embodiments of the present disclosure.

[0047] FIGS. 35A and 35B are isometric and side views of overtube assemblies including a primary tube, a secondary tube, and an asymmetrical balloon according to one or more embodiments of the present disclosure.

[0048] FIGS. 36A-36C are cross-sectional and isometric views of overtube assemblies including an integrally formed air supply lumen according to one or more embodiments of the present disclosure.

[0049] FIGS. 37A-37F are cross-sectional and isometric views of overtube assemblies including a separately formed air supply lumen according to one or more embodiments of the present disclosure.

[0050] FIG. 38 is a side assembly view of a balloon assembly for use with an overtube assembly according to one or more embodiments of the present disclosure.

[0051] FIG. 39 is a side assembly view of another balloon assembly for use with an overtube assembly according to one or more embodiments of the present disclosure.

[0052] FIG. 40 is a side assembly view of yet another balloon assembly for use with an overtube assembly according to one or more embodiments of the present disclosure. [0053] FIGS. 41 A and 41 B are isometric views of an overtube assembly for use with an endoscope according to one or more embodiments of the present disclosure.

[0054] FIGS. 42A and 42B are side views of the overtube assembly shown in FIGS. 41A and 41B.

[0055] FIG. 43 is a side view of an overtube assembly for use with an endoscope according to one or more embodiments of the present disclosure.

[0056] FIG. 44 is an isometric view of the overtube assembly shown in FIG. 43.

[0057] FIGS. 45A and 45B are side views of the overtube assembly shown in FIG. 43.

[0058] FIGS. 46A-51 B are isometric and end views of endcaps for use with an overtube according to one or more embodiments of the present disclosure.

[0059] FIGS. 52A and 52B are side and assembly views of a handle assembly for use with an overtube assembly according to one or more embodiments of the present disclosure.

[0060] FIGS. 53A-53C are side and isometric views of a handle assembly for use with an overtube assembly according to one or more embodiments of the present disclosure.

[0061] FIG. 54 is a top perspective view of an overtube assembly including a handle assembly according to one or more embodiments of the present disclosure.

[0062] FIG. 55 is a side perspective view of an overtube assembly according to one or more embodiments of the present disclosure.

[0063] FIGS. 56A and 56B are cross-sectional and side perspective views of an overtube with a primary lumen, a secondary tube, and an air tube according to one or more embodiments of the present disclosure.

[0064] FIGS. 57A and 57B are top perspective and side views of an overtube assembly including a handle assembly according to one or more embodiments of the present disclosure.

[0065] FIGS. 58A is the same view as FIG. 57B, except enlarged.

[0066] FIG. 58B is a longitudinal cross section of the overtube assembly as taken along section line D-D of FIG. 58A.

[0067] FIG. 580 is an enlarged view of a region of the longitudinally cross sectioned overtube assembly as circled in detail E in FIG. 58B. [0068] FIG. 58D is a transverse cross section of the overtube assembly as taken along section line G-G in FIG. 57B.

Detailed Description

[0069] Reference will now be made in detail to the exemplary embodiments, which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[0070] There is a need for improved medical tool access for endoscopic procedures within the Gl tract. Specifically, there is a need for overtube devices and assemblies for elongate surgical tools for use in intraluminal surgery to remove lesions within the Gl tract. A balloon overtube may be used in such procedures to enable deeper access and/or greater stabilization of the Gl tract wall while providing additional working channel access to the endoscopist through the overtube. The overtube may include an inner coating and/or layer with a reduced friction response for easier advancement of surgical tools through the overtube, specifically through the curves and bends of the highly tortuous Gl tract, such as, but not limited to, an endoscope or a catheter.

[0071] In addition to the working channel for insertion and manipulation of an endoscope, the overtube devices and assemblies described herein also include a second working channel for insertion and manipulation of a second surgical tool, such as, but not limited to, a forceps, a knife, a pair of scissors, or a clamp. Thus, the overtube devices and assemblies described herein allow for (1) insertion and rotation of the endoscope within the working channel, (2) insertion and rotation of the second surgical tool within the second working channel, and (3) rotation of the second surgical tool relative to the endoscope in the working channel. The independent rotation of the second surgical tool relative to the endoscope may facilitate improved surgical visibility and target tissue accessibility.

[0072] FIG. 1 is a perspective view of an operational environment 100 corresponding to an example application of devices and systems according to the present disclosure. More specifically, operational environment 100 illustrates a colon 110 of a patient, which generally includes a colon wall 112 that defines a physiological lumen 114. In the specific procedure illustrated in operational environment 100, a lesion 116 is in the process of being surgically removed from colon 110 using a tool assembly 200.

[0073] As shown in FIG. 1, tool assembly 200 generally includes an endoscope 202 disposed within and extending through an overtube assembly 210. To facilitate removal of lesion 116, tool assembly 200 includes a first tool 206 (illustrated as a snare tool) and a second tool 222 (illustrated as a forceps tool). More specifically, first tool 206 is shown as being inserted through endoscope 202 and extending out of a first opening 218 in a distal end 204 of endoscope 202. Similarly, second tool 222 is shown as being inserted through overtube assembly 210 and extending out of a second opening 220 in a distal end 216 of overtube assembly 210.

[0074] Overtube assembly 210 generally includes an overtube 212 that defines a primary lumen through which the endoscope 202 or a similar elongate tool may be inserted. Overtube assembly 210 further includes a balloon 214 coupled to overtube 212 and selectively inflatable by a clinician to anchor overtube assembly 210 to colon wall 112 of colon 110. More generally and considering other applications, the inflatable balloon is selectively inflatable to anchor the overtube assembly to a wall of a physiological lumen within which the overtube assembly is disposed.

[0075] The balloon 214 can also be selectively inflated to position the endoscope 202 and tools as desired within the physiological lumen. In some uses, selectively inflating the balloon allows for the user to then “rock” the overtube assembly forward and/or backward (causing the endoscope and tools to pitch). In other uses, selectively inflating the balloon allows the user to rotate the balloon assembly slightly to put tension on the tissue in contact with the secondary lumen 224 (e.g., the working channel) shown in FIG. 1.

[0076] In addition to providing a robust support for endoscope 202, anchoring of overtube assembly 210 to colon wall 112 facilitates pulling and straightening of colon wall 112, e.g., to flatten or smooth the plications of colon wall 112. While not illustrated in FIG. 1 , balloon 214 is generally connected to a proximal air supply via air lumens extending through overtube assembly 210 (e.g., defined in a wall of overtube 212 or in the form of separate tubules coupled to or integrated into overtube 212).

[0077] Overtubes according to this disclosure include supplemental or secondary lumens (also referred to herein as “working channels”) to provide additional functions and capabilities to the operating clinician. For example, FIG. 1 illustrates overtube assembly 210 includes a secondary lumen 224 that terminates in a second opening 220 at the distal end 216 of overtube assembly 210. In the illustrated application, the second tool 222 (e.g., in the form of a gripping tool) is inserted through secondary lumen 224 and extends out of second opening 220 to provide additional capabilities to the clinician.

[0078] In general, secondary lumen 224 provides a channel between a proximal end of overtube assembly 210 and some distal location of overtube assembly 210. While shown as opening at distal end 216 of overtube assembly 210, the opening of secondary lumen 224 may be disposed anywhere along overtube 212 depending on the procedure being performed. Moreover, while secondary lumen 224 is generally described as being used to guide and retain secondary tools, secondary lumen 224 is more generally a conduit/channel that may be used for other purposes. For example, and without limitation, in certain implementations the secondary lumen 224 may be used to provide irrigation, suction, inflation, insufflation, and other similar actions involving communication of fluid to or from the physiological lumen. Also, while FIG. 1 illustrates overtube assembly 210 as including a single secondary lumen, overtubes according to this disclosure may include multiple secondary lumens.

[0079] While the overtube assembly 210 in example FIG. 1 has been described as assisting surgery and tissue manipulation, the overtube assembly 210 also serves as a conduit for the endoscope 202. In some embodiments, the overtube assembly 210 remains in place while the endoscope 202 is partially or fully removed from the patient. The endoscope or other instruments can then be reinserted and easily advanced to the surgical site. That is, the size, shape, and/or material of the overtube assembly 210 may facilitate the overtube assembly 210 maintaining its position within the physiological lumen without collapsing or buckling.

[0080] The overtube assembly 210 is designed to maintain the primary lumen without significant deflection when the endoscope 202 is removed, even in highly tortuous environments. These tortuous environments are known to buckle or kink other overtubes, such as that known in the prior art, when the endoscope is removed. Removal of the endoscope mid-procedure or at procedure completion may facilitate removal of larger portions of tissue without dissecting it or using additional nets or baskets. That is, whole, en bloc, tissue portions can be pulled out by the endoscope and tool through the endoscope grasper, facilitating easier analysis of the removed tissue to determine if all diseased tissue is removed with proper margins.

[0081] Removal of the endoscope 202 without needing to remove the overtube assembly 210 may also facilitate simplified instrument swapping, such as changing endoscopes or other instruments during the procedure, without losing position within the physiological lumen or wasting time navigating back to the surgical site. In practice, the procedure may be initiated with one endoscope, perhaps a larger diameter and more stiff endoscope, to establish the surgical location and theatre. During the procedure, the endoscope may then be removed and a second endoscope may be introduced, perhaps a slimmer endoscope with a smaller diameter. Larger and stiffer endoscopes may facilitate improved advancement through the tortuous anatomy, while slimmer and more flexible endoscopes may facilitate greater maneuverability for surgical dissection and tissue removal. [0082] The specific application illustrated in FIG. 1 is intended to be a non-limiting example provided primarily for illustrative purposes and to provide context for this disclosure. While gastrointestinal and, more specifically, lower intestine/lower bowel applications are relied on as a primary example throughout this disclosure, this disclosure contemplates that various features and concepts included in this disclosure may be readily adapted for other applications including, but not limited to, esophagogastroduodenoscopy- (EGD) and enteroscopy-based procedures and applications.

[0083] While not strictly limited to gastro-intestinal applications, such applications present unique problems due in part to the geometry and tissue of the large intestine. FIG. 2A is a drawing of an example large intestine 118 that illustrates the typical geometry and relative positioning of the cecum, colon, and rectum. As shown, large intestine 118 includes multiple bends/flexures of approximately 90-degrees. Accordingly, for a tool (e.g., an endoscope) to perform a surgical procedure, such as removal of a lesion, within the large intestine, the tool and overtube must be capable of navigating the bends of the large intestine required to reach the target of the procedure. In the case of procedures to be performed within the ascending colon, for example, the tool and overtube must be sufficiently flexible to navigate four 90-degree bends. FIG. 2B, for example, illustrates overtube assembly 210 in a state corresponding to a procedure performed in the ascending colon.

[0084] Conventional overtube assemblies generally rely on increasing flexibility of the overtube to navigate anatomical bends, such as the flexures of the large intestine; however, the general approach of increasing flexibility can raise challenges when a secondary lumen/working channel is incorporated into the overtube.

[0085] As a first example, during a particular process, a clinician may want to change the position of second opening 220 of secondary lumen 224, e.g., to provide better access to a lesion or similar target. To do so, overtube assembly 210 may be rotated, thereby rotating second opening 220 about endoscope 202 and modifying the location of second opening 220 and approach of second tool 222. Mid-procedure, the clinician is generally limited to applying the necessary torque for such a rotation at a proximal end of overtube assembly 210 due to the remainder of overtube assembly 210 being disposed within the patient. However, conventional flexible overtube assemblies generally lack adequate torsional stiffness to reliably transfer torque applied at a proximal end of the overtube assembly to cause rotation of a distal end. Among other things, this results in unpredictable rotational response of the overtube assembly when torque is applied at a proximal end. In certain instances, conventional overtube assemblies may even act as torsional springs when torqued from the proximal end. For example, frictional engagement of a distal portion of the overtube assembly with the walls of the physiological lumen may prevent rotation of the distal portion when a torque is applied to a proximal end of the overtube assembly. In such cases, as torque is applied and the overtube of the overtube assembly twists, energy is stored in the overtube of the overtube assembly. If the stored energy becomes sufficient to overcome frictional forces on the overtube assembly, the overtube assembly may suddenly, unpredictably, and undesirably uncoil, resulting in a loss of control by the physician, loss of progress in the procedure, and potential harm to the patient.

[0086] A related phenomenon, referred to as “snap through”, can also be observed in certain overtube applications. Snap through generally refers to a type of buckling that can occur in elastic systems in which the system passes spontaneously and suddenly between non-adjacent equilibrium configurations. So, for example, a structure may be bent or manipulated into a first equilibrium shape but may undergo sudden and rapid change into an inverted configuration. Jumping popper toys are a common example of snap-through phenomena. Such toys are generally dome-shaped and formed from an elastic material such that they can be inverted into a first stable configuration. If left, the toy eventually undergoes snap-through and suddenly reverts to its original configuration, releasing the energy stored in the toy and propelling it upwards.

[0087] In the medical field, snap through is a known phenomenon in applications involving elongate tools and related equipment, such as catheters, overtubes, and endoscopes. In general, as a device’s length and the tortuosity of the device’s path increase, snap-through effects become more prevalent with the phenomenon most likely to occur at bends in the device. Snap-through effects have also been observed to be more likely to occur in devices having non-axisymmetric cross-sections. Like the torsional spring effect noted above, snap through can result in a sudden, unpredictable, and undesirable release of stored energy.

[0088] To address the foregoing issues, among others, this disclosure provides various novel overtube assemblies and improvements to conventional overtube assemblies. Implementations of this disclosure are directed to overtube assemblies, e.g., for use with endoscopes or similar elongate tools, that include secondary lumens/working channels while also addressing the various issues noted above related to torsional performance and snap-through.

[0089] The overtube devices and assemblies described further herein provide an overtube to accommodate a range of endoscopes in addition to a second working channel to accommodate a second surgical tool for access to target tissue within the Gl tract. In order to advance effectively through the Gl tract, the overtube devices and assemblies described herein are laterally flexible while retaining a sufficient torsional stiffness for steady rotation at a distal end when a torque is applied to a proximal end with minimized rotational lag and snap through. For example, this disclosure includes overtubes reinforced with an inner layer, such as a laser-cut thin-walled steel tube, a wire braid, or a wire coil, for a flexible overtube with consistent torqueability along its length. The torqueability of the overtube may be further enhanced by reducing the coefficient of friction between the endoscope and the inner surface of the overtube, such as with a hydrophilic coating.

[0090] Additionally, for example, this disclosure includes overtube assemblies with an overtube and a second working channel. Some overtube assemblies described herein integrate the overtube and the second working channel into a common cross section along the length of the assembly. While these overtube assemblies are sufficiently laterally flexible to navigate the Gl tract, a relatively straight second working channel along the overtube may lead to a build up and release of energy through a “snap through” movement as the assembly is rotated. Thus, other overtube assemblies described herein position the second working channel at a radial offset from the overtube and arrange the second working channel in a symmetrical cross-sectional layout along the length of the overtube, thereby maintaining the flexibility of the overtube assembly while retaining steady torqueability along its length for minimized rotational lag between the proximal and distal ends.

[0091] FIGS. 3A-3C illustrate an overtube assembly 300 according to this disclosure. Specifically, FIG. 3A is a distal perspective view of overtube assembly 300, FIG. 3B is an elevation view of overtube assembly 300, and FIG. 3C is a proximal perspective view of overtube assembly 300.

[0092] As shown, overtube assembly 300 generally includes a handle assembly 302 and a primary tube 304 extending distally from handle assembly 302. Overtube assembly 300 further includes a secondary tube 306 (also referred to herein as a working channel) extending parallel to primary tube 304.

[0093] Primary tube 304 defines a primary lumen 308, which, in endoscope-related applications, is shaped and configured to receive an endoscope or similar elongate tool and terminates in a distal opening 309. The primary lumen 308 is sized to accommodate elongate tools such as an endoscope with diameters (or cross-sectional widths) of about 6 mm to about 15 mm. In other embodiments, the primary lumen 308 is sized for elongate tools with diameters (or cross-sectional widths) of about 2 mm to about 7 mm. In other embodiments the primary lumen 308 is sized for elongate tools with diameters (or cross-sectional widths) of about 12 mm to about 20 mm. Secondary tube 306 defines a secondary lumen 310 through which auxiliary tools, fluids, or other elements may be inserted to supplement the endoscope. Secondary tube 306 similarly terminates in a distal opening 311. The secondary lumen 310 is sized to accommodate elements with diameters (or cross-sectional widths) of about 1.5 mm to about 3.8 mm. In other embodiments, the secondary lumen 310 may be sized for elements with diameters (or cross-sectional widths) of about 1 mm to about 2 mm. In other embodiments, the secondary lumen 310 may be sized for elements with diameters (or cross-sectional widths) of about 2.2 mm to about 6.5 mm.

[0094] As described later in this disclosure, certain implementations may include multiple secondary tubes with various configurations; however, for purposes of this introductory implementation, overtube assembly 300 includes a single working channel, e.g., secondary tube 306, that extends longitudinally and parallel to primary tube 304 such that the secondary lumen

310 of secondary tube 306 and primary lumen 308 of primary tube 304 are substantially parallel. Also in this introductory implementation, distal opening 309 of primary tube 304 and distal opening

311 of secondary tube 306 are positioned at a distal end 301 of overtube assembly 300 such that a working space for overtube assembly 300 is generally with a region that is distal from distal end 301.

[0095] In at least certain implementations, the primary tube 304 and secondary tube 306 may be formed from at least one of Nylon, PFA, PET, PTFE, FEP, HDPE, TPPE, silicone, PVC, other thermopolymers or any other suitable material. In one embodiment, the primary tube 304 is extruded 70 Shore A silicone. In other embodiments, the primary tube 304 may be 20 Shore A or 80 Shore A. In one embodiment, the primary tube 304 and the secondary tube 306 may be formed from the same material. In other embodiments, the lumen and/or the corresponding tubes may be formed of one or more different materials. In use, the overall assembly will generally exhibit bending flexibility and pushable stiffness comparable with an endoscope.

[0096] The material of each tube, such as, but not limited to, the primary tube 304 and/or the secondary tube 306, may also include additives to reduce or increase surface friction of the corresponding lumen. For example, in one specific implementation, the primary tube 304 may be formed from Hytrel Thermoplastic Polyester Elastomer with Everglide. In another specific implementation, the primary tube 304 and the secondary tube 306 are both coated with a hydrophilic coating to decrease friction when elongate tools are inserted and advanced through the corresponding lumen. Although not limited to such implementations, thinner walled tubular bodies according to the present disclosure may generally be formed from a more rigid polymer than thicker-walled tubular bodies such that the thinner walled tubular bodies have sufficient rigidity to advance within the physiological lumen of the patient (e.g., the Gl tract). In one specific implementation, the wall thickness of the primary lumen 308 may be about 0.75 mm. In certain implementations, the primary tube 304 and the secondary tube 306 may have a wall thickness from and including about 0.25 mm to and including about 1.0 mm. In another implementation, the primary tube 304 and the secondary tube 306 may have a wall thickness from and including about 0.75 mm to and including about 5.0 mm.

[0097] In certain implementations, overtube assembly 300 may also include one or more inflatable balloons, such as balloon 312, which may be selectively inflated from handle assembly 302 and used to anchor overtube assembly 300 within a physiological lumen of a patient, e.g., as shown in FIG. 1. To facilitate inflation and deflation of balloon 312, overtube assembly 300 may further include an air supply lumen 314 (indicated in FIG. 3A) extending from handle assembly 302 to balloon 312.

[0098] A balloon used with an overtube assembly, such as the balloon 312 for the overtube assembly 300, may have a wall thickness that is uniform or non-uniform. In some implementations, the wall thickness of the balloon 312 may be about 0.05 mm to about 0.35 mm. In other implementations, the wall thickness of the balloon 312 may be about 0.25 mm to about 0.95 mm.

[0099] The balloon 312 may be of an uninflated resting cross section width of about 20 mm to about 55 mm. In certain implementations, the balloon 312 may be about 5 mm to about 25 mm in cross sectional width. In other implementations, the balloon 312 may be about 50 mm to about 85 mm in cross sectional width when uninflated. When inflated, the balloon 312 may increase in volume by about 5% to about 50%. In certain implementations, the balloon 312 may be designed to accommodate and conform to the physiological lumen geometry. In other implementations, the balloon 312 may increase beyond about 50% up to about200% in volume when inflated compared to when uninflated.

[0100] A balloon used with an overtube assembly, such as the balloon 312 for the overtube assembly 300, may be inflated to pressures between about 1 kPa to about 10 kPa. For example, the balloon 312 may be inflated to a pressure of 7 kPa. In other embodiments, the balloon 312 may be inflated to a pressure between about 0.1 kPa to about 1 kPa, or between about 10 kPa to about 100 kPa. The balloon 312 may be made of at least one non-rigid material. For example, in one example implementation the balloon 312 may be formed of a material that includes one or more of low-density polyethylene (LDPE), latex, polyether block amide (e.g., PEBAX®), silicone, polyethylene terephthalate (PET/PETE), nylon, polyurethane, and any other thermoplastic elastomer, siloxane, or other similar non-rigid materials. In certain implementations, the balloon 312 may be formed from one material. In other implementations, the balloon 312 may be formed from multiple materials.

[0101] Although not limited to specific dimensions, in at least certain implementations, the air supply lumen 314 may have a cross-sectional width of approximately 0.8 mm and a wall thickness of approximately 0.33 mm. In other embodiments the air supply lumen 314 cross-sectional width may be from about 0.5 mm to about 3.5 mm, with a wall thickness of about 0.10 mm to about 1.75 mm. In general, however, the diameter and/or the wall thickness of the air supply lumen 314 may be as small and thin as possible in order to minimize the size of the primary tube 304 and, as a result, minimize the volume invaded within the physiological lumen. Similarly, other features of the primary tube 304 may be formed to be as thin and small as possible, as thinner and smaller features generally result in the primary tube 304 being more flexible and better able to move through any turns of the physiological lumen within which it is deployed. Nevertheless, for certain materials (e.g., silastic polymers), minimum wall thickness and other dimensions may be limited by manufacturing. The air supply lumen 314 may be manufactured with the same or similar materials as the primary tube 304. If the air supply lumen 314 is intended to deliver and/or remove fluids other than air, the diameter of the air supply lumen 314 may need to be larger compared to the diameter needed to move air to account for the increased viscosity of the fluid. Accordingly, during use of the overtube assembly 300, the balloon 312 may be selectively inflated and deflated by injection or evacuating air from the balloon 312 via the air supply lumen 314, respectively. While air can be used, inflation of the balloon could also be done using other gases, such as carbon dioxide, as well as liquids, including saline and water.

[0102] FIG. 3C illustrates handle assembly 302 in further detail. Handle assembly 302 is intended as a non-limiting example of a handle assembly. Nevertheless, handle assembly 302 includes various features and elements intended to illustrate certain functions and aspects of overtube assemblies of this disclosure. Handle assembly 302 may be manufactured with the same or similar materials as primary tube 304. In some embodiments, handle assembly 302 may be manufactured with stiffer materials, such as a material including ABS or polycarbonate. For the embodiments in which the handle assembly 302 and the primary tube 304 are formed of the same, or similar, material, the handle assembly 302 may have a different durometer so the handle assembly 302 retains a greater stiffness as compared to the primary tube 304 to facilitate easier advancement and rotation of the device. [0103] As indicated in FIG. 3C, handle assembly 302 may include a handle body 316 that terminates in a port assembly 318 and that has a pistol-style configuration. In use, handle assembly 302 is designed to easily enable advancement, retraction, and/or rotation of the overall device within the physiological lumen. Port assembly 318 includes proximal inlets for various lumens of overtube assembly 300. For example, as shown, port assembly 318 includes each of a primary tube inlet 320 and a secondary tube inlet 322. In general, primary tube inlet 320 is sized and shaped to receive a primary tool, such as an endoscope, while secondary tube inlet 322 is sized and shaped to receive a supplemental tool.

[0104] Port assembly 318 further includes a water inlet 324 in communication with primary lumen 308 and that may be used to introduce fluid into primary lumen 308 for flushing or eliminating air bubbles within primary lumen 308. Introduction of fluid may also serve to lubricate the interface between the endoscope (or other element within the primary tube) and the primary lumen 308.

[0105] In the specific implementation illustrated, handle assembly 302 also includes a lever 326 and valve switch 328 to facilitate selective inflation and deflation of balloon 312. More specifically, lever 326 is squeezable to actuate a pumping mechanism (not shown) disposed within handle body 316 and configured to selectively inject air into or draw air out of air supply lumen 314 based on a position of valve switch 328. So, for example, with valve switch 328 in a first position, lever 326 results in air being injected into air supply lumen 314 and corresponding inflation of balloon 312. Conversely, with valve switch 328 in a second position, lever 326 results in air being withdrawn from air supply lumen 314, thereby deflating balloon 312.

[0106] In other implementations, inflation and deflation may be controlled by an external air supply, such as an automated air pump, within the operating theater. In such implementations, lever 326 and valve switch 328 may be omitted or selectively disabled and port assembly 318 may further include an air supply port (not shown) adapted to be coupled to the external air supply for facilitating introduction and evacuation of air from balloon 312 via air supply lumen 314. Balloon inflation and/or deflation times may be in the range of between about 1-5 seconds. In other embodiments, the balloon inflation and/or deflation times may be in a range of between about 0.1 seconds to about 1 seconds, or between the range of about 4 seconds to about 25 seconds.

[0107] FIGS. 4A and 4B illustrate a system 400 in which an endoscope 402 and associated tools are inserted into/coupled to overtube assembly 300. As shown in the figures, during use, endoscope 402 is generally inserted through primary lumen 308 of primary tube 304 and exits distal opening 309. Similarly, an auxiliary tool 404 may be inserted through secondary lumen 310 or secondary tube 306 and exits distal opening 311. In the specific implementation shown in FIGS. 4A and 4B, auxiliary tool 404 is a gripper-type tool. Notably, as shown, endoscope 402 further includes a tool lumen 406 through which a tool 408 (e.g., a cutter tool) is shown extending. Accordingly, auxiliary tool 404 may be used to supplement and enhance tool-related features and functions of endoscope 402.

[0108] FIG. 5 is an isometric view of an overtube assembly 500 according to another implementation of the present disclosure. Overtube assembly 500 includes a handle assembly 502 and a tube assembly 501 including a primary tube 504 extending distally from handle assembly 502. Tube assembly 501 further includes a secondary tube 506 extending parallel to primary tube 504. In contrast to the pistol-style handle arrangement of handle assembly 302, handle assembly 502 has a cylindrical- or barrel-style grip that extends substantially parallel to primary tube 504. In some applications, a cylindrical grip allows for easier rotation during clinical use.

[0109] As in the previous implementation, primary tube 504 defines a primary lumen 508 shaped and configured to receive an endoscope or similar elongate tool and that terminates in a distal opening 509. Secondary tube 506 defines a secondary lumen 510 through which auxiliary tools, fluids, or other elements, such as auxiliary tool 550, may be inserted to supplement the endoscope. Secondary tube 506 similarly terminates in a distal opening 511.

[0110] Overtube assembly 500 further includes a balloon 512 inflatable by one or more air supply lumens, such as air supply lumen (not shown). For example, handle assembly 502 may include a squeezable pump mechanism and corresponding valve to direct air into and out of balloon 512 via the air supply lumen. Alternatively, handle assembly 502 may include a port configured to couple to and communicate air or other fluids with an external supply.

[0111] As in the case of handle assembly 302, handle assembly 502 is generally configured to receive each of an endoscope or similar tool, e.g., via a primary tube inlet 520 (not shown in FIG. 5) disposed on a proximal end of primary tube 504. Handle assembly 502 is further configured to receive auxiliary tool 550 in a proximal opening or port of secondary tube 506. While not specifically illustrated in FIG. 5, handle assembly 502 may also include a fluid/flush port in communication with primary lumen 508 and configured to facilitate injection and circulation of fluid within primary lumen 508 and at a distal end of overtube assembly 500.

[0112] As noted above in the context of FIGS. 2A and 2B, procedures that rely on overtubes can often include navigating the overtube through a complex/tortuous path. Such applications often require and result in bending, twisting, and other similar manipulation of the overtube. Conventional overtubes are generally formed of flexible/elastic materials and experience “rotational lag” between rotation applied at a proximal end of the overtube and a corresponding rotation resulting at a distal end of the overtube. So, for example, a half-rotation applied at a proximal end of a conventional overtube may result in less than a half-rotation at a distal end of the overtube. This is particularly true with softer and more flexible materials.

[0113] The amount of rotational lag between the proximal and distal end of the overtube may be unpredictable and highly dependent on multiple factors, including the construction of the overtube, the cross-sectional shape of the overtube, and the configuration of the overtube. For example, an overtube may have minimal lag when torqued in a substantially straight configuration, but when bent (e.g., when navigating the various flexures of the colon), substantial lag may occur.

[0114] Notably, in certain cases, torsional lag may build up in the overtube with the overtube acting like a torsional spring and storing torsional energy. If sufficient lag builds up, the overtube may suddenly release the stored energy and snap into alignment, resulting in a sudden and uncontrolled movement of the overtube.

[0115] In general, the lack of continuous and reliable control and possibility for uncontrolled torsional release related to rotational lag present notable safety concerns. Accordingly, implementations of this disclosure may include overtubes configured to be sufficiently pliable in bending to navigate the various anatomical flexures and bends of a patient while having sufficient torsional stiffness to reduce rotational lag or impart predictable relationships between rotation applied at a proximal end of the overtube and resulting rotation of a distal end of the overtube.

[0116] FIG. 6A is an isometric view of an overtube assembly 600 according to this disclosure. As shown, overtube assembly 600 includes a tube assembly 601 A that further includes each of a primary tube 602A and a secondary tube 604A. FIG. 6A illustrates overtube assembly 600A with tube assembly 601 A in a neutral rotational state prior to application of a torque (indicated by arrow 650) at a proximal end 606A of tube assembly 601A. As illustrated by arrow 652, such torque generally results in a corresponding rotation or torque at a distal end 608A of overtube assembly 600A.

[0117] FIG. 6A is intended to illustrate an example overtube assembly according to this disclosure with its tube assembly in a starting/neutral position. Each of FIGS. 6B and 6C illustrate respective overtube assemblies following a 180-degree rotation of the proximal end of their respective tube assemblies from the neutral position shown in FIG. 6A. [0118] Referring to FIG. 6B, an overtube assembly 600B is shown that includes a tube assembly 601 B for providing a one-to-one relationship between rotation applied at a proximal end 606B of tube assembly 601 B and a resulting rotation of a distal end 608B of tube assembly 601 B. Stated differently, tube assembly 601 B of overtube assembly 600B is configured such that a rotation of proximal end 606B results in an equal rotation of distal end 608B (i.e., 180-degrees in the illustrated example).

[0119] FIG. 6C, in contrast, illustrates an overtube assembly 600C that includes a tube assembly 601 C for providing a two-to-one relationship between rotation applied at a proximal end 606C of tube assembly 601C and resulting rotation of a distal end 608C of tube assembly 601C. Stated differently, tube assembly 601 C of overtube assembly 600C is configured such that a rotation of proximal end 606C results in half of the rotation of distal end 608C (i.e., a 180-degree rotation applied at proximal end 606C results in a 90-degree rotation of distal end 608C).

[0120] FIGS. 7A-7D are isometric views of overtube sections illustrating different internal constructions for overtubes according to this disclosure. In general, each of the constructions is provided to increase torsional stiffness of the overtube while providing minimal impact on bending stiffness. As noted above, such configurations allow the overtube to have sufficient flexibility to navigate patient anatomy but also sufficient torsional stiffness to avoid issues related to rotational lag.

[0121] Overtubes according to this disclosure may include any one of the constructions illustrated in FIGS. 7A-7D or constructions implementing similar concepts. Alternatively, overtubes may include more than one of the constructions in a layered configuration and/or or a segmented configuration (e.g., a first longitudinal segment of the overtube has a first construction while a second longitudinal segment has a second construction). Moreover, overtubes according to this disclosure may include any of the constructions as an internal layer but may further include additional layers of material applied to an internal or exterior surface of the layer. For example, a layer providing torsional reinforcement may include each of an inner and outer layer formed from a low friction material or coating to improve interaction with tools inserted through the overtube and surfaces of the physiological lumen, respectively.

[0122] FIG. 7A is an isometric view of an overtube segment 700A including torsion resistance features in accordance with an implementation of this disclosure. As shown, overtube segment 700A includes a primary tube 702A along which a spine element 704A extends longitudinally. [0123] Spine element 704A may be integrally formed with primary tube 702A, co-formed with primary tube 702A (e.g., by a co-extrusion or co-molding process), or may be separately formed from and subsequently coupled to primary tube 702A (e.g., by an adhesive, ultrasonic welding, or other coupling technique). Spine element 704A may be made with the same, or similar, material as primary tube 702A, the same, or similar, material but with a different durometer or stiffness, or with a different material. Spine element 704A may extend along substantially all of primary tube 702A or along one or more discrete segments of primary tube 702A. Moreover, while illustrated in FIG. 7A as extending longitudinally along only one side of primary tube 702A, spine element 704A may alternatively extend in a partially circumferential direction or overtube segment 700A may include multiple spine elements extending along primary tube 702A.

[0124] In general, spine element 704A is formed using a material and/or with a construction such that spine element 704A provides increased torsional resistance as compared to the material/construction of primary tube 702A. So, for example, primary tube 702A may be formed from a first material while spine element 704A may be formed from one or more second, substantially more rigid material. As another example, spine element 704A may be formed from substantially the same material as primary tube 702A but may have a greater thickness or an alternative orientation (e.g., in the case of anisotropic materials or composites) such that overtube segment 700A has greater torsional resistance than if spine element 704A was absent.

[0125] While illustrated in FIG. 7A as extending longitudinally, in certain implementations, spine element 704A may be configured to extend around primary tube 702A, at least in part. For example, spine element 704A may extend helically (or be otherwise wrapped) about primary tube 702A along at least some of the length of primary tube 702A. In such implementations, torsional properties of overtube segment 700A may be further controlled by modifying the pitch of the helical spine (e.g., relatively low pitch resulting in low torsional rigidity and vice versa). Moreover, while illustrated as including a single spine element, this disclosure contemplates implementations that may include one or more additional spine elements.

[0126] FIG. 7B is an isometric view of an overtube segment 700B including an alternative torsion resistance feature in the form of a braided reinforcement. More specifically, overtube segment 700B includes a primary tube 702B within which a braid element 706B is embedded or about which braid element 706B is wrapped. For example, in certain implementations, braid element 706B may be formed from one or more braided wires (e.g., nitinol wires and/or fibers or wires formed from other materials including other metallic materials and polymer materials (e.g., polyamide materials)) embedded within primary tube 702B. Alternatively, braid element 706B may be braided over primary tube 702B or formed as a separate sheet that is co-formed with primary tube 702B or separately formed from and subsequently attached to primary tube 702B.

[0127] Torsional properties, e.g., torsional stiffness, of overtube segment 700B may be selectively controlled by altering properties of braid element 706B. For example, and without limitation, torsional stiffness of overtube segment 700B may be selectively controlled by modifying the number of braid wires, the thickness of one or more braid wires, the material of one or more braid wires, the braid density (e.g., a programmable picks per inch (PPI) value), the braid pattern, and the like. Properties of the matrix (e.g., material, wall thickness, etc.) within which the braid may be impregnated or against which the braid may be coupled may also be modified to selectively control torsional properties of overtube segment 700B.

[0128] FIG. 7C is an isometric view of an alternative torsion resistance feature in the form of a laser-cut tube 700C, e.g., a hypotube. As shown, laser-cut tube 700C includes a tubular body 702C along which cuts may be distributed to selectively impart flexibility to laser-cut tube 700C. Laser-cut tube 700C may be integrated into overtubes according to this disclosure, e.g., by overmolding or extruding the flexibly overtube body onto laser-cut tube 700C such that laser-cut tube 700C is embedded within the overtube body or otherwise forms an internal layer of the overtube body assembly. The laser-cut tube 700C may also be embedded within the overtube body and sandwiched between two or more layers of other materials.

[0129] As illustrated, the cuts to tubular body 702C include a first set of cuts 704C extending along a first side 706C of tubular body 702C and a second set of cuts 708C extending along a second side 710C of tubular body 702C. In the illustrated implementation, each cut of tubular body 702C extends in a lateral direction, i.e. , along a plane perpendicular to the longitudinal axis of tubular body 702C and extends to an approximate midline of tubular body 702C. The two sets of cuts are also shown as being offset relative to each other such that cuts of first set of cuts 704C alternate longitudinally with cuts of second set of cuts 708C. While these cuts are shown to be perpendicular to the longitudinal axis of tubular body 702C, these cuts can also exhibit a pitch, where they are cut in a helical pattern along the longitudinal axis. Helical cut pitch can vary and cut length can vary to affect torsional stiffness and bending flexibility.

[0130] The lateral cuts of tubular body 702C substantially increase the relative flexibility of tubular body 702C in bending as compared to when tubular body 702C is substantially uncut/a solidwalled tube. Despite this reduction in bending stiffness, the lateral cuts have little, if any, impact on the torsional stiffness of tubular body 702C. Accordingly, by introducing tubular body 702C into an overtube assembly, the overtube assembly can be made rotationally stiff yet remain substantially pliable when bent.

[0131] As a final non-limiting example, FIG. 7D is an isometric view of an overtube segment 700D including an alternative torsion resistance feature in the form of variable material segments. More specifically, overtube segment 700D includes a primary tube 702D having discrete segments formed from different materials and/or having different dimensional characteristics (e.g., wallthicknesses) such that selective portions of primary tube 702D have different bending and torsional stiffness. For example, a proximal segment 704D may be formed from a relatively rigid material to facilitate torque transfer, while a medial segment 706D and a distal segment 708D may be formed from one or more relatively flexible/softer materials to permit navigation of primary tube 702D through the bends of a physiological lumen, such as the Gl tract.

[0132] In at least certain implementations, overtube segment 700D may be configured to transition from a relatively hard/stiff material at a proximal end to a relatively soft/flexible material at a distal end. So, for example, proximal segment 704D may be formed from a first and stiffest material, medial segment 706D may be formed from a second material having an intermediate stiffness, and distal segment 708D may be formed from a third and most flexible material.

[0133] One or more of the various flexibility and torsion control features illustrated in FIGS. 7A- 7D may be combined in a given overtube. Similarly, an overtube according to this disclosure may include different longitudinal sections with each longitudinal section having a respective construction and respective torsional properties. For example, one or more types of features (e.g., spine, braid, hypotube, etc.) in sections may vary. As another and (not necessarily mutually exclusive) example, one or more sections may include the same general type or feature but may vary in the specific configuration of the feature in different sections of the overtube. For example, one implementation of an overtube may include a braid element for providing torsional stiffness but may vary the density, weave pattern, etc., of the braid along sections of the overtube to modify and control stiffness within the sections.

[0134] FIGS. 8A-8M are cross-sectional views of different overtubes for use in overtube assemblies according to this disclosure.

[0135] In general, each of the overtube designs illustrated in FIGS. 8A-8M include a primary tubular structure defining a primary lumen sized and shaped to receive a tool, such as an endoscope. The primary tubular structure may be integrally formed with or coupled to one or more secondary tubular structures that provide respective secondary lumens. Each primary and/or secondary lumen may be coated with a coating that alters frictional properties of the lumen surface. In one specific implementation, the primary lumen and secondary lumen are both coated with a hydrophilic coating to decrease friction when elongate tools are inserted and advanced through their corresponding lumens.

[0136] Overtubes according to this disclosure may have a layered construction in which the primary and secondary tubular structures are further supplemented with layers that provide reinforcement, bonding, protective surfaces, surfaces with enhanced frictional properties, and the like. In at least certain implementations, the layers are assembled using a mandrel-based technique in which the overtube layers are applied to and supported by the mandrel before being subjected to a reflow operation that bonds the layers together. Depending on the number and arrangement of layers, a given overtube may require multiple assembly phases with each phase including the application of one or more layers and a corresponding bonding/reflow operation. In other implementations, the more flexible outer layer is expanded to accommodate the inner layer.

[0137] A given layer may be applied in various ways during assembly. For example, a given layer may have a tubular or sleeve-like shape and may be slid over the mandrel and any inwardly disposed layers of the overtube. As another example, a layer may be in the form of a strip wrapped (e g., spiral wound) about the mandrel and any inwardly disposed layers of the overtube. Similarly, a layer may be wound or braided onto the mandrel such as in the case of the braided construction shown in FIG. 7B.

[0138] In another implementation, the layers can be assembled by dipping the device to add a coating to the outside or inside of one of the lumens. Layers can also be added by pouring materials (such as silicone) on the inner or outer surface.

[0139] Construction of an overtube may also include the placement of other components along the overtube and, in some implementations, between layers of the overtube. For example, each of the implementations illustrated in FIGS. 8D-8F include a separately formed tubular structure that forms a secondary lumen of their respective overtubes. Accordingly, assembly of such overtube constructions may include positioning the tubular structures along the length of the underlying overtube layers and optionally adhering or otherwise coupling the tubular structure to the underlying overtube layers before applying one or more additional layers.

[0140] Layer thicknesses are generally designed to be thin so as to minimize overall device size for insertion into the physiological lumen. In one embodiment, wall thicknesses of the primary tube, secondary tube, and/or air lumen are about 0.1 mm to about 0.5 mm. In another embodiment, wall thicknesses are about 0.25 mm to about 1.25 mm. In yet another embodiment, the primary tube has a wall thickness of about 0.25 mm while the secondary lumen has a wall thickness of about 1.25 mm and the air lumen has a wall thickness of about 0.50 mm.

[0141] FIG. 8A is a cross-sectional view of an overtube 800A. Overtube 800A includes a primary tube 802A defining a primary lumen 804A (e.g., for an endoscope or similar elongate tool). Overtube 800A further includes a secondary tube 806A or working channel defining a secondary lumen 808A. In the illustrated implementation, secondary tube 806A is disposed on an exterior surface of primary tube 802A and is integrally formed with primary tube 802A, e.g., by an extrusion process.

[0142] Since secondary tube 806A extends along an exterior surface of primary tube 802A, primary lumen 804A is generally unobstructed and is substantially concentric with any scope/tool inserted through primary tube 802A. Among other advantages, such concentricity can help to minimize or control gapping between the inner wall of primary tube 802A and a scope/tool inserted through primary tube 802A and to reduce the likelihood of tissue becoming caught or pinched between the scope/tool and the inner wall of primary tube 802A.

[0143] In certain implementations, overtube 800A may correspond to a one-piece overtube with general benefits associated with ease of manufacturing (e.g., suitable for an extrusion-type process). Given the offset of secondary lumen 808A from secondary tube 806A, overtube 800A may be suitable for applications in which the overall length of overtube 800A is relatively short and/or torsional stiffness is less critical (e.g., procedures involving relatively straight/non-tortuous physiological lumens or tool paths), particularly when secondary lumen 808A extends in a substantially longitudinal direction along secondary tube 806A. As discussed throughout this disclosure, torsional, and snap-through properties of overtube 800A may be improved, e.g., by wrapping secondary tube 806A helically or otherwise around primary tube 802A.

[0144] The primary tube is sized to accommodate elongate tools such as an endoscope with diameters (or cross-sectional widths) of about 6 mm to about 15 mm. In other embodiments, the primary tube is sized for elongate tools with diameters (or cross-sectional widths) of about 2 mm to about 7 mm. In still other embodiments, the primary tube is sized for elongate tools with diameters (or cross-sectional widths) of about 12 mm to about 20 mm. The secondary tube is sized to accommodate elements with diameters (or cross-sectional widths) of about 1.5 mm to about 3.8 mm. In other embodiments, the secondary tube is sized for elements with diameters (or cross-sectional widths) of about 1 mm to about 2 mm. In still other embodiments, the secondary tube is sized for elements with diameters (or cross-sectional widths) of about 2.2 mm to about 6.5 mm.

[0145] The center-to-center spacing between the primary tube and secondary tube can be consistent along the length of the assembly or vary along the length. In one embodiment, the center-to-center spacing is about 1.75 mm to about 5 mm. In another embodiment, the center-to- center spacing is about 4 mm to about 13.25 mm.

[0146] FIG. 8B is a cross-sectional view of an overtube 800B including a primary tube 802B defining a primary lumen 804B and a secondary tube 806B defining a secondary lumen 808B. In contrast to overtube 800A, secondary tube 806B is disposed on an interior surface of primary tube 802B and, as a result, extends through 804B. As in overtube 800A, primary tube 802B and secondary tube 806B are integrally formed, e g., by an extrusion process.

[0147] Like overtube 800A, overtube 800B may correspond to a one-piece overtube with general benefits associated with ease of manufacturing (e.g., suitable for an extrusion-type process) and may be particularly suitable for applications in which the overall length of overtube 800B is relatively short and/or torsional stiffness is less critical (e.g., procedures involving relatively straight/non-tortuous physiological lumens or tool paths). However, like overtube 800A, torsional properties of overtube 800B may be improved, e.g., by forming secondary lumen 808B with a helical or other non-linear path along the interior surface of primary tube 802B. Moreover, by disposing secondary tube 806B within primary tube 802B, the exterior surface of primary tube 802B may be made relatively consistent, e.g., circular. Among other things, such an exterior shape may be beneficial in manufacturing and, more specifically, for coupling additional elements (e.g., inflatable balloons) to the exterior surface of overtube 800B. A smooth and cylindrical outer surface may be beneficial for medical applications in which advancing or rotating a tube with an asymmetric outer surface is undesirable.

[0148] FIG. 80 is a cross-sectional view of an overtube 8000 including multiple layers. More specifically, overtube 800C includes a primary tube 8020 defining a primary lumen 8040. Like the implementation of FIG. 8B, overtube 800C further includes a secondary tube 806C defining a secondary lumen 808C extending through primary lumen 804B. Primary tube 802C includes additional layers in the form of a reinforcement layer 810C and a jacket 8120. For example, reinforcement layer 8100 may be a layer of braided material (like that shown in FIG. 7B) or a laser-cut tube layer (like that shown in FIG. 70) adapted to provide torsional rigidity to primary tube 8020. Jacket 8120, in contrast, may be formed from a low-friction material or otherwise provide a protective barrier between overtube 8000 and a physiological lumen within which overtube 800C is used. In one embodiment, reinforcement layer 81 OC is less than about 0.25 mm in thickness, while jacket 812C is about 0.25 mm in thickness, and primary tube 802C is about 0.75 mm in thickness.

[0149] Primary tube 802C and secondary tube 806C of overtube 800C are substantially like the corresponding elements of overtube 800B and, as a result, provide similar benefits regarding ease of manufacture. The substantially circular outer shape of primary tube 802C also facilitates application of reinforcement layer 810C and jacket 812C during manufacturing.

[0150] Reinforcement layer 810C (and similar reinforcement layers of other implementations discussed in this section) provides various benefits including, but not limited to, improved torsional performance, resistance to kinking, and enabling the use of softer materials for other layers of overtube 800C (e.g., primary tube 802C and jacket 812C). Among other things, the improved torsional performance provided by reinforcement layer 810C permits longer overtube constructions and/or overtube constructions suitable for more tortuous tool paths. Reinforcement layer 810C may have various constructions; however, in at least certain implementations, reinforcement layer 810C may be formed using a hypotube, a layer of braided material, or a similar reinforced tubular structure.

[0151] Jacket 812C (and similar jackets of other implementations discussed in this section) may be formed from any suitable biocompatible material and may be selected to have various properties and characteristics based on the intended application of overtube 800C. For example, in certain implementation, jacket 812C may be selected to provide a lubricious or other low-friction outer surface to overtube 800C and to have resistance to various chemicals (e.g., bodily fluids, sterilization fluids, etc.).

[0152] FIG. 8D is a cross-sectional view of an overtube SOOD including a primary tube 802D defining a primary lumen 804D. In contrast to previous implementations in which the secondary tubes are illustrated as being integrally formed with the overtube body, the implementation of overtube 800D includes a secondary tube shaft 806D defining a secondary lumen 808D that is disposed within an external recess 809D of primary tube 802D. Retention of secondary tube shaft 806D onto primary tube 802D is further facilitated by a jacket 812D. Like jacket 812C of overtube 800C, jacket 812D of overtube 800D may also be selected to provide a protective layer between overtube 800D and a physiological lumen in addition to facilitating retention of secondary tube shaft 806D onto primary tube 802D. In alternative implementations, secondary tube shaft 806D may be coupled to primary tube 802D, e.g., using an adhesive, welding, etc., such that the primary purpose of jacket 812D is as a protective layer. As illustrated, secondary tube shaft 806D is a separate component that is assembled with primary tube 802D. Accordingly, secondary tube shaft 806D may be formed from materials or constructed using techniques that are different than those of primary tube 802D.

[0153] FIG. 8E is a cross-sectional view of an overtube 800E including a primary tube 802E defining a primary lumen 804E. Like overtube 800D of FIG. 8D, overtube 800E includes a secondary tube shaft 806E defining a secondary lumen 808E and that is retained within an external recess 809E of primary tube 802E. In contrast to overtube 800D, overtube 800E further includes a reinforcement layer 810E, e.g., to provide additional torsional stiffness to overtube 800E. As shown, the exterior surface of overtube 800E is also covered by a jacket 812E.

[0154] FIG. 8F is a cross-sectional view of an overtube 800F including a primary tube 802F defining a primary lumen 804F. Like the previous overtubes, overtube 800E includes a secondary tube shaft 806F defining a secondary lumen 808F and that is retained within an external recess 809F of primary tube 802F. Overtube 800F further includes a reinforcement layer 81 OF, e.g., to provide additional torsional stiffness to overtube 800E. Overtube 800F also includes each of an internal jacket 812F radially inward of reinforcement layer 810F and an exterior jacket 814F radially outward of reinforcement layer 81 OF.

[0155] In at least certain implementations, the construction illustrated in FIG. 8F provides additional benefits for manufacturability. More specifically, internal jacket 812F may facilitate assembly by retaining secondary tube shaft 806F relative to primary tube 802F during application of reinforcement layer 81 OF. So, for example, secondary tube shaft 806F may be disposed onto primary tube 802F. Internal jacket 812F may then be disposed over secondary tube shaft 806F and primary tube 802F and reflowed to couple secondary tube shaft 806F to primary tube 802F, thereby maintaining secondary tube shaft 806F in position and in alignment during application of reinforcement layer 810F and exterior jacket 814F.

[0156] FIG. 8G is a cross-sectional view of an overtube 800G. Overtube 800G includes a primary tube 802G defining a primary lumen 804G and a secondary tube 806G defining a secondary lumen 808G. Secondary tube 806G is illustrated as being disposed on an exterior surface of primary tube 802G and integrally formed with primary tube 802G. In contrast to previous implementations in which layers were added to the exterior surface of the overtube body, overtube 800G includes internal layers in the form of a liner 816G and an inner reinforcement layer 818G. In certain implementations, liner 816G may be formed from a low friction/lubricated material or a material suitable for application of a lubricious layer to facilitate insertion and translation of an elongate tool (e.g., an endoscope) relative to primary tube 802G. As shown, liner 816G also provides a base layer or substrate for supporting inner reinforcement layer 818G.

[0157] FIG. 8H is a cross-sectional view of an overtube 800H including a primary lumen 804H and a secondary tube shaft 806H defining a secondary lumen 808H. In contrast to previous implementations in which the overtubes included a primary tube defining primary lumen 804H, overtube 800H is formed exclusively from layers that were supplemental to the primary tube of the previous implementations. More specifically, overtube 800H includes a liner 816H surrounded by a reinforcement layer 818H such that liner 816H defines primary lumen 804H. As a result, overtube 800H has a generally lower profile as compared to the constructions illustrated in FIGS. 8A-8G. Secondary tube shaft 806H is disposed on an exterior surface of reinforcement layer 818H with both secondary tube shaft 806H and reinforcement layer 818H surrounded by a jacket 812H.

[0158] FIG. 8I is a cross-sectional view of an overtube 800I including a primary lumen 804I and a secondary tube shaft 806I defining a secondary lumen 808I. Like overtube 800H, overtube 800I includes a liner 8161 surrounded by a reinforcement layer 8181 such that liner 8161 defines primary lumen 8041. In contrast to overtube 800H, overtube 8001 includes a first jacket 8201 surrounding reinforcement layer 8181 and against which the secondary tube shaft 8061 is disposed. Overtube 8001 further includes a second jacket 8221 surrounding first jacket 8201 and secondary tube shaft 8061.

[0159] Among other things, the construction shown in FIG. 8I provides jacket material that fully surrounds and encapsulates secondary tube shaft 806I. Doing so may provide improved coupling of secondary tube shaft 806I to the underlying overtube structure.

[0160] FIG. 8J is a cross-sectional view of an overtube 800J including a primary lumen 804J and a secondary tube shaft 806J defining a secondary lumen 808J. Overtube 800J is substantially like overtube 800H of FIG. 8H but omits a reinforcement layer. Stated differently, overtube 800J includes a liner 816J with secondary tube shaft 806H disposed on an exterior surface of liner 816J, both of which are surrounded by a jacket 812J.

[0161] FIG. 8K is a cross-sectional view of an overtube 800K including a primary lumen 804K and a secondary tube shaft 806K defining a secondary lumen 808K. Like overtube 800J of FIG. 8J, overtube 800K includes an internal liner 816K against which secondary tube shaft 806K is disposed. 800K further includes a reinforcement layer 818K extending about both of secondary tube shaft 806K and reinforcement layer 818K and a further jacket layer 812K disposed about reinforcement layer 818K.

[0162] FIG. 8L is a cross-sectional view of an overtube 800L including a primary lumen 804L and a secondary tube shaft 806L defining a secondary lumen 808L. Overtube 800L is substantially like overtube 800H of FIG. 8H but omits a liner. Stated differently, overtube 800J includes a reinforcement layer 818L which defines primary lumen 804L. Accordingly, the construction shown in FIG. 8L may be best suited for implementations in which reinforcement layer 818L is a standalone tubular structure (e.g., a hypotube) as opposed to a braid or similar structure that must be wrapped, wound, or otherwise applied to an underlying base/substrate layer. Secondary tube shaft 806L is disposed on an exterior surface of reinforcement layer 818L, both of which are surrounded by a jacket 812L.

[0163] Finally, FIG. 8M is a cross-sectional view of an overtube 800M including a primary lumen 804M and a secondary tube shaft 806M defining a secondary lumen 808M. Like overtube 800L, overtube 800M includes a reinforcement layer 818M defining primary lumen 804M. Overtube 800M includes a first jacket 820M surrounding reinforcement layer 818M and against which the secondary tube shaft 806M is disposed. Overtube 800M further includes a second jacket 822M surrounding first jacket 820M and secondary tube shaft 806M.

[0164] The various constructions illustrated in FIGS. 8A-8M are intended as examples only and should be considered non-limiting. For example, overtubes according to this disclosure may combine aspects of the various constructions or otherwise modify the illustrated constructions for a given application or overtube. The various constructions may also be modified to include additional structures and features including additional secondary lumens, e.g., for communicating air to balloons coupled to the overtube, for irrigation/suction, or for providing additional working channels through which other tools may be inserted.

[0165] Previous implementations of this disclosure generally included overtube assemblies in which a secondary tube extends along a primary tube. The secondary tube can extend along either an interior or exterior surface of the primary tube and may be integrally formed with or coupled to the primary tube. The previous implementations also included configurations in which the primary tube includes a distinct tubular structure (e.g., an extruded primary tubular body) optionally including internal or external functional layers formed to the primary tubular body. In still other implementations, the overtubes exclude a primary tubular body and are formed by various liner, reinforcement, and jacket layers. Unless otherwise stated, subsequently discussed features and concepts may be adapted to include any suitable overtube construction including, but not limited to, the general construction concepts illustrated in FIGS. 8A-8M.

[0166] For purposes of simplicity and clarity, subsequent implementations of this disclosure will generally refer to a primary tube as defining the primary lumen of the overtube assembly and one or more secondary tubes that define respective secondary lumens. Unless otherwise specified, such language should not be considered limiting regarding the specific construction of the overtube assembly. Stated differently, the various concepts and constructions provided in this disclosure may be adapted and combined in any suitable combination.

[0167] Previous implementations of this disclosure generally included overtube assemblies in which a single secondary tube extends along and parallel to a primary tube. In other implementations of this disclosure, the secondary tube may extend along the primary tube in a non-linear manner. Such implementations include those including helically wound secondary tubes, as illustrated in FIGS. 9A-9C.

[0168] During testing, implementations of overtube assemblies including helically wound secondary tubes demonstrated improved resistance to snap-through effects as compared to those including substantially longitudinal secondary tubes. As previously noted, snap-through effects are generally found to be more prevalent in tubular structures having non-axisymmetric cross-sections. By helically winding the secondary tube about the primary tube, the average cross-section of the overtube assembly over a pitch of the secondary tube is approximately axisymmetric, likely resulting in improved resistance to snap-through effects.

[0169] Experimental testing has shown that to remove snap-through effects, the helical pitch of the secondary tube can be reduced in an amount proportional to the tightest bend radius that that portion of the device passes through. In other words, to maintain the same level of snap-through effect, tighter physiological bends lead to greater snap through, which require additional helical winding of the secondary tube to minimize snap through.

[0170] Secondary tube helical pitch can be defined as an axial distance to complete one full circumferential rotation of the secondary tube along the primary tube. In one implementation, the secondary tube pitch is about 20 cm consistently along the length of the assembly. In other implementations, the secondary pitch averages about 20 cm along the length of the assembly, but has variable pitch with portions at about 10 cm and other portions at about 25 cm. In another implementation, the helical pitch averages about 10 cm for a portion of the length of the assembly, about 20 cm for another portion, and about 30 cm for still another portion. [0171] FIG. 9A is an isometric view of an overtube assembly 900A including a primary tube 902A about which a secondary tube 904A is helically wound. As shown, secondary tube 904A is wound about primary tube 902A with a constant pitch along a full length of primary tube 902A.

[0172] FIG. 9B is an isometric view of an overtube assembly 900B including a primary tube 902B about which a secondary tube 904B is helically wound. In contrast to overtube assembly 900A, secondary tube 904B of overtube assembly 900B is wound about primary tube 902B with a variable pitch. More specifically, overtube assembly 900B includes a proximal section 906B having a first pitch and a distal section 908B having a second pitch, the second pitch being shorter than the first pitch. The pitch can be varied to more easily accommodate anticipated physiological lumen tortuosity. Maintaining only a minimal amount of overall secondary tube winding is desirable. Assemblies with significant secondary tube winding may inhibit advancement of tools through the working channel (secondary lumen). Significant winding may also inhibit actuation and use of the tools. Therefore, there is a tradeoff between minimizing snap-through and maintaining effective use of the working channel tools.

[0173] This disclosure contemplates that pitch may vary along the length of primary tube 902B in any suitable manner and may include any suitable number of sections having respective helical pitches. In at least certain implementations, portions of secondary tube 904B may have relatively small pitch in regions of overtube assembly 900B that are typically bent during a given application, thereby providing increased torsional stiffness and snap-through resistance in those regions.

[0174] FIG. 9C is an isometric view of an overtube assembly 900C including a primary tube 902C about which a secondary tube 904C is helically wound. More specifically, secondary tube 904C is coupled to primary tube 902A such that secondary tube 904C is partially wound about primary tube 902C. More specifically, secondary tube 9040 includes a proximal section 9100, a medial section 912C, and a distal section 914C. Each of proximal section 9100 and distal section 9140 extend longitudinally and parallel to primary tube 902C while primary tube 902B includes a single helical winding about primary tube 9020.

[0175] Like the previous implementation, helical segments of primary tube 902C may correspond to portions of overtube assembly 9000 that would undergo bending in a particular application of overtube assembly 9000, thereby providing additional torsional stiffness and resistance to snap- through effects in those regions. Also, while medial section 9120 includes a complete helical winding of primary tube 9020, helical sections of primary tube 9020 may alternatively include only a partial winding, multiple windings, left-handed windings, right-handed windings, or any combination thereof. [0176] Previous implementations of this disclosure generally illustrated overtube assemblies in which the secondary tube is coterminal with the primary tube such that a distal opening of the secondary tube is substantially coplanar with a distal opening of the primary tube. The distal opening of the secondary tube may also be directed in a different direction than the distal opening of the primary tube and, in some implementations, may be steerable from a proximal end of the overtube assembly. Directing the secondary tube in a direction that is not co-axial with the primary tube enables a “biasing” of the tool to exit the secondary tube in a non-co-axial manner. This may facilitate easier interaction with the physiological lumen as the overtube assembly is advanced and rotated.

[0177] One example of an overtube assembly including a steerable secondary tube is shown in FIGS. 10A-10F. More specifically, FIGS. 10A-10F illustrate a distal section of an overtube assembly 1000 including a primary tube 1002 and a secondary tube 1004 extending along an exterior surface of primary tube 1002. The secondary tube 1004 includes a distal tip 1006 that is steerable to direct tools, fluid, or other things introduced into and through the secondary tube 1004.

[0178] To facilitate steering of distal tip 1006, a distal portion 1008 of secondary tube 1004 is uncoupled to primary tube 1002. Accordingly, as a user steers distal tip 1006, distal portion 1008 is free to bend relative to primary tube 1002.

[0179] In one specific implementation, distal tip 1006 is steerable using a cable- or wire-based system. More specifically, distal tip 1006 includes a pull ring 1010 to which one or more cables (not shown) are coupled. The cables extend to a proximal control assembly (not shown) which includes various control elements for selectively applying and releasing tension on the cables/wires.

[0180] FIG. 10A and 10B, for example, illustrate a first cable 1012 extending from pull ring 1010 with first cable 1012 in a pulled/tensioned state such that distal tip 1006 is pulled laterally away from primary tube 1002. FIGS. 10C and 10D similarly illustrate a second cable 1014 extending from pull ring 1010 with second cable 1014 in a pulled/tensioned state such that distal tip 1006 is pulled in a first direction along a plane parallel to a longitudinal axis of primary tube 1002. Finally, FIGs. 10E and 10F illustrate a third cable 1016 extending from pull ring 1010 with third cable 1016 in a pulled/tensioned state such that distal tip 1006 is pulled in a second, opposite direction as that shown in FIGS. 10C and 10D. [0181] FIGS. 11A-11 E illustrate an alternative steering mechanism for a distal tip of a secondary tube of an overtube assembly 1100. FIGS. 11A and 11 B are isometric and cross-sectional views of a distal portion 1150 of overtube assembly 1100. As shown, overtube assembly 1100 includes a primary tube 1102 and a secondary tube assembly 1152 extending along primary tube 1102. Secondary tube assembly 1152 includes a secondary tube 1104 defining a secondary lumen 1106 through which a secondary tube shaft 1154 extends, secondary tube shaft 1154 being hollow and defining a shaft lumen 1155. A distal tip 1156 is coupled to a distal end of secondary tube shaft 1154 such that distal tip 1156 projects beyond a distal extent of primary tube 1102.

[0182] During use, secondary tube shaft 1154 is rotatable from a corresponding control (e.g., a knob or wheel) disposed at a proximal end of overtube assembly 1100 with rotation of secondary tube shaft 1154 resulting in corresponding rotation of distal tip 1156. As shown, distal tip 1156 has a curved shape such that as secondary tube shaft 1154 is rotated, an outlet 1158 of distal tip 1156 changes direction, thereby changing the direction of secondary tube assembly 1152 and any tool, fluid, etc., introduced through secondary tube assembly 1152.

[0183] FIGS. 11C-11E are additional isometric views of overtube assembly 1100 illustrating a 180-degree rotation of secondary tube shaft 1154 and distal tip 1156.

[0184] In certain implementations of this disclosure, overtube assemblies may include secondary tubes that extend along the primary tube and are either integrally formed with the primary tube or coupled to the primary tube along substantially the full length of the tubes. In other implementations, the secondary tube may be only partially coupled to the primary tube.

[0185] FIG. 12A is an isometric view of an overtube assembly 1200A including selective coupling of a secondary tube 1204A to a primary tube 1202A. More specifically, secondary tube 1204A is illustrated as including a proximal section 1206A, a medial section 1208A, and a distal section 1210A. In contrast to previous implementations in which the secondary tube is shown as being coupled to the primary tube along substantially the entire length of the secondary tube, secondary tube 1204A is coupled to primary tube 1202A at select locations. For example, each of proximal section 1206A and distal section 1210A is coupled to primary tube 1202A while medial section 1208A is decoupled from primary tube 1202A and generally able to move relative to primary tube 1202A.

[0186] FIG. 12B is an isometric view of an overtube assembly 1200B including a single coupling location of a secondary tube 1204B to a primary tube 1202B. More specifically, secondary tube 1204A is illustrated as including a distal section 1210B that is coupled to primary tube 1202B but is otherwise detached from primary tube 1202B.

[0187] As previously noted, overtube assemblies according to this disclosure may include secondary tubes that are integrally formed or coupled to a primary tube. FIG. 13A, for example, is an isometric view of an overtube assembly 1300A including a secondary tube 1304A that is integrally formed with a primary tube 1302A. Notably, secondary tube 1304A is also illustrated in FIG. 13A as being an enclosed structure that fully defines a secondary lumen 1306A extending through secondary tube 1304A.

[0188] FIGS. 13B and 13C illustrate alternative implementations in which the secondary tube is only partially defined and includes an open side or slit extending along its length. For example, FIG. 13B is an isometric view of an overtube assembly 1300B including a primary tube 1302B. In contrast to secondary tube 1304A of overtube assembly 1300A, overtube assembly 1300B substitutes an enclosed tube with an open channel 1308B. As shown, open channel 1308B is generally in the form of a U-shaped tube with an open side. As with the enclosed tube of previous implementations, a secondary tool may be inserted into open channel 1308B from a proximal end of open channel 1308B and longitudinally translated along primary tube 1302B. Alternatively, open channel 1308B enables a secondary tool to be inserted into open channel 1308B laterally. In at least some implementations, open channel 1308B may have an opening with a width that is less than the diameter of the secondary tool such that the secondary tool may be snapped into open channel 1308B and positively retained within open channel 1308B.

[0189] FIG. 13C is an isometric view of an overtube assembly 1300C including a primary tube 1302C. In contrast to secondary tube 1304A of overtube assembly 1300A, overtube assembly 1300C substitutes an enclosed tube with a slit tube 1308C. As shown, slit tube 1308C is in the form of a C-shaped tube with an open side. As with the enclosed tube of previous implementations, a secondary tool may be inserted into slit tube 1308C from a proximal end of slit tube 1308C and longitudinally translated along slit tube 1308C. Alternatively, the secondary tool may be inserted laterally through the slit of slit tube 1308C. As with open channel 1308B of overtube assembly 1300B, the slit of slit tube 1308C may have a width that is less than the diameter of the secondary tool such that the secondary tool may be snapped into slit tube 1308C and positively retained within slit tube 1308C.

[0190] Overtube assemblies according to this disclosure may include or otherwise be used with an external sheath. In certain implementations, such an external sheath may simply provide another protective layer between the overtube assembly and the walls of the physiological lumen within which the overtube assembly is inserted. However, in other implementations, the sheath may also facilitate retention of the secondary tube, particularly when the secondary tube is only partially coupled to the primary tube (e.g., in the implementations of FIG. 12A and 12B).

[0191] For example, FIGS. 14A and 14B are isometric views of respective sheathed overtube assemblies. More specifically, FIG. 14A illustrates an overtube assembly 1400A in which a sheath 1450A is fit over a primary tube 1402A and a secondary tube 1404A of overtube assembly 1400A. In such a configuration, sheath 1450A may be loose along the entire length of overtube assembly 1400A.

[0192] FIG. 14B illustrates an overtube assembly 1400B that also includes a sheath 1450B fit over a primary tube 1402B and a secondary tube 1404B of the overtube assembly 1400B. In contrast to sheath 1450A of overtube assembly 1400A, sheath 1450B of overtube assembly 1400B is coupled to primary tube 1402B at a distal end of primary tube 1402B. Accordingly, sheath 1450B forms a volume about primary tube 1402B through which secondary tube 1404B extends and within which secondary tube 1404B is retained. Accordingly, implementations in which the sheath 1450B is partially coupled to primary tube 1402B can be particularly useful when secondary tube 1404B is only partially coupled to primary tube 1402B as sheath 1450B and the volume it defines provides a loose constraint on secondary tube 1404B.

[0193] Overtube assemblies according to this disclosure may include primary tubes along which secondary tubes extend. For example, FIG. 15A is an isometric view of an overtube assembly 1500A including a primary tube 1502A that is integrally formed with a secondary tube 1504A. Similarly, FIG. 15B is an isometric view of an overtube assembly 1500B including primary tube 1502B and a separately formed secondary tube 1504B. As previously discussed, in implementations in which separately formed secondary tube 1504B is formed separately from primary tube 1502B, separately formed secondary tube 1504B may be fully or partially coupled to primary tube 1502B, e.g., by an adhesive or welding. Retention of separately formed secondary tube 1504B onto primary tube 1502B may be further enhanced by a supplemental jacket or sheath (not shown) disposed about primary tube 1502B and separately formed secondary tube 1504B.

[0194] In the implementations of FIGS. 15A and 15B, the secondary tubes are illustrated as being substantially linear. FIGS. 16A and 16B, in contrast, illustrate implementations in which the secondary tubes extend helically about the primary tube. For example, FIG. 16A illustrates an overtube assembly 1600A, which is a helical variation of overtube assembly 1500A of FIG. 15A. More specifically, overtube assembly 1600A includes a primary tube 1602A about which a secondary tube 1604A extends in a helical configuration. As in the case of secondary tube 1504A of overtube assembly 1500A, secondary tube 1604A is integrally formed with primary tube 1602A.

[0195] FIG. 16B illustrates an overtube assembly 1600B, which is a helical variation of overtube assembly 1500B of FIG. 15B. More specifically, overtube assembly 1600B includes a primary tube 1602B about which a secondary tube 1604B extends in a helical configuration. As in the case of secondary tube 1504B of overtube assembly 1500B, secondary tube 1604B is separately formed but coupled to primary tube 1602B.

[0196] Previous implementations of this disclosure generally included a single secondary tube and a single corresponding secondary lumen defined through the secondary tube; however, overtube assemblies according to this disclosure may alternatively include multiple secondary tubes.

[0197] For example, FIG. 17A is a cross-section of an overtube assembly 1700A including a primary tube 1702A and one secondary tube 1704A. In contrast, FIG. 17B is a cross-section of an overtube assembly 1700B including a primary tube 1702B about which multiple secondary tubes are distributed. More specifically, overtube assembly 1700B includes four secondary tubes (e.g., secondary tube 1704B) distributed about primary tube 1702B. As shown, the secondary tubes are substantially the same and evenly distributed about primary tube 1702B such that the secondary tubes are positioned at approximately 90-degree offsets.

[0198] More generally, overtube assemblies according to this disclosure may include any number of secondary tubes distributed about the external or internal surface of the primary tube. Notably, by including multiple secondary tubes/working channels, axisymmetry of the overtube assembly may be improved, thereby reducing snap-through effects and improving torsional characteristics of the overtube assembly. In implementations including multiple secondary tubes, the secondary tubes may be evenly distributed and may be substantially similar (as in the case of overtube assembly 1700B). More broadly, this disclosure contemplates that the distribution, size, orientation, etc. of the secondary tubes may vary within a given overtube assembly.

[0199] FIGS. 18A-18C illustrate an overtube assembly 1800 including a primary tube 1802 and multiple secondary tubes disposed around an exterior surface of primary tube 1802. More specifically and like overtube assembly 1700B, overtube assembly 1800 includes four secondary tubes 1804-1810 evenly distributed about primary tube 1802. [0200] FIG. 18A illustrates overtube assembly 1800 in a first configuration in which secondary tubes 1804-1810 extend linearly along primary tube 1802. FIG. 18C, on the other hand, illustrates overtube assembly 1800 with secondary tubes 1804-1810 having a helical configuration.

[0201] FIGS. 19A-19C illustrate an alternative implementation of an overtube assembly 1900 including a primary tube 1902 and configured to include multiple secondary tubes disposed around an exterior surface of primary tube 1902. More specifically, overtube assembly 1900 includes four channels 1904-1910 evenly distributed about primary tube 1902. In certain implementations, each of the channels 1904-1910 may be configured to retain a corresponding secondary tool. Alternatively, one or more of the channels 1904-1910 may be configured to receive a secondary tube shaft or similar structure that provides a secondary lumen, e.g., as shown in FIGS. 8D-8F.

[0202] FIG. 19A illustrates overtube assembly 1900 in a first configuration in which channels 1904-1910 extend linearly along primary tube 1902. FIG. 19C, on the other hand, illustrates overtube assembly 1900 with channels 1904-1910 having a helical configuration.

[0203] FIGS. 20A-20C illustrate an alternative implementation of an overtube assembly 2000 including a primary tube 2002. Overtube assembly 2000 includes each of a secondary tube 2004 and channels 2006-2010 distributed about an exterior surface of primary tube 2002. As in the previous implementations, each of channels 2006-2010 may be configured to retain a corresponding secondary tool. Alternatively, one or more of the channels 2006-2010 may be configured to receive a secondary tube shaft or similar structure that provides a secondary lumen, e.g., as shown in FIGS. 8D-8F.

[0204] FIG. 20A illustrates overtube assembly 2000 in a first configuration in which secondary tube 2004 and channels 2006-2010 extend linearly along primary tube 2002. FIG. 20C, on the other hand, illustrates overtube assembly 2000 with secondary tube 2004 and channels 2004- 2010 having a helical configuration.

[0205] FIGS. 21A-21C are isometric views of various overtube sections according to this disclosure illustrating different longitudinal placements of secondary tube openings. First, FIG. 21A is an isometric view of an overtube assembly 2100A, which includes a primary tube 2102A and a secondary tube 2104A, which may be integrally formed with or coupled to primary tube 2102A. As illustrated, primary tube 2102A includes a distal opening 2106A and secondary tube 2104A includes a distal opening 2108A that are substantially co-terminal. [0206] In contrast, FIG. 21 B is an isometric view of an overtube assembly 2100B, which includes a primary tube 2102B and a secondary tube 2104B. Primary tube 2102B includes a distal opening 2106B and secondary tube 2104B includes a distal opening 2108B. In contrast to the previous implementation, primary tube 2102B and secondary tube 2104B are configured such that distal opening 2106B of primary tube 2102B is proximal relative to distal opening 2108B of secondary tube 2104B. Stated differently, secondary tube 2104B extends distally beyond a distal extent of primary tube 2102B.

[0207] As yet another example, FIG. 21 C is an isometric view of an overtube assembly 2100C, which includes a primary tube 2102C and a secondary tube 2104C. Primary tube 2102C includes a distal opening 2106C and secondary tube 2104C includes a distal opening 2108C. In overtube assembly 2100C, primary tube 2102C and secondary tube 2104C are configured such that distal opening 2108C of secondary tube 2104C is proximal relative to distal opening 2108B. Stated differently, primary tube 2102C extends distally beyond a distal extent of secondary tube 2104C.

[0208] Previous implementations of this disclosure generally include secondary tubes that are substantially contiguous along the length of the primary tube. In contrast, FIGS. 22A and 22B illustrate implementations including discontinuous secondary tubes.

[0209] First, FIG. 22A is an isometric view of an overtube assembly 2200A including a primary tube 2202A and a secondary tube assembly 2204A. As illustrated, secondary tube assembly 2204A includes a series of discontinuous but aligned tubules (e g., tubule 2206A) coupled to and distributed along primary tube 2102A. Collectively, the tubules of secondary tube assembly 2204A approximate a continuous tubular structure through which a secondary tool may be inserted.

[0210] FIG. 22B is an isometric view of an overtube assembly 2200B including a primary tube 2202B and a secondary tube assembly 2204B. In contrast to the tubules of secondary tube assembly 2204A, secondary tube assembly 2204B is formed from a series of aligned rings (e.g., ring 2208B) coupled to and distributed along primary tube 2202B. Like the tubules of secondary tube assembly 2204A, the rings of secondary tube assembly 2204B approximate a continuous tubular structure through which a secondary tool may be inserted.

[0211] In general, the discontinuous structure of the secondary tube assemblies illustrated in FIGS. 22A and 22B reduce any bending stiffness that may be imparted on the primary tube by an otherwise continuous secondary tube. As in other implementations of this disclosure, the discontinuous structure illustrated in FIGS. 22A and 22B has been demonstrated to provide improved torsional characteristics and reduction of snap-through effects. Stated differently, the discontinuous secondary tube assemblies of overtube assembly 2200A and overtube assembly 2200B effectively function as a living hinge that provides reduced resistance to bending. Notably, in certain implementations, a jacket, sheath, or similar external layer may be applied about the secondary tube assemblies to form a substantially continuous internal volume of the secondary tube assembly. In such implementations, the jacket, sheath, etc. may be formed from a thin or otherwise pliable material to reduce any impact on flexibility of the overtube assembly.

[0212] As previously noted in implementations of this disclosure, overtube assemblies according to the present disclosure may include secondary tubes with steerable distal tips. As an alternative to a steerable configuration, the distal tip of the secondary tube may be fixed such that tools and material exiting the distal end of the secondary tube are directed in a particular direction.

[0213] For example, FIGS. 23A and 23B are isometric and side elevation views of an overtube assembly 2300 including a primary tube 2302 and a secondary tube 2304 coupled to and extending along primary tube 2302. Secondary tube 2304 terminates in a distal tip 2306 that extends distally beyond a distal extent of primary tube 2302. As shown, distal tip 2306 is angled such that a distal opening 2308 of secondary tube 2304 is directed toward a longitudinal axis 2310 of primary tube 2302. More generally, distal tip 2306 may be rotated from the orientation shown in FIGS. 23A and 23B to bias any tool or material exiting distal opening 2308 into a desired direction. Directing the secondary tube in a direction that is not co-axial with the primary tube enables a “biasing” of the tool to exit the secondary tube in a non-co-axial manner. This may facilitate easier interaction with the physiological lumen as the overtube assembly is advanced and rotated.

[0214] Overtube assemblies according to this disclosure may include one or more inflatable balloons to facilitate anchoring of the overtube assembly within a physiological lumen. In general, the overtube assembly includes or is coupleable to a supply of air or other fluid and includes one or more air supply lumens extending through the overtube assembly from the supply to the balloons to facilitate controlled inflation and deflation of the balloons.

[0215] When anchored within a physiological lumen, the balloon may substantially resist both longitudinal and rotation movement. Accordingly, certain implementations of this disclosure include bearings or similar support elements that enable rotation of the overtube relative to the inflatable balloon.

[0216] FIGS. 24A and 24B, for example, are isometric views of an overtube assembly 2400.

Overtube assembly 2400 includes a primary tube 2402 and a secondary tube 2404 coupled to the primary tube 2402 and a balloon 2406 coupled to a distal portion of overtube assembly 2400. FIG. 24A illustrates overtube assembly 2400 in a first state prior to rotation of primary tube 2402 and secondary tube 2404 relative to balloon 2406, while FIG. 24B illustrates overtube assembly 2400 in a second state after rotation of primary tube 2402 and secondary tube 2404 relative to balloon 2406.

[0217] To facilitate rotation of primary tube 2402 and secondary tube 2404 relative to balloon 2406, overtube assembly 2400 may include one or more bearings or similar elements that longitudinally fix balloon 2406. For example, overtube assembly 2400 includes a proximal bearing 2408 coupled to a proximal end of balloon 2406 and a distal bearing 2410. In certain implementations, each of proximal bearing 2408 and distal bearing 2410 may include an inner race shaped to receive primary tube 2402 and secondary tube 2404 or otherwise mate with the tubular structure of overtube assembly 2400 in a longitudinally fixed manner. Each of proximal bearing 2408 and distal bearing 2410 may also include an external race or similar bearing element that is longitudinally constrained relative to the inner race but freely rotatable relative to the inner race. The external races are further coupled to balloon 2406, thereby longitudinally constraining balloon 2406 while permitting rotation of balloon 2406 relative to primary tube 2402 and secondary tube 2404. Each of proximal bearing 2408 and distal bearing 2410 may be sealed or otherwise include a sealing element that prevents air from escaping balloon 2406 through the bearings.

[0218] FIGS. 25A and 25B illustrate an overtube assembly 2500 including an alternative handle design for overtube assemblies according to this disclosure. Overtube assembly 2500 is substantially like overtube assembly 500, discussed above in the context of FIG. 5.

[0219] Referring first to FIG. 25A, overtube assembly 2500 includes a tube assembly 2501 including a primary tube 2502 and a secondary tube 2504 with a balloon 2506 coupled to a distal portion of the tube assembly 2501 . A handle assembly 2508 is coupled to a proximal end of the tube assembly 2501. Among other things, handle assembly 2508 includes a control element 2510 configured to modify inflation and deflation of balloon 2506 and, more specifically to control an air supply in communication with an internal volume of balloon 2506.

[0220] As shown in FIG. 25A, overtube assembly 2500 is a standalone overtube assembly in which control element 2510 is in the form of a lever or switch. During operation, a user may depress control element 2510 to control airflow into or out of balloon 2506 resulting in inflation and deflation of balloon 2506, respectively. For example, in certain implementations the handle assembly 2508 may include an internal mechanical pumping mechanism driven by depressing the control element 2510. In such implementations, a user may repeatedly depress control element 2510 to actuate the pumping mechanism to cause airflow to/from the balloon 2506. Alternatively, handle assembly 2508 may include an electromechanical pump with control element 2510 functioning as a switch for selectively activating and deactivating the electromechanical pump. In yet another implementation, handle assembly 2508 may contain pressurized air or other fluid and actuation of control element 2510 may mechanically or electromechanically actuate a valve element within handle assembly 2508 to release the pressurized fluid into balloon 2506.

[0221] FIG. 25B illustrates an alternative implementation in which overtube assembly 2500 is coupled by an air supply line 2512 to an external air supply system (not shown). In such implementations, control element 2510 may similarly facilitate mechanical or electromechanical control of air flow into and/or out of balloon 2506. For example, air supply line 2512 may be in communication with air supply lumens extending through tube assembly 2501 and a valve element may be disposed along the airflow path. In such implementations the control element 2510 may mechanically or electromechanically open and close the valve, thereby permitting airflow to or from the balloon 2506 depending on the airflow direction of the external air supply system.

[0222] Alternatively, handle assembly 2508 may include suitable electronics and an interface for communicating with the external air supply system. For example, handle assembly 2508 may connect to and communicate with the external air supply system by a wired or wireless communication link. In such implementations, control element 2510 may act as a control input such that when control element 2510 is manipulated or otherwise activated by a user, handle assembly 2508 may transmit a corresponding control signal to the external air supply system to control operation of the air supply system (e.g., to start or stop flow to balloon 2506, to change direction of flow, to change the amount of flow, etc.).

[0223] As previously discussed in the context of FIGS. 24A and 24B, certain implementations of this disclosure may include inflatable balloons that can rotate independently relative to the tube assembly to which the balloon is coupled. This disclosure contemplates that in at least certain implementations, the balloon and tube assembly may be coupled together by a ratchet-style coupling such that rotation of the tube assembly in a first direction results in the tube assembly rotating independently of the balloon but rotation of the tube assembly in a second direction results in torque transfer from the tube assembly to the balloon, driving rotation of the balloon.

[0224] This ratchet concept is illustrated in FIGS. 26A-26C, which are isometric views of an overtube assembly 2600 in various stages of ratchet-style rotation. Overtube assembly 2600 includes a tube assembly 2601 including a primary tube 2602 and a secondary tube 2604, which extend from a handle assembly 2608. Tube assembly 2601 is both longitudinally and rotationally fixed to handle assembly 2608 such that longitudinal movement of handle assembly 2608 translates tube assembly 2601 and rotation of handle assembly 2608 imparts a torque on tube assembly 2601. Overtube assembly 2600 further includes a balloon 2606 coupled to a distal end of tube assembly 2601. Balloon 2606 is longitudinally fixed to tube assembly 2601 but includes ratchet-style bearings that enable selective rotation of balloon 2606 relative to tube assembly 2601.

[0225] Referring first to FIG. 26A, overtube assembly 2600 is illustrated in a first state in which a clockwise torque (relative to a perspective of an operator) is applied to handle assembly 2608, as indicated by arrow 2620. FIG. 26B illustrates overtube assembly 2600 after application of the torque corresponding to arrow 2620 and shows handle assembly 2608 and tube assembly 2601 having undergone a clockwise rotation but balloon 2606 remaining rotationally stationary.

[0226] FIG. 26B further indicates a second torque (e.g., by arrow 2622) applied at handle assembly 2608 in a counterclockwise direction. Due to the ratchet-style coupling of balloon 2606 to tube assembly 2601 , the torque applied at handle assembly 2608 is transferred to balloon 2606, e.g., as indicated by arrow 2624, resulting in rotation of handle assembly 2608, tube assembly 2601, and balloon 2606.

[0227] In general, during use of overtube assemblies of this disclosure with elongate tools, such as endoscopes, the elongate tool is extended through at least a portion of a handle assembly of the overtube assembly. To improve usability of the overtube assembly and control of the elongated tool, in at least certain implementations the handle assembly may include a mechanism for affixing or otherwise locking elongate tool relative to the overtube assembly.

[0228] By way of non-limiting example, FIG. 27 is a partial cross-sectional top view of an overtube assembly 2700 including a pinch-style locking mechanism. More specifically, overtube assembly 2700 includes a tube assembly 2701 that further includes a primary tube 2702 and a secondary tube (hidden). Tube assembly 2701 is coupled to a handle assembly 2708 at a proximal end and supports an inflatable balloon 2706 at a distal end.

[0229] Overtube assembly 2700 is illustrated in use with an elongate tool 2750. More specifically, elongate tool 2750 is shown as being partially inserted into handle assembly 2708 and prior to further insertion through tube assembly 2701. As shown, handle assembly 2708 includes a pinch lock 2710 that may be selectively engaged by a user of overtube assembly 2700. In certain implementations, pinch lock 2710 may be configured to engage corresponding locking features of elongate tool 2750; however, in other implementations, pinch lock 2710 may include one or more blocks or similar elements configured to frictionally engage elongate tool 2750, thereby prohibiting or at least providing substantial resistance to longitudinal movement of elongate tool 2750 relative to overtube assembly 2700.

[0230] In certain implementations, pinch lock 2710 may be engaged and disengaged using a cam-style mechanism. As another example, pinch lock 2710 may include a spring-loaded mechanism that engages pinch lock 2710 when depressed a first time and releases pinch lock 2710 when depressed a second time. Other locking mechanisms suitable for use in overtube assembly 2700 may include a wedge-style lock that selectively frictionally engages elongate tool 2750 and a Touhy Borst-style clamping mechanism.

[0231] FIGS. 28 and 29 are a side view and isometric view, respectively, of an overtube assembly 2800 coupled to an elongate tool 2850. As shown, overtube assembly 2800 includes a tube assembly 2801 coupled to and extending distally from a handle assembly 2808.

[0232] As most clearly illustrated in FIG. 29, tube assembly 2801 may be coupled to handle assembly 2808 such that a proximal end and opening of tube assembly 2801 is co-terminal with a proximal end of handle assembly 2808. Elongate tool 2850 is then inserted into the proximal opening of tube assembly 2801.

[0233] During operation, elongate tool 2850 may be subject to bending and other movement, which can impart strain and stress on overtube assembly 2800 and, in particular, the proximal portion of tube assembly 2801. In the implementation illustrated in FIGS. 28 and 29, a substantial amount of the proximal portion of tube assembly 2801 typically subject to strain is received within and rigidly supported by handle assembly 2808. Stated differently, handle assembly 2808 functions as a strain relief mechanism for tube assembly 2801.

[0234] As noted throughout this disclosure, overtube assemblies according to this disclosure generally include a primary lumen within which an endoscope or similar elongate tool may be disposed and a supplemental working channel/secondary tube through which supplemental tools may extend. In implementations with working channels/secondary tubes, the overtube assemblies may include a proximal control assembly including a control element adapted to selectively control extension and retraction of the supplemental tool relative to a distal end of the overtube assembly.

[0235] By way of non-limiting example, FIGS. 30A-30C are isometric views of an overtube assembly 3000. Overtube assembly 3000 includes a primary tube 3002 defining a primary lumen 3003 and a secondary tube 3004 defining a secondary lumen 3005 through which a tool 3006 is shown extending. More specifically, tool 3006 is illustrated as protruding from a distal end 3008 of overtube assembly 3000.

[0236] As shown, overtube assembly 3000 includes a proximal handle assembly 3010 shaped to receive and engage primary tube 3002. Among other features, proximal handle assembly 3010 includes a control element 3012 configured to selectively extend and retract tool 3006 from secondary lumen 3005 of secondary tube 3004.

[0237] In certain implementations, control element 3012 may be in the form of a slider configured to engage a proximal portion of tool 3006 and to move longitudinally relative to primary tube 3002. As illustrated, control element 3012 is generally positioned to be readily manipulated by an operator of overtube assembly 3000, e.g., using the thumb. By distally translating the slider, tool 3006 may be retracted relative to distal end 3008 of overtube assembly 3000 (e.g., as shown in FIG. 30B) and by proximally translating the slider, tool 3006 may be may to extend relative to distal end 3008 of overtube assembly 3000 (e.g., as shown in FIG. 30A). In an alternative implementation, control element 3012 may be in the form of a rotatable wheel that frictionally engages tool 3006 such that rotation of control element 3012 toward distal end 3008 results in distal extension of tool 3006 relative to primary tube 3002 and rotation of control element 3012 in a proximal direction away from distal end 3008 results in proximal retraction of tool 3006 relative to primary tube 3002.

[0238] FIG. 31 is an isometric view of an overtube assembly 3100 including multiple balloons. More specifically, overtube assembly 3100 includes a first balloon 3106A disposed at a first location corresponding to a distal end of overtube assembly 3100 and a second balloon 3106B disposed at a location proximal the first balloon 3106A. As further shown in FIG. 31 , overtube assembly 3100 includes each of a primary tube 3102 and a secondary tube 3104 extending through each of the inflatable balloons to a distal end of the overtube assembly 3100.

[0239] As previously discussed, implementations of this disclosure may include or be coupleable to an air supply for selective inflating and deflating inflatable balloons of the overtube assembly. More specifically, a proximal portion of the overtube assembly may include an air supply mechanism (e.g., a hand pump) or an air supply port coupleable to external air supply equipment for providing air to one or more air supply lumens. The air supply lumens extend through the overtube body of the overtube assembly and are in communication with internal volumes of the inflatable balloons. Accordingly, air can be injected or withdrawn by the air supply mechanism or air supply equipment through the air supply lumens to selectively control inflation of the balloons. [0240] This disclosure contemplates that overtube assemblies including multiple balloons may include various mechanisms for sequencing inflation of the balloons. For example, in certain implementations two or more balloons may be configured to be simultaneously inflatable by sharing an air supply lumen. In other implementations, the inflatable balloons of the overtube assembly may be divided into subsets of one or more balloons, with each subset inflatable by a respective air supply lumen. In implementations including multiple air supply lumens, the proximal portion of the overtube assembly may include respective air supply mechanisms or ports for each air supply lumen or may include switch/valving mechanisms configured to selectively direct air from an air supply mechanism or port to a subset of air supply lumens.

[0241] FIGS. 32A-32C are isometric views of overtube assembly 3100 in various states of inflation to demonstrate selective inflation of balloons in multi-balloon implementations of this disclosure. First, FIG. 32A illustrates overtube assembly 3100 with each of first balloon 3106A and second balloon 3106B in a deflated or low-inflation state. In contrast, FIG. 32B illustrates both first balloon 3106A and second balloon 3106B in fully or substantially inflated states while FIG. 32C illustrates the first balloon 3106A in a fully/substantially inflated state and the second balloon 3106B in a deflated or low-inflation state. While not specifically illustrated, overtube assembly 3100 may also be configured such that first balloon 3106A is in a deflated or low-inflation state with second balloon 3106B in a fully/substantially inflated state.

[0242] As previously discussed, in certain implementations of this disclosure, first balloon 3106A and second balloon 3106B may be configured to be simultaneously inflated and deflated, e.g., using a single air supply lumen in communication with both balloons and a single air supply source (e.g., a hand pump or supplemental air supply equipment). In such implementations, overtube assembly 3100 may be transitioned between the state shown in FIGS. 32A and 32B by simultaneous addition or removal of air from first balloon 3106A and second balloon 3106B.

[0243] In implementations in which first balloon 3106A and second balloon 3106B are independently controllable, overtube assembly 3100 may be readily transitioned between any of the states shown in FIGS. 32A-32C as well as the unillustrated state in which first balloon 3106A is deflated and second balloon 3106B is substantially inflated. For example, each of first balloon 3106A and second balloon 3106B may be coupled to a respective air supply and a respective control (e.g., a valve or switch) adapted to control whether air is provided to the corresponding balloon or evacuated from the corresponding balloon. Alternatively, the proximal control assembly of overtube assembly 3100 may include a first control for selecting a specific balloon and a second control for modifying the direction of air flow for the balloon. [0244] Previous examples of overtube assemblies included in this disclosure generally included at least one inflatable balloon disposed at or near a distal end of the overtube assembly. Implementations of this disclosure are not limited to such configurations and this disclosure contemplates that balloons may be positioned or distributed in any manner suitable for the intended application of the overtube assembly. By way of non-limiting example, FIG. 33A is an isometric view of an overtube assembly 3300A illustrating a first alternative balloon placement. More specifically, overtube assembly 3300A illustrates an example implementation in which an inflatable balloon 3306A is disposed in a distal portion of overtube assembly 3300A but is proximally offset from a distal end of each of a primary tube 3302A and a secondary tube 3304A of the overtube assembly 3300A. FIG. 33B illustrates a more general example implementation of an overtube assembly 3300B in which an inflatable balloon 3306B is positioned at any suitable position and at any suitable proximal offset relative to a distal end of an overtube body 3302B and a secondary tube 3304B of the overtube assembly 3300B.

[0245] As illustrated in the figures and as discussed in preceding portions of this disclosure, overtube assemblies according to this disclosure may include one or more inflatable balloons disposed along the length of an overtube body.

[0246] In general, each of the preceding example implementations included balloons configured to expand symmetrically about an overtube body of the overtube assembly. For example, FIGS. 34A and 34B are isometric and side elevation views of an overtube assembly 3400. Overtube assembly 3400 includes an overtube body 3402 defining a primary channel adapted to receive an elongate tool, such as an endoscope, and a secondary tube 3404 extending along the primary channel and configured to receive a supplemental tool. Overtube assembly 3400 further includes a balloon 3406 that is selectively inflatable from a proximal port (not shown) of overtube assembly 3400. As shown in FIG. 34A and 34B, balloon 3406 is coupled to overtube body 3402 such that balloon 3406 extends substantially equally around overtube body 3402. Accordingly, when inflated and deflated and absent obstruction, balloon 3406 generally expands and collapses uniformly and symmetrically about overtube body 3402.

[0247] In contrast, FIGS. 35A and 35B are isometric and side elevation views of an overtube assembly 3500 including an asymmetric balloon. More specifically, overtube assembly 3500 includes an overtube body 3502 defining a primary channel adapted to receive an elongate tool, such as an endoscope, and a secondary tube 3504 extending along the primary channel and configured to receive a supplemental tool. Overtube assembly 3500 further includes a balloon 3506 that is selectively inflatable from a proximal port (not shown) of overtube assembly 3500. In contrast to balloon 3406 of overtube assembly 3400, which is configured to be symmetrically mounted and to expand/collapse substantially uniformly about overtube body 3402, balloon 3506 is asymmetrically mounted to a side of overtube body 3502 such that as balloon 3506 is inflated and deflated, it extends in a substantially lateral direction from one side of overtube body 3502.

[0248] More generally, implementations of this disclosure may include balloons configured to expand and collapse non-uniformly about the overtube bodies to which they are coupled. Such non-uniformity may be achieved in various ways including, but not limited to, asymmetrically coupling a given balloon to its overtube and selectively modifying properties (e.g., material selection/elasticity, thickness, etc.) of the balloon about its circumference such that certain portions of the balloon have varying strain characteristics.

[0249] As discussed, implementations of overtube assemblies according to this disclosure may include inflatable balloons that are selectively inflatable from a proximal end of the overtube assembly by a pumping mechanism, such as a manual, hand-actuated pump or by connection to an auxiliary air/fluid supply system. To do so, the overtube assembly includes one or more air supply lumens (or fluid supply lumens, more generally) extending from a proximal end of the overtube assembly and in communication with an internal volume of the one or more inflatable balloons of the overtube assembly.

[0250] Overtube assemblies according to this disclosure may include one or more air supply lumens. The air supply lumens may be integrally formed with the primary tube of the overtube assembly (e.g., like the secondary tubes of the example overtubes illustrated in FIGS. 8A-8C and 8G) or may be separately formed and coupled to primary tube (e.g., like the secondary tubes of the example overtubes illustrated in FIGS. 8D-8F and 8H-8M). Moreover, like the secondary tubes discussed above, the air supply lumens may be routed longitudinally, helically, or any combination thereof along the primary tube. When helically wound, the pitch of the air supply lumen may be constant or variable, e.g., smaller in sections of the overtube assembly generally subject to bending to reduce potential snap-through effects.

[0251] Further details regarding air supply lumens and example configurations of air supply lumens with inflatable balloons can be found in U.S. Patent Application No. US 17/721,157, which is incorporated herein by reference for all purposes.

[0252] FIG. 36A is a cross-sectional view of an overtube 3600 including an integrally formed air supply lumen. Specifically, overtube 3600 includes a primary tube 3602 defining a primary lumen 3604 (e.g., for an endoscope or similar elongate tool). Overtube 3600 further includes a secondary tube 3606 or working channel defining a secondary lumen 3608, with secondary tube 3606 disposed on an exterior surface of primary tube 3602 and integrally formed with primary tube 3602, e.g., by an extrusion process. Overtube 3600 further includes an air supply lumen 3610 integrally formed with primary tube 3602.

[0253] As shown in FIG. 36A, air supply lumen 3610 is disposed at a 90-degree offset relative to secondary tube 3606; however, implementations of this disclosure are not limited to any placement of air supply lumen 3610 relative to secondary tube 3606 or primary tube 3602. Moreover, while including only air supply lumen 3610, overtube 3600 may include multiple air supply lumens, each of which may be integrally formed with primary tube 3602 or formed using separate tubular structures (e.g., as shown and discussed in FIG. 37A et seq.). More generally, FIG. 36A is intended to illustrate one example implementation in which an air supply lumen is integrally formed with another tubular structure of the overtube assembly. While illustrated as being integrally formed with primary tube 3602, in multi-layer implementations, air supply lumen 3610 (and additional air supply lumens) may be integrated with other layers of the overtube assembly.

[0254] Referring to FIG. 36B, a first example configuration is illustrated in which air supply lumen 3610 extends substantially longitudinally along primary tube 3602. In contrast, FIG. 36C illustrates an alternative configuration in which air supply lumen 3610 is configured to wind helically about primary tube 3602. Other implementations of this disclosure may include arrangements in which air supply lumen 3610 is divided into multiple sections, varying between longitudinal, helical, or other paths.

[0255] FIG. 37A is a cross-sectional view of an overtube 3700 including a separately formed air supply tubule defining an air supply lumen. Specifically, overtube 3700 includes a primary lumen 3704 and a secondary tube shaft 3706 defining a secondary lumen 3708. Overtube 3700 includes a liner 3716 surrounded by a reinforcement layer 3718 such that liner 3716 defines primary lumen 3704. Secondary tube shaft 3706 is disposed on an exterior surface of reinforcement layer 3718. Overtube 3700 further includes an air supply shaft 3720 defining an air supply lumen 3710. Like secondary tube shaft 3706, air supply shaft 3720 is separately formed and disposed on an exterior surface of reinforcement layer 3718. Secondary tube shaft 3706, air supply shaft 3720, and reinforcement layer 3718 are collectively surrounded by a jacket 3712.

[0256] Like the preceding example, overtube 3700 is intended to be illustrative only. So, for example, this disclosure contemplates that overtube assemblies of this disclosure may include additional air supply shafts and air supply lumens. Moreover, while illustrated as being generally adjacent to secondary tube shaft 3706, air supply shaft 3720 may be disposed at other locations about overtube 3700 and relative to secondary tube shaft 3706.

[0257] In certain implementations, each of secondary tube shaft 3706 and air supply shaft 3720 may extend longitudinally; however, in at least certain implementations, one or both of secondary tube shaft 3706 and air supply shaft 3720 may be at least partially helically wound. For example, FIG. 37B illustrates a first example configuration of overtube 3700 (with jacket 3712 removed and the internal layers defining primary lumen 3704 combined for clarity) in which air supply shaft 3720 extends longitudinally while secondary tube shaft 3706 is wound helically about reinforcement layer 3718. As previously discussed, helically wound tubular structures (e.g., secondary tube shaft 3706 and/or air supply shaft 3720 in the subsequent examples) may facilitate improved torsional strength and snap-through characteristics. To the extent a tubular structure is helically wound about the primary lumen, the pitch of the helically tubular structure may vary along the length of the overtube assembly and/or may include both helical and nonhelical sections.

[0258] FIGS. 37C-37F show alternatives of overtube 3700 intended to illustrate alternative, but non-limiting, configurations of overtube 3700 with different routing of secondary tube shaft 3706 and air supply shaft 3720. FIG. 37C, for example, illustrates one implementation in which air supply shaft 3720 and secondary tube shaft 3706 are both helically wound with a substantially similar pitch and direction. In the illustrated implementation, air supply shaft 3720 runs adjacent to secondary tube shaft 3706. Stated differently, air supply shaft 3720 has a nominal angular offset from secondary tube shaft 3706 about the longitudinal axis of overtube 3700. FIG. 37D, in contrast, illustrates a configuration in which the angular offset between secondary tube shaft 3706 and air supply shaft 3720 is more substantial, e.g., approximately 180 degrees. More generally, the angular offset between secondary tube shaft 3706 and air supply shaft 3720 may vary in implementations of this disclosure and is not limited to the adjacent and 180-degree offset configurations shown in FIGS. 37C and 37D.

[0259] FIG. 37E illustrates an implementation of overtube 3700 in which the secondary tube shaft 3706 and air supply shaft 3720 are helically wound in the same direction but have differing pitches. Specifically, air supply shaft 3720 is shown as having a shorter pitch than secondary tube shaft 3706. In such implementations, air supply shaft 3720 may cross secondary tube shaft 3706, e.g., by extending under or over secondary tube shaft 3706.

[0260] As a final, non-limiting example, FIG. 37F illustrates an implementation of overtube 3700 in which the secondary tube shaft 3706 and air supply shaft 3720 are helically wound with approximately the same pitch but in opposite directions. Like the preceding configuration, such opposite winding of secondary tube shaft 3706 and air supply shaft 3720 results in periodic crossing of secondary tube shaft 3706 and air supply shaft 3720.

[0261] The foregoing implementations of overtubes including secondary lumens/working channels and air lumens are provided only as non-limiting examples. The general concepts regarding the secondary and air supply lumens may be readily adapted to overtubes and overtube assemblies including other features and concepts discussed throughout this disclosure. For example, while FIGS. 36A-37F illustrate implementations of overtube assemblies including only one secondary lumen and one air supply lumen, implementations of this disclosure may include one or more secondary lumens and one or more air supply lumens with each secondary lumen and air supply lumen constructed according to any of the implementations included in this disclosure. So, for example, implementations may include a combination of integrally formed secondary lumens and/or air supply lumens with separately formed secondary lumens and/or air supply lumens.

[0262] In some examples, the secondary lumens/working channels and/or the air lumens may be attached to the overtube only at a proximal end and a distal end. That is, the secondary lumens/working channels and/or the air lumens may not be attached to the overtube along an entirety of the length of the secondary lumen/working channel and/or the air lumen, but only at the ends with the remainder of the length dangling free. The secondary lumens/working channels and/or the air lumens only attached at the ends may extend longitudinally along the overtube or may wrap helically around the overtube. In other examples, the secondary lumens/working channels and/or the air lumens may be attached to the overtube at several locations, such as by rigid means (e.g., via one or more tacks) or semi-rigid means (e.g., via one or more rubber bands). In other examples, the secondary lumens/working channels and/or the air lumens may be proximate to the overtube but not attached, such that the secondary lumens/working channels and/or the air lumens may float freely within a sleeve surrounding the overtube and the secondary lumen/working channel and/or the air lumen. The secondary lumens/working channels and/or the air lumens not being attached along an entirety of their length to the overtube may facilitate easier rotation of the overtube and/or decreased snap through of the overtube. That is, free movement of the secondary lumens/working channels and/or the air lumens against an exterior of the overtube, even if limited, may improve rotation and snap through of the overtube.

[0263] FIG. 38 is a side assembly view of a balloon assembly 3800 for use with an overtube assembly according to this disclosure. The balloon assembly 3800 includes a balloon 3814 with a balloon shoulder 3862 and a balloon neck 3864 at each end of the balloon 3814. The balloon assembly 3800 may be positioned around an overtube 3812, with the balloon shoulder 3862 and the balloon neck 3864 forming a tapered diameter from the balloon 3814 towards the overtube 3812 (e.g., radially inward) at the ends of the balloon 3814. In some examples, the balloon assembly 3800 may be positioned at an end of the overtube 3812. In other examples, the balloon assembly 3800 may be positioned such that the overtube 3812 extends through and out each end of the balloon 3814. That is, the overtube 3812 may extend through and out the balloon shoulder 3862 and the balloon neck 3864 at each end of the balloon 3814.

[0264] The thickness of the balloon assembly 3800 may be greatest (e.g., thickest) at the balloon neck 3864, with the thickness decreasing radially inwards from the balloon neck 3864 to the balloon shoulder 3862 to the balloon 3814. Tapering the thickness of the balloon assembly 3800 from the minimum diameter at the balloon neck 3864 to the maximum diameter at a center of the balloon 3814 may facilitate improved stability of the balloon assembly 3800 and/or larger diameter expansion of the balloon 3814 under low inflation pressure.

[0265] The tapering of the thickness of the balloon assembly 3800 may be uniform, as shown in FIG. 38, or non-uniform, as shown in FIG. 39. FIG. 39 is a side assembly view of the balloon assembly 3900 for use with an overtube assembly according to this disclosure. The balloon assembly 3900 includes a balloon 3914 with a balloon shoulder 3962 and a balloon neck 3964 at each end of the balloon 3914. The balloon assembly 3900 may be positioned around an overtube 3912, with the balloon shoulder 3962 and the balloon neck 3964 forming a tapered diameter from the balloon 3914 towards the overtube 3912 (e.g., radially inward) at the ends of the balloon 3914.

[0266] The balloon assembly 3900 may be similar to the balloon assembly 3800 shown in FIG. 38, with the difference being a non-uniform tapering of the thickness of the balloon assembly 3900. Specifically, the thickness of the balloon shoulder 3962 varying based on the shape of the balloon shoulder 3962. In some embodiments, the balloon shoulder 3962 may be shaped into fingers, as shown in FIG. 39, with the thickness of the balloon shoulder 3962 varying between portions of the finger shapes. For example, the thickness of the balloon shoulder 3962 could taper from proximate the balloon neck 3964 to the tips of the finger shapes. In other embodiments, the balloon shoulder 3962 may be formed into one or more alternate shapes, with the thickness of the balloon shoulder 3962 varying between portions of the alternate shapes. Non-uniform tapering of the thickness of the balloon assembly 3900, specifically of the balloon shoulder 3962, may facilitate improved folding of the balloon assembly 3900 when deflated (such as for insertion) while retaining the needed stability. In some examples, the balloon shoulder 3962 may be visibly distinct from a surface of the balloon 3914. In other examples, the balloon shoulder 3962 may transition into the surface of the balloon 3914 for a seamless external appearance.

[0267] FIG. 40 is a side assembly view of a balloon assembly 4000 for use with an overtube assembly according to this disclosure. The balloon assembly 4000 includes a balloon 4014 with a balloon shoulder 4062 and a balloon neck 4064 at each end of the balloon 3814. The balloon assembly 4000 may be positioned around an overtube 4012, with the balloon shoulder 4062 and the balloon neck 4064 forming a tapered diameter from the balloon 4014 towards the overtube 4012 (e.g., radially inward) at the ends of the balloon 4014.

[0268] The balloon assembly 4000 may be similar to the balloon assemblies 3800, 3900 shown in FIGS. 38 and 39, with the difference being a non-uniform thickness of the balloon assembly 3900. Specifically, the balloon 4014 may have one or more ridges 4066 and one or more valleys 4068 around the circumference of the balloon 4014 formed by changes in thickness circumferentially around the balloon 4014. In some examples, the thickness of the balloon 4014 may be greater at the one or more ridges 4066 than at the one or more valleys 4068. Although illustrated in FIG. 40 as extending laterally around the balloon 4014, the one or more ridges 4066 and the one or more valleys 4068 could extend longitudinally along a length of the balloon 4014.

[0269] FIGS. 41 A and 41 B are isometric views of an overtube assembly 4100 for use with an endoscope 4102. The overtube assembly 4100 includes a collar 4170 for attachment to a distal end of the endoscope 4102. This differentiates the overtube assembly 4100 from previously described overtube assemblies of the present disclosure, which received the entire length of the endoscope through the overtube. The overtube assembly 4100 also includes a balloon 4114, a secondary tube 4106 (also referred to herein as a working channel) and an air supply lumen 4172. In some examples, a securement mechanism 4174 may be used to attach the secondary tube 4106 and/or the air supply lumen 4172 to the endoscope 4102 when the distal end of the endoscope 4102 is received by the collar 4170. The securement mechanism 4174 may be a strap, a band, or a helical wrapping, among others. In other examples, the secondary tube 4106 and/or the air supply lumen 4172 may freely float alongside the endoscope 4102 when the distal end of the endoscope 4102 is received by the collar 4170. FIGS. 42A and 42B are side views of the overtube assembly 4100 for use with the endoscope 4102.

[0270] FIG. 43 is a side view of an overtube assembly 4300. The overtube assembly 4300 includes an overtube 4312 and a balloon 4314, the overtube 4312 having one or more ridges 4376 extending radially outwards from the exterior surface of the overtube 4312. The overtube assemblies with balloons as described herein may include texturing on the balloon to facilitate improved anchoring of the overtube to the wall of the surrounding lumen. The ridges 4376 of the overtube assembly 4300 may be an alternate feature to improve the anchoring of an overtube 4312 to the wall of a surrounding lumen. For example, the ridges 4376 may be smooth, flat, ribbed, or textured to facilitate improved positioning of the overtube 4312 with a lumen. The overtube 4312 may also have one or more air holes 4378 positioned proximate the ridges 4376. A vacuum may be applied to the air holes 4378 from an interior of the overtube 4312 to facilitate improved positioning of the overtube 4312 with a lumen. For example, the vacuum pulled through the air holes 4378 may facilitate removal of air pockets between the overtube 4312 and the surrounding lumen to hold the overtube 4312 in place. The ridges 4376 may have a height of radial extension from the overtube 4312 to minimize the sucking of tissue through the air holes 4378 when vacuum is applied.

[0271] FIG. 44 is an isometric view of the overtube assembly 4300. The overtube assembly 4300 may include a secondary tube 4306. In some examples, the overtube assembly 4300 may include the balloon 4314, as shown. In other examples, the overtube assembly 4300 may not include a balloon. The overtube assembly 4300 may be used with an endoscope 4302.

[0272] FIGS. 45A and 45B are isometric and side sectional views of the overtube assembly 4300. The overtube 4312 may include one or more air channels 4380 in fluid communication with the air holes 4378. When vacuum is applied to the air holes 4378 from an interior of the overtube 4312, air may be pulled through the air holes 4378 and along the air channels 4380. In some examples, one or more air holes 4378 may be in fluid communication with one or more shared air channels 4380. In other examples, one or more of the air holes 4378 may have distinct air channels 4380.

[0273] The overtube assemblies described herein may include an endcap at a proximal end of the overtube to facilitate easier insertion of the overtube into a lumen of a patient. FIGS. 46A and 46B are end and isometric views of an endcap 4600 for use with an overtube, such as one or more of the overtubes described herein. The endcap 4600 on the proximal end of the overtube may facilitate decreased tissue damage when the overtube is inserted into a lumen. The endcap 4600 may be composed of a soft durometer material to aid in the insertion of the overtube into the lumen. The endcap 4600 may be formed from at least one of Nylon, PFA, PET, PTFE, FEP, HDPE, TPPE, silicone, PVC, other thermopolymers or any other suitable material. The endcap 4600 may be formed with material of 20 Shore A up to 80 Shore A. The endcap 4600 may also be formed using multiple materials. The end cap may be coated to enable desirable friction performance. The endcap 4600 may be sized and/or shaped to minimize the gap between the scope and the overtube of the overtube assembly, thereby minimizing tissue entrance into the gap

[0274] The endcap 4600 includes an endcap body 4682, one or more sizing features 4683, one or more orientation features 4684, and a body slit 4685 to receive a tool inserted through the working channel of the overtube assembly. Sizing features 4683 allow a range of endoscopes to pass through while maintaining a minimal gap between the endoscope and the side surface of the endcap 4600. In one embodiment, endoscopes with a cross-sectional width of about 7.0 mm up to about 13 mm may be accommodated by the endcap 4600. In other embodiments, the endcap 4600 may accommodate endoscopes with a cross-sectional width of about 3.0 mm up to about 8 mm. In still other embodiments, the endcap 4600 may accommodate endoscopes with a range of cross-sectional widths of about 9 mm up to about 15 mm. Minimizing this gap prevents tissue from potentially entering the endcap 4600 and being injured during use. The endcap body 4682 may have a streamlined (e.g., chamfered) profile. The width and/or the height of the body slit 4685 may vary to accommodate a range of tools received by the working channel. In some examples, the body slit 4685 may have a width that is substantially equal to the width of the tool received by the working channel. In other examples, the body slit 4685 may have a width that is sized small enough to not be visibly noticeable.

[0275] The number, shape, and/or size of the sizing features 4683 may vary to accommodate a range of scope sizes. Additionally, the number, shape, and/or size of the orientation features 4684 may vary. For example, the number, shape, and/or size of the sizing features 4683 and/or the orientation features 4684 may accommodate a range of scope diameters while minimizing gaps between the endcap 4600 and the scope.

[0276] FIGS. 47A and 47B are end views of an endcap 4700 for use with an overtube, such as one or more of the overtubes described herein. The endcap 4700 is similar to the endcap 4600 shown in FIGS. 46A and 46B, with the differences being a less streamlined (e.g., chamfered) endcap body 4782 and a different number, size, and shape of the sizing features 4783.

[0277] FIGS. 48A and 48B are isometric views of an endcap 4800 for use with an overtube, such as one or more of the overtubes described herein. The endcap 4800 is similar to the endcap 4600 shown in FIGS. 46A and 46B, with the differences being a less streamlined (e.g., chamfered) endcap body 4882 and a different size and shape of the body slit 4885.

[0278] FIGS. 49A and 49B are isometric and end views of an endcap 4900 for use with an overtube, such as one or more of the overtubes described herein. The endcap 4900 is similar to the endcap 4600 shown in FIGS. 46A and 46B, with the differences being a different size and shape of the sizing features 4983 and a different size and shape of the body slit 4985.

[0279] FIGS. 50A and 50B are isometric and end views of an endcap 5000 for use with an overtube, such as one or more of the overtubes described herein. The endcap 5000 is similar to the endcap 4700 shown in FIGS. 47A and 47B, with the differences being a different size and shape of the sizing features 5084 and a different size and shape of the body slit 5085.

[0280] FIGS. 51 A and 51 B are isometric and end views of an endcap 5100 for use with an overtube, such as one or more of the overtubes described herein. The endcap 5100 is similar to the endcap 4700 shown in FIGS. 47A and 47B, with the differences being a different size and shape of the sizing features 5184 and a different size and shape of the body slit 5185.

[0281] FIGS. 52A and 52B are side and assembly views of a handle assembly 5200 for use with an overtube assembly, such as one or more of the overtube assemblies described herein. The handle assembly 5200 includes a handle body 5286 to facilitate improved insertion and rotation of the overtube assembly when in use. The proximal end of the handle body 5268 includes a handle seal 5287 to provide a seal against a scope when received by the overtube assembly. FIGS. 53A-53C are side and isometric views of the handle body 5286 and the handle seal 5287 at the proximal end of the handle body 5286.

[0282] The handle assembly 5200 also includes a working channel port 5288 for insertion of a tool into the working channel of the overtube assembly. The working channel port 5288 may include a tuohy borst 5289 to close the working channel port 5288. During use, the tip end of the endoscope may be insufflated (e.g., pressurized) and the tuohy borst 5289 may be closed to prevent air release from the tip end of the endoscope through the working channel port 5288. Additionally, the tuohy borst 5289 may facilitate improved handling of the tool within the working channel. For example, the tuohy borst 5289 may allow the tool to be clamped down while within the working channel to hold the tool in place during use. The handle assembly 5200 further includes an inflation port 5285 and corresponding tubing for connection to an insufflator, and a flush port 5290, and corresponding tubing that may be used to add saline and/or water to the gap between the overtube and the scope during use. The handle assembly 5200 is designed to be grasped while simultaneously keeping the inflation port 5285 and the flush port 5290 tubing free from entanglement. FIG. 54 is a perspective view of an example overtube assembly including the handle assembly 5200. [0283] FIG. 55 is a perspective view of an example overtube assembly according to the present disclosure. As shown in FIG. 55, the overtube assembly may be configured to allow for retroflexion of a scope of the overtube assembly during use. That is, multiple tools/instruments may be used with the overtube assembly, such as a scope and an additional tool through a working channel, such that retroflexion of the scope is enabled.

[0284] FIGS. 56A and 56B are cross-sectional and perspective views of an overtube 5600. Overtube 5600 includes a primary tube 5602 defining a primary lumen 5604 (e.g., for an endoscope or similar elongate tool). Overtube 5600 further includes a secondary tube 5606 or working channel defining a secondary lumen 5608 and an air tube 5605 defining an air lumen 5607. In the illustrated implementation, secondary tube 5606 and air tube 5605 are disposed on an exterior surface of primary tube 5602 and are integrally formed with primary tube 5602, e.g., by an extrusion process. The overtube 5600 is formed from layers. More specifically, overtube 5600 includes a liner 5616 that defines the primary lumen 5604.

[0285] Since secondary tube 5606 and air tube 5605 extend along an exterior surface of primary tube 5602, primary lumen 5604 is generally unobstructed and is substantially concentric with any scope/tool inserted through primary tube 5602. Among other advantages, such concentricity can help to minimize or control gapping between the liner 5616 around the interior of the primary tube 5602 and a scope/tool inserted through primary tube 5602 and to reduce the likelihood of tissue becoming caught or pinched between the scope/tool and the liner 5616.

[0286] In certain implementations, overtube 5600 may correspond to a one-piece overtube with general benefits associated with ease of manufacturing (e.g., suitable for an extrusion-type process). Given the offset of secondary lumen 5608 and air lumen 5607 from primary tube 5602, overtube 5600 may be suitable for applications in which the overall length of overtube 5600 is relatively short and/or torsional stiffness is less critical (e.g., procedures involving relatively straight/non-tortuous physiological lumens or tool paths), particularly when secondary lumen 5608 extends in a substantially longitudinal direction along secondary tube 5606. As discussed throughout this disclosure, torsional and snap-through properties of overtube 5600 may be improved, e.g., by wrapping secondary tube 5606 and/or air tube 5605 helically or otherwise around primary tube 5602.

[0287] Primary tube 5602 is sized to accommodate elongate tools such as an endoscope with a diameter (or a cross-sectional width) of about 6 mm to about 15 mm. In other embodiments, the primary tube 5602 is sized for elongate tools with a diameter (or a cross-sectional width) of about 2 mm to about 7 mm. In still other embodiments, the primary tube 5602 is sized for elongate tools with a diameter (or a cross-sectional width) of about 12 mm to about 20 mm. The secondary tube 5606 is sized to accommodate elements with a diameter (or a cross-sectional width) of about 1.5 mm to about 3.8 mm. In other embodiments, the secondary tube 5606 is sized for elements with a diameter (or a cross-sectional width) of about 1 mm to about 2 mm. In still other embodiments, the secondary tube 5606 is sized for elements with a diameter (or a cross-sectional width) of about 2.2 mm to about 6.5 mm.

[0288] The center-to-center spacing between the primary tube 5602 and the secondary tube 5606 may be consistent along the length of the assembly or may vary along the length. In one embodiment, the center-to-center spacing is about 1.75 mm to about 5 mm. In another embodiment, the center-to-center spacing is about 4 mm to about 13.25 mm.

[0289] FIG. 57A is a top perspective view, and FIG. 57B is a side view, of an overtube assembly 5700. The overtube assembly 5700 includes an overtube 5712 and a balloon 5714. The overtube assemblies with balloons as described herein, including the overtube assembly 5700 as shown in FIGS. 57A and 57B, may include texturing on the balloon to facilitate improved anchoring of the overtube assembly to the wall of the surrounding lumen. The overtube assembly 5700 includes a handle assembly 5703, an air tube 5705, a secondary tube 5706, and an endcap 5715.

[0290] FIG. 58A is the same view as FIG. 57B, except enlarged. FIG. 58B is a longitudinal cross- sectional view of the overtube assembly 5700, taken along section line D-D of FIG. 58A. FIG. 58C is an enlarged cross-sectional view of the overtube assembly 5700, specifically detail E of FIG. 58B. FIG. 58D is a transverse cross-sectional view of the overtube assembly 5700, taken along section line G-G of FIG. 57B.

[0291] The overtube assembly 5700 is similar to the overtube assemblies described herein, in that the overtube assembly 5700 is laterally flexible while retaining a sufficient torsional stiffness for steady rotation at a distal end when a torque is applied to a proximal end with minimized rotational lag and snap through. As described with reference to FIGS. 57A-58D, the air tube 5705 and the secondary tube 5706 are positioned at a radial offset from the overtube 5712 and are arranged in a symmetrical cross-sectional layout along the length of the overtube 5712, thereby maintaining the flexibility of the overtube assembly 5700 while retaining torqueability along its length for steady rotation of the distal end and minimized rotational lag between the proximal and distal ends. Thus, the overtube assembly 5700 may be used in the Gl tract to navigate unexpected turns and an unpredictable in vivo environment that may require separate advancement and/or rotation of an endoscope within the overtube and a second surgical tool within the second working channel for proper surgical positioning. The torqueability along the length of the overtube assembly 5700 facilitates stable and consistent positioning of the overtube 5712 and the endoscope advanced therethrough, as well as the secondary tube 5706 and the second surgical tool advanced therethrough.

[0292] As illustrated in FIG. 57B, the overtube 5712 has a length L1, which may range from 20 cm to about 120 cm. The balloon 5714 has a length L2a of the inflated balloon, which may range from 30 mm to about 70 mm, a length L2b of the balloon including the shoulders, which may range from 50 mm to about 90 mm, and an uninflated resting diameter D1, which may range from 40 mm to about 80 mm. The handle assembly 5703 has a length L3, which may range from 10 cm to about 18 cm, for an overall length L4 of the overtube assembly 5700, which may range from 28 cm to about 138 cm, the overall length L4 being the combined lengths L3 of the handle assembly 5703 and L1 of the overtube 5712. The endcap 5715 has a height H, which may range from 18 mm to about 26 mm, and a width W, which may range from 8 mm to about 14 mm. The overtube 5712 has a diameter D2, which may range from 15 mm to about 19 mm.

[0293] The torqueability along the length of the overtube assembly 5700 may facilitate steady rotation of the distal end at the endcap 5715 when a torque force of up to 1 N*m of torque is applied at the proximal end to the handle assembly 5703. That is, when the torque force is applied to the handle assembly 5703, the proximal end of the overtube 5712 proximate the handle assembly 5703 may rotate a first rotation amount and the distal end of the overtube 5712 proximate the endcap 5715 may rotate a second rotation amount. The balance of the torsional stiffness and the torqueability of the overtube assembly may result in the second rotation amount lagging the first rotation amount by up to 90 degrees.

[0294] For example, the handle assembly 5703 may be rotated 360 degrees by a torque force of up to 1 N*m of torque, applied when the overtube assembly 5700 is free of any torque-resisting structures along its length (e.g., with the overtube assembly 5700 extending straight on a bench top), and this may result in steady rotation of the endcap 5715 that lags the rotation of the handle assembly 5703 by up to 90 degrees. In some embodiments, the steady rotation of the endcap 5715 may lag the rotation of the handle assembly 5703 by 15 degrees to 90 degrees. In other embodiments, the steady rotation of the endcap 5715 may lag the rotation of the handle assembly 5703 by 15 degrees to 45 degrees. In still other embodiments, steady rotation of the endcap 5715 may lag the rotation of the handle assembly 5703 by up to 20 degrees. Additionally, for example, further rotation of the handle assembly 5703 past the first 360 degree rotation by a torque force of up to 1 N*m of torque may result in further steady rotation of the endcap 5715 with an additional lag of up to 10 degrees. This rotational lag may apply to overtubes with a length of about 1 m. [0295] The air tube 5705 and the secondary tube 5706 are wrapped around the overtube 5712 in a symmetrical cross-sectional layout along the length L1 of the overtube 5712 with a helical pitch HP defined as an axial distance to complete one full circumferential rotation around the overtube 5712. Decreasing the helical pitch HP, and thereby increasing the number of full circumferential rotations along the length L1, may facilitate improved performance of the overtube 5712 in that the decreased helical pitch HP may decrease snap-through when the overtube 5712 is navigated through corners (e.g., turns) in a lumen. However, increasing the helical pitch HP, and thereby decreasing the number of full circumferential rotations along the length L1, may facilitate improved navigation of tools through the air tube 5705 and/or the secondary tube 5706 in that tools are subject to less friction and changes in direction for easier advancement. Therefore, the helical pitch HP of the air tube 5705 and/or the secondary tube 5706 may vary along the length L1 of the overtube 5712 to balance the snap-through performance and the tool navigation.

[0296] The helical pitch HP of the air tube 5705 and the secondary tube 5706 may range from 14 cm to about 19 cm. The helical pitch HP of the air tube 5705 and the secondary tube 5706 may depend on the diameter D2 of the overtube 5712. For example, the helical pitch HP of the air tube

5705 and/or the secondary tube 5706 may be substantially equal to or less than the diameter D2 of the overtube 5712. That is, if the diameter D2 of the overtube 5712 is 15 mm, the helical pitch HP of the air tube 5705 and/or the secondary tube 5706 may be up to about 15 mm.

[0297] In some embodiments, the air tube 5705 and/or the secondary tube 5706 may be coextruded with the overtube 5712 in the desired helical pitch HP. In other embodiments, the air tube 5705 and/or the secondary tube 5706 may be externally coupled to the overtube 5712. The length of the external coupling may impact snap-through of the overtube 5712. For example, externally coupling the air tube 5705 and/or the secondary tube 5706 along an entirety of the length L1 of the overtube 5712 may increase snap-through as the overtube assembly 5700 is advanced through the tortuous Gl tract. Therefore, the helical pitch HP of the air tube 5705 and the secondary tube 5706 may be lowered for such overtube assemblies to improve the snap- through performance of the overtube assembly 5700.

[0298] Additionally, for example, externally coupling the air tube 5705 and/or the secondary tube

5706 only at distinct locations along the length L1 of the overtube 5712 may decrease snap- through by allowing the air tube 5705 and/or the secondary tube 5706 to move slightly in relation to the overtube 5712 as the overtube assembly 5700 is advanced through the tortuous Gl tract. Therefore, the helical pitch HP of the air tube 5705 and the secondary tube 5706 may be increased for such overtube assemblies without degrading the snap-through performance of the overtube assembly 5700. In some embodiments, the air tube 5705 and/or the secondary tube 5706 may be coupled to the overtube 5712 at the proximal end (e.g., proximate the handle assembly 5703) and at the distal end (e.g., proximate the endcap 5715). In other embodiments, the air tube 5705 and/or the secondary tube 5706 may be coupled to the overtube 5712 in segments (e.g., at specific intervals for specific lengths) along the length L1 of the overtube 5712. The air tube 5705 and the secondary tube 5706 may be coupled to the overtube 5712 using any suitable method, including, but not limited to, adhesive, tape, rubber bands, or the like.

[0299] As illustrated in FIG. 58C, the overtube 5712 may include a plurality of layers 5711 defining the lumen therethrough, such as a first layer 5711a, a second layer 5711b, and a third layer 5711c. The first layer 5711a is the outermost layer and has a thickness T1, which may range from 0.10 mm to about 3.75 mm. The second layer 5711 b is the middle layer and has a thickness T2, which may range from 0.025 mm to about 2.25 mm. The third layer 5711c is the innermost layer and has a thickness T3, which may range from 0.001 mm to about 1.75 mm. The overtube 5712 may have an inner diameter D3 that extends to an innermost edge of the third layer 5711c, which may range from 5.5 mm to about 17.5 mm.

[0300] As illustrated in FIG. 58D, a center 5705C of the air tube 5705 may be positioned at a radial offset R1 from a center 5717 of the overtube 5712, which may range from 3.25 mm to about 12.5 mm. A center 5706C of the secondary tube 5706 may be positioned at a radial offset R2 from the center 5717 of the overtube 5712, which may range from 3.5 mm to about 13.5 mm. The air tube 5705 may have an inner diameter D4, which may range from 0.5 mm to about 3.25 mm, and an outer diameter D5, which may range from 0.75 mm to about 6.5 mm, with a thickness of the air tube 5705 being the difference between the inner diameter D4 and the outer diameter D5. Additionally, the secondary tube 5706 may have an inner diameter D6, which may range from 1.5 mm to about 4 mm, and an outer diameter D7, which may range from 1.75 mm to about 7.5 mm, with a thickness of the secondary tube 5706 being the difference between the inner diameter D6 and the outer diameter D7.

[0301] The dimensions of the overtube assembly 5700 may differ from the dimensions of the overtube assemblies described herein depending on the intended use of the overtube assembly 5700. In one embodiment, the dimensions of the overtube assembly 5700 may be for use with a shorter endoscope and/or in a shorter patient lumen tract. For example, smaller dimensions of the overtube assembly 5700 may support more optimal use in a proximal portion of the colon with a shorter endoscope, such as a gastroscope, and/or in the upper gastrointestinal tract for esophageal and stomach procedures due to the shorter overall length and the smaller diameter. When compared to a colonoscope, a gastroscope is usually smaller in diameter and shorter in length, while also being more flexible and easier to control for surgical procedures.

[0302] As illustrated in FIG. 57B, the overtube assembly 5700 for use with a shorter endoscope and/or in a shorter patient lumen tract may include one or more of the following dimensions: the height H of the endcap 5715 of about 22.5 mm, the width l/l/of the endcap 5715 of about 10 mm, the uninflated resting diameter D1 of the balloon 5714 of about 56.7 mm to about 57 mm, the length L2a of the inflated balloon 5714 of about 41.1 mm, the length L2b of the balloon 5714 including the shoulders of about 60 mm, the length L1 of the overtube 5712 of about 486 mm, the length L3 of the handle assembly 5703 of about 143 mm, the diameter D2 of the overtube 5712 of about 15.29 mm, the overall length L4 of about 629 mm, and the helical pitch HP of the air tube

5705 and/or the secondary tube 5706 of about 1 wrap per 165 mm to about 1 wrap per 170 mm.

[0303] As illustrated in FIG. 58C, the overtube assembly 5700 for use with a shorter endoscope and/or in a shorter patient lumen tract may include one or more of the following dimensions: the thickness T1 of the first layer 5711a of about 0.499 mm, the thickness T2 of the second layer 5711 b of about 0.405 mm, the thickness T3 of the third layer 5711c of about 0.253 mm, and the inner diameter D3 of the overtube 5712 of about 12.972 mm.

[0304] As illustrated in FIG. 58D, the overtube assembly 5700 for use with a shorter endoscope and/or in a shorter patient lumen tract may include one or more of the following dimensions: the radial offset R1 of the air tube 5705 of about 9.6 mm, the radial offset R2 of the secondary tube

5706 of about 10.6 mm, the inner diameter D4 of the air tube 5705 of about 2 mm, the outer diameter D5 of the air tube 5705 of about 4 mm, the inner diameter D6 of the secondary tube 5706 of about 3.5 mm, and the outer diameter D7 of the secondary tube 5706 of about 6 mm.

[0305] In another embodiment, the dimensions of the overtube assembly 5700 may be for use with a larger and/or longer endoscope. For example, larger dimensions of the overtube assembly 5700 may support more optimal use in a distal portion of the right colon with a larger and longer endoscope, such as a colonoscope, due to the longer overall length and the larger diameter. When compared to a gastroscope, colonoscopes are usually less flexible and easier to advance over a longer distance in the gastrointestinal tract.

[0306] As illustrated in FIG. 57B, the overtube assembly 5700 for use with a larger and/or longer endoscope may include one or more of the following dimensions: the height H of the endcap 5715 of about 24.2 mm, the width l/l/of the endcap 5715 of about 10 mm, the uninflated resting diameter D1 of the balloon 5714 of about 57 mm, the length L2a of the inflated balloon 5714 of about 41.1 mm, the length L2b of the balloon 5714 including the shoulders of about 60 mm, the length L1 of the overtube 5712 of about 1100 mm, the length L3 of the handle assembly 5703 of about 143 mm, the diameter D2 of the overtube 5712 of about 17 mm, the overall length L4 of about 1243 mm, and the helical pitch HP of the air tube 5705 and/or the secondary tube 5706 of about 1 wrap per 165 mm.

[0307] The helical pitch HP of the air tube 5705 and/or the secondary tube 5706 may decrease proximate the handle assembly 5703 to improve the tool navigation along this segment of the length L1 of the overtube 5712 that is not inserted as far into the patient lumen for the overtube assembly 5700 for use with the larger and/or longer endoscope. Additionally, the helical pitch HP of the air tube 5705 and/or the secondary tube 5706 may increase, either progressively or in segments, along the length L1 of the overtube 5712 moving away from the handle assembly 5703 (e.g., towards the balloon 5714) to improve the snap-through performance of the overtube 5712 inserted further into the patient lumen for the overtube assembly 5700 for use with the larger and/or longer endoscope. The decrease of the helical pitch HP of the air tube 5705 and/or the secondary tube 5706 proximate the handle assembly 5703 may depend on (e.g., be in relationship with) the increase of the helical pitch HP of the air tube 5705 and/or the secondary tube 5706 at the distal end of the overtube 5712.

[0308] As illustrated in FIG. 58C, the overtube assembly 5700 for use with a larger and/or longer endoscope may include one or more of the following dimensions: the thickness T1 of the first layer 5711a of about 0.499 mm, the thickness T2 of the second layer 5711b of about 0.5 mm, the thickness T3 of the third layer 5711 c of about 0.253 mm, and the inner diameter D3 of the overtube 5712 of about 14.5 mm.

[0309] As illustrated in FIG. 58D, the overtube assembly 5700 for use with a larger and/or longer endoscope may include one or more of the following dimensions: the radial offset R1 of the air tube 5705 of about 10.5 mm, the radial offset R2 of the secondary tube 5706 of about 11.5 mm, the inner diameter D4 of the air tube 5705 of about 2 mm, the outer diameter D5 of the air tube 5705 of about 4 mm, the inner diameter D6 of the secondary tube 5706 of about 3.5 mm, and the outer diameter D7 of the secondary tube 5706 of about 6 mm.

[0310] As discussed previously herein, an overtube assembly may require a specific torsional stiffness to reliably transfer torque applied at a proximal end of the overtube assembly to cause rotation of a distal end of the overtube assembly. In the embodiment for use with a shorter endoscope and/or in a shorter patient lumen tract, the overtube assembly 5700 may require a decreased torsional stiffness to reliably transfer torque due to the shorter lengths (such as, but not limited to, L1, L2a, L2b, L3, and/or L4), the smaller diameters (such as, but not limited to, D1, D2, D3, D4, D5, D6, and/or D7), and/or the smaller radial offsets (such as, but not limited to, R1 and/or R2) of the overtube assembly 5700. As such, the overtube 5712, the air tube 5705, and/or the secondary tube 5706 may be formed of a softer material (e.g., a material with a lower durometer), such as, but not limited to, PTFE (Polytetrafluoroethylene), other thermopolymers, TPPE (Thermoplastic Polyolefin Elastomer), silastic polymers (can vary; typically around here), extruded 70 Shore A silicone, silicone, and/or 20 Shore A.

[0311] To further increase the flexibility, the overtube 5712, the air tube 5705, and/or the secondary tube 5706 may be formed to include one or more additives, such as, but not limited to, Hytrel Thermoplastic Polyester Elastomer with Everglide. Alternatively, or additionally, the overtube 5712, the air tube 5705, and/or the secondary tube 5706 may be formed with layers and/or segments of decreased thickness to increase the flexibility.

[0312] In the embodiment for use with a larger and/or longer endoscope, the overtube assembly 5700 may require an increased torsional stiffness to reliably transfer torque due to the longer lengths (such as, but not limited to, L1, L2a, L2b, L3, and/or L4), the larger diameters (such as, but not limited to, D1, D2, D3, D4, D5, D6, and/or D7), and/or the larger radial offsets (such as, but not limited to, R1 and/or R2) of the overtube assembly 5700. As such, the overtube 5712, the air tube 5705, and/or the secondary tube 5706 may be formed of a harder material (e.g. , a material with a higher durometer), such as, but not limited to, 80 Shore A, PET (Polyethylene Terephthalate), nylon, PFA (Perfluoroalkoxy Alkane), FEP (Fluorinated Ethylene Propylene), HDPE (High-Density Polyethylene), and/or PVC (Polyvinyl Chloride).

[0313] To further increase the hardness (e.g., the stiffness), the overtube 5712, the air tube 5705, and/or the secondary tube 5706 may be formed to include one or more additives, such as, but not limited to, ABS or polycarbonate. Alternatively, or additionally, the overtube 5712, the air tube 5705, and/or the secondary tube 5706 may be formed with layers and/or segments of increased thickness to increase the stiffness. Alternatively, or additionally, the overtube 5712, the air tube 5705, and/or the secondary tube 5706 may be formed to include an embedded or wrapped braided reinforcement to increase the stiffness.

[0314] Alternatively, or additionally, the overtube 5712 may be formed to include laser cuts along the tube length. For example, the overtube 5712 may incorporate a laser-cut hypotube that is placed within the extruded overtube. The laser-cut hypotube may be a thin-walled metal, such as, but not limited to, stainless steel, nitinol, or aluminum, with small cuts (e.g., windows) made around its circumference by a laser. The laser cuts made around the hypotube may allow the hypotube to maintain its rotational stiffness while increasing its flexibility, thereby increasing the flexibility of the overtube 5712.

[0315] Incorporation of the laser-cut hypotube into the overtube 5712 may impact the kink resistance performance of the overtube assembly 5700. Advancement of the overtube assembly 5700 through the tortuous Gl tract requires the overtube 5712 to have a sufficient resistance to kinking (e.g., buckling) when the endoscope is removed from the overtube 5712. That is, the endoscope needs to be able to be advanced partially or entirely, and retracted, partially or entirely, through the overtube 5712 when the overtube assembly 5700 is positioned in the Gl tract. For example, when forces up to 42 N are applied to advance or retract the endoscope through the overtube 5712, the overtube 5712 may be sufficiently resistant to kinking (e.g., buckling) if the overtube 5712 does not compress or extend more than 5% when axially loaded. The overtube 5712 may retain the sufficient resistance to kinking described herein when bent about a radius and subjected to a bending force applied when the overtube 5712 is free of any bending-resisting structures along its length (e.g., with the overtube assembly 5700 extending straight on a bench top and being bent), as follows: about a radius of 20 mm subjected to a maximum bending force of 19 N, about a radius of 25 mm subjected to a maximum bending force of 14 N, about a radius of 35 mm subjected to a maximum bending force of 8 N, about a radius of 45 mm subjected to a maximum bending force of 3.5 N, about a radius of 55 mm subjected to a maximum bending force of 1.2 N, about a radius of 65 mm subjected to a maximum bending force of 0.5 N, and about a radius of 75 mm subjected to a negligible maximum bending force of approximately 0 N. The laser-cut hypotube may be added and/or the thickness or design of the laser-cut hypotube may be altered to change the kinking resistance performance of the overtube 5712.

[0316] To further increase the flexibility, the diameter of the overtube 5712 may be decreased, the outer extrusion wall thickness of the overtube 5712 may be decreased, the wall thickness of the hypotube incorporated in the overtube 5712 may be decreased, the outer extrusion durometer may be decreased, the number of cuts in the hypotube incorporated in the overtube 5712 may be increased, and/or the size of the cuts in the hypotube incorporated in the overtube 5712 may be increased. Similarly, to decrease the rotational stiffness, the diameter of the overtube 5712 may be increased, the outer extrusion wall thickness of the overtube 5712 may be increased, the wall thickness of the hypotube incorporated in the overtube 5712 may be increased, the outer extrusion durometer may be increased, the number of cuts in the hypotube incorporated in the overtube 5712 may be decreased, and/or the size of the cuts in the hypotube incorporated in the overtube 5712 may be decreased.

[0317] As used herein, unless defined otherwise, all technical and scientific terms generally have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Generally, the nomenclature used herein is those well-known and commonly employed in the art.

[0318] As used herein, the articles “a” and “an” refer to one or to more than one (i.e., to at least one) of the grammatical object of the article. By way of example, “an element” means one element or more than one element.

[0319] As used herein, the term “about” will be understood by persons of ordinary skill in the art and will vary to some extent on the context in which it is used. As used herein, “about” when referring to a measurable value such as an amount, a temporal duration, and the like, is meant to encompass variations of ±20% or ±10%, more preferably ±5%, even more preferably ±1%, and still more preferably ±0.1% from the specified value, as such variations are appropriate to perform the disclosed methods.

[0320] Throughout this disclosure, various aspects of the present disclosure may be presented in a range format. The description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the present disclosure. Accordingly, the description of a range should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range and, when appropriate, partial integers of the numerical values within ranges. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1 , 2, 2.7, 3, 4, 5, 5.3, and 6. This applies regardless of the breadth of the range.

[0321] Every formulation or combination of components described or exemplified can be used to practice implementations of the current disclosure, unless otherwise stated. Specific names of compounds are intended to be exemplary, as it is known that one of ordinary skill in the art can name the same compounds differently. When a compound is described herein such that a particular isomer or enantiomer of the compound is not specified, for example, in a formula or in a chemical name, that description is intended to include each isomer and enantiomer of the compound described individual or in any combination. [0322] Although the description herein contains many example implementations, these should not be construed as limiting the scope of the current disclosure but as merely providing illustrative examples.

[0323] All references throughout this disclosure (for example, patent documents including issued or granted patents or equivalents; patent application publications; and non-patent literature documents or other source material) are hereby incorporated by reference herein in their entireties, as though individually incorporated by reference, to the extent each reference is at least partially not inconsistent with the disclosure in this application (for example, a reference that is partially inconsistent is incorporated by reference except for the partially inconsistent portion of the reference).

[0324] Those skilled in the art will recognize or be able to ascertain using no more than routine experimentation, numerous equivalents to the specific procedures, embodiments, claims, and examples described herein. Such equivalents were considered to be within the scope of this disclosure and covered by the claims appended hereto. In general, the terms and phrases used herein have their art-recognized meaning, which can be found by reference to standard texts, journal references, and contexts known to those skilled in the art. Any preceding definitions are provided to clarify their specific use in the context of the present disclosure.

[0325] It is to be understood that wherever values and ranges are provided herein, all values and ranges encompassed by these values and ranges, are meant to be encompassed within the scope of the present disclosure. Moreover, all values that fall within these ranges, as well as the upper or lower limits of a range of values, are also contemplated by the present disclosure.

[0326] The disclosures of each patent, patent application, and publication cited herein are hereby incorporated herein by reference in their entirety.

[0327] While this disclosure includes reference to specific embodiments, it is apparent that other embodiments and variations of this disclosure may be devised by others skilled in the art without departing from the true spirit and scope of the disclosure. The appended claims are intended to be construed to include all such embodiments and equivalent variations.

Claims

Claims We claim:

1 . An overtube assembly for use with a first elongate medical device and a second elongate medical device within a physiological lumen of a patient, the overtube assembly comprising: a primary tubular body defining a primary lumen configured to receive the first elongate medical device, the primary tubular body having a length extending from a proximal end oriented to receive the first elongate medical device to a distal end; and a secondary lumen extending along the length of the primary tubular body, the secondary lumen being configured to receive the second elongate medical device; wherein, when a torque force is applied to the proximal end of the primary tubular body to cause the proximal end of the primary tubular body to rotate by a first rotation amount, the distal end of the primary tubular body responds by rotating a second rotation amount, the second rotation amount lagging behind the first rotation amount by a rotation lag amount less than 90 degrees.

2. The overtube assembly of claim 1 , wherein the secondary lumen is wrapped helically about the primary tubular body.

3. The overtube assembly of claim 2, wherein a helical pitch of the secondary lumen about the primary tubular body is symmetrical along the length of the primary tubular body.

4. The overtube assembly of claim 3, wherein the helical pitch is about 1 circumferential wrap per 165 mm to about 1 circumferential wrap per 170 mm.

5. The overtube assembly of claim 1 , wherein the torque force applied to the proximal end of the primary tubular body is up to 1 N*m of torque.

6. The overtube assembly of claim 1 , wherein the first rotation amount is 360 degrees.

7. The overtube assembly of claim 6, wherein further rotation of the proximal end of the primary tubular body past the first rotation amount corresponds to rotation of the distal end of the primary tubular body lagging behind the further rotation within 10 degrees of the rotation lag amount.

8. The overtube assembly of claim 1 , wherein the primary tubular body comprises a low durometer elastomer.

9. The overtube assembly of claim 1 , wherein the primary tubular body comprises a hypotube, the hypotube having one or more cuts distributed along the length of the primary tubular body.

10. The overtube assembly of claim 9, wherein the hypotube comprises a thin-walled metal.

11. The overtube assembly of claim 1 , wherein the secondary lumen is coupled to the primary tubular body along an entirety of the length of the primary tubular body.

12. The overtube assembly of claim 1 , wherein the secondary lumen is coupled to the primary tubular body at distinct locations along the length of the primary tubular body.

13. The overtube assembly of claim 2, wherein the secondary lumen remains proximate the primary tubular body along the length of the primary tubular body due to the helical winding of the secondary lumen.

14. The overtube assembly of claim 1, wherein the first elongate medical device comprises one of an endoscope or a catheter.

15. The overtube assembly of claim 1 , wherein the second elongate medical device comprises one of a forceps, a knife, a pair of scissors, or a clamp.

16. The overtube assembly of claim 1, wherein the rotation lag amount is 15 degrees to 90 degrees.

17. The overtube assembly of claim 1, wherein the rotation lag amount is 15 degrees to 45 degrees.

18. The overtube assembly of claim 1 , wherein the rotation lag amount is less than 20 degrees.

19. The overtube assembly of claim 1, wherein the length of the primary tubular body is 20 cm to 120 cm.

20. The overtube assembly of claim 19, wherein the length of the primary tubular body is 100 cm.

21. The overtube assembly of claim 1 , wherein a center of the secondary lumen is positioned at a radial offset from a center of the primary lumen, the radial offset being 3.5 mm to 13.5 mm.

22. The overtube assembly of claim 1 , wherein the primary tubular body comprises a plurality of layers, one or more of the plurality of layers having an increased thickness.

23. The overtube assembly of claim 2, wherein the secondary lumen is wrapped at a first helical pitch proximate the proximal end of the primary tubular body and at a second helical pitch proximate the distal end of the primary tubular body, the first helical pitch being less than the second helical pitch.

24. The overtube assembly of claim 23, wherein the first helical pitch is based on the second helical pitch.

25. The overtube assembly of claim 13, wherein the secondary lumen is coupled at a first location proximate the proximal end of the primary tubular body and at a second location proximate the distal end of the primary tubular body.

26. The overtube assembly of claim 25, wherein the coupling of the secondary lumen at the first and second locations along the length of the primary tubular body allows the secondary lumen to move in relation to the primary tubular body.

27. The overtube assembly of claim 1 , further comprising an air lumen extending along the primary tubular body, the air lumen being coupled along the length of the primary tubular body.

28. The overtube assembly of claim 27, wherein each of the secondary lumen and the air lumen are wrapped helically about the primary tubular body.

29. The overtube assembly of claim 28, wherein a helical pitch of each of the secondary lumen and the air lumen about the primary tubular body is symmetrical along the length of the primary tubular body.

30. The overtube assembly of claim 29, wherein the helical pitch of the secondary lumen is radially offset from the helical pitch of the air lumen.

31. The overtube assembly of claim 27, wherein a center of the secondary lumen is positioned at a first radial offset from a center of the primary lumen and a center of the air lumen is positioned at a second radial offset from the center of the primary lumen, the first radial offset being 3.5 mm to 13.5 mm and the second radial offset being 3.25 mm to 12.5 mm.

32. The overtube assembly of claim 27, further comprising a balloon selectively inflatable about the primary tubular body to anchor the overtube assembly to a wall of the physiological lumen of the patient, wherein the balloon is connected to the air lumen for selective inflation and deflation.

33. The overtube assembly of claim 32, wherein an inflated length of the balloon is 30 mm to 70 mm.

34. The overtube assembly of claim 33, wherein the inflated length of the balloon is 41.1 mm.

35. The overtube assembly of claim 32, wherein an uninflated resting diameter of the balloon is 40 mm to 80 mm.

36. The overtube assembly of claim 35, wherein the uninflated resting diameter of the balloon is 56.7 mm to 57 mm.

37. An overtube assembly for use with a first elongate medical device and a second elongate medical device within a physiological lumen of a patient, the overtube assembly comprising: a primary tubular body including a first circumferential outer wall and a primary lumen configured to receive the first elongate medical device, the primary tubular body having a length extending from a proximal end oriented to receive the first elongate medical device to a distal end, the first circumferential outer wall including a first radially inward circumferential surface, a first radially outward circumferential surface and a first radial wall thickness of between approximately 0.126 mm and approximately 7.75 mm, the first radially inward circumferential surface defining the primary lumen and having a first internal diameter of between approximately 5.5 mm and approximately 17.5 mm, the first radially outward circumferential surface having a first outer diameter of between approximately 15 mm and approximately 19 mm; and at least one of a fluid tubular body or a secondary tubular body, each such tubular body extending along, coupled to, and helically wrapped about the primary tubular body at a helical pitch of between approximately 1 circumferential wrap per 165 mm and approximately 1 circumferential wrap per 170 mm, wherein the fluid tubular body includes a second radially inward circumferential surface, a second radially outward circumferential surface and a second radial wall thickness defined between the second radially inward circumferential surface and the second radially outward circumferential surface, the second radially inward circumferential surface defining a fluidconveying lumen and having a second internal diameter of between approximately 0.5 mm and approximately 3.25, the second radially outward circumferential surface having a second outer diameter of between approximately 0.75 mm and approximately 6.5 mm, wherein the secondary tubular body includes a third radially inward circumferential surface, a third radially outward circumferential surface and a third radial wall thickness defined between the third radially inward circumferential surface and the third radially outward circumferential surface, the third radially inward circumferential surface defining a secondary lumen and having a third internal diameter of between approximately 1.5 mm and approximately 4 mm, the third radially outward circumferential surface having a third outer diameter of between approximately 1.75 mm and approximately 7.5 mm, the secondary lumen configured to receive the second elongate medical device, and wherein a distance between a center of the primary lumen and a center of the fluidconveying lumen is between approximately 3.25 mm and approximately 12.5 mm, and a distance (R2) between a center of the primary lumen and a center of the secondary lumen is between approximately 3.5 mm and approximately 13.5 mm.

38. The overtube assembly of claim 37, wherein the first radial wall thickness is formed of at least one of a first, second or third radial layer, the first radial layer having a thickness of between approximately 0.1 mm and approximately 3.75 mm, the second radial layer having a thickness of between approximately 0.025 mm and approximately 2.25 mm, and the third radial layer having a thickness of between approximately 0.001 mm and approximately 1.75 mm.

39. The overtube assembly of claim 37, wherein the first radial wall thickness is formed of at least one of a first, second or third radial layer, the first radial layer having a thickness of approximately 0.499 mm, the second radial layer having a thickness of approximately 0.405 mm, and the third radial layer having a thickness of approximately 0.253 mm.

40. The overtube assembly of claim 37, wherein the first internal diameter is approximately 12.972 mm.

41. The overtube assembly of claim 37, wherein the first outer diameter is approximately 15.29 mm.

42. The overtube assembly of claim 37, wherein the second internal diameter is approximately 2 mm.

43. The overtube assembly of claim 37, wherein the second outer diameter is approximately 4 mm.

44. The overtube assembly of claim 37, wherein third internal diameter is approximately 3.5 mm.

45. The overtube assembly of claim 37, wherein the third outer diameter is approximately 6 mm.

46. The overtube assembly of claim 37, the distance between the center of the primary lumen and the center of the fluid-conveying lumen is approximately 10.5 mm.

47. The overtube assembly of claim 37, wherein the distance between the center of the primary lumen and the center of the secondary lumen is approximately 11.5 mm.

48. The overtube assembly of claim 37, wherein the helical pitch along the primary tubular body is symmetrical along the length of the primary tubular body.

49. The overtube assembly of claim 37, wherein the helical pitch is equal to or less than the first outer diameter.

50. The overtube assembly of claim 37, wherein the primary tubular body comprises a low durometer elastomer.

51. The overtube assembly of claim 37, wherein the primary tubular body comprises a hypotube, the hypotube having one or more cuts distributed along the length of the primary tubular body.

52. The overtube assembly of claim 37, wherein at least one of the fluid tubular body or the secondary tubular body is continuously coupled along an entirety of the length of the primary tubular body.

53. The overtube assembly of claim 37, wherein at least one of the fluid tubular body or the secondary tubular body is coupled at distinct locations along the length of the primary tubular body.

54. The overtube assembly of claim 37, wherein the first elongate medical device comprises one of an endoscope or a catheter.

55. The overtube assembly of claim 37, wherein the second elongate medical device comprises one of a forceps, a scalpel, a pair of scissors, or a clamp.

56. The overtube assembly of claim 37, wherein, when a force is applied to the primary tubular body, each of a compression and an expansion of the primary lumen is 5% or less.

57. The overtube assembly of claim 56, wherein the force applied to the primary tubular body is an axial load force up to up to 42 N.

58. The overtube assembly of claim 56, wherein the force applied to the primary tubular body is a maximum bending force of 19 N and the primary tubular body is bent about a radius of 20 mm.

59. The overtube assembly of claim 56, wherein the force applied to the primary tubular body is a maximum bending force of 14 N and the primary tubular body is bent about a radius of 25 mm.

60. The overtube assembly of claim 56, wherein the force applied to the primary tubular body is a maximum bending force of 8 N and the primary tubular body is bent about a radius of 35 mm.

61. The overtube assembly of claim 56, wherein the force applied to the primary tubular body is a maximum bending force of 3.5 N and the primary tubular body is bent about a radius of 45 mm.

62. The overtube assembly of claim 56, wherein the force applied to the primary tubular body is a maximum bending force of 1.2 N and the primary tubular body is bent about a radius of 55 mm.

63. The overtube assembly of claim 56, wherein the force applied to the primary tubular body is a maximum bending force of 0.5 N and the primary tubular body is bent about a radius of 65 mm.

64. The overtube assembly of claim 56, wherein the force applied to the primary tubular body is a negligible bending force of about 0 N and the primary tubular body is bent about a radius of 75 mm.