WO2025171405A1

WO2025171405A1 - Methods and apparatuses for navigating using a pair of rigidizing devices

Info

Publication number: WO2025171405A1
Application number: PCT/US2025/015302
Authority: WO
Inventors: Natalie FERRANTE; James M. Hayes; Francisco G. Lopez; Michael Costa; Neal Tanner
Original assignee: Neptune Medical Inc
Current assignee: Neptune Medical Inc
Priority date: 2024-02-08
Filing date: 2025-02-10
Publication date: 2025-08-14
Anticipated expiration: 2026-08-08

Abstract

Disclosed herein are methods and apparatuses for retroflexing a scope, such as a colonoscope. These methods and apparatuses may provide a minimum bending radius and may be safer and more efficient than convention retroflexing. In general, these methods and apparatuses may include a pair of nested elongate members, one of which is configured as the scope (e.g., colonoscope). These methods and apparatuses may be partially or fully automated.

Description

METHODS AND APPARATUSES FOR NAVIGATING USING A PAIR OF RIGIDIZING DEVICES

PRIORITY CLAIM

[0001] This patent application claims priority to U.S. provisional patent application no. 63/551,276, titled “METHODS AND APPARATUSES FOR RETROFLEXING USING A PAIR OF RIGIDIZING DEVICES,” and filed on February 8, 2024, herein incorporated by reference in its entirety.

INCORPORATION BY REFERENCE

[0002] All publications and patent applications mentioned in this specification are herein incorporated by reference in their entirety to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.

BACKGROUND

[0003] During medical procedures using an endoscope, it may be particularly helpful to steer the endoscope so that the distal end of the apparatus is pointed back towards the proximal end, allowing visualization of the proximal region. This procedure may be referred to as retroflexing. In colonoscopy, retroflexing may help with improved detection of neoplasia in the distal rectum, may aid in detection in the proximal colon, especially the ascending colon, and may be useful when removing lesions that are difficult to access in the forward view. Early studies reported a substantial gain in polyp detection with retroflexion, including detection of large lesions. Unfortunately, there are also risks associated with retroflexion. For example, retroflexing may result in perforations (by some estimates greater than 10% of all colonoscopy perforations).

[0004] Accordingly, there is a need for apparatuses that may provide safe and accurate retroflexing, particularly within anatomical regions including the gastrointestinal tract. In particular, there is a need for methods and apparatuses that can safely and efficiently coordinate retroflexing of telescoping members of a nested apparatus.

SUMMARY OF THE DISCLOSURE

[0005] Described herein are methods and apparatuses (e.g., devices, systems, etc.) for controlling a pair of nested elongate members during advancement and retraction within a body lumen in the performance of retroflexing. In general, the apparatuses described herein may include a rigidizing first elongate member that is configured to transition between a flexible configuration and a rigid (e.g., less flexible) configuration, and a second elongate member nested with the rigidizing first elongate member and axially movable relative to the rigidizing first elongate member. The first elongate member may also be referred to equivalently herein as a first elongate device or the rigidizing first elongate device. The second elongate member may be equivalently referred to as the second elongate device or steerable second elongate member/device.

[0006] In general, the term “retroflexion” or “retroflexing” may refer to making a U-turn with the bending section of an endoscope (such as, but not limited to a colonoscope), so that the viewing lens at the distal end of the scope is looking backward and the insertion tube may be visible to the endoscopist. In some cases, retroflexing may refer to intraluminal retroflexing, in which the endoscope bends back on itself within the same lumen. However, the methods and apparatuses for retroflexing described herein are not limited to intraluminal retroflexing, and may be used for any procedure in which the endoscope, and particularly the distal end region of the endoscope, doubles back on itself.

[0007] The second elongate member (and in some examples both the second elongate member and the first elongate member) of the nested elongate members may be configured to be steered, by controllably bending or curving and/or straightening a distal end region of the member. In some examples, the first elongate member may also be steerable, e.g., configured to be controllably bent/curved and/or straightened at the distal end region, typically by the application of force from the proximal end. In any of these apparatuses the second elongate member may be configured to be rigidized, and may controllably be transitioned between a flexible and a rigid (e.g., less flexible) configuration. In examples in which only one of the nested elongate member has a distal end region that is configured to be steered, such as the second elongate member, the other nested elongate member may be configured to be rigidizing. In some examples both nested devices may be configured to be steerable. In examples in which both nested elongate members, e.g., the rigidizing first elongate member and the second elongate member, are configured to be controllably rigidized, the two devices can be alternately rigidized and advanced (or retracted) distally or proximally through a body lumen.

[0008] The rigidizing first elongate member may be nested over the second elongate member, so that the second elongate member may advance or retract (e.g., slide proximal/distal) relative to the first elongate member from within the first elongate member. Alternatively, in some examples the first elongate member may be nested in the second elongate member so that the second elongate member may advance or retract (e.g., slide proximal/distal) relative to the first elongate member from over the first elongate member. [0009] The second elongate member may be configured as a scope, e.g., including a camera and/or lighting on a distal end region, including, but not limited to, the distal face of the device. In some examples the second elongate member may include one or more lumen (e.g., channels) including working channels for passing one or more tools, which may include one or more cameras. The rigidizing first elongate member may also/or include one or more cameras, lights and/or working channels for passing one or more tools, which may include one or more cameras.

[0010] In general, the apparatuses described herein may include a controller, including one or more processors, that is configured to coordinate the retroflexing movement of the apparatus. Any of these apparatuses may be configured as robotic apparatuses (e.g., systems and devices) that may automatically or semi-automatically perform retroflexing. In some cases, these methods and apparatuses may perform retroflexing of a nested rigidizing apparatus upon activation of one or more controls (e.g., buttons, switches, etc.). As used herein, a processor may include hardware that runs computer program code. Specifically, the term ‘processor’ may include or may be part of a controller and may encompass not only computers having different architectures such as single/multi-processor architectures and sequential (Von Neumann)/parallel architectures but also specialized circuits such as field- programmable gate arrays (FPGA), application specific circuits (ASIC), signal processing devices and other devices. Thus, any of the apparatuses described herein may be configured to perform any of the methods described herein, including retroflexing.

[0011] For example, a method of retroflexing a nested endoscope system may include first positioning a nested system within a body region and commanding a curve on a distal end region of the second elongate member while advancing the second elongate member distally away from the rigidizing first elongate member so that a portion of the distal end region of the second elongate member that is distal to the rigidizing first elongate member bends against the rigidizing first elongate member as the second elongate member is advanced distally.

[0012] For example, described herein are methods of retroflexing a nested endoscope system, the method comprising: positioning a nested system within a body region, wherein the nested system comprises a rigidizing first elongate member that is configured to transition between a flexible configuration and a rigid configuration, and a second elongate member nested with the rigidizing first elongate member and axially movable relative to the rigidizing first elongate member; and commanding a curve on a distal end region of the second elongate member while advancing the second elongate member distally away from the rigidizing first elongate member so that a portion of the distal end region of the second elongate member that is distal to the rigidizing first elongate member bends against the rigidizing first elongate member as the second elongate member is advanced distally.

[0013] Positioning may include advancing the nested apparatus to a target location so that the distal end region of the rigidizing first elongate member (e.g., device) is positioned at the target location where the second elongate member will retroflex. Once in position, the rigidizing first elongate member may be rigidized. For example, in any of these methods, positioning may include moving the rigidizing first elongate member to a target location within the body region in the flexible configuration and transitioning the rigidizing first elongate member to the rigid configuration when a distal end of the rigidizing first elongate member is at the target location.

[0014] In general, the method may include determining the local anatomy of the body region, such as determining the diameter of the body region, e.g., at or near the target region. In some examples, the diameter of the body region may be used to determine if the apparatus may be retroflexed before beginning the method. In some cases, the method or apparatus may be configured to determine the relative position of the distal end or the apparatus, and in particular the position of the distal end of the rigidizing first elongate member relative to the wall(s) of the body lumen. This relative position may be used to orient or help position the distal end region of the rigidizing first elongate member. In some cases, positioning may include positioning the distal end (or distal end region) of the rigidizing first elongate member near or against a wall of the body region near or at the target. Positioning may also include rotating the apparatus (e.g., either the rigidizing first elongate member and/or the second elongate member), so that working channel is adjacent to the wall either before or after performing the retroflexing.

[0015] Thus, any of these methods may include estimating the position of the distal end region of the rigidizing first elongate member and/or second elongate member relative to the wall(s) of the body region and/or orientating the rigidizing first elongate member and/or the second elongate member, relative to the wall(s). In some cases, the method may include orienting the second elongate member so that a working channel of the apparatus (e.g., in the second elongate member and/or in or on the rigidizing first elongate member) is positioned near the wall(s) of the body region. For example, the rigidizing first elongate member and/or the second elongate member adjacent to the wall(s). In some cases, the camera or imaging portion of the apparatus may be positioned opposite to the wall. [0016] Thus, any of these methods may confirm the diameter (e.g., inner diameter) of the body region prior to commanding the curve. Any of these methods and apparatuses may include using images from the camera or imaging portion of the apparatus to determine the relative position of the wall, the relative diameter of the target region of the body, the relative distance between the distal end of the apparatus (e.g., the distal end of the second elongate member) and the wall, etc. In some examples the method and apparatus may confirm that the is sufficient room for apparatus to automatically retroflex at the target region of the body lumen (e.g., where the distal tip is positioned). For example, the apparatus may include software, hardware and/or firmware for determining, based on imaging data from the camera of the second elongate member, the relative position and/or orientation of the second elongate member relative to the wall of the body lumen, and/or the relative diameter of the body lumen at the targe region, etc. In some case the apparatus may use a trained pattern matching agent (e.g., a trained neural network) to determine the relative dimensions of the target region, or to determine if the target region is sufficiently large to allow retroflexing as described herein. The trained pattern matching agent may an artificial intelligence agent, including a machine learning agent. The machine learning agent may be a deep learning agent. In some examples, the trained pattern matching agent may be trained neural network. Any appropriate type of neural network may be used, including generative neural networks. The neural network may be one or more of: perceptron, feed forward neural network, multilayer perceptron, convolutional neural network, radial basis functional neural network, recurrent neural network, long short-term memory (LSTM), sequence to sequence model, modular neural network, etc. In some examples a trained pattern matching agent may be trained using a training data set including images taken with the same or similar camera and/or second elongate member in which the dimensions of the body region are known or estimated.

[0017] Positioning may include orienting the apparatus, and particularly the second elongate member, so that it will curve/bend towards the portion of the body region that has the largest distance from the distal end of the rigidizing first elongate member.

[0018] Any of these methods and apparatuses may include receiving a user command to retroflex and automatically rigidizing and commanding the curve on the distal end of the second elongate member. As mentioned, the apparatus may be configured to either orient the second elongate member so that the retroflexing is performed in the direction of a region of maximum (or sufficient) diameter of the target body region relative to the distance between the distal end of the rigidizing first elongate member (e.g., device) and the wall of the body region, or to determine which actuators (e.g., pull wires, tendons, cables, etc.) to actuate in order to direct bending/curving of the second elongate member towards the direction of the region of maximum (or sufficient) diameter of the target body region relative to the distance between the distal end of the rigidizing first elongate member. Orienting may include moving the distal end region of the rigidizing first elongate member. In some examples orienting may include rotating the second elongate member (or the rigidizing first elongate member and the second elongate member) to radially reorient the second elongate member relative to the wall of the body lumen. Thus, in general, any of these methods may include selecting a direction of bending for commanding the curve prior to commending the curve. Selecting the bending may include selecting the direction of bending based on an estimate of diameter of body region and a position of the distal end region of nested system within the body region.

[0019] As mentioned, positioning may include moving the apparatus through the body lumen until a target region is reached where it is desired or beneficial to retroflex the second elongate member (e.g., to look back proximally relative to the apparatus). The target location may be predetermined. In some examples the target location may be determined on the fly, based on local conditions. In any of these methods and apparatuses, positioning may include advancing the nested system within a lumen of the body while the rigidizing first elongate member is in the flexible configuration. For example, positioning may include moving the apparatus, and particularly the rigidizing first elongate member over a guidewire to a target location. In some examples positioning may include alternately advancing the rigidizing first elongate member and second elongate member of the nested pair.

[0020] During the retroflexing process, the rigidizing first elongate member may remain in the rigid configuration (e.g., a configuration that is more rigid than the flexible configuration, including, without limitation, l. lx or more as rigid, 1.2x or more as rigid, 1.3x or more as rigid, 1.4x or more as rigid, 1.5x or more as rigid, 1.6x or more as rigid, 1.7x or more as rigid, 1.8x or more as rigid, 1.9x or more as rigid, 2x or more as rigid, 2.5x or more as rigid, 3x or more as rigid, 3.5x or more as rigid, 4x or more as rigid, 4.5x or more as rigid, 5x or more as rigid, etc.).

[0021] Any of these methods may include stopping the advance of the second elongate member once the distal end region of the second elongate member is retroflexed relative to the rigidizing first elongate member. The apparatus may determine when the retroflexion is complete based on the imaging data (e.g., camera images), based on one or more shape sensors within the second elongate member, etc.

[0022] The rigidizing first elongate member may be configured to transition between the flexible configuration and the rigid configuration by the application of positive and/or negative pressure. In some examples the rigidizing first elongate member may be configured to transition between the flexible and the rigid states based on the application of positive pressure. For example, positive pressure may drive a compression layer (e.g., bladder, etc.) against a rigi dizing layer (e.g., in some examples comprising a plurality of lengths of filaments that slide over each other in the flexible, uncompressed, configuration but that are locked together in the compressed, rigid configuration). In some examples the rigidizing first elongate member is configured to rigidize by the application of negative pressure. In some examples, the rigidizing first elongate member is configured to rigidize by the application of both positive and negative pressure.

[0023] In general, the second elongate member may be configured as an endoscope. The endoscope may be any appropriate endoscope, including, but not limited to, a colonoscope, gastroscope, bronchoscope, colposcope, cystoscope, esophagoscope, gastroscope, laparoscope, thoracoscope, enteroscope, etc.

[0024] In general, the rigidizing first elongate member and the second elongate member may be configured to move axially relative to each other. As mentioned, the rigidizing first elongate member and the second elongate member may be nested so that the rigidizing first elongate member is outside of the second elongate member, or so that the rigidizing first elongate member is nested within the second elongate member.

[0025] The methods and apparatuses described herein may maintain a surprisingly tighter retroflexion by bending the distal end region of the second elongate member against the more rigid rigidizing first elongate member. For example, the second elongate member may be steered, e.g., by commanding a curve on a distal end region of the second elongate member, while advancing the second elongate member distally away from the rigidizing first elongate member. This may allow the second elongate member to immediately curve to a near- maximal amount as it moves distally relative to the rigidizing first elongate member. The portion of the distal end region of the second elongate member that is distal to the rigidizing first elongate member bends against the rigidizing first elongate member as the second elongate member is advanced distally. Thus, in general, advancing the second elongate member distally away from the rigidizing first elongate member may include maintaining the rigidizing first elongate member in the rigid configuration. In some examples, the second rigidizing member may be moved distally out of the rigidizing first elongate member. For example, advancing may comprise advancing the second elongate member distally out of a lumen of the rigidizing first elongate member. Alternatively, advancing may comprise advancing the second elongate member over the rigidizing first elongate member.

[0026] The methods and apparatuses described herein may reduce or prevent forces on the wall(s) of the body region during retroflexion. For example, these methods and apparatuses may maintain a shear force on a wall of the body region that is less a threshold value while commanding a curve on the distal end of the second elongate member while advancing the second elongate member distally away from the rigidizing first elongate member. The threshold for the shear force may be 60 N or less (e.g., 55 N or less, 50 N or less, 45 N or less, 40 N or less, 35 N or less, 30 N or less, 25 N or less, 20 N or less, etc.). [0027] These methods and apparatuses may be used in any appropriate body region. In some examples the body region is the gastrointestinal (GI) tract. For example, any of these methods and apparatuses may include positioning the nested system within a gastrointestinal tract.

[0028] The steerable distal end region of the second elongate member (and optionally, the rigidizing first elongate member) may be steered by any appropriate technique, including (but not limited to) pulling or pushing a rod, tendon, wire, etc. In some examples commanding the curve of the distal end region of the second elongate member comprises applying force to one or more tendons within the second elongate member.

[0029] As mentioned above, any of these methods may include reversing the retroflexing by withdrawing the distal end region of the second elongate member proximally relative to the rigidizing first elongate member so that the distal end region of the second elongate member that is proximal to a distal end of the rigidizing first elongate member straightens out as the second elongate member is retracted proximally. Reversing may include setting the tension applied to steer the distal end region of the second elongate member (e.g., the steering tension) to approximately the minimum tension (+/- x%, e.g., 1%, 2%, 5%, 7.5%, 10%, 12%, 15%, 20%, etc. or the minimum tension) to maintain the maximum curvature of the distal end region when additional force (e.g., load) is not being applied to the second elongate device. Thus, may allow the distal end region to straighten as it is drawn proximally against the rigidizing first elongate member. The apparatus may adjust the tensioning force as the device is drawn proximally. In general, any of these apparatuses may include one or more force sensors for sensing the forces applied to steer the distal end region of the second elongate member. The force applied to steer the distal end region of the second elongate member may also be monitored/regulated, e.g., when retroflexing by maximally bending and advancing the second elongate member.

[0030] For example, a method of retroflexing a nested endoscope system may include: positioning a nested system within a body region, wherein the nested system comprises a rigidizing first elongate member that is configured to transition between a flexible configuration and a rigid configuration by the application of pressure and a second elongate member nested within the rigidizing first elongate member; rigidizing the rigidizing first elongate member; and commanding a curve on a distal end region of the second elongate member while advancing the second elongate member distally out of the rigidizing first elongate member while the rigidizing first elongate member is in the rigid configuration, so that a portion of the distal end region of the second elongate member that is distal to the rigidizing first elongate member bends against the rigidizing first elongate member as the second elongate member is advanced distally. Commanding a curve of the distal end region may refer to steering, bending or curving the steerable distal end region. In some cases, commanding a curve may include maximally curving/bending the distal end region.

[0031] As mentioned, also described herein are systems for performing any of these methods. For example a system may be configured as a nested system comprising a rigidizing first elongate member that is configured to transition between a flexible configuration and a rigid configuration, and a second elongate member nested with the rigidizing first elongate member and axially movable relative to the rigidizing first elongate member; one or more processors; and a memory coupled to the one or more processors, the memory storing computer-program instructions, that, when executed by the one or more processors, perform a computer-implemented method for retroflexing the nested system, the method comprising: rigidizing the rigidizing first elongate member; and commanding a curve on a distal end region of the second elongate member while advancing the second elongate member distally away from the rigidizing first elongate member so that a portion of the distal end region of the second elongate member that is distal to the rigidizing first elongate member bends against the rigidizing first elongate member as the second elongate member is advanced distally.

[0032] In some examples the computer-implemented method may further comprise receiving a user command to retroflex prior to rigidizing and commanding the curve on the distal end of the second elongate member. Positioning may comprise advancing the nested system within a lumen of the body while the rigidizing first elongate member is in the flexible configuration. The computer-implemented method may further comprise stopping the advance of the second elongate member once the distal end region of the second elongate member is retroflexed relative to the rigidizing first elongate member. The rigidizing first elongate member may be configured to transition between the flexible configuration and the rigid configuration by the application of positive and/or negative pressure. The second elongate member may comprise an endoscope.

[0033] The first elongate member and the second elongate member may be configured to move axially relative to each other. In some cases, the first elongate member may be nested over the second elongate member. In some cases, the first elongate member may be nested within the second elongate member.

[0034] The computer-implemented method may further comprise confirming a diameter of the body region prior to commanding the cure. For example, the one or more processors may be configured (e.g., using a trained machine learning agent, using one or more sensors, etc.) to determine a dimension, such as diameter, of the body region and/or the relative position of the distal end of the first and/or second elongate members relative to the wall(s) of the body region.

[0035] In some examples the computer-implemented method further comprises selecting a direction of bending for commanding the curve prior to commending the curve. Selecting the bending may comprise selecting the direction of bending based on an estimate of diameter of body region and a position of the distal end region of nested system within the body region. Advancing the second elongate member distally away from the rigi dizing first elongate member may comprise maintaining the rigidizing first elongate member in the rigid configuration. In some cases, advancing comprises advancing the second elongate member distally out of a lumen of the rigidizing first elongate member. The second elongate member may comprise a rigidizing device that is configured to transition between a flexible configuration and a rigid configuration.

[0036] The computer-implemented method may further comprise maintaining a shear force on a wall of the body region that is less a threshold value while commanding a curve on the distal end of the second elongate member while advancing the second elongate member distally away from the rigidizing first elongate member. Commanding the curve may comprise applying force to one or more tendons within the second elongate member.

[0037] For example, a system may include: a nested system comprising a rigidizing first elongate member that is configured to transition between a flexible configuration and a rigid configuration, and a second elongate member nested within the rigidizing first elongate member and configured to be axially movable relative to the rigidizing first elongate member; one or more processors; and a memory coupled to the one or more processors, the memory storing computer-program instructions, that, when executed by the one or more processors, perform a computer-implemented method for retroflexing the nested system, the method comprising: rigidizing the rigidizing first elongate member; and commanding a curve on a distal end region of the second elongate member while advancing the second elongate member distally out of the rigidizing first elongate member while the rigidizing first elongate member is in the rigid configuration, so that a portion of the distal end region of the second elongate member that is distal to the rigidizing first elongate member bends against the rigidizing first elongate member as the second elongate member is advanced distally.

[0038] In the absence of constraints, retroflexing an endoscope within a body lumen, such as a colon, may apply force against the walls of the body lumen, including shear force and radial force, that may be harmful to the anatomy. There is a need for methods and apparatuses (e.g., device, and systems) that can provide safe and smooth retroflexing.

[0039] In any of these examples, the apparatus may be de-retroflexed (or configured to de-retroflex), by reversing the process described above, e.g., withdrawing the steerable second elongate device proximally back into the rigidizing first elongate device, with the first elongate device in the rigid (e.g., less flexible) configuration. In some cases, the tension on steering member (e.g., tendon, wire, etc.) of the second elongate device may be reduced to a minimum tension at which the distal end region maintains its maximum curvature. In some the tension on the steering (steering tension) may be reduced to approximately the minimum tension (+/- x%, e.g., 1%, 2%, 5%, 7.5%, 10%, 12%, 15%, 20%, etc. or the minimum tension) to maintain the maximum curvature when additional force (e.g., load) is not being applied to the second elongate device.

[0040] As mentioned, the apparatuses described herein may include a controller. A controller may include control circuitry, e.g., one or more processors (microprocessors), memory, timers, registers, etc.) and control logic, which may be software, hardware and/or firmware. These controllers may equivalently be referred to herein as “control circuitry.” Controllers may be implemented in software, firmware, hardware, or some suitable combination of at least two of the three.

[0041] In some examples the system may be configured to automatically perform the method. For example, the system may comprise a controller and a controller comprising one or more processors; and a memory coupled to the one or more processors, the memory storing computer-program instructions, that, when executed by the one or more processors, perform a computer-implemented method to retroflex and/or de-retroflex the device within a body lumen.

[0042] The methods an apparatuses described herein may be related to and may be used with any of the methods and apparatuses described in International patent application no. PCT/US2023/064999, titled “METHODS AND APPARATUSES FOR NAVIGATING USING A PAIR OF RIGIDIZING DEVICES,” filed on March 27, 2023, which claims priority to U.S. provisional patent application no. 63/324,011, titled “METHODS AND APPARATUSES FOR NAVIGATING USING A PAIR OF RIGIDIZING DEVICES,” filed on March 25, 2022, each of which is herein incorporated by reference in its entirety. [0043] All of the methods and apparatuses described herein, in any combination, are herein contemplated and can be used to achieve the benefits as described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The novel features of the invention are set forth with particularity in the claims that follow. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:

[0045] FIG. 1 shows an example of a rigidizing device.

[0046] FIGS. 2A-2B show exemplary rigidized shapes of a rigidizing device.

[0047] FIGS. 3A-3B show an example of a portion of a vacuum rigidizing apparatus as described herein. FIG 3 A shows a section through the exemplary vacuum rigidizing member of the apparatus. FIG. 3B shows an enlarged view of a portion of the section, illustrating the arrangement of layers in the un-rigidized configuration.

[0048] FIGS. 3C- 3F show an example of a portion of a vacuum rigidizing apparatus having multiple rigidizing layers as described herein. FIG. 3C shows a perspective view of the vacuum rigidizing member with the outer layer removed (showing the outermost braid layer). FIG. 3D is an enlarged view of a portion of FIG. 3C. FIG. 3E shows a longitudinal section though the vacuum rigidizing member of FIG. 3C. FIG. 3F is a cross-section through the rigidizing member of FIG. 3C.

[0049] FIGS. 4A-4B show an exemplary pressure rigidizing device.

[0050] FIG. 5 shows a rigidizing device with a distal end section.

[0051] FIG. 6A shows a rigidizing device with a distal end section having a plurality of actively controlled linkages.

[0052] FIG. 6B shows a nested rigidizing system.

[0053] FIGS. 7A-7N illustrate one example of a system including a nested first elongate and rigidizing member and a second elongate and rigidizing member. FIGS. 7A-7E illustrate one example of a rigidizing shield that may form a second elongate member. FIGS. 7F-7H show the rigidizing shield of FIGS. 7A-7E coupled with an endoscope to form the second elongate and rigidizing member. FIGS. 7I-7M illustrate an example of a first elongate member (configured as a rigidizing overtube). FIG. 7N shows an example of a system including a first elongate member and a second elongate member.

[0054] FIGS. 8A-8H show exemplary use of a nested rigidizing system. [0055] FIGS. 9A-9B illustrate a manual method of retroflexing an endoscope (e.g., colonoscope). FIG. 9A shows the relative movement between the distal end region of the endoscope and the body region (e.g., colon). FIG. 9B schematically illustrates the forces acting on the colon wall during the procedure illustrated in FIG. 9A.

[0056] FIGS. 10A-10E illustrate the relative movements of sub-regions (e.g., segments) of a distal end region of an endoscope during typical manual retroflexing. FIGS. 10A-10C illustrate the distances between adjacent segments during steering (e.g., bending) of the distal end region. FIG. 10E shows the distal end region fully retroflexed.

[0057] FIGS. HA and 11B illustrate a nested, e.g., robotic, retroflexing an endoscope (e.g., a second elongate member configured as an endoscope). FIG. 11A shows the relative movement of the distal end region of the second elongate member, a rigidized first elongate member in a rigid configuration, and the body region (e.g., colon). FIG. 11B schematically illustrates the forces acting on the colon wall during the procedure illustrated in FIG. 11 A. [0058] FIGS. 12A-12D illustrate the method of robotic retroflexing of a nested endoscope. FIG. 12A shows the apparatus positioned at a target region within the body (e.g., colon) lumen. FIG. 12B shows the first rigi dizing elongate member in a rigid configuration while the second elongate member (e.g., colonoscope) is extended distally while maximally bending/curving the distal end region of the second elongate member and advancing the second elongate member. FIG. 12C shows the second elongate member further distally extended relative to the rigidizing first elongate member, in which the second elongate member is partially retroflexed. FIGS. 12D shows the second elongate member fully retroflexed within the body.

[0059] FIGS. 13A-13D schematically illustrate the relative movements of sub-regions (e.g., segments) of a distal end region of a second elongate member (e.g., endoscope) during a retroflexing of the second elongate member that is nested with a rigidized first elongate member. FIGS. 13A-13C illustrate the distances between adjacent segments during steering (e.g., bending) of the distal end region. FIG. 13D shows the distal end region fully retroflexed.

[0060] FIG. 14 is a graph showing an example of the different tip positions and orientations of an endoscope during typical manual retroflexing and during the nested retroflexing apparatus and method described herein.

[0061] FIGS. 15A-15B illustrate examples of sweep radius using a traditional retroflexing maneuver (FIG. 15 A) and a nested retroflexing maneuver (FIG. 15B).

[0062] FIGS. 16A-16D illustrate an example of a robotic nested retroflexing maneuver as described herein. [0063] FIGS. 17A-17B schematically illustrate a comparison between some of the relative forces acting on the endoscope in a traditional retroflexing maneuver (FIG. 17A) and a nested retroflexing maneuver (FIG. 17B).

[0064] FIGS. 18A-18D are graphs showing the load on a body wall model (e.g., in shear) during various examples of retroflexing as described herein. FIGS. 18A-18C show examples of shear forces on the lumen wall during robotically-assisted retroflexing while FIG. 18D shows shear force on the lumen wall using a traditional retroflexing maneuver.

[0065] FIGS. 19A-19D are graphs showing the load on a body wall model (e.g., in shear) during various examples of reversing retroflexing as described herein. FIGS. 19A-19C show examples of shear forces arising on the lumen wall during robotically-assisted reversal of retroflexing while FIG. 19D shows shear force on the lumen using a traditional reversal of retroflexing maneuver.

DETAILED DESCRIPTION

[0066] In general, described herein are methods and apparatuses for automatic or semiautomatic control of nested elongate members within a body lumen for retroflexing. These apparatuses generally consist of a first elongate member, which may be referred to as a rigidizing first elongate member, that is capable of transitioning between a flexible and a rigid configuration. The apparatus also includes a second elongate member, referred to as the steerable second elongate member (or second elongate device), that is nested within the rigidizing first elongate member and that is axially movable relative to the rigidizing first elongate member.

[0067] The second elongate member, and in some instances both the second and the first elongate members, can be steered by bending or curving the distal end region of the member. The first elongate member may also be steerable, allowing controlled bending or curving at its distal end region, typically through force applied from the proximal end. The second elongate member may also be configured for controllable rigidization, transitioning between flexible and rigid states. The rigid state(s) are typically more rigid than the flexible state. In cases where only one of the nested elongate members is steerable, the other may be configured for rigidization. Alternatively, both nested devices can be steerable, or both may be configured for controllable rigidization.

[0068] In any of these methods and apparatuses, the second or first rigidizing member may be or may include a rigidizing shield or sheath. For example, the second elongate member may comprise an endoscope that is itself rigidizing, or may be an endoscope within a rigidizing shield. The endoscope may be reusable and the rigidizing shield may be removable/replaceable. In some cases, the rigidizing shield may be configured to couple to at least the end of the endoscope and may be rigidizing while the endoscope may be steerable. Once the endoscope is engaged with the rigidizing shield, it may be referred to as a rigidizing member (e.g., the second elongate member) and may be inserted into the first rigidizing member to form a nested system as described herein.

[0069] These methods and apparatuses may maintain a tight retroflexion by bending the distal end region of the second elongate member against the more rigid rigidizing first elongate member. Thus, these methods and apparatuses may be much more safely operated, particularly automatically, and may require substantially less space within the body (e.g., a lumen of a GI tract, etc.) in order to retroflex and/or de-retroflex than conventional endoscopes, including manual or robotic endoscopes. Furthermore, these apparatuses and methods may allow retroflexing in a way that exerts minimal (or no) forces on the body lumen walls, including shear forces. In contrast, conventional retroflexing using a steerable endoscope typically requires using the wall of the body lumen to provide force against the distal end region of the endoscope in order to assist in performing the retroflexion within the body. Retroflexing within a body lumen, like the colon, can exert forces on the lumen walls, making it essential to have safe and smooth retroflexing methods and apparatuses.

[0070] As used herein, a rigidizing apparatus (or rigidizing device) refers to a device capable of modulating its stiffness and/or flexibility. In general, these rigidizing devices may be intentionally placed within a body, and are designed to be transitionable between at least a first more flexible (e.g., less stiff) state and a second state that is less flexible (e.g., stiffer) than the first state.

[0071] The rigidizing first elongate member may be either nested over the second elongate member, allowing it to advance or retract relative to the first elongate member, or nested within the second elongate member, enabling the second elongate member to advance or retract relative to the first elongate member. The second elongate member may function as a scope (e.g., an endoscope), featuring a camera and/or lighting on its distal end region. It may also include one or more lumens for tools, such as cameras or other instruments. Similarly, the rigidizing first elongate member may include cameras, lights, and/or working channels.

[0072] These apparatuses may incorporate a controller, including one or more processors, to coordinate retroflexing movements. They can be configured as robotic systems capable of automatic or semi-automatic retroflexing upon user activation. The controller(s) may coordinate the movement of the first and second elongate members in order to perform the retroflexing movement(s), either or both retroflexing the apparatus and de-retroflexing. De- retroflexing may refer to moving the second elongate member from fully or partially retroflexed configuration to a configuration in which the second elongate member is extending in approximately the same direction as the rigi dizing first elongate member. For example, a retroflexing method for a nested endoscope system may include positioning the system within a body region, commanding a curve on the distal end region of the second elongate member, and advancing the second elongate member distally away from the rigidizing first elongate member, causing a portion of the distal end region to bend against the rigidizing first elongate member. This may be continued until the second elongate member is parallel to the rigidizing first elongate member, facing the opposite direction.

[0073] Thus, described herein are methods for retroflexing a nested endoscope system that may include positioning the nested system within a body region, comprising a rigidizing first elongate member transitioning between flexible and rigid states and a second elongate member nested within it. A curve is commanded on the distal end region of the second elongate member while advancing it distally, causing bending against the rigidizing first elongate member. Positioning may involve moving the rigidizing first elongate member to a target location within the body region in a flexible configuration and transitioning to the rigid configuration when the distal end reaches the target location.

[0074] Any of these methods may include determining the local anatomy of the body region, confirming the diameter, and positioning the distal end of the rigidizing first elongate member near or against a wall of the body region. These methods may include orienting the second elongate member so that a working channel is positioned near the wall, with the camera or imaging portion opposite to the wall. In some cases, these methods may include estimating the position of the distal end regions relative to the wall and orienting the elongate members accordingly. A trained pattern matching agent, such as a neural network, may be used for image analysis.

[0075] Positioning may include orienting the apparatus so that it curves toward the region with the largest distance from the distal end of the rigidizing first elongate member. In some cases, the methods may include receiving a user command to retroflex and automatically rigidizing and commanding the curve on the second elongate member. The apparatus may orient the second elongate member toward the region of maximum diameter.

[0076] In general, the apparatus may be moved through the body lumen, alternately advancing the rigidizing first elongate member and the second elongate member.

[0077] During retroflexing, the rigidizing first elongate member may remain rigid, and the second elongate member may be advanced out of the rigidizing first elongate member. The methods may include stopping the advance of the second elongate member once retroflexion is complete, which may be determined by imaging data or shape sensors. Shape sensing may be performed using an optical (e.g., fiber optic) shape sensor, and/or using an electromagnetic shape sensor.

[0078] In general, the apparatus may be rigidized by the application of positive and/or negative pressure. For example, the rigi dizing first elongate member may transition between flexible and rigid states through positive and/or negative pressure.

[0079] The methods and apparatuses described herein are applicable to various body regions, including the gastrointestinal (GI) tract. In general, the second elongate member (and optionally the rigidizing first elongate member) may be steered by the use of one or more (e.g., two or more, three or more, four or more, etc.) tendons (e.g., wires, flexible rods, cables, etc.). For example, the distal end region of the second elongate member may be steered by applying force to tendons within the second elongate member.

[0080] A retroflexing method may include rigidizing the rigidizing first elongate member and commanding a curve on the distal end region of the second elongate member while advancing it distally. As will be described below, in general, the retroflexing process can be reversed by withdrawing the second elongate member proximally into the rigidizing first elongate member, adjusting tension as needed. Systems for retroflexing may comprise a nested system, processors, and memory storing computer-program instructions for executing retroflexing methods. De-retroflexion can be achieved by reversing the retroflexing process, withdrawing the second elongate device while maintaining tension for optimal curvature. [0081] The rigidizing first elongate member, and optionally the second elongate member, of the nested pair of elongate members (elongate devices) may be rigidizing devices that may be controllably converted from a more flexible configuration to one or more less flexible configurations, e.g., a stiffer, more rigidi configuration. In general, the rigidizing members (rigidizing devices) described herein, including the rigidizing first elongate member, can be long, thin, and hollow (having one or more lumen extending therethrough) and can transition quickly from a flexible configuration (i.e., one that is relaxed, limp, or floppy) to one or more rigid configurations (i.e., one that is stiff and/or holds the shape it is in when it is rigidized). The rigidizing apparatus may include a plurality of layers (e.g., coiled or reinforced layers, slip layers, rigidizing layers, bladder layers and/or sealing sheaths) can together form the wall of the rigidizing devices, which may be referred to as “layered rigidizing apparatuses.” Unless the context makes clear otherwise, the methods and apparatuses described herein may refer to any appropriate rigidizing device, including layered rigidizing apparatuses. For example, the rigidizing devices (members, apparatuses, etc.) described herein may be rigidized by jamming particles, by phase change, by interlocking components (e.g., cables with discs or cones, etc.) or any other rigidizing mechanism. The rigidizing devices can transition from the flexible configuration to the rigid configuration, for example, by applying a vacuum or pressure to the wall of the rigidizing device or within the wall of the rigidizing device. With the vacuum or pressure removed, the layers can easily shear or move relative to each other. With the vacuum or pressure applied, the layers can transition to a condition in which they exhibit substantially enhanced ability to resist shear, movement, bending, torque and buckling, thereby providing system rigidization. Any of the apparatuses described herein may be configured for use in one or more of: the neurovasculature (e.g., aortic arch, subclavian, carotid, vertebral, basilar, posterior cerebral, circle of Willis, middle cerebral, anterior cerebral, etc.), the upper GI tract (mouth esophagus, stomach, pylorus, bile duct and pancreatic duct, etc.), the small bowel (e.g., small intestine, duodenumjejunum, ilium, etc.), the lower GI tract (rectum, regions of colon, e.g., sigmoid, descending, transverse, ascending, cecum, ileocecal valve, etc.), the urinary tract (urethra, bladder, kidneys, ureters, etc.), the peripheral vasculature (e.g., femoral, iliac, mesenteric, lumbar, renal, celiac trunk, hepatic, thoracic, etc.), the cardiac region (e.g., aorta, right coronary artery, left coronary artery, etc.), the left heart (e.g., aorta, aortic valve, left ventricle, etc.), the right heart (e.g., vena cava, right atrium, left atrium, mitral valve, coronary sinus, tricuspid valve, right ventricle, pulmonary valve, pulmonary vasculature, etc.) and/or the right pulmonary region (e.g., mouth, larynx, trachea, bronchial tree and lobes etc.).

[0082] Any of the rigidizable apparatuses described herein may include rigidizing layers or regions that engage with a compression layer (which may be or may include a bladder) that applies force to the rigidizing layer to rigidize the rigidizing layer or in some cases to de- rigidize (e.g., release from rigidization) the rigidizing layer. In some examples, these rigidizable apparatuses may include a rigidizing layer that could include a braid, knit, woven, chopped segments, randomly distributed or randomly oriented filaments or strands, engagers, links, scales, plates, segments, particles, granules, crossing filaments, or combinations of these (e.g., crossing filaments and longitudinal lengths of filaments or wires), forming the rigidizing layer. For example, the rigidizing layer may comprise multiple strand lengths or strand segments that cross over each other (e.g., as part of a braid, knit, woven, etc.); the compression layer may apply force to drive the crossing strand lengths or strand segments against each other. Although many of the examples shown herein are braids, any of these apparatuses may instead or in addition include a general rigidizing layer comprising crossing strand lengths or strand segments. [0083] The rigidizing apparatuses described herein may use pressure (positive pressure) and/or negative pressure to selectively and controllable rigidize. In some examples the method described herein may be used with any appropriate rigidizing apparatus.

[0084] Examples of devices configured to rigidize is shown in FIGS. 1-9, illustrating features that may be included with any of the rigidizing devices described herein. The example shown in FIG. 1 includes a rigidizing device 300 having a wall with a plurality of layers including a rigidizing layer, an outer layer (part of which is cut away in this example to show the rigidizing layer thereunder, configured as a braid layer in this example), and an inner layer. The system further includes a handle 342 having a vacuum or pressure inlet 344 to supply vacuum or pressure to the rigidizing device 300. An actuation element 346 can be used to turn the vacuum or pressure on and off to thereby transition the rigidizing device 300 between flexible and rigid configurations. The distal tip 339 of the rigidizing device 300 can be smooth, flexible, and atraumatic to facilitate distal movement of the rigidizing device 300 through the body. Further, the tip 339 can taper from the distal end to the proximal end to further facilitate distal movement of the rigidizing device 300 through the body. In this example, the rigidizing apparatus is configured as an overtube, but other configurations may be used.

[0085] Exemplary rigidizing devices in a rigidized configuration are shown in FIGS. 2 A and 2B. As the rigidizing device is rigidized, it locks into the shape it was in before vacuum or pressure was applied, i.e., it does not straighten, bend, or otherwise substantially modify its shape (e.g., it may stiffen in a looped configuration as shown in FIG. 2A or in a serpentine shape as shown in FIG. 2B). The air stiffening effect on the inner or outer layers (e.g., made of coil-wound tube) can be a small percentage (e.g., 5%) of the maximum load capability of the rigidizing device in bending, thereby allowing the rigidizing device to resist straightening. Upon release of the vacuum or pressure, strands within the rigidizing layer of the device can unlock relative to one another and again move so as to allow bending of the rigidizing device. Again, as the rigidizing device is made more flexible through the release of vacuum or pressure, it does so in the shape it was in before the vacuum or pressure was released, i.e., it does not straighten, bend, or otherwise substantially modify its shape. Thus, the rigidizing devices described herein can transition from a flexible, less-stiff configuration to a rigid configuration of higher stiffness by restricting the motion between the overlapping strands of rigidizing layers (e.g., braid layer), by applying vacuum or pressure.

[0086] The rigidizing apparatuses described herein can toggle between a rigid configuration and a flexible configuration quickly, and in some examples with an indefinite number of transition cycles. In some examples the degree of rigidization (e.g., the stiffness) of the apparatus may also be adjusted, for example, by adjusting the positive pressure (in examples that are rigidized by positive pressure) or vacuum (in examples rigidized by vacuum). As interventional medical devices are made longer and inserted deeper into the human body, and as they are expected to do more exacting therapeutic procedures, there is an increased need for precision and control. Selectively rigidizing devices (including selectively rigidizing overtubes) as described herein can advantageously provide both the benefits of flexibility (when needed) and the benefits of stiffness (when needed). Further, the rigidizing devices described herein can be used, for example, with classic endoscopes, colonoscopes, robotic systems, and/or navigation systems, such as those described in U.S. Patent Application No. 17/644,758, filed December 16, 2021, titled “DEVICE FOR ENDOSCOPIC ADVANCEMENT THROUGH THE SMALL INTESTINE,” the entirety of which is incorporated by referenced herein.

[0087] The rigidizing devices described herein can additionally or alternatively include any of the features described with respect to U.S. Patent Application No. 17/644,758, filed December 16, 2021, titled “DEVICE FOR ENDOSCOPIC ADVANCEMENT THROUGH THE SMALL INTESTINE,” U.S. Patent Application No. 16/631,473, filed on July 19, 2018, titled “DYNAMICALLY RIGIDIZING OVERTUBE,” U.S. Patent Application No. 17/604,203, filed on January 16, 2020, titled “DYNAMICALLY RIGIDIZING COMPOSITE MEDICAL STRUCTURES,” U.S. Patent Application No. 17/902,770, filed on September 2, 2022, titled “NESTED RIGIDIZING DEVICES,” U.S. Patent Application No. 17/995,294, filed March 29, 2021, titled “LAYERED WALLS FOR RIGIDIZING DEVICES,” and U.S. Patent Application No. 18/044,027, filed September 3, 2021, titled “DYNAMICALLY RIGIDIZING GUIDERAIL AND METHODS OF USE,” the entireties of which are incorporated by reference herein.

[0088] The rigidizing devices described herein can be provided in multiple configurations, including different lengths and diameters. In some examples, the rigidizing devices can include working channels (for instance, for allowing the passage of typical endoscopic tools within the body of the rigidizing device), balloons, nested elements, and/or side-loading features.

[0089] For example, a rigidizing apparatus 100 (also referred to as an apparatus, e.g., system and/or device, including a rigidizable member) may be configured to be rigidized by the application of vacuum, e.g., negative pressure. These apparatuses may generally be formed of layers that are configured to form a laminates structure when negative pressure is applied, so that one or more rigidizing layers may be reversibly fused to a flexible outer layer that is driven against a more rigid inner layer. FIGS. 3A-3B illustrate one example of a section through a rigidizing member of an apparatus (e.g., device, system) that is rigidized by the application of vacuum. FIG. 3B shows an enlarged view of the arrangement of the layers of FIG. 3 A in the un-rigidized configuration. In this example, the rigidizable member includes an innermost layer 115 that is configured to provide an inner surface against which the remaining layers can be consolidated (e.g., when vacuum is applied). The innermost layer 115 can include a reinforcement element or coil. The rigidizing member may also include a slip layer 113 over (e.g., radially outwards of) the innermost layer. The slip layer may be, e.g., a lubrication, coating and/or powder (e.g., talcum powder) on the outer surface of the inner layer 115 and/or within the gap layer 111. A radial gap layer 111 may separate the slip layer 113 from a rigidizing layer (shown in this example as a braid or woven layer) 109 (referred to herein for convenience as a “rigidizing layer”), providing a space between the rigidizing layer and the slip layer for the rigidizing layer(s) thereover to move within, e.g., when no vacuum is applied; this space or gap may be removed when vacuum is applied, allowing the rigidizing layer(s) (e.g., in some examples a braided or woven layer) to move radially inward upon application of vacuum. A second gap layer 107 may be present between the rigidizing layer 109 and may be similar to layer 111. As will be described in reference to FIGS. 3C-3F, multiple rigidizing layers may be included (e.g., 2, 3 4 or more rigidizing layers may be included) and may be separated by additional gap layers and/or slip layers. The outermost layer 101 can be separated from the rigidizing layer(s) by a gap layer and can be configured to move radially inward when a vacuum is applied to pull down against the rigidizing layer(s) and conform onto the surface(s) thereof. The outermost layer 101 can be soft and atraumatic and can be sealed at both ends to create a vacuum-tight chamber with the innermost layer 115. The outermost layer 101 can be elastomeric, e.g., made of urethane. The hardness of the outermost layer 101 can be, for example, 30Ato 80A. Further, the outermost layer 101 can have a thickness of 0.0001-0.01”, such as approximately 0.001”, 0.002, 0.003” or 0.004”. Alternatively, the outermost layer can be plastic, including, for example, LDPE, nylon, or PEEK.

[0090] FIGS. 3C- 3F illustrate an example of a tubular rigidizing member of an apparatus 100 that includes multiple rigidizing layers. As in FIGS. 3A-3B, the apparatus includes a tube having a wall formed of a plurality of layers positioned around a lumen 120 (e.g., for placement of an instrument or endoscope therethrough). A vacuum can be supplied between the layers to rigidize the rigidizing device 100. Any of the tubular apparatuses described herein may instead include a solid core forming the inner layer 115.

[0091] The innermost layer 115 can be configured to provide an inner surface against which the remaining layers can be consolidated, for example, when a vacuum is applied within the walls of the rigi dizing device 100. The structure can be configured to minimize bend force and/or maximize flexibility in the non-vacuum condition. In some examples, the innermost layer 115 can include a reinforcement element 150z or coil within a matrix, as described above. In the example shown in FIG. 3E, the layer 113 over (i.e., radially outwards of) the innermost layer 115 can be a slip layer. The layer 111 can be a radial gap (i.e., a space). The gap layer 111 can provide space for the rigidizing layer(s) thereover to move within (when no vacuum is applied) as well as space within which the rigidizing layer(s) can move radially inward (upon application of vacuum).

[0092] The layer 109 can be a first rigidizing layer including, in this example, braided strands 133 similar to as described elsewhere herein. The rigidizing layer can be, for example, 0.001” to 0.040” thick. For example, a rigidizing layer can be 0.001”, 0.003”, 0.005”, 0.010”, 0.015”, 0.020”, 0.025” or 0.030” thick. In some examples, as shown in FIG. 3D, the rigidizing layer may comprise a braid having a tensile or hoop fibers 137. Hoop fibers 137 can be spiraled and/or woven into the rigidizing layer. Further, the hoop fibers 137 can be positioned at 2-50, e.g., 20-40 hoops per inch. The hoop fibers 137 can advantageously deliver high compression stiffness (to resist buckling or bowing out) in the radial direction but can remain compliant in the direction of the longitudinal axis 135 of the rigidizing device 100. That is, if compression is applied to the rigidizing device 100, the rigidizing layer 109 will try to expand in diameter as it compresses. The hoop fibers 137 can resist this diametrical expansion and thus resist compression. Accordingly, the hoop fiber 137 can provide a system that is flexible in bending but still resists both tension and compression.

[0093] The layer 107 can be another radial gap layer similar to layer 111.

[0094] In some examples, the rigidizing devices described herein can have more than one rigidizing layer. For example, the rigidizing devices can include two, three, or four rigidizing layers. Referring to FIG. 3E, the layer 105 can be a second rigidizing layer 105. The second rigidizing layer 105 can have any of the characteristics described with respect to the first rigidizing layer 109. In some examples, the second rigidizing layer 105 can be identical to the first rigidizing layer 109. In other examples, the second rigidizing layer 105 can be different than the of the first rigidizing layer 109. For example, in some examples the rigidizing layer is a braided layer; in FIG. 3E, the braid of the second braid layer 105 can include fewer strands and have a larger braid angle a than the braid of the first braid layer 109. Having fewer strands can help increase the flexibility of the rigidizing device 100 (relative to having a second strand with equivalent or greater number of strands), and a larger braid angle a can help constrict the diameter of the of the first braid layer 109 (for instance, if the first braid layer is compressed) while increasing/maintaining the flexibility of the rigidizing device 100. As another example, the braid of the second braid layer 105 can include more strands and have a larger braid angle a than the braid of the first braid layer 109. Having more strands can result in a relatively tough and smooth layer while having a larger braid angle a can help constrict the diameter of the first braid layer 109.

[0095] The layer 103 can be another radial gap layer similar to layer 111. The gap layer 103 can have a thickness of 0.0002-0.04”, such as approximately 0.03”. A thickness within this range can ensure that the strands 133 of the rigidizing layer(s) can easily slip and/or bulge relative to one another to ensure flexibility during bending of the rigidizing device 100. [0096] The outermost layer 101 can be configured to move radially inward when a vacuum is applied to pull down against the rigidizing layers 105, 109 and conform onto the surface(s) thereof. The outermost layer 101 can be soft and atraumatic and can be sealed at both ends to create a vacuum -tight chamber with layer 115. The outermost layer 101 can be elastomeric, e.g., made of urethane. The hardness of the outermost layer 101 can be, for example, 30Ato 80A. Further, the outermost layer 101 can have a thickness of 0.0001-0.01”, such as approximately 0.001”, 0.002, 0.003” or 0.004”. Alternatively, the outermost layer can be plastic, including, for example, LDPE, nylon, or PEEK.

[0097] In some examples, the outermost layer 101 can, for example, have tensile or hoop fibers 137 extending therethrough. The hoop fibers 137 can be made, for example, of aramids (e.g., Technora, nylon, Kevlar), Vectran, Dyneema, carbon fiber, fiber glass or plastic. Further, the hoop fibers 137 can be positioned at 2-50, e.g., 20-40 hoops per inch. In some examples, the hoop fibers 137 can be laminated within an elastomeric sheath. The hoop fibers can advantageously deliver higher stiffness in one direction compared to another (e.g., can be very stiff in the hoop direction, but very compliant in the direction of the longitudinal axis of the rigidizing device). Additionally, the hoop fibers can advantageously provide low hoop stiffness until the fibers are placed under a tensile load, at which point the hoop fibers can suddenly exhibit high hoop stiffness.

[0098] In some examples, the outermost layer 101 can include a lubrication, coating and/or powder (e.g., talcum powder) on the outer surface thereof to improve sliding of the rigidizing device through the anatomy. The coating can be hydrophilic (e.g., a Hydromer® coating or a Surmodics® coating) or hydrophobic (e.g., a fluoropolymer). The coating can be applied, for example, by dipping, painting, or spraying the coating thereon.

[0099] The innermost layer 115 can similarly include a lubrication, coating (e.g., hydrophilic or hydrophobic coating), and/or powder (e.g., talcum powder) on the inner surface thereof configured to allow the bordering layers to more easily shear relative to each other, particularly when no vacuum is applied to the rigi dizing device 100, to maximize flexibility.

[0100] In some examples, the outermost layer 101 can be loose over the radially inward layers. For instance, the inside diameter of layer 101 (assuming it constitutes a tube) may have a diametrical gap of 0”-0.200” with the next layer radially inwards (e.g., with a rigidizing layer). This may give the vacuum rigidized system more flexibility when not under vacuum while still preserving a high rigidization multiple. In other examples, the outermost layer 101 may be stretched some over the next layer radially inwards (e.g., the rigidizing layer). For instance, the zero-strain diameter of a tube constituting layer 101 may be from 0- 0.200” smaller in diameter than the next layer radially inwards and then stretched thereover. When not under vacuum, this system may have less flexibility than one wherein the outer layer 101 is looser. However, it may also have a smoother outer appearance and be less likely to tear during use.

[0101] In some examples, the outermost layer 101 can be loose over the radially inward layers. A small positive pressure may be applied underneath the layer 101 in order to gently expand layer 101 and allow the rigidizing device to bend more freely in the flexible configuration. In this example, the outermost layer 101 can be elastomeric and can maintain a compressive force over the rigidizing layer, thereby imparting stiffness. Once positive pressure is supplied (enough to nominally expand the sheath off of the rigidizing layer, for example, 2 psi), the outermost layer 101 is no longer a contributor to stiffness, which can enhance baseline flexibility. Once rigidization is desired, positive pressure can be replaced by negative pressure (vacuum) to deliver stiffness.

[0102] A vacuum can be carried within rigidizing device 100 from minimal to full atmospheric vacuum (e.g., approximately 14.7 psi). In some examples, there can be a bleed valve, regulator, or pump control such that vacuum is bled down to any intermediate level to provide a variable stiffness capability. The vacuum pressure can advantageously be used to rigidize the rigidizing device structure by compressing the layer(s) of rigidizing layer (e.g., a braided sleeve) against neighboring layers. The rigidizing layer, such as a braid, knit or woven material, may be naturally flexible in bending (i.e. when bent normal to its longitudinal axis), and the lattice structure formed by the interlaced strands distort as the sleeve is bent in order for the rigidizing layer to conform to the bent shape while resting on the inner layers. In some examples, this results in lattice geometries where the comer angles of each lattice element change as the braided sleeve bends. When compressed between conformal materials, such as the layers described herein, the lattice elements become locked at their current angles and have enhanced capability to resist deformation upon application of vacuum, thereby rigidizing the entire structure in bending when vacuum is applied. Further, in some examples, the hoop fibers through or over the braid can carry tensile loads that help to prevent local buckling of the braid at high applied bending load.

[0103] The stiffness of the rigidizing device 100 can increase from 2-fold to over 30- fold, for instance 10-fold, 15-fold, or 20-fold, when transitioned from the flexible configuration to the rigid configuration. In one specific example, the stiffness of a rigidizing device similar to rigidizing device 100 was tested. The wall thickness of the test rigidizing device was 1.0 mm, the outer diameter was 17 mm, and a force was applied at the end of a 9.5 cm long cantilevered portion of the rigidizing device until the rigidizing device deflected 10 degrees. The forced required to do so when in flexible mode was only 30 grams while the forced required to do so in rigid (vacuum) mode was 350 grams.

[0104] In some examples of a vacuum rigidizing device 100, there can be only one rigidizing layer. In other examples of a vacuum rigidizing device 100, there can be two, three, or more rigidizing layers. In some examples, one or more of the radial gap layers or slip layers of rigidizing device 100 can be removed. In some examples, some or all of the slip layers of the rigidizing device 100 can be removed.

[0105] The rigidizing layers described herein can act as a variable stiffness layer. The variable stiffness layer can include one or more variable stiffness elements or structures that, when activated (e.g., when vacuum is applied), the bending stiffness and/or shear resistance is increased, resulting in higher rigidity. Other variable stiffness elements can be used in addition to or in place of the rigidizing layer. In some examples, engagers can be used as a variable stiffness element, as described in International Patent Application No.

PCT/US2018/042946, filed July 19, 2018, titled “DYNAMICALLY RIGIDIZING OVERTUBE,” the entirety of which is incorporated by reference herein. Alternatively or additionally, the variable stiffness element can include particles or granules, jamming layers, scales, rigidizing axial members, rigidizers, longitudinal members or substantially longitudinal members.

[0106] The rigidizable apparatuses described herein may also be rigidized by the application of positive pressure, rather than vacuum. For example, referring to FIGS. 4A-4B, the rigidizing apparatus (e.g., device or system) 2100 can be similar to rigidizing apparatus 100 described above, except that it can be configured to hold pressure (e.g., of greater than 1 atm) therein for rigidization rather than vacuum. A pressure-activated rigidizing device 2100 can also include a plurality of layers positioned around a lumen 2120 (e.g., for placement of an instrument or endoscope therethrough). [0107] For example, FIGS. 4A-4B illustrate longitudinal and radial sections through an example of a pressure-activated rigidizable member of a rigidizing apparatus. The rigidizing device 2100 shown in FIGS. 4 A and 4B can include an innermost layer 2115 (similar to innermost layer 115), a slip layer 2113 (similar to slip layer 113), a pressure gap 2112, a bladder layer 2121, a gap layer 2111 (similar to gap layer 111), a rigidizing layer 2109 (similar to rigidizing layer 109, e.g., a braid layer) or other variable stiffness layer as described herein, a gap layer 2107 (similar to layer 107), and an outermost containment layer 2101.

[0108] The pressure gap 2112 can be a sealed chamber that provides a gap for the application of pressure to layers of rigidizing device 2100. The pressure can be supplied to the pressure gap 2112 using a fluid or gas inflation/pressure media. The inflation/pressure media can be water or saline or, for example, a lubricating fluid such as oil or glycerin. The lubricating fluid can, for example, help the layers of the rigidizing device 2100 flow over one another in the flexible configuration. The inflation/pressure media can be supplied to the gap 2112 during rigidization of the rigidizing device 2100 and can be partially or fully evacuated therefrom to transform the rigidizing device 2100 back to the flexible configuration. In some examples, the pressure gap 2112 of the rigidizing device 2100 can be connected to a pre-filled pressure source, such as a pre-filled syringe or a pre-filled insufflator, thereby reducing the physician’s required set-up time.

[0109] The bladder layer 2121 can be made, for example, of a low durometer elastomer (e.g., of shore 20Ato 70A) or a thin plastic sheet. The bladder layer 2121 can be formed out of a thin sheet of plastic or rubber that has been sealed lengthwise to form a tube. The lengthwise seal can be, for instance, a butt or lap joint. For instance, a lap joint can be formed in a lengthwise fashion in a sheet of rubber by melting the rubber at the lap joint or by using an adhesive. In some examples, the bladder layer 2121 can be 0.0002-0.020” thick, such as approximately 0.005” thick. The bladder layer 2121 can be soft, high-friction, stretchy, and/or able to wrinkle easily. In some examples, the bladder layer 2121 is a polyolefin or a PET. The bladder 2121 can be formed, for example, by using methods used to form heat shrink tubing, such as extrusion of a base material and then wall thinning with heat, pressure and/or radiation. When pressure is supplied through the pressure gap 2112, the bladder layer 2121 can expand through the gap layer 2111 to push the rigidizing layer 2109 against the outermost containment layer 2101 such that the relative motion of the rigidizing layer strands is reduced.

[0110] The outermost containment layer 2101 can be a tube, such as an extruded tube. Alternatively, the outermost containment layer 2101 can be a tube in which a reinforcing member (for example, metal wire, including round or rectangular cross-sections) is encapsulated within an elastomeric matrix, similar to as described with respect to the innermost layer for other examples described herein. In some examples, the outermost containment layer 2101 can include a helical spring (e.g., made of circular or flat wire), and/or a tubular rigidizing layer (such as one made from round or flat metal wire) and a thin elastomeric sheet that is not bonded to the other elements in the layer. The outermost containment layer 2101 can be a tubular structure with a continuous and smooth surface. This can facilitate an outer member that slides against it in close proximity and with locally high contact loads (e.g., a nested configuration as described further herein). Further, the outer layer 2101 can be configured to support compressive loads, such as pinching. Additionally, the outer layer 2101 (e.g., with a reinforcement element therein) can be configured to prevent the rigidizing device 2100 from changing diameter even when pressure is applied.

[OHl] Because both the outer layer 2101 and the inner layer 2115 include reinforcement elements therein, the rigidizing layer 2109 can be reasonably constrained from both shrinking diameter (under tensile loads) and growing in diameter (under compression loads).

[0112] Using pressure instead of (or in addition to vacuum) to transition from the flexible state to the rigid state may increase the rigidity of the rigidizing device 2100. For example, in some examples, the pressure supplied to the pressure gap 2112 can be between 1 and 40 atmospheres, such as between 2 and 40 atmospheres, such as between 4 and 20 atmospheres, such as between 5 and 10 atmospheres. In some examples, the pressure supplied is approximately 2 atm, approximately 4 atmospheres, approximately 5 atmospheres, approximately 10 atmospheres, approximately 20 atmospheres. In some examples, the rigidizing device 2100 can exhibit change in relative bending stiffness (as measured in a simple cantilevered configuration) from the flexible configuration to the rigid configuration of 2-100 times, such as 10-80 times, such as 20-50 times. For example, the rigidizing device 2100 can have a change in relative bending stiffness from the flexible configuration to the rigid configuration of approximately 10, 15, 20, or 25, 30, 40, 50, or over 100 times.

[0113] Any of the rigidizing devices (rigidizing members) described herein can have a distal end section or sections with a different design that the main elongate body of the rigidizing device. As shown in FIG. 5, for example, rigidizing device 5500 can have a main elongate body 5503z and a distal end section 5502z. Only the distal end section 5502z, only the main elongate body 5503z, or both the distal end section 5502z and the main elongate body 5503z can be rigidizing as described herein (e.g., by vacuum and/or pressure). In some examples, one section 5502z, 5503z is activated by pressure and the other section 5502z, 5503z is activated by vacuum. In other examples, both sections 5502z, 5503z are activated by pressure and/or vacuum, respectively.

[0114] Any of the rigidizing devices (e.g., the inner and/or outer rigidizing devices) may be configured to be steered (e.g., controllably bent or curved), particularly at their distal end regions. Any of these apparatuses may include one or more actuating steering members that are configured to be actually, e.g., from a proximal end of the device, to steer the device. The actuating steering members may be any appropriate steering member, including mechanical steering (e.g., one or more tendons, cables, wires, etc., actuators, etc.), pneumatic steering, magnetic steering, thermal steering (e.g., using a shape memory alloy or shape memory polymers, etc.). Although the examples described herein include primarily actuating steering members comprising one or more cables, any appropriate actuating steering member may be used in any of these apparatuses and methods.

[0115] Referring to FIG. 6 A, in other examples, the distal end section 7602z can include a plurality of linkages 7604z that are actively controlled, such as via actuating steering members (e.g., cables 7624), for steering of the rigidizing device 7600. The device 7600 is similar to device 5800 except that it includes cables 7624 configured to control movement of the device. While the passage of the cables 7624 through the rigidizing elongate body 7603z (i.e., with outer wall 7601, rigidizing layer 7609, and inner layer 7615) is not shown in FIG. 6A, the cables 7624 can extend therethrough in any manner as described elsewhere herein. In some examples, one or more layers of the rigidizing elongate body 7603z can continue into the distal end section 7602z. For example, and as shown in FIG. 6A, the inner layer 7615 can continue into the distal end section 7602z, e.g., can be located radially inwards of the linkages 7604z. Similarly, any of the additional layers from the rigidizing proximal section (e.g., the rigidizing layer 7609 or the outer layer 7601 may be continued into the distal section 7602z and/or be positioned radially inwards of the linkages 7604z). In other examples, none of the layers of the rigidizing elongate body 7603z continue into the distal section 7602z. The linkages 7604z (and any linkages described herein) can include a covering 7627z thereover. The covering 7627z can advantageously make the distal section 7602z atraumatic and/or smooth. The covering 7627z can be a film, such as expanded PTFE. Expanded PTFE can advantageously provide a smooth, low friction surface with low resistance to bending but high resistance to buckling.

[0116] In some examples, the rigidizing devices described herein can be used in conjunction with one or more other rigidizing devices described herein. For example, an endoscope can include the rigidizing mechanisms described herein, and a rigidizing device can include the rigidizing mechanisms described herein. Used together, they can create a nested system that can advance, one after the other, allowing one of the elements to always remain stiffened, such that looping is reduced or eliminated (i.e., they can create a sequentially advancing nested system).

[0117] In general, the methods and apparatuses may be configured as a nested system including a rigidizing first elongate member and a second elongate member. The second elongate member may be rigidizing or may not be rigidizing. The distal end region of the second elongate member is steerable, e.g., using one or more tendons. The distal end region of the rigidizing first elongate member may be steerable (e.g., using one or more tendons) or may not be steerable. The rigidizing first elongate member may be nested over the second elongate member, or the second elongate member may be nested over the rigidizing first elongate member.

[0118] An exemplary nested apparatus (e.g., system) 2300z is shown in FIG. 6B. The system 2300z can include an outer rigidizing first elongate member (device 2300) and a second elongate member that is configured as an inner rigidizing device 2310 (here, configured as a rigidizing scope) that are axially movable with respect to one concentrically, though in some examples they may be nested non-concentrically. The outer rigidizing first member 2300 and the inner second (rigidizing) elongate member 2310 can include any of the rigidizing features as described herein. For example, the outer rigidizing device 2300 can include an outermost layer 2301a, a rigidizing layer 2309a, and an inner layer 2315a including a coil wound therethrough. The outer rigidizing device 2300 can be, for example, configured to receive vacuum between the outermost layer 2301a and the inner layer 2315a to provide rigidization. Similarly, the inner scope 2310 can include an outer layer 2301b (e.g., with a coil wound therethrough), a rigidizing layer 2309b, a bladder layer 2321b, and an inner layer 2315b (e.g., with a coil wound therethrough). The inner scope 2310 can be, for example, configured to receive pressure between the bladder 2321b and the inner layer 2315b to provide rigidization. Further, an air/water channel 2336z and a working channel 2355 can extend through the inner rigidizing device 2310. Additionally, the inner rigidizing scope 2310 can include a distal section 2302z with a camera 2334z, lights 2335z, and steerable linkages 2304z. A cover 2327z can extend over the distal section 2302z. In another example, the camera and/or lighting can be delivered in a separate assembly (e.g., the camera and lighting can be bundled together in a catheter and delivered down the working channel 2355 and/or an additional working channel to the distalmost end 2333z).

[0119] An interface 2337z can be positioned between the inner rigidizing device 2310 and the outer rigidizing device 2300. The interface 2337z can be a gap, for example, having a dimension d (see FIG. 5) of 0.001”-0.050”, such as 0.0020”, 0.005”, or 0.020” thick. In some examples, the interface 2337z can be low friction and include, for example, powder, coatings, or laminations to reduce the friction. In some examples, there can be seals between the inner rigi dizing device 2310 and outer rigi dizing device 2300, and the intervening space can be pressurized, for example, with fluid or water, to create a hydrostatic bearing. In other examples, there can be seals between the inner rigi dizing device 2310 and outer rigi dizing device 2300, and the intervening space can be filled with small spheres to reduce friction. [0120] The inner rigi dizing device 2310 and outer rigi dizing device 2300 can move relative to one another and alternately rigidize so as to transfer a bend or shape down the length of the nested system 2300z. For example, the inner device 2310 can be inserted into a lumen and bent or steered into the desired shape. Pressure can be applied to the inner rigi dizing device 2310 to cause the rigi dizing layer elements to engage and lock the inner rigi dizing device 2310 in the configuration. The rigi dizing device (for instance, in a flexible state) 2300 can then be advanced over the rigid inner device 2310. When the outer rigidizing device 2300 reaches the tip of the inner device 2310, vacuum can be applied to the rigidizing device 2300 to cause the layers to engage and lock to fix the shape of the rigidizing device. The inner device 2310 can be transitioned to a flexible state, advanced, and the process repeated. Although the system 2300z is described as including a rigidizing device and an inner device configured as a scope, it should be understood that other configurations are possible. For example, the system might include two overtubes, two catheters, or a combination of overtube, catheter, and scope.

[0121] As described above, in some cases the apparatus may be configured as a nested system comprising a rigidizing first elongate member that is configured to transition between a flexible configuration and a rigid configuration, and a second elongate member nested with the rigidizing first elongate member and axially movable relative to the rigidizing first elongate member. The second elongate member may be configured as a rigidizing shield (or sheath) that is coupled to a steerable endoscope. This is illustrated in FIG. 7A-7N. The apparatus may also include one or more processors and a memory coupled to the one or more processors, the memory storing computer-program instructions, that, when executed by the one or more processors, perform a computer-implemented method for retroflexing the nested system. This software (e.g., the computer-program instructions) will be described in greater detail below. But may generally control the rigidizing of the first elongate member and the second elongate member and may control bending (e.g., commanding a curve) of at least a distal end region of the second elongate member while advancing the second elongate member distally away from the rigidizing first elongate member so that a portion of the distal end region of the second elongate member that is distal to the rigidizing first elongate member bends against the rigidizing first elongate member as the second elongate member is advanced distally.

[0122] For example, FIG. 7A shows an example of a rigidizing shield 701 that is configured to couple to an endoscope to convert the endoscope into a rigidizing endoscope, which may form a first or second elongate (rigidizing) member. In FIG. 7A the rigidizing shield 701 includes an elongate body, a distal cap 705 at the distal end, and a proximal handle 709 having a venting port 713 and a pressure port 711. The pressure port may be used to apply pressure (positive and/or negative pressure) between layers forming the rigidizing shield. Similarly, the vent 713 (venting port) may be used to passively (by applying suction) or actively (by applying negative pressure) vent another region between layers forming the rigidizing shield. The roles of the pressure port and venting port may be switched, applying negative pressure to the pressure port 711 and positive pressure to the venting port 713.

[0123] In general, the rigidizing shield 701 may rigidize with the application of positive and/or negative pressure between two or more layers of the rigidizing shield 701. FIG. 7B shows a section B through the rigidizing shield 701 shown in FIG. 7A. The rigidizing shield 701 includes an outer layer, which may be reinforced (e.g., as a coil re-informed layer), that is both highly flexible in bending but may also limit or prevent expansion radially outwards. The rigidizing shield can be coated with and/or may be formed of a lubricous material. For example an outer layer may include a lubricious material, such as, but not limited to, a hydrophilic coating. The rigidizing shield also includes an inner rigidizing layer 727 formed of a plurality of lengths of filament that cross over each other. This layer may be a knitted, braided, and/or woven layer of material. The rigidizing shield also includes bladder layer 723 that may be driven against the reinforced outer layer 721, e.g., by the application of pressure, to compress the rigidizing layer against the reinforced outer layer. In some cases the bladder layer 723 may be an out-and-back bladder layer in which the bladder layer is doubled-back on itself to form a dual-layer structure within which pressure may be applied. Alternatively the bladder layer may be a single layer. FIG. 7C shows an enlarged section through the wall of the rigidizing shield 701 shown in FIGS. 7A-7B. In FIG. 7C, the wall of the rigidizing shield 701 includes an outer, reinforced layer 721. In this example the reinforced layer is an outer coil-wound tube (OCWT) that includes a metallic coil 723 within the outer layer 721 to prevent it from expanding outwards, without significantly decreasing the flexibility of the layer and device. The outer layer coil could be comprised of other materials, including polymers and fibers. The rigidizing shield 701 also includes a rigidizing layer 727 between the outer, reinforced layer 721 and a bladder layer 723 (shown as an out-and-back, dual layer bladder with one of the layers indriven against the reinforced layer 721 and another of the layers at the inner perimeter of the rigidizing shield 701). The rigidizing layer may include a plurality of filaments that cross over each other (e.g., a braid) and are free to slide relative to each other when pressure is not being applied or maintained within gap regions 725, 725’ on either side of the rigidizing layer 727, when the rigidizing shield 701 is in the flexible configuration. The outer layer 721 may include an optional coating 761, such as a lubricous coating (e.g., hydrophilic coating) layer.

[0124] To rigidize the rigidizing shield 701, negative pressure 730 may be applied between the outer coil-wound tube 721 and the bladder layer 723, as shown in FIG. 7D. In FIG. 7E an alternative configuration is shown in which positive pressure 731 is applied within the bladder layer 723. The region between the bladder layer 723 and the outer layer 721 may be vented 730’ (actively or passively) or negative pressure may be applied to assist in rigidizing the rigidizing shield 701 by driving the rigidizing layer 727 against the outer layer 721. Optionally, in any of these examples the rigidizing shield 701 may further include an inner reinforced layer (not shown).

[0125] The rigidizing shield 701 may be applied over an endoscope and secured to the distal end of the endoscope by the tip region 705. This is shown schematically in FIG. 7F, showing an endoscope 407 being inserted into a rigidizing shield, such as the shield shown in FIGS. 7A-7E. In this example the proximal end 709 of the shield may also be coupled to the endoscope, or to a mount to which the endoscope is attached, so that the two may move together.

[0126] The example of the rigidizing shield 701 shown in FIGS. 7A-7E also includes a pair of internal shields 707 that are configured to be inserted through the endoscope lines (e.g., suction/vacuum line, fluid line, working channel).

[0127] FIGS. 7G and 7H illustrate a section through a second elongate member formed of a rigidizing shield and an endoscope. The section shown in FIG. 7G is similar to that shown in FIG. 7B, but includes the endoscope 407 shown within the lumen 720 of the shield. For simplicity, internal features of the endoscope are not shown but may be present (including one or more lumen, pullwires, fiber optics, camera lines, etc.). Similarly, FIG. 7H shows an enlarged view or region H, showing the device in which a positive pressure 731 is applied to the bladder layer 723 (shown as an out-and-back bladder layer in this example), driving the bladder layer against the outer surface of the endoscope on one side, and against the rigidizing layer 727 (while venting 730’ the rigidizing layer) and against the reinforced outer layer 721 to rigidize the second elongate member.

[0128] The second elongate member may be nested with a first elongate rigidizing member, as described above. For example, FIGS. 7I-7M illustrate an example of a first elongate member configured as a rigidizing overtube 206. FIG. 71 shows an example of a rigi dizing overtube 206 that may be used with the rigidizing shield 701 (and endoscope) of FIGS. 7A-7H. In this example, the rigidizing overtube 206 includes an elongate body, which may be slightly shorter than the elongate body of the rigidizing shield. The rigidizing overtube 206 includes a plurality of layers, as shown in the detailed sections in FIG. 7J and FIGS. 7K-7M. In the section shown in FIG. 7 J the rigidizing overtube includes a reinforced outer layer 741 and reinforced inner layer (e.g., a coil-wound inner tube) 742, with a rigidizing layer 747 and a bladder layer 743. The bladder layer 743 may be a single layer or an out-and-back (e.g., double) layer.

[0129] In FIG. 71 the rigidizing overtube 206 includes a handle 252 that may be mounted to a robotic driver. The handle may be configured to allow rotation of the elongate, rigidizing body relative to the mount and to a second portion of the handle that is rigidly coupled to the mount. In general, the rigidizing overtube 206 may be converted from a flexible configuration, that may move relatively freely in bending, to a more rigid configuration. In FIG. 7K the section (K) through the wall shows that the rigidizing layer 747 is somewhat expanded and is free to slide, including sliding of the filaments forming the rigidizing layer relative to each other. The rigidizing layer 747 is between the reinforced inner layer 742 and the reinforced outer layer 741 but may be compressed by applying pressure 751 (positive and/or negative) to drive the bladder layer 743 and rigidizing layer 747 within the gap region 745, 745’ and against the outer (or in some cases inner) reinforced layer. In FIG. 7L the section (K) through the wall of the rigidizing overtube 206 is shown when positive pressure 751 is applied to the bladder layer 743 and negative pressure 750 is applied within the gap region. Alternatively or additionally, positive pressure 751 may be applied against the bladder layer on a side that is opposite from the rigidizing layer 747; in any of these examples the side facing the bladder layer may be vented passively or actively. If an out-and-back bladder layer is used, as shown in FIG. 7M, the bladder layer may expand within the space as positive pressure 751 is applied, rigidizing the overtube.

[0130] The nested apparatuses described herein may include nested rigidizing first elongate member (e.g., overtube) and second elongate member (e.g., rigidizing shield and endoscope), such as the example shown in FIG. 7N. In this example, a system is a nested system 700 comprising a rigidizing first elongate member (e.g., rigidizing overtube 206) that is configured to transition between a flexible configuration and a rigid configuration, and a second elongate member (e.g., rigidizing shield and endoscope 701) that is nested with the rigidizing first elongate member and that is axially movable relative to the rigidizing first elongate member. The system includes a first drive (e.g., drive motor 786) that may move the first elongate and rigidizing member axially (e.g., proximally/distally) and in some cases may roll the first elongate and rigidizing member. The system may also include a second drive (e.g., drive motor 787) that may move the second elongate member axially (e.g., proximally/distally) and may roll the second elongate and rigidizing member. The system may include a robotic drive system to which both the first and second drives may be coupled for moving them together (including proximally/distally); in some cases, the first or second drives may be configured as a robotic drive system to which the other drive may be coupled. [0131] The system may also include one or more pressure source(s) 789 for applying positive and/or negative pressure for selectively rigidizing either or both the first and second elongate members. The system may include one or more sensors (not shown) for sensing pressure and/or force. These sensors may be used as feedback for controlling operation of the system.

[0132] In general, the systems described herein may also include a controller 788 that may include hardware, software and/or firmware. The controller may include one or more processors. A processor may include hardware that runs the computer program code. Specifically, a processor may include or may be part of a controller and may encompass computers having different architectures such as single/multi-processor architectures and sequential (Von Neumann)/parallel architectures and also specialized circuits such as field- programmable gate arrays (FPGA), application specific circuits (ASIC), signal processing devices and other devices. The controller may include a memory coupled to the one or more processors, the memory storing computer-program instructions, that, when executed by the one or more processors, perform a computer-implemented method for retroflexing the nested system as described herein.

[0133] FIGS. 8A-8H show the exemplary use of a nested system 2400z as described herein. In FIG. 8 A, a steerable inner second elongate member 2410 is positioned within the outer rigidizing first member 2400 such that the distal end of the inner device 2410 extends outside of the outer rigidizing device 2400. As mentioned, the second elongate member may be rigidizing or not rigidizing. In FIGS. 8A-8H the exemplary nested apparatus includes both a rigidizing first elongate member and a second elongate member that is both steerable and rigidizing. In FIG. 8B, the distal end of the inner second elongate member 2410 is bent in the desired direction/orientation (e.g., via actuating steering members, such as cables 7624) and, in this example, is then rigidized (e.g., using vacuum or pressure as described herein). At FIG. 8C, the outer rigidizing device 2400 (in the flexible configuration) is advanced over the rigidized inner rigidizing device 2410 (including over the bending distal section). Once the distal end of the outer rigidizing device 2400 is sufficiently advanced over the distal end of the inner rigi dizing device 2410, then the outer rigi dizing device 2400 can be rigidized (e.g., using vacuum or pressure as described herein). At FIG. 8D, the inner rigi dizing device 2410 can then be transitioned to the flexible state (e.g., by removing the vacuum or pressure as described herein and by allowing the steering cables to go slack such that tip can move easily) and can be advanced and directed/oriented/steered as desired. Alternately, in FIG. 8D, the inner rigi dizing device 2410 can be actively steered (either manually or via computational control) as it emerges such that it minimizes the load on the rigidized outer tube. Minimizing the load on the outer rigi dizing device 2400 makes it easier for this tube to hold the rigidized shape. Once the inner rigi dizing device 2410 is rigidized, the outer rigi dizing device 2400 can be transitioned to the flexible state and advanced thereover (as shown in FIG. 8E). The process can then be repeated as shown in FIGS. 8F-8H. The repeated process can result in “shape copying,” whereby the inner and outer rigi dizing devices 2410, 2400 in the flexible configuration continuously conform to (or copy) the shape of whichever device 2410, 2400 is in the rigid configuration. In some examples, at the completion of the sequence shown in FIGS. 8A-8H, a third rigi dizing device can be slid over the first two rigi dizing devices (2400, 2410) and rigidized. Rigi dizing devices 2400 and 2410 can then be withdrawn. Finally, a fourth rigidizing device can be inserted through the inner lumen of the third tube. This fourth rigi dizing device may have a larger diameter and more features than rigidizing device 2410. For instance, it may have a larger working channel, more working channels, a better camera, or combinations thereof. This technique can allow two smaller tubes, which tend to be more flexible and maneuverable, to reach deep into the body while still ultimately delivering a larger tube for therapeutic purposes. Alternatively, in the example above, the fourth rigidizing device can be a regular endoscope as is known in the art.

[0134] In some examples, after completion of the sequence shown in FIGS. 8A-8H and the completion of any therapies conducted with the system 2400z in place, the entire system 2400z can be removed from the anatomy. In one exemplary method of withdrawing, the system 2400z can be transitioned to the flexible configuration (i.e., both the inner and outer devices 2410, 2400 can be transitioned to the flexible configuration), and the flexible system 2400z can be pulled proximally. In this method, the tension between the patient’s body (e.g., the anus) and a robotic arm (e.g., arm 1023y described below) can prevent the system 2400z from falling out of the body as it is removed (e.g., as more of the flexible system 2400z is positioned outside of the body than inside of the body).

[0135] As another exemplary method of withdrawing, shape copying can be performed similar to as described with respect to FIGS. 8A-8H, but in reverse. In this example, for example, the inner rigidizing device 2410 can be rigidized and the outer rigidizing device 2400 can be withdrawn proximally (while in the flexible configuration) over the inner rigi dizing device 2410. The outer rigi dizing device 2400 can then be rigidized and the inner rigi dizing device 2410 can be relaxed and moved proximally within the outer rigi dizing device 2400 (e.g., until the distal end of the inner rigidizing device 2410 is flush with the distal end of the outer rigidizing device 2400). In this example, when the inner rigidizing device 2410 is withdrawn into the outer rigidizing device 2400, tension on the steering cables can be held constant (e.g., at a low value, such as 141b or less) to ensure that the steerable distal end section will move into the shape of the outer rigidizing device 2400 without disturbing the fixed shape of the outer rigidizing device 2400. Alternatively or additionally, if the outer rigidizing device 2400 is rigidized in a straight shape, then the inner rigidizing device 2410 can be pulled into the outer rigidizing device 2400 and tension on each of the steering cables can be made equal (i.e., the same value, thus conforming the child shape to shape of the inside of the mother ).

[0136] As another exemplary method of withdrawing, the steerable distal tip of the inner rigidizing device 2410 can be actively steered proximally into the known, assumed, or measured shape of the outer rigidizing device 2400 either as or after the distal tip is retracted into the outer rigidizing device 2410. That is, the distal tip of the inner rigidizing device 2410 can be steered to match the shape of the section of the outer rigidizing device 2400 that is immediately proximal to the distal tip of the inner rigidizing device 2410. In one specific example, the inner rigidizing device 2410 may project from the outer rigidizing device 2400 by 4 inches, and the last 4 inches of the outer rigidizing device 2400 may form a 90 degree curve around a 2.5 inch radius of curvature. In this example, the inner rigidizing device 2410 can be steered into a 90 degree curve around a 2.5 inch radius of curvature and then withdrawn (in that shape) into the outer rigidizing device 2400. This may advantageously ensure that the inner rigidizing device 2410 pulls easily into the outer rigidizing device 2400 (i.e., because their shapes are matched).

[0137] Methods, controls, and/or algorithms can be used to enhance the advancement or withdrawal of nested rigidizing devices like those described herein, including for performing retroflexing. As described above, during advancing or withdrawing a nested system, the devices may be alternately made flexible and rigidized to travel along the body lumen. Once the flexible device is advanced over or within the rigidized device and the flexible device copies the shape of the rigidized device, the rigidized device may then be made flexible to be advanced or withdrawn. In some examples, actuating steering members (e.g., such as steering cables 7624) can be used to control the shape of the rigidized device and/or to maintain control of the device as/when it moves to its flexible state. [0138] For example, when advancing a nested system, after the outer rigi dizing device (e.g. outer rigidizing device 2400) has been advanced over the inner rigidizing device and has copied its shape, the inner rigidizing device (e.g., inner rigidizing device 2410) is transitioned to a flexible state prior to its advancement. In some examples, at the point shown in FIG. 8D, the inner rigidizing device can be steered to maintain the previously commanded curvature of the inner rigidizing device. The previously commanded curvature can refer to the curvature imposed by the actuating steering member(s) prior to rigidization of the inner device.

[0139] Maintaining the previously commanded curvature can have advantages over allowing the inner rigidizing device to transition to the flexible state with the steering cables slack. For example, during a partial copy of the inner rigidizing device, in which the outer rigidizing device is not fully advanced over the inner rigidizing device, it may be undesirable to allow the exposed length of the inner device to straighten at the completion of the partial copy. In some examples, in the absence of either rigidization or tension from the cables, the inner rigidizing device may tend to relax into an uncurved (or less curved) state. For another example, during a complete copy of the inner rigidizing device, in which the outer rigidizing device is fully advanced over the inner rigidizing device, to advance the inner rigidizing device out of the outer device, the inner device must initially be driven straight out of the outer device before it can be articulated.

[0140] In some examples, the actuating steering member(s) (e.g., cables 7624) can provide a bending moment that is maintained at approximately the same bending moment during shape copying. Maintaining the bending moment can advantageously help the inner rigidizing device to hold its current shape during the copying process, improving shape copying fidelity. Maintaining the bending moment during shape copying can also reduce artificial ‘tightening’ of the bend as the exposed length of the inner rigidizing device is reduced. Additionally, maintaining the bending moment may allow for retaining/setting/resetting a desired curvature for the inner rigidizing device while it is positioned within the outer device. When the inner rigidizing device is subsequently advanced, it may advance along a constant curvature arc. This control can allow, for example, a user to drive the inner rigidizing device out along the tightest bend possible.

[0141] The actuating steering member(s) may use two primary components to control the inner device distal tip bending section. For example, when a steering cable (or tendon or the like) is used, the first is by imparting a bending moment. Abending moment can be generated by stretching the steering cables. The second component is by imparting a geometric change. A geometric change can be imparted by displacing the steering cable, causing different path lengths along different steering cables, resulting in bends being formed. The effect of steering cable displacement depends upon the shape of the whole bending section, including the portion of the bending section, if any, positioned within the outer device.

[0142] As such, in some examples, the shape of the outer rigidized device may be used to control the shape of the inner rigidizing device as it transitions to a flexible state. The shape can be known using shape sensing technology. In some examples, tracking the movements of the inner rigidizing device can allow estimation of the copied shape of the outer device. [0143] The shape of the inner device may generally be preserved during a shape copy. This can allow for a smooth exit from the shape copying sequence, because there is no change to the actuating steering member(s) control. It can still be important to know the distal shape of the outer device as the inner device advances, because less and less of the inner device distal tip will be subject to the shape constraint of the outer device as the inner device advances.

RETROFLEXING

[0144] At any point during the navigation of a nested system the system may be retroflexed in order to view and/or access a region proximal to the distal end. Conventional retroflexing of an endoscope may be performed as shown in FIGS. 9A-9B by bending the distal end region of the endoscope, e.g., colonoscope 903. In FIG. 9A, the colonoscope 903 is shown within a region of the body (e.g., colon 901), initially in a linear configuration 909. In order to retroflex the colonoscope, the user may bend or cure the distal tip region, e.g., by pulling one or more tendons to bend the distal end region. The distal end region bends (in this example, bends upwards), curving through a partially retroflexed configuration 911, in which the tip of the scope is separated from the long axis of the rest of the scope by a distance, r2, and ending in a retroflexed configuration in which the distal tip is full retroflexed 913 and is separated from the long axis of the scope by a distance, rl. In FIG. 9Athe tip of the scope must push against the wall of the colon 901 during the retroflexing movement. Because the tip must pass through a relatively large curve when bending (being steered) into the partially retroflexed configuration 911 (e.g., having radius r2), the tip of the endoscope must be driven against the wall of the colon, resulting in sheer 908 and radial 910 force components, as shown in FIG. 9B. In practice, the user may use these forces to assist in retroflexing. For example, the force needed to bend the distal end region may be reduced by advancing the scope distally, so that the shear and/or radial force may push the tip towards retroflexing, e.g., the force used to advance the tip distally may assist in bending and retroflexing the tip, decreasing the force needed to be applied on the tendons to retroflex the tip region. However, as discussed above, the shear forces 908 and radial force 910 may damage the colon wall, including perforating the wall. [0145] FIGS. 10A-10E illustrate the kinematics of conventional retroflexing, similar to that shown in FIGS. 9A-9B. The steerable distal end region may be considered to have a plurality of segments arranged in series, as shown in FIG. 10 A. Each of these segments (labeled as segments “a” to “g” in FIG. 10 A) are approximately the same length, and are separated from each other, midpoint to midpoint, by a distance, x (shown as xl, x2, x3, x4, x5, and x6). At rest, this separation distance is the same (e.g., xl=x2=x3=x4=x5=x6). During bending, e.g., during retroflexing, when the distal end region is bent, e.g., by pulling on one or more tendons or otherwise applying force to bend the tip, the distances between the segments changes along the length of the distal tip region. As shown in FIG. 10B, in the inside curve region the distances between the midpoints of each segment are shortened when the distal end region is curved, as shown by the distances yl, y2, y3, y4, y5, and y6, so that y<x (e.g., yl<xl, y2<x2, etc.). Further, the distance between each segment remains approximately the same as the distal end region is bent, e.g., yl=y2=y3=y4=y5=y6. This relationship continues as the distal tip region is bent during the movement of the tip from the linear configuration up to 90 degree displacement of the tip during retroflexing. For example, further bending is shown in FIG. 10C, in which the distances between the midpoints of the tips (zl, z2, z3, z4, z5, z6) remain approximately equal to each other (zl=z2=z3=z4=z5=z6). Further bending to achieve retroflexing is shown in FIG. 10D and the final retroflexed configuration is shown in FIG. 10E. Thus, as the tip is maneuvered into a retroflex, each segment moves in unison with the others to close the gaps between the top edges. Thus, the space between the top edges, and therefore the spacing between the midpoints of the segments, is the same throughout the entire maneuver.

[0146] As illustrated in FIG. 9A, this may therefore require a relatively large sweep radius of bending during retroflexing, so that the distance between the tip of the scope and the long axis of the scope may be greater than the diameter of the body region (e.g., colon), resulting it shear and radial forces against the wall of the body region, which may lead to perforation and/or may prevent retroflexing. The sweep radius (sometimes referred to herein as simply the radius) may refer to the path taken by the distal end region of the endoscope when retroflexing. It would be best to minimize or eliminate the shear and radial forces. In some cases, this may be achieved by minimizing the sweep radius of the curved path taken by the tip during retroflexing. The methods and apparatuses described herein, which may include a rigidizing first elongate member nested with a scop including a nested distal end region may provide a potentially safer and retroflexing, having a much smaller bending sweep radius. [0147] For example, FIGS. 11A-11B illustrate one example of a method of retroflexing using a nested system including a rigi dizing first elongate member 1153 that is configured to transition between a flexible configuration and a rigid configuration, and a second elongate member 1155 nested with the rigidizing first elongate member and axially movable relative to the rigidizing first elongate member. In FIG. 11 A the rigidizing first elongate member 1153 is configured as an outer member in which the second elongate member 1155 is nested. The apparatus is shown inserted into the colon 1101. During retroflexing, the apparatus may be automatically retroflexed by actuating a control that is coupled to one or more processors storing instructions to coordinate movement of the first and second elongate members. Once positioned in the colon at the location where it is desired to be retroflexed, the rigidizing first elongate member may be rigidized (or maintained in a rigid configuration) and the second elongate member 1155 may be advanced distally out of the rigid first elongate member 1153 while commanding a curve on the distal end region of the second elongate member. As the (inner) second elongate member is advanced distally the maximum curvature may be commanded, so that the portion of the second elongate member that extends out of the first elongate member 1153 is bent to the smallest radius of curvature possible, while the portion of the distal end region that is within the lumen of the first elongate member is constrained and prevented from bending. In FIG. 11 A the second elongate member is shown in a few intermedial extended and curved configurations 1111, 1112 as the retroflexing is occurring. As the second elongate member 1155 is advanced distally out of the rigid rigidizing first elongate member, the second elongate member bends against the rigidizing first elongate member and the more proximal portion is prevented from bending by the first elongate member. Thus, the bending of the distal end region of the second elongate member is concentrated to the region distal to the first elongate member, and the minimum bending radius, rl, may be maintained through the retroflexing until the second elongate member is fully retroflexed 1113, as shown in FIG. 11 A. As shown in FIG. 11B, this may minimize or eliminate the radial 1110 a shear 1108 forces action on the wall of the body (e.g., colon 1101). [0148] FIGS. 12A-12D illustrate this method for retroflexing using a nested pair of elongate members in which one of the member is rigidizing and converts from a flexible configuration to a more rigid configuration and a second member has a steerable distal end region. The apparatus may be positioned within the colon with the rigidizing first elongate member 1253 in a flexible configuration (or alternating between flexible and rigid configurations, e.g., using shape copying as described above). Once in position, e.g., within a colon 1201 as shown in FIG. 12A, the rigidizing first elongate member 1253 may be rigidized and the second elongate member 1255 may be advanced distally out of the rigidizing first elongate member 1253 while actuating one or more tendons to bend the second elongate member 1255. This is illustrated in FIGS. 12B-12D. Advancing the second elongate member 1255 while pulling with sufficient force to maximally bend the region of the second elongate member 1255 that extends distally from the rigid rigidizing first elongate member 1253 maintains a minimum bend radius. FIG. 12B shows the second elongate member 1255 partially extended and maximally bent 1211, and FIG. 12C shows the second elongate member 1255 further extended and maximally bent. Finally, FIG. 12D shows the second elongate member 1255 fully retroflexed 1213.

[0149] In FIGS. 12A-12D, the force applied to maximally bend the second elongate member 1255 as it is driven distally out of the rigid rigidizing first elongate member 1253 may be dynamically adjusted. For example, the apparatus may sense the shape of the distal end region and may maintain the minimum force necessary to maintain the maximum bend; this force may change as more of the distal end region of the second elongate member 1255 is extended distally from the rigidizing first elongate member 1253. The rigidizing first elongate member 1253 may be maintained in a sufficient rigid configuration so that it may prevent bending of the region of the second elongate member still within the lumen of the rigidizing first elongate member 1253.

[0150] In practice, the apparatus may be oriented within the body (e.g., within the colon lumen) prior to starting the retroflexing. For example, the apparatus may be positioned so that the rigidizing first elongate member 1253 is far enough from the wall of the lumen to allow sufficient space to minimize contact with the wall during retroflexing. For example, as shown in FIGS. 12A-12D, the rigidizing first elongate member 1253 may be positioned close to one side of the lumen, and the apparatus may be controlled to retroflex in the direction that is furthest away from the wall of the lumen. Thus, in general, the apparatus and/or method may detect the relative position of the rigidizing first elongate member 1253 and the body lumen. This detection may be performed by one or more sensors (e.g., optical sensors, ultrasound sensors, etc.) either or both on the apparatus (e.g., on the rigidizing first elongate member 1253 and/or second elongate member) and external to the apparatus (e.g., using imaging such as fluoroscopy, etc.). In some examples the images from the camera(s) associated with the apparatus (e.g., the scope), including the camera on the second elongate member, may be analyzed to determine the dimensions of the body region and/or orientation of the apparatus, e.g., the rigidizing first elongate member 1253 and/or second elongate member, relative to the body region. Alternatively or additionally, the methods and apparatuses may determine or confirm that the region of the body that may be close or may contact the apparatus during retroflexing do not include a lesion. [0151] For example, these methods and apparatuses may detect the dimensions such as the diameter of the body region (e.g., lumen) and/or the distance between the distal end of the apparatus (e.g., rigidizing first elongate member 1253) and the wall(s) of the body region. In some cases, the apparatus may prevent retroflexing i the distance is greater than the maximum radius of the retroflexing curve (e.g., rl in FIG. 11 A), or in some cases if the distance is greater than the maximum radius of the retroflexing curve plus some acceptable additional distance (e.g., 2%, 5%, 7%, 10%, etc. of the maximum radius).

[0152] The apparatus may also consider and/or adjust the orientation of the apparatus within the body region so that retroflexing occurs in the direction having sufficient distance to permit retroflexing without contacting the wall (or with acceptable/minimal contact of the wall) of the body region. For example, the apparatus may reorient the apparatus so that the rigidizing first elongate member 1253 is adjacent to a wall opposite from the direction that the tip region of the second elongate member will bend during retroflexing. Alternatively or additionally, the apparatus may rotate the apparatus (both the rigidizing first elongate member 1253 and the second elongate member and/or just the second elongate member) so that the second elongate member will bend in the desired direction. In general, the apparatus may control bending, e.g., select the one or more tendons to actuate to bend the distal end region of the second elongate member, so that the bending occurs in a direction having sufficient room to perform the retroflexing. Alternatively or additionally, the method and/or apparatus may be configured to orient the apparatus so that the bending of retroflexing results in the structures on the second elongate member (e.g. working channel(s), camera, etc.) positioned in a desirable manner when the second elongate member is retroflexed. For example, the apparatus or method may orient, either automatically or semi-automatically, by providing instructions to the user, so that the working channel will end up positioned near a structure to be treated by a tool sent through the working channel, e.g., on the wall of the body region.

[0153] For example, any of these methods and apparatuses may be configured so that the second elongate member will be oriented when retroflexing so the camera will end up in the more central location (towards the center of the body lumen) and one or more working channels will be oriented more closely to the wall of the body lumen. Thus, the camera may be oriented more centrally at the start and finish of the retroflexing. This may position a tool in the working channel close to the wall, and the camera may be radially oriented up, toward the direction of bending during retroflexing.

[0154] As described in reference to FIG. 11B, in contrast to conventional methods of retroflexing, the method illustrated in FIGS. 12A-12D provide a minimum radius of bending during retroflexing, preventing or reducing the force applied to the wall of the body region. This is because the maximum bending radius may be maintained at all points of the retroflexing procedure, as illustrated by the kinematic drawing shown in FIGS. 13A-13D. Similar to FIGS. 10A-10E, the retroflexing member (e.g., the second elongate member 1355, configured as a scope) can be divided up into segments (a, b, c, d, e, f, g, etc.) that are separated from each other, midpoint-to-midpoint, by a constant distance in the linear configuration, e.g., xl, x2, x3, x4, x5, x6. The second elongate member 1355 is shown in this example within an outer rigi dizing elongate member 1353.

[0155] In FIG. 13 A the outer rigidizing elongate member 1353 is rigidized, and retroflexing may be started by advancing the distal end region of the second elongate member 1355 distally out of the now rigid outer rigidizing elongate member 1353, while simultaneously bending the second elongate member 1355, e.g., by pulling on one or more tendons (not shown). Because the more proximal portion of the second elongate member 1355 is constrained by the rigid outer rigidizing elongate member 1353, only the first distal portion (in FIG. 13 A) bends, reducing just the distance between the first (a) and second (b) segments, xl, so that xl<x2, while x2=x3=x4=x5=x6. In FIGS. 13B-13D, this procedure continues, so that as each segment of the second elongate member 1355 extends distally out of the rigidizing elongate member 1353, the maximum bend is applied, so that the distance between the segments outside of the rigidizing elongate member 1353 are equal to each other (e.g., in FIG. 13B, yl=y2) and less than the distance between the segments within the lumen of the rigidizing elongate member 1353 (e.g., in FIG. 13B, yl and y2 are less than y3=y4=y5=y6). In FIG 13C, zl=z2=z3, and z4=z5=x6, and zl, z2 and z3 < z4, z5 and z6.

[0156] Thus, in the automatic or semiautomatic methods and apparatuses descried herein, which may be referred to herein as robotic retroflexing methods and/or apparatuses, the rigid first elongate member may allow closing of all of the gaps between the tops of each segment as they are released from the constraint of the rigid first elongate member, in a furling up motion rather than a gross bending motion. For example, in FIGS. 13A-13D, by forcing each segment into its maximum bend radius immediately when it exits the rigidizing elongate member 1353, and constraining the other segments within the lumen of the rigidizing elongate member 1353, the apparatus is able to achieve a smaller swept radius of the tip of the second elongate member 1355, and still end up in the same retroflexed position, as shown in FIG. 13D.

[0157] FIG. 14 illustrates the relative tip positions and orientations during retroflexing using the robotic retroflexing technique described above in FIGS. 11A-11B, 12A-12D and 13A-13D as compared to a convention retroflexing of a scope. As shown, the tip position and orientation using a robotic retroflexing technique 1427 results in a much smaller movement in the x and z directions, and therefore smaller radius of curvature, as compared with convention retroflexing movements 1425. Note that the y direction remains constant in both types of retroflexing movements. In any of the figures herein, the values shown for dimensions or magnitude are intended to be non-limiting examples. Other dimensions may be used.

[0158] This is also illustrated in the examples shown in FIGS. 15A-15B and 16A-16D. FIGS. 15A-15B illustrate a first method of retroflexing using a nested apparatus that is similar to convention retroflexing with just a bending scope. In FIG. 15Athe second (e.g., inner) elongate member 1555 is first extended from the rigidizing first elongate member 1553 so that the steerable distal end region of the second (e.g., inner) elongate member fully distal to the rigidizing first elongate member 1553, and then the second (e.g., inner) elongate member 1555 is bend (e.g., upwards in this example) to retroflex. FIG. 15 A shows the second (e.g., inner) elongate member halfway retroflexed (90 degrees from the linear configuration) and the tip is separated from the linear configuration by a distance of 100 mm. FIG. 15B shows the second (e.g., inner) elongate member fully retroflexed, with the tip separated from the linear configuration by a distance that is less than 100 mm (e.g., approximately 87 mm). [0159] FIGS. 16A-16D illustrate an example of the same nested apparatus shown in FIGS. 15A-15B robotically rigidized as described above, by commanding bending of the second (e.g., inner) elongate member 1655 to assume a maximum bend as the distal end region leaves the rigidizing first elongate member 1653. The distal end of the second (e.g., inner) elongate member 1655 does not extend further than the final distance (87 mm) from the elongate configuration (shown in FIG. 16D) at any intermediate configuration (FIGS. 16A-16C).

[0160] As a result, the forces applied by the apparatus against the tissue, e.g., lumen wall, may be much lower. For example, FIGS. 17A and 17B show a comparison of the forces acting on the scope and on the wall of the lumen in a conventional retroflexing maneuver (FIG. 17A) and a robotic/automatic retroflexing maneuver as described herein (FIG. 17B). In both cases the scope achieves the same final retroflexed configuration and distance from the tip to the elongate length of the scope, r. However, in the conventional, fully manual embodiment, shown in FIG. 17A, the shear force 1774, Fl, acting between the wall of the vessel and the tip of the scope, as well as the insertion force 1780, F3, applied as to advance the scope distally are much higher (represented by the relative sizes of the arrows) than in the robotic/automatic methods described herein. These forces are higher in the convention methods because the conventional technique uses more of the tissue shear force to push the tip of the device over into the retroflex, limiting or reducing the tendon forces F2 1776 and F4 1782. In contrast, the robotic technique may have higher tendon forces, including the tendon steering load 1776’, F2, and the force of the tendon reacting proximally along the length 1782’, F4, and lower shear force 1774’, Fl, and insertion force 1780’, F3.

[0161] The graphs shown in FIGS. 18A-18D illustrate examples of force profiles showing the resulting load on a model of a colon (e.g., primarily the insertion force, e.g., F3 in FIGS. 17A-17B) using various techniques for performing retroflexing. FIG. 18A shows the force profile using a robotic methods similar to that described above in FIGS. 11A-11B, 12A- 12D and 13A-13D, in which the rigidizing first elongate member is rigidized to constrain bending of the portion of the distal end region of the second elongate member when a maximum bend is commanded, while advancing the second elongate member distally relative to the rigidizing first elongate member. In this example, the force remains less than 5 N.

[0162] Also described herein are methods and apparatuses in which a nested apparatus may mimic the conventional retroflexing of a non-nested scope, as shown in FIGS. 15A-15B. This configuration may be beneficial, even as compared to conventional non-nested scopes, as the rigidizing first elongate member may maintain the position of the apparatus during the procedure and may reduce the applied forces. For example, FIG. 18B shows an example in which the rigidizing first elongate member is rigidized, and the second elongate member is then advanced distally so that the steerable distal end region is further than the distal end of the rigidizing first elongate member, and the elongate member is then retroflexed by bending the distal end of the second elongate member. In this case although, as shown in FIG. 18B, the insertion force applied by the second elongate member against the wall may be low (and may be lower than in FIG. 18A), the radial force, which is not shown in FIGS. 18A-18D, may be significantly greater. Similarly, FIG. 18C shows the radial force in a retroflexing technique using a nested apparatus in which the second elongate member is retroflexed manually. FIG. 18D shows the insertion forces acting on the vessel using a non-nested scope. In this example, the insertion forces are significantly higher than the nested configurations.

[0163] FIGS. 19A-19D show similar force profiles during de-retroflexing. FIG. 19A shows insertion forces on the wall of the lumen using a nested apparatus when de-retroflexing by reversing the robotic retroflexing method described above. For example, from the retroflexed configuration the rigidizing first elongate member may be maintained in a rigid configuration and the second elongate member is withdrawn proximally while the tendons are manipulated to maintain the curve at the minimum force necessary to prevent the radius of curvature from increasing as the second elongate member is withdrawn proximally into the rigidizing first elongate member. [0164] FIG. 19B shows de-retroflexing using a method that reverses the method shown in FIGS. 15A-15B. FIG. 19D shows de-retroflexing using a conventional method of a nonnested scope.

[0165] All publications and patent applications mentioned in this specification are herein incorporated by reference in their entirety to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. Furthermore, it should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein and may be used to achieve the benefits described herein.

[0166] Any of the methods (including user interfaces) described herein may be implemented as software, hardware or firmware, and may be described as a non-transitory computer-readable storage medium storing a set of instructions capable of being executed by a processor (e.g., computer, tablet, smartphone, etc.), that when executed by the processor causes the processor to control perform any of the steps, including but not limited to: displaying, communicating with the user, analyzing, modifying parameters (including timing, frequency, intensity, etc.), determining, alerting, or the like. For example, any of the methods described herein may be performed, at least in part, by an apparatus including one or more processors having a memory storing a non-transitory computer-readable storage medium storing a set of instructions for the processes(s) of the method.

[0167] While various embodiments have been described and/or illustrated herein in the context of fully functional computing systems, one or more of these example embodiments may be distributed as a program product in a variety of forms, regardless of the particular type of computer-readable media used to actually carry out the distribution. The embodiments disclosed herein may also be implemented using software modules that perform certain tasks. These software modules may include script, batch, or other executable files that may be stored on a computer-readable storage medium or in a computing system. In some embodiments, these software modules may configure a computing system to perform one or more of the example embodiments disclosed herein.

[0168] As described herein, the computing devices and systems described and/or illustrated herein broadly represent any type or form of computing device or system capable of executing computer-readable instructions, such as those contained within the modules described herein. In their most basic configuration, these computing device(s) may each comprise at least one memory device and at least one physical processor. [0169] The term “memory” or “memory device,” as used herein, generally represents any type or form of volatile or non-volatile storage device or medium capable of storing data and/or computer-readable instructions. In one example, a memory device may store, load, and/or maintain one or more of the modules described herein. Examples of memory devices comprise, without limitation, Random Access Memory (RAM), Read Only Memory (ROM), flash memory, Hard Disk Drives (HDDs), Solid-State Drives (SSDs), optical disk drives, caches, variations or combinations of one or more of the same, or any other suitable storage memory.

[0170] In addition, the term “processor” or “physical processor,” as used herein, generally refers to any type or form of hardware-implemented processing unit capable of interpreting and/or executing computer-readable instructions. In one example, a physical processor may access and/or modify one or more modules stored in the above-described memory device. Examples of physical processors comprise, without limitation, microprocessors, microcontrollers, Central Processing Units (CPUs), Field-Programmable Gate Arrays (FPGAs) that implement softcore processors, Application-Specific Integrated Circuits (ASICs), portions of one or more of the same, variations or combinations of one or more of the same, or any other suitable physical processor.

[0171] Although illustrated as separate elements, the method steps described and/or illustrated herein may represent portions of a single application. In addition, in some embodiments one or more of these steps may represent or correspond to one or more software applications or programs that, when executed by a computing device, may cause the computing device to perform one or more tasks, such as the method step.

[0172] In addition, one or more of the devices described herein may transform data, physical devices, and/or representations of physical devices from one form to another. Additionally or alternatively, one or more of the modules recited herein may transform a processor, volatile memory, non-volatile memory, and/or any other portion of a physical computing device from one form of computing device to another form of computing device by executing on the computing device, storing data on the computing device, and/or otherwise interacting with the computing device.

[0173] The term “computer-readable medium,” as used herein, generally refers to any form of device, carrier, or medium capable of storing or carrying computer-readable instructions. Examples of computer-readable media comprise, without limitation, transmission-type media, such as carrier waves, and non-transitory-type media, such as magnetic-storage media (e.g., hard disk drives, tape drives, and floppy disks), optical-storage media (e.g., Compact Disks (CDs), Digital Video Disks (DVDs), and BLU-RAY disks), electronic-storage media (e.g., solid-state drives and flash media), and other distribution systems.

[0174] A person of ordinary skill in the art will recognize that any process or method disclosed herein can be modified in many ways. The process parameters and sequence of the steps described and/or illustrated herein are given by way of example only and can be varied as desired. For example, while the steps illustrated and/or described herein may be shown or discussed in a particular order, these steps do not necessarily need to be performed in the order illustrated or discussed.

[0175] The various exemplary methods described and/or illustrated herein may also omit one or more of the steps described or illustrated herein or comprise additional steps in addition to those disclosed. Further, a step of any method as disclosed herein can be combined with any one or more steps of any other method as disclosed herein.

[0176] The processor as described herein can be configured to perform one or more steps of any method disclosed herein. Alternatively or in combination, the processor can be configured to combine one or more steps of one or more methods as disclosed herein.

[0177] When a feature or element is herein referred to as being "on" another feature or element, it can be directly on the other feature or element or intervening features and/or elements may also be present. In contrast, when a feature or element is referred to as being "directly on" another feature or element, there are no intervening features or elements present. It will also be understood that, when a feature or element is referred to as being "connected", "attached" or "coupled" to another feature or element, it can be directly connected, attached or coupled to the other feature or element or intervening features or elements may be present. In contrast, when a feature or element is referred to as being "directly connected", "directly attached" or "directly coupled" to another feature or element, there are no intervening features or elements present. Although described or shown with respect to one embodiment, the features and elements so described or shown can apply to other embodiments. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed "adjacent" another feature may have portions that overlap or underlie the adjacent feature. [0178] Terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. For example, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items and may be abbreviated as "/".

[0179] Spatially relative terms, such as "under", "below", "lower", "over", "upper" and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is inverted, elements described as "under”, or "beneath" other elements or features would then be oriented "over" the other elements or features. Thus, the exemplary term "under" can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Similarly, the terms "upwardly", "downwardly", "vertical", "horizontal" and the like are used herein for the purpose of explanation only unless specifically indicated otherwise.

[0180] Although the terms “first” and “second” may be used herein to describe various features/elements (including steps), these features/elements should not be limited by these terms, unless the context indicates otherwise. These terms may be used to distinguish one feature/element from another feature/element. Thus, a first feature/element discussed below could be termed a second feature/element, and similarly, a second feature/element discussed below could be termed a first feature/element without departing from the teachings of the present invention.

[0181] In general, any of the apparatuses and methods described herein should be understood to be inclusive, but all or a sub-set of the components and/or steps may alternatively be exclusive and may be expressed as “consisting of’ or alternatively “consisting essentially of’ the various components, steps, sub-components or sub-steps. [0182] As used herein in the specification and claims, including as used in the examples and unless otherwise expressly specified, all numbers may be read as if prefaced by the word "about" or “approximately,” even if the term does not expressly appear. The phrase “about” or “approximately” may be used when describing magnitude and/or position to indicate that the value and/or position described is within a reasonable expected range of values and/or positions. For example, a numeric value may have a value that is +/- 0.1% of the stated value (or range of values), +/- 1% of the stated value (or range of values), +/- 2% of the stated value (or range of values), +/- 5% of the stated value (or range of values), +/- 10% of the stated value (or range of values), etc. Any numerical values given herein should also be understood to include about or approximately that value, unless the context indicates otherwise. For example, if the value " 10" is disclosed, then "about 10" is also disclosed. Any numerical range recited herein is intended to include all sub-ranges subsumed therein. It is also understood that when a value is disclosed that "less than or equal to" the value, "greater than or equal to the value" and possible ranges between values are also disclosed, as appropriately understood by the skilled artisan. For example, if the value "X" is disclosed the "less than or equal to X" as well as "greater than or equal to X" (e.g., where X is a numerical value) is also disclosed. It is also understood that the throughout the application, data is provided in a number of different formats, and that this data, represents endpoints and starting points, and ranges for any combination of the data points. For example, if a particular data point “10” and a particular data point “15” are disclosed, it is understood that greater than, greater than or equal to, less than, less than or equal to, and equal to 10 and 15 are considered disclosed as well as between 10 and 15. It is also understood that each unit between two particular units are also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

[0183] Although various illustrative embodiments are described above, any of a number of changes may be made to various embodiments without departing from the scope of the invention as described by the claims. Optional features of various device and system embodiments may be included in some embodiments and not in others. Therefore, the foregoing description is provided primarily for exemplary purposes and should not be interpreted to limit the scope of the invention as it is set forth in the claims.

[0184] The examples and illustrations included herein show, by way of illustration and not of limitation, specific embodiments in which the subject matter may be practiced. As mentioned, other embodiments may be utilized and derived there from, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Such embodiments of the inventive subject matter may be referred to herein individually or collectively by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept, if more than one is, in fact, disclosed. Thus, although specific embodiments have been illustrated and described herein, any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.

Claims

CLAIMS What is claimed is:

1. A method of retroflexing a nested endoscope system, the method comprising: positioning a nested system within a body region, wherein the nested system comprises a rigidizing first elongate member that is configured to transition between a flexible configuration and a rigid configuration, and a second elongate member nested with the rigidizing first elongate member and axially movable relative to the rigidizing first elongate member; and commanding a curve on a distal end region of the second elongate member while advancing the second elongate member distally away from the rigidizing first elongate member so that a portion of the distal end region of the second elongate member that is distal to the rigidizing first elongate member bends against the rigidizing first elongate member as the second elongate member is advanced distally.

2. The method of claim 1, wherein positioning comprises moving the rigidizing first elongate member to a target location within the body region in the flexible configuration and transitioning the rigidizing first elongate member to the rigid configuration when a distal end of the rigidizing first elongate member is at the target location.

3. The method of claim 1, further comprising receiving a user command to retroflex and automatically rigidizing and commanding the curve on the distal end of the second elongate member.

4. The method of claim 1, wherein positioning comprises advancing the nested system within a lumen of the body while the rigidizing first elongate member is in the flexible configuration.

5. The method of claim 1, further comprising stopping the advance of the second elongate member once the distal end region of the second elongate member is retroflexed relative to the rigidizing first elongate member.

6. The method of claim 1, wherein the rigidizing first elongate member is configured to transition between the flexible configuration and the rigid configuration by the application of positive and/or negative pressure.

7. The method of claim 1, wherein the second elongate member comprises an endoscope.

8. The method of claim 1, wherein the rigi dizing first elongate member and the second elongate member are configured to move axially relative to each other.

9. The method of claim 1, further comprising confirming a diameter of the body region prior to commanding the cure.

10. The method of claim 1, further comprising selecting a direction of bending for commanding the curve prior to commending the curve.

11. The method of claim 10, wherein selecting the bending comprises selecting the direction of bending based on an estimate of diameter of body region and a position of the distal end region of nested system within the body region.

12. The method of claim 1, wherein advancing the second elongate member distally away from the rigidizing first elongate member comprises maintaining the rigidizing first elongate member in the rigid configuration.

13. The method of claim 1, wherein advancing comprises advancing the second elongate member distally out of a lumen of the rigidizing first elongate member.

14. The method of claim 1, wherein the second elongate member, comprises a second rigidizing device that is configured to transition between a flexible configuration and a rigid configuration.

15. The method of claim 1, further comprising maintain a shear force on a wall of the body region that is less a threshold value while commanding a curve on the distal end of the second elongate member while advancing the second elongate member distally away from the rigidizing first elongate member.

16. The method of claim 1, wherein positioning the nested system within the body region comprises positioning the nested system within a gastrointestinal tract.

17. The method of claim 1, wherein commanding the curve comprises applying force to one or more tendons within the second elongate member.

18. The method of claim 1, further comprising reversing the retroflexing by withdrawing the distal end region of the second elongate member proximally relative to the rigidizing first elongate member so that the distal end region of the second elongate member that is proximal to a distal end of the rigidizing first elongate member straightens out as the second elongate member is retracted proximally.

19. A method of retroflexing a nested endoscope system, the method comprising: positioning a nested system within a body region, wherein the nested system comprises a rigidizing first elongate member that is configured to transition between a flexible configuration and a rigid configuration by the application of pressure and a second elongate member nested within the rigidizing first elongate member; rigidizing the rigidizing first elongate member; and commanding a curve on a distal end region of the second elongate member while advancing the second elongate member distally out of the rigidizing first elongate member while the rigidizing first elongate member is in the rigid configuration, so that a portion of the distal end region of the second elongate member that is distal to the rigidizing first elongate member bends against the rigidizing first elongate member as the second elongate member is advanced distally.

20. A system comprising: a nested system comprising a rigidizing first elongate member that is configured to transition between a flexible configuration and a rigid configuration, and a second elongate member nested with the rigidizing first elongate member and axially movable relative to the rigidizing first elongate member; one or more processors; and a memory coupled to the one or more processors, the memory storing computer-program instructions, that, when executed by the one or more processors, perform a computer-implemented method for retroflexing the nested system, the method comprising: rigidizing the rigidizing first elongate member; and commanding a curve on a distal end region of the second elongate member while advancing the second elongate member distally away from the rigidizing first elongate member so that a portion of the distal end region of the second elongate member that is distal to the rigidizing first elongate member bends against the rigidizing first elongate member as the second elongate member is advanced distally.

21. The system of claim 20, wherein the computer-implemented method further comprises receiving a user command to retroflex prior to rigidizing and commanding the curve on the distal end of the second elongate member.

22. The system of claim 20, wherein positioning comprises advancing the nested system within a lumen of the body while the rigidizing first elongate member is in the flexible configuration.

23. The system of claim 20, wherein the computer-implemented method further comprises stopping the advance of the second elongate member once the distal end region of the second elongate member is retroflexed relative to the rigidizing first elongate member.

24. The system of claim 20, wherein the rigidizing first elongate member is configured to transition between the flexible configuration and the rigid configuration by the application of positive and/or negative pressure.

25. The system of claim 20, wherein the second elongate member comprises an endoscope.

26. The system of claim 20, wherein the first elongate member and the second elongate member are configured to move axially relative to each other.

27. The system of claim 20, wherein the computer-implemented method further comprises confirming a diameter of the body region prior to commanding the cure.

28. The system of claim 20, wherein the computer-implemented method further comprises selecting a direction of bending for commanding the curve prior to commending the curve.

29. The system of claim 27, wherein selecting the bending comprises selecting the direction of bending based on an estimate of diameter of body region and a position of the distal end region of nested system within the body region.

30. The system of claim 20, wherein advancing the second elongate member distally away from the rigidizing first elongate member comprises maintaining the rigidizing first elongate member in the rigid configuration.

31. The system of claim 20, wherein advancing comprises advancing the second elongate member distally out of a lumen of the rigidizing first elongate member.

32. The system of claim 20, wherein the second elongate member comprises a rigidizing device that is configured to transition between a flexible configuration and a rigid configuration.

33. The system of claim 20, wherein the computer-implemented method further comprises maintaining a shear force on a wall of the body region that is less a threshold value while commanding a curve on the distal end of the second elongate member while advancing the second elongate member distally away from the rigidizing first elongate member.

34. The system of claim 20, wherein commanding the curve comprises applying force to one or more tendons within the second elongate member.

35. A system comprising: a nested system comprising a rigidizing first elongate member that is configured to transition between a flexible configuration and a rigid configuration, and a second elongate member nested within the rigidizing first elongate member and configured to be axially movable relative to the rigidizing first elongate member; one or more processors; and a memory coupled to the one or more processors, the memory storing computer-program instructions, that, when executed by the one or more processors, perform a computer-implemented method for retroflexing the nested system, the method comprising: rigidizing the rigidizing first elongate member; and commanding a curve on a distal end region of the second elongate member while advancing the second elongate member distally out of the rigidizing first elongate member while the rigidizing first elongate member is in the rigid configuration, so that a portion of the distal end region of the second elongate member that is distal to the rigidizing first elongate member bends against the rigidizing first elongate member as the second elongate member is advanced distally.