BR112021001155B1 - Medical implants with symmetrical shape, method for their manufacture, and mold. - Google Patents

Abstract

"IMPLANTS WITH SYMMETRICAL SHAPE". The present invention relates to implants with symmetry. The implant may comprise a biocompatible material and have at least two planes of symmetry, including symmetry around an equator of the implant. The implant may be a body contour implant, wherein a posterior side of the implant is symmetrical around the equator to an anterior side of the implant.

Description

CROSS-REFERENCE TO RELATED REQUEST(S)

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application No. 62/703.056, filed July 25, 2018, the entirety of which is incorporated herein by reference.

TECHNICAL FIELD

[0002] The modalities of the present description refer in general to medical implants and related methods of manufacturing and use thereof.

FUNDAMENTALS

[0003] Many implants currently available on the market are vulnerable to malplacement during and/or after implantation in a patient. For example, breast implants, particularly round breast implants, can rotate under certain circumstances, so that the flat posterior surface faces the skin instead of the chest wall. This susceptibility to malplacement can complicate the implantation procedure. Care must be taken to maintain proper orientation when introducing an implant through small incision sites and/or tortuous anatomy to avoid irregular implant placement. Implant rotation can occur after implantation, where the patient may notice an abnormal appearance, such as swelling in the breast. In addition to aesthetic problems, this could cause insecurity on the part of the patient that something went wrong with the surgery, or that there is another potentially serious medical problem.

SUMMARY OF DESCRIPTION

[0004] Implants and methods of manufacturing and use thereof are described. The present description includes a medical implant comprising a biocompatible material and having at least two planes of symmetry, optionally three planes of symmetry, wherein one of at least two planes of symmetry corresponds to an equator of the implant. The implant may be a body contouring implant, such as a breast implant or a gluteal implant, a tissue expander, a sizer, or a tissue bisector, for example, wherein the posterior side of the implant is symmetrical about the equator with the anterior side of the implant. According to some aspects herein, the implant may have a round shape, an oval shape, or a teardrop shape.

[0005] The implants herein may include a shell and a filling, optionally wherein the shell has an adhesive attached to it. For example, the implant may have a first side and a second side symmetrical around the equator, the implant including an adhesive located between an apex of the first side and the equator, or between an apex of the second side and the equator, optionally wherein the adhesive is located less than or equal to 20 mm from the equator, less than or equal to 18.9 mm from the equator, less than or equal to 15 mm from the equator, less than or equal to 10 mm from the equator, less than or equal to 7.5 mm from the equator, less than or equal to 5.5 mm from the equator, less than or equal to 5 mm from the equator, optionally wherein at least a portion of the adhesive is located on the equator. In some examples, the implant includes an adhesive having a diameter less than or equal to 30 mm, such as less than or equal to 27 mm, less than or equal to 25 mm, less than or equal to 20 mm, or less than or equal to 19 mm. Additionally, or alternatively, the implant may include a printed label to identify the implant, optionally including a manufacturer's name and/or location, an implant model number, one or more size dimensions, a manufacturing date, or a combination thereof. For example, the label may be printed on the adhesive. The implants herein may include a transponder, optionally placed in a filling near an apex (e.g., posterior or anterior apex) of the implant.

[0006] In some examples, the implant is a breast implant comprising a filling in the form of a fluid, for example, a gel filling, having a viscosity or penetration value suitable to simulate natural breast tissue movement. For example, the filling may comprise a gel having a penetration value (1/10 mm) ranging from about 10 to about 60.

[0007] At least a portion of an external surface, or the entire external surface, of the implant may be textured with surface features on the order of nanometers to micrometers. Optionally, the implant comprises a housing that includes an adhesive, the external surface of the adhesive being textured with surface features on the order of nanometers to micrometers.

[0008] The present description also includes the use of the implants herein, including any implant described previously or elsewhere herein, in a minimally invasive implantation procedure.

[0009] The present description further includes a method of manufacturing such implants. For example, the methods herein include manufacturing an implant comprising a biocompatible material, wherein the implant comprises a shell comprising exactly a low diffusion barrier that forms an outermost surface of the shell. In some examples, preparing an implant shell may comprise applying a first silicone dispersion to a mold surface to form at least a first layer of the shell; and applying a second silicone dispersion to at least a first layer to form at least a second layer; wherein the first silicone dispersion or the second silicone dispersion comprises a colored silicone elastomer that includes a dye or a pigment, and the other of the first silicone dispersion or the second silicone dispersion does not include a dye or a pigment. The second silicone dispersion may comprise, for example, colored silicone elastomer, at least one second layer being a low diffusion barrier layer, optionally wherein the second silicone dispersion comprises from about 0.01% to about 0.05% by weight of the blue silicone elastomer, relative to the total weight of the second silicone dispersion. The colored silicone elastomer may be blue, green, yellow, pink, orange, or purple, for example. According to some aspects hereof, the method includes applying 2, 3, 4, or 5 first layers, and then applying only a second layer over the first layers. Additionally, the manufacturing methods may include applying exactly 6 layers, the shell optionally having a total thickness ranging from about 0.010 inch to about 0.040 inch before and/or after shell curing.

[0010] The method may further comprise curing the casing, optionally wherein the curing is carried out at a temperature ranging from about 115.0°C to about 135.0°C. Additionally, or alternatively, the method may comprise removing the casing from the mold and inverting the casing, optionally wherein one surface of the mold is textured with surface features on the order of nanometers to micrometers, so that an outermost surface of the casing, when inverted, is textured. Additionally, for example, the method may comprise introducing a gel into a cavity of the housing, optionally wherein the gel has a penetration value (1/10 mm) ranging from 10 to 60. The method may further comprise applying an adhesive to a hole in the housing and sealing the adhesive to the housing, optionally wherein the adhesive includes a transponder embedded between layers of the housing or adhesive or affixed to an internal surface of the housing or adhesive. In some examples, the transponder is not affixed to the housing or adhesive. The method may further comprise introducing a transponder into a cavity of the housing, for example, before or after introducing a filler into the cavity. Thus, for example, the transponder may be (a) disposed in the gel and not affixed to an internal surface of the housing, or (b) affixed to an internal surface of the housing or incorporated into a portion of the housing. The method may also involve heating the implant to cure a gel placed within a cavity of the housing, in which the implant is placed on a substrate, such as in a cavity of a substrate, during heating to maintain a symmetrical shape of the implant.

[0011] The present description also includes molds for preparing implants described previously and elsewhere herein. For example, the mold may be or comprise a mandrel comprising a head and a handle, the head having a symmetrical shape having at least two planes of symmetry corresponding to at least two planes of symmetry of the implant, optionally wherein the head has a textured surface. The head of the mandrel may be centered or offset relative to the handle.

BRIEF DESCRIPTION OF THE FIGURES

[0012] The attached drawings, which are incorporated herein and form part of this specification, illustrate various exemplary embodiments and, together with the description, serve to explain the principles of the embodiments described.

[0013] Figs. 1A-1C show cross-sections of an exemplary implant, according to embodiments of the present description.

[0014] Figs. 2A-2C show cross-sections of another exemplary implant, according to embodiments of the present description.

[0015] Figs. 3A-3C show side views of implants with different shell configurations, according to embodiments of the present description.

[0016] Fig. 4 shows an exemplary configuration of layers of an implant shell, according to one or more embodiments of the present description.

[0017] Fig. 5 shows different implants discussed in Example 1.

DETAILED DESCRIPTION

[0018] The terminology used below may be interpreted in its broadest reasonable manner, even though it is being used in combination with a detailed description of certain specific examples of the present description. Certainly, certain terms may be further emphasized below; however, any terminology intended to be interpreted in any restricted manner will be clearly and specifically defined as such in this Detailed Description section. Both the preceding general description and the detailed description below are illustrative and explanatory only and are not restrictive of the characteristics as claimed.

[0019] In this description, the expression "based on" means "based at least in part". The singular forms "a", "an", and "the" include plural referents unless the context dictates otherwise. The term "exemplificative" is used in the sense of "example" rather than "ideal". The terms "comprises", "comprising", "includes", "including", or other variations thereof, are intended to cover a non-exclusive inclusion so that a process, method, or product comprising a list of elements does not necessarily include only those elements, but may include other elements not expressly listed or inherent to such a process, method, article, or apparatus. Relative terms, such as "about" and "in general", are used to indicate a possible variation of ± 5% of the stated or understood value.

[0020] As used herein, the term "posterior" refers to a patient's back, and the term "anterior" refers to a patient's front. Thus, for example, the side of a breast implant closest to the skin is the anterior side, while the side of a gluteal implant closest to the skin is the posterior side.

[0021] The present description includes implants having a symmetrical shape, for example, having at least one plane of symmetry. The implant can be any type of implant suitable for implantation in the body, including, but not limited to, aesthetic implants such as breast, buttock, and calf implants. In this way, the implant can be inserted into a patient so that either side of the implant can face posteriorly or anteriorly.

[0022] Symmetrical implant features may allow for a similar or identical projection at the apex of the posterior side of the implant as on the anterior side. The implant may prevent or eliminate problems related to potential implant rotation after surgery and/or during the implantation process. Additionally, having a symmetrical shape may provide benefits in minimally invasive implant procedures. For example, the ability to introduce the implant in different orientations may allow for a smaller incision. The implants herein may be implanted in a patient in a hybrid-type procedure, for example, as described in PCT Application PCT/US19/38536, which claims priority from US Provisional Application No. 62/688,778 filed on June 22, 2018, by introducing a filler material such as autologous fat along with the implant during the implantation procedure.

[0023] In some examples here, the implant is a body contour implant. For example, the body contour implant may have a plane of symmetry along its equator, corresponding to an xy plane (the length dimension x extending in the direction from top to bottom of the implant, and the width dimension y extending in the direction from left to right of the implant). Such implants may generally have a round, oval, or teardrop shape.

[0024] Figs. 1A, 1B, and 1C show an exemplary implant100 having a round or oval shape, the implant 100 having symmetry according to one or more embodiments of the present description. Such implants include, for example, body contouring implants such as breast implants, pectoral implants, gluteal implants, as well as other types of implants associated with aesthetic and/or reconstructive procedures, such as calibrators (e.g., breast calibrators or any device that is configured to define the final size of the implant), tissue expanders (e.g., breast expander or any temporary implant used for reconstructions), and tissue bisectors (e.g., breast bisectors or any device that is configured to separate tissue or muscle in order to create space to place a permanent implant). Fig. 1A shows a cross-sectional view of implant 100 in the xz plane, Fig. 1B shows a cross-sectional view of implant 100 in the yz plane, and Fig. 1C shows a cross-sectional view of implant 100 in the xy plane. The xy plane corresponds to a plane generally parallel to the chest wall of a patient when the implant is implanted, referred to as the equator 102. Thus, Fig. 1C represents a cross-section of implant 100 along the equator 102. The upper and lower portions of implant 100 are separated by the yz plane, and the left and right portions of implant 100 are separated by the xz plane.

[0025] As shown in Figs. 1A and 1B, the 100 implant has symmetry around the xy plane (above and below the equator 102), so that the anterior and posterior sides of the implant are symmetrical. That is, a first side 104 is symmetrical to a second side 106 around the equator 102, so that the first side 104 can correspond to the posterior side and the second side 104 can correspond to the anterior side, or vice versa, when implanted in a patient. As shown in Figs. 1A and 1C, the 100 implant also has symmetry around the yz plane, so that the upper and lower sides of the 100 implant are symmetrical to each other (see upper and lower sides 108, 110). As shown in Figs. In figures 1B and 1C, the 100 implant also has symmetry around the xz plane, so that the left and right sides of the 100 implant are symmetrical to each other (see left and right sides 112, 114). Thus, the 100 implant has at least three planes of symmetry.

[0026] Other exemplary implants may have at least one plane of symmetry, but fewer than three planes of symmetry. For example, the implant may have a teardrop shape. Such implants include, for example, body-contouring implants such as breast implants, pectoral implants, gluteal implants, and facial implants. Figs. 2A, 2B, and 2C show cross-sectional views of an exemplary implant 200 having a teardrop shape, according to one or more embodiments of the present description. Fig. 2A shows a cross-sectional view of the implant 200 in the xz plane, and Fig. 2B shows a cross-sectional view of the implant 200 in the yz plane, wherein the equator 202 lies along the xy plane. Figure 2C shows a cross-sectional view of implant 200 in the xy plane, along the equator 202. Implant 200 has symmetry around the xy plane (above and below the equator 202 in Figures 2A and 2B, corresponding to the anterior and posterior sides 204, 206 when implanted), and around the xz plane (see left and right sides 208, 210 in Figures 2B and 2C). Implant 200 does not have symmetry around the yz plane (see upper and lower sides 212, 214 in Figures 2A and 2C). In this example, implant 200 has two planes of symmetry. Additional examples of body-contouring implants and other types of implants are included here.

[0027] One or more implant surfaces may have a surface texture (e.g., microtexture or nanotexture) to promote biocompatibility. For example, the implant may have a surface texture as described in WO 2017/196973, WO 2015/121686, and/or WO 2017/093528, each of which is incorporated herein by reference. For example, the surface texture may include uniform surface features on the order of nanometers to micrometers.

[0028] According to some examples herein, the implant may comprise a shell and a filling (for example, a fluid such as a gel or a liquid) within a cavity formed by the shell. The shell and the filling may each comprise a biocompatible material, such as silicone. Any of the materials and/or features discussed in US 9,901,438, US 2015/0150675 and/or WO 2017/196973, each incorporated by reference herein, may be used for the implants herein.

[0029] The implant shell may comprise a biocompatible material, for example, formed as a plurality of layers. An external and/or internal surface of the shell may have a surface texture, for example, as described in WO 2017/196973, WO 2015/121686 and/or WO 2017/093528, each of which is incorporated by reference herein.

[0030] According to some examples herein, the implant may comprise a shell having a total thickness ranging from about 0.010 inch to about 0.040 inch, such as from about 0.013 inch to about 0.040 inch, from about 0.010 inch to about 0.020 inch, from about 0.012 inch to about 0.015 inch, from about 0.010 inch to about 0.015 inch, from about 0.013 inch to about 0.025 inch, from about 0.015 inch to about 0.030 inch, or from about 0.020 inch to about 0.040 inch. The shell may comprise at least one layer or a plurality of layers, for example, having a total thickness of at least 0.01 inch, at least 0.012 inch, at least 0.015 inch, at least 0.02 inch, at least 0.025 inch, at least 0.03 inch, at least 0.035 inch, or at least 0.04 inch. Elongation and ultimate breaking strength of the shell may be measured in accordance with Non-active surgical implants - Mammary implants - Particular requirements ISO 14607:2018.

[0031] According to some aspects of the present description, the implant shell may comprise a plurality of layers. For example, the shell may comprise from 1 to 15 layers, from 2 to 8 layers, from 3 to 7 layers, from 4 to 15 layers, from 6 to 8 layers, from 10 to 13 layers, or from 12 to 15 layers. For example, the shell may comprise at least 1, 2, 3, 4, 5, 6, or 7 or more layers, for example, 2 to 15 layers, 3 to 7 layers, 1 to 5 layers, or 4 to 8 layers. In some cases, one or more of the layers, or all of the layers, may comprise silicone. For example, one or more of the layers, or all of the layers, may comprise polydimethylsiloxane.

[0032] According to some examples herein, the shell comprises at least two different types of layers, for example, having different chemical compositions. In some examples, the number of each of the two types of layers may be 1, 2, or 3 layers. Each layer may have the same thickness, or one or more layers may have a different thickness from one or more other layers of the shell. The shell may include at least two layers including a colored layer, for example, a low-diffusion barrier layer. One or more low-diffusion barrier layers may be useful, for example, for implants intended to remain in the body for a relatively long period of time, for example, to inhibit leakage of materials within the implant into the body. For example, implants that contour the body such as breast implants with a filler may include one or more low-diffusion barrier layers. In some cases, for example, for implants that do not include a filling and/or implants intended to be placed inside the body for a relatively shorter amount of time, the implant does not include a low-diffusion barrier layer. For example, such an implant may include a single type of layer, for example, one or more layers having the same chemical composition. Exemplary implants that do not comprise a barrier layer may include, for example, calibrators, tissue expanders, and tissue bisectors.

[0033] When present, the barrier layer(s) may have any desired color, such as blue, green, yellow, pink, orange, purple, or other colors. In some cases, the barrier layer has the same color as the other layers (including non-barrier layers) present in the enclosure. The low-diffusion barrier layer(s) may have a different chemical composition from the chemical composition of other layers. For example, the barrier layer(s) may comprise a silicone elastomer having a polysiloxane backbone and substituted or pendant functional groups that inhibit silicone permeation through the layer. The silicone elastomer may comprise polydimethylsiloxane. Exemplary functional groups include, but are not limited to, phenyl groups and fluorine groups. For example, the barrier layer(s) may comprise silicone substituted with one or more diphenyl groups, methylphenyl groups, trifluoropropyl groups, and combinations thereof.

[0034] Fig. 4 shows an exemplary configuration of shell layers, according to some aspects of the present description. As illustrated, the shell 400 comprises a plurality of layers, including one or two types of layers. For example, the shell may comprise one or more first layers 402 and one or more second layers 404. In this example, the shell 400 is represented with five first layers 402 and one second layer 404; however, the shell may include more or less than five first layers and/or more than one second layer 404. Fig. 4 shows the second layer 404 as the innermost layer of the shell (for example, in contact with a fill 406 enclosed in the shell 400). In other examples, the enclosure may include two or more second layers positioned as the outermost layer(s) of the enclosure or between two first layers 402. Additionally, the enclosure may include two or more second layers 404 with one or more first layers 402 between the second layers 404.

[0035] The second layer(s) 404 may have a different chemical composition from the first layer(s) 402. For example, the second layer(s) may be low-diffusion barrier layer(s), which may minimize or prevent diffusion of the filling through the shell wall (e.g., to minimize or prevent filling leakage out of the implant). As shown in Fig. 4, the low-diffusion barrier layer(s) may form the innermost layer of the shell, following the filling 406, such as saline solution or a gel (e.g., silicone gel). The shell layers may be in direct contact with each other, so that the outer and/or inner surface of one layer is completely covered by an adjacent layer.

[0036] The implant may include an adhesive, for example, affixed to the shell. For example, the shell may be prepared by a molding process that leaves an opening in the shell, wherein the adhesive is affixed to the shell to cover the opening. In an exemplary process, a mandrel may be used to prepare a body contour implant, such as a breast implant. The adhesive may comprise the same or different material(s) as the shell. The implants herein may include an adhesive possessing any of the characteristics of skin adhesives described in US 9,901,438 and/or WO 2017/196973, each of which is incorporated by reference herein.

[0037] The adhesive can be located in any suitable position along the sheath. Figs. 3A, 3B, and 3C illustrate, in side view, examples of implants 300, 320, 340 with skin adhesives 302, 322, 342 placed in different locations, according to the present description. Each implant 300, 320, 340 is symmetrical about the xy plane around its equator 306, 326, 346, respectively, each implant 300, 320, 340 having two apices 304, 324, 344 opposite each other, corresponding to a posterior lateral apex and an anterior lateral apex. Fig. 3C shows an implant 340 having an adhesive 342 on one of the two apices 344.

[0038] According to some aspects of the present description, the implant may include an adhesive located in a position other than an apex. For example, Figs. 3A and 3B show implants 300, 320 having respective skin adhesives 302, 322 located between an apex 304, 324 and the equator 306, 326 of each implant. The shortest distance between the adhesive and the equator (for example, a shortest distance d in Fig. 3B) can be greater than zero and/or less than about 25 mm, such as a distance of at least 1 mm, at least 2 mm, at least 5.5 mm, at least 7 mm, at least 9 mm, at least 10 mm, at least 13 mm, at least 15 mm, at least 18 mm, at least 19 mm, at least 20 mm, at least 22 mm, or at least 24 mm. Additionally, or alternatively, the shortest distance between the adhesive and the equator may be greater than zero and less than or equal to 30 mm, less than or equal to 25 mm, less than or equal to 20 mm, less than or equal to 19 mm, less than or equal to 18 mm, less than or equal to 15 mm, less than or equal to 13 mm, less than or equal to 10 mm, less than or equal to 9 mm, less than or equal to 7 mm, less than or equal to 5 mm, less than or equal to 3 mm, less than or equal to 2 mm, or less than or equal to 1 mm. For example, the minimum distance between the adhesive and the equator can vary from approximately 1 mm to approximately 30 mm, approximately 5 mm to approximately 25 mm, approximately 10 mm to approximately 20 mm, approximately 1 mm to approximately 5 mm, approximately 3 mm to approximately 7 mm, approximately 5 mm to approximately 10 mm, approximately 2 mm to approximately 12 mm, approximately 7 mm to approximately 15 mm, approximately 3 mm to approximately 6 mm, approximately 8 mm to approximately 12 mm, approximately 7 mm to approximately 9 mm, approximately 10 mm to approximately 15 mm, or approximately 17 mm to approximately 23 mm, for example, as a minimum distance of approximately 3 mm, approximately 3.5 mm, approximately 4 mm, approximately 4.5 mm, approximately 5 mm, approximately 5.5 mm, approximately 6 mm, approximately 6.5 mm, or about 7 mm. In some examples, at least a portion of the adhesive is located at the equator. For example, the center of the adhesive may lie along or near the equator, for instance, located at an angle of about 90 degrees with respect to the posterior lateral apex and/or anterior lateral apex.

[0039] The shape of the sticker can generally be circular, elliptical or polygonal (e.g., triangular, square, rectangular, pentagonal, etc.). The width and/or length of the sticker (diameter in the case of a circular shape) can vary from about 10 mm to about 40 mm. For example, the sticker may have a length, width and/or diameter varying from about 10 mm to about 35 mm, about 15 mm to about 25 mm, about 10 mm to about 15 mm, about 12 mm to about 18 mm, about 24 mm to about 28 mm, about 20 mm to about 25 mm, or about 25 mm to about 35 mm.

[0040] According to some aspects of this description, the implant may include text (e.g., letters, words, numbers, signs and/or symbols) printed on it. For example, the implant may include one or more labels with identifying information, such as the name and/or location of the manufacturer, the model number, size dimensions (e.g., diameter, volume, projection, etc.), the date of manufacture and/or other identifying information. The label(s) may be located on or incorporated within the outer surface of the implant. In the case of an implant with a shell, such as a breast implant or other body contouring implant, one or more labels may be printed on or within a portion of the shell or a component attached to the shell.

[0041] For example, the implant may include an adhesive as discussed previously, where the adhesive includes printed text useful for identifying the implant. In some cases, the text may be printed on the outer surface of the adhesive, so that the text is raised relative to the rest of the implant's outer surface. Additionally, or alternatively, the printing surface may be inverted, where the text is recessed relative to the rest of the implant's outer surface and/or printed on the inner surface of the adhesive that makes contact with the implant filling. Having an inverted printing surface can help promote implant symmetry and avoid an irregular outer surface that could lead to adverse reactions upon contact with breast tissue once implanted. In some examples, the outer surface of the implant may include a label that does not have raised text, the printing surface being inverted. Additionally, for example, a portion of the implant's outer surface other than the adhesive may include a label.

[0042] The outer surface of the adhesive may be textured, for example, with the same or different surface texture as the adjacent surfaces of the surrounding housing. For example, the adhesive may have any of the surface features described in WO 2017/196973, WO 2015/121686 and/or WO 2017/093528, each of which is incorporated herein by reference. When the adhesive has the same or substantially the same surface texture as the rest of the housing, the implant may have a homologous surface texture. The implant filling herein may comprise a fluid, such as a gel, a liquid, or a gas. Exemplary gels include, but are not limited to, silicone and other biocompatible polymers. Exemplary liquids include, but are not limited to, saline solution. Exemplary gases include, but are not limited to, air. Additionally, or alternatively, the filling may comprise a solid material, such as a biocompatible scaffold, optionally a biocompatible polymer. According to some aspects of the present description, the filling may comprise a gel having a viscosity suitable to simulate natural tissue, for example, the gel being gravity-responsive so that the maximum projection point of the implant changes as the patient moves from a resting position to a supine position. Suitable exemplary gels for fillings herein may have a gel penetration value (1/10 mm) ranging from about 10 to about 60. For example, the implants herein may comprise a gel filling having a penetration value (1/10 mm) ranging from about 10 to about 30, from about 20 to about 35, from about 50 to about 60, from about 35 to about 55, from about 15 to about 30, or from about 10 to about 20. The penetration value is a factor that measures the firmness of a colloid, such as a silicone gel. The penetration value can be measured according to ISO 14607:2018. The combination of shell elasticity and gel viscosity can provide certain benefits for implantation in a minimally invasive procedure, for example, in an incision of about 2 cm or less.

[0043] The implants herein may include information useful in identifying and/or characterizing the implant. In some aspects of the present description, the implant may include a guidance mark (e.g., a radiopaque marker), a traceability device such as a radio frequency identification (RFID) device, and/or one or more sensors. For example, the implant may include a unique device identifier (UDI), optionally attached to, or otherwise incorporated into, a portion of the implant shell and/or adhesive. The UDI may include, for example, a transponder. In cases where the implant shell includes an adhesive, the transponder may be located close to the adhesive (e.g., positioned near an inner surface of the adhesive) or may be located in an area of the implant different from the adhesive (including, for example, near an inner surface of the shell separate from the adhesive).

[0044] Figs. 3A-3C illustrate exemplary transponders 308, 328, 348 (also referred to as micro-transponders) associated with their respective implants 300, 320, 340. The transponder may be in any area at or near an apex (e.g., posterior apex or anterior apex) and/or may be near the adhesive. For example, Figs. 3A and 3B illustrate examples where transponders 308, 328 are placed as fillers at or near the posterior or anterior apex, while skin adhesives 302, 322 are located between the posterior or anterior apex and the equator, while Fig. 3C illustrates an example where transponder 348 and adhesive 342 are both at or near the posterior or anterior apex. In some examples, the transponder may be placed within the filler close to the adhesive, but not affixed or otherwise coupled to the adhesive. In other examples, the transponder may be coupled to an inner surface of the housing or adhesive, or placed between two layers of the housing or adhesive, for example, if it is desired to have the transponder located in a position other than the rear or front apex.

[0045] The transponder may have RFID capability for post-implant device recognition and traceability. For example, information stored in the transponder may be readable by an external device, such as an RFID reader. Any of the transponders and/or readers described in US 9,673,516 and/or US 10,176,412, each incorporated by reference herein, may be included in the implants of the present description. Exemplary transponders may comprise, for example, an antenna assembly comprising ferromagnetic and/or non-ferromagnetic materials.

[0046] In at least one instance, the implant comprises a transponder that does not include ferromagnetic materials. For example, the transponder may comprise one or more plastics, such as polyetheretherketone (PEEK), a ceramic, silica, or other nonferromagnetic material(s). In this way, the implant may be compatible with diagnostic imaging procedures, such as magnetic resonance imaging (MRI). The transponder antenna assembly may comprise a conductive nonferromagnetic material, such as copper or aluminum, among other suitable nonferromagnetic metals. Such metals may be in the form of a metal wire, optionally an enameled wire, for example, configured in a coil wound around a nonferromagnetic core.

[0047] As mentioned earlier, the implant shell can be prepared by dip molding. For example, each layer can be formed by immersing a mold (e.g., a mandrel) in a dispersion, for example, comprising a silicone material, and waiting a sufficient period of time for the solvent to volatilize (devolatilization time), so that the dispersion forms a layer. The mold can have a symmetrical shape in order to produce an implant shell with the desired symmetry as discussed earlier. For example, a mandrel can have a head that is generally round, oval, or teardrop-shaped, the mandrel having a handle or rod attached to or protruding from the head for gripping during the dip molding process. When it is desired that the adhesive be located at an apex (e.g., anterior apex or posterior apex), the mandrel head can be centered with respect to the handle so as to leave an opening in the shell at the apex. When it is desired that the adhesive be located in a position other than an apex (for example, between the equator and the anterior or posterior apex), the mandrel head can be offset relative to the handle in such a way as to leave an opening between the apex and the equator. That is, a longitudinal geometric axis of the handle is offset from a geometric z-axis of the mandrel head that connects the two apices of the head.

[0048] Suitable exemplary dispersions for forming silicone layers for an implant shell according to the present description are discussed below. The dispersions for preparing the first layer(s) 402 and the second layer(s) 404 and/or additional layers may be a silicone dispersion, for example, prepared from two components.

[0049] For example, to prepare the first layer(s) 402, a first dispersion can be prepared from a two-part curable system (part A and part B), for example, using a platinum catalyst. Each component/part may comprise a dispersion of siloxanes and silicones. For example, part A may comprise a high-strength silicone dispersion of siloxanes and silicones, dimethyl, vinyl-terminated group and silanamine, 1,1,1-trimethyl-N(trimethylsilyl)-, hydrolysis products with silica. Part B may comprise a high-strength silicone dispersion of siloxanes and silicones, dimethyl, vinyl-terminated group and siloxanes and silicones, dimethyl, hydrogen methyl.

[0050] Additionally, for example, to prepare the second layer(s) 404 (e.g., low diffusion barrier layer(s)), a second dispersion can also be prepared from a two-part curable system (part A and part B), for example, using a platinum catalyst, optionally with a pigment or dye (e.g., in the form of a colored liquid silicone elastomer) to result in a colored dispersion. Incorporating a pigment or dye can aid in quality control to visually confirm that the low diffusion barrier layer(s) is/are present and continuous throughout the enclosure. Part A may comprise a silicone dispersion comprising xylenes (o-, m-, p- isomers) and silanamine, 1,1,1-trimethyl-N-(trimethylsilyl)-, hydrolysis products with silica. Part B may comprise a silicone dispersion comprising xylenes (o-, m-, p-isomers), silanamine, 1,1,1-trimethyl-N-(trimethylsilyl)-, hydrolysis products with silica, siloxanes and silicones, dimethyl, methyl hydrogen and cyclohexanol, 1-ethynyl-. The colored dispersion may comprise a silicone elastomer having any desired color, such as blue, green, yellow, pink, orange, purple, etc. For example, a second blue 404 layer may be prepared from a liquid silicone elastomer comprising blue pigment 15:2, phthalo blue (NC a-Form), phthalocyanine blue bs, or (29H,31H-phthalocyaninate(2-)-N29,N30,N31,N32)copper. Other biocompatible dyes and/or pigments compatible with silicone dispersions may be used in the shell layer(s), for example, one or more second layers 404, for the implants herein.

[0051] For any of the first dispersion used to prepare the first layer(s) 402 and/or the second dispersion used to prepare the second layer(s) 404, parts A and B may be combined in a weight ratio ranging from about 1:2 to about 2:1, such as in a ratio of about 1:1. In some embodiments, for each layer, parts A and B may be combined in a weight ratio of at least about 1:10, 1:9, 1:8, 1:7, 1:6, 1:5, 1:4, 1:3, 1:2, 1:1 or more. In some embodiments, for each layer of the implant shell, parts A and B may be combined in a weight ratio of at most about 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, 1:1 or less. An organic solvent, such as xylene, may be added to achieve a desired viscosity or viscosity range.

[0052] For the dispersion used to prepare the second layer(s) 404 (e.g., low diffusion barrier layer(s)), the amount of colored liquid silicone elastomer (containing the pigment or dye) may vary from about 0.01% to about 0.05% by weight, such as from about 0.01% to about 0.05% by weight, relative to the weight of the dispersion formed from mixing part A and part B. For example, the second dispersion used to prepare low diffusion barrier layers 404 may comprise part A and part B in a weight ratio of about 1:1, and from 0.01% to about 0.05% by weight of blue pigment 15:2, phthalo blue (NC α-Form), phthalocyanine blue bs, or (29H,31H-phthalocyaninato(2-)-N29,N30,N3 l,N32)copper. The amount of colored liquid silicone elastomer may be at least 0.01%, at least 0.05%, at least 0.1%, at least 0.15%, at least 0.2%, at least 0.3%, at least 0.4%, or at least 0.5% by weight relative to the weight of the dispersion formed from mixing part A and part B. Additionally, or alternatively, the amount of colored liquid silicone elastomer may be less than or equal to 0.5%, less than or equal to 0.4%, less than or equal to 0.3%, less than or equal to 0.2%, less than or equal to 0.1%, less than or equal to 0.05%, less than or equal to 0.03%, or less than or equal to 0.01% by weight relative to the weight of the dispersion formed from mixing part A and part B.

[0053] Exemplary methods for manufacturing implant housings according to the present description may comprise one or more steps of testing dispersions, mixing the dispersions, molding a housing (dip molding), curing the housing, removing the housing from the mold and/or performing quality inspections. The manufacturing methods according to the present description may comprise some, but not all, of the steps discussed above. The methods herein may be used to manufacture a plurality of housings simultaneously.

[0054] In an exemplary method, a silicone dispersion can be prepared for each type of layer 402, 404 to be included in the implant shell. Part A and Part B for each type of dispersion can be mixed in a suitable ratio as discussed previously, such as a 1:1 ratio, a 1:2 ratio, a 2:1 ratio, or a 1:1.5 ratio. A solvent can be added to obtain a desired viscosity or range of viscosities, as described herein. For the second layer(s) 404 (e.g., low diffusion barrier layer(s)), a pigment, optionally in the form of a colored liquid silicone elastomer, can be added once Part A and Part B have been combined. The viscosity in combination with the solvent devolatilization time can allow the shell to be substantially free of, or not possessing, cosmetic defects, and in a thickness or range of thicknesses.

[0055] Molds can be selected according to the desired implant type. For example, molds suitable for use here may have a symmetrical shape, possessing at least one plane of symmetry. Then, the mold can be introduced into the selected dispersion (e.g., a first dispersion to prepare a first layer 402) to coat the mold for a period of time equal to the devolatilization time, and then the coated mold can be reintroduced into the same dispersion (e.g., the first dispersion to prepare another first layer 402) or a different dispersion (e.g., a second dispersion to prepare a second layer 404) to build another layer in the shell. Immersion molding can be repeated until the desired number of layers and total shell thickness are obtained. Illustrative devolatilization times may vary from about 10 minutes to about 45 minutes, such as from about 15 minutes to about 35 minutes, from about 20 minutes to about 40 minutes, from about 10 minutes to about 20 minutes, or from about 35 minutes to about 45 minutes. The devolatilization time may be at least 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes or more. In some embodiments, the devolatilization time may be at most 45 minutes, 40 minutes, 35 minutes, 30 minutes, 25 minutes, 20 minutes, 15 minutes, 10 minutes, 5 minutes or less.

[0056] Table 1 below illustrates several exemplary 6-layer shells that include two different types of layers, for example, one or more first layers 402 and one or more second layers 404, wherein the second layer(s) 404 have a different chemical composition from the first layer(s) 402. The second layer(s) 404 may optionally be low-diffusion barrier layer(s), or may be non-barrier layers having a different chemical composition from the other non-barrier layer(s). In Table 1, implant shell A corresponds to the example shown in Fig. 4. For example, to prepare implant shell A, a mold (e.g., mandrel for a body contour implant) may be immersed in a first dispersion to form a layer 402 close to the surface of the mold. After the devolatilization time, the coated mold can be re-immersed in the first dispersion to form an additional 4O2 layer; and after the devolatilization time, the coated mold can again be immersed in the first dispersion to form an additional 4O2 layer, and so on, until the coated mold is immersed in a second dispersion to form a second 4O2 layer, as a low-diffusion barrier layer. One skilled in the art will recognize that the configurations in Table 1 are illustrative only, and some or more than 6 layers may be prepared, and layers may be provided in a different order.

[0057] The shell can be cured to catalyze the polymerization of the shell material (e.g., silicone). When the dispersion comprises silicone, for example, the curing can crosslink the silicone layers. The curing temperature can vary from about 115.0°C to about 135.0°C, such as from about 120.0°C to about 130.0°C, from about 122.0°C to about 128.0°C, from about 125.0°C to about 130.0°C, or from about 125.0°C to about 135.0°C. For example, the curing temperature can be 125.0°C ± 5.0°C. The curing temperature can be at least 100.0°C, 105.0°C, 110.0°C, 115.0°C, 120.0°C, 125.0°C, 130.0°C, 135.0°C, 140.0°C or more. The curing temperature can be at most 140.0°C, 135.0°C, 130.0°C, 125.0°C, 120.0°C, 115.0°C, 110.0°C, 105.0°C, 100.0°C or less. The healing process can be carried out for a period of time (or healing time) ranging from approximately 60 minutes to approximately 100 minutes, such as approximately 70 minutes to approximately 90 minutes, approximately 85 minutes to approximately 95 minutes, or approximately 80 minutes to approximately 90 minutes. The healing time can be 82.0 ± 5.0 minutes or 85.0 ± 2.0 minutes. The healing time can be at least approximately 50 minutes, 55 minutes, 60 minutes, 65 minutes, 70 minutes, 75 minutes, 80 minutes, 85 minutes, 90 minutes, 95 minutes, 100 minutes or more. In some modalities, the healing time can be a maximum of approximately 100 minutes, 95 minutes, 90 minutes, 85 minutes, 80 minutes, 75 minutes, 70 minutes, 65 minutes, 60 minutes, 55 minutes, 50 minutes or less.

[0058] The casing can be removed from the mold after curing. The casing can then be inverted, so that the layer furthest from the mold defines the innermost surface of the casing, and the previous layer in contact with the mold defines the outermost surface of the casing.

[0059] In some cases, the mold surface may have a texture, so that the outermost surface of the implant is textured. For example, the shell may be prepared using a mandrel having a textured surface, optionally wherein the mandrel surface has been textured using sandblasting with abrasive particles to achieve the desired surface characteristics (a mirror image of the desired peaks, valleys, roughness, kurtosis, density of contact points, etc.). In some instances, the shell may be prepared using a mandrel as described in WO 2017/196973, incorporated herein by reference.

[0060] The enclosure may optionally be inspected for quality, for example, to identify and discard any defective enclosures. In some cases the thickness of the enclosure may be measured, for example, at various locations on the enclosure.

[0061] As mentioned earlier, the implant may comprise a filling, which may be introduced into a cavity formed by the shell, such that the filling partially or completely fills the cavity. In some examples herein, the filling comprises a silicone gel. The silicone gel may be prepared by combining a first mixture and a second mixture. The first mixture may comprise a mixture of siloxanes and silicones, dimethyl, and a vinyl-terminated group. The second mixture may comprise a mixture of siloxanes and silicones, dimethyl, hydrogen methyl, dimethyl, and a vinyl-terminated group. To prepare the filter, the first mixture may be mixed with the second mixture in a ratio that provides a suitable gel penetration value, such as between 50-60 1/10 mm. In some embodiments, the first mixture and the second mixture may be combined in a weight ratio ranging from about 1:2 to about 2:1, such as in a ratio of about 1:1. In some embodiments, the first mixture and the second mixture may be combined in a weight ratio (first mixture : second mixture) ranging from about 1:4 to about 4:1 (about 0.25 to about 4), such as a weight ratio ranging from about 1:3 to about 3:1 (about 0.33 to about 3), or about 1:2 to about 2:1 (about 0.5 to about 2). For example, the weight ratio of the first mixture to the second mixture may range from about 0.5 to about 2, about 1 to about 3.5, about 2.5 to about 3.5, about 3 to about 3.3, or about 2.8 to about 3.2. In some examples, the first mixture and the second mixture may be combined in a weight ratio (first mixture : second mixture) of at least 1:10, 1:9, 1:8, 1:7, 1:6, 1:5, 1:4, 1:3, 1:2, 1:1 or more. Additionally, for example, the first mixture and the second mixture may be combined in a weight ratio (first mixture : second mixture) of at most about 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, 1:1 or less.

[0062] Implants can be mounted by introducing the filler material into the shell, which can occur before or after an adhesive is applied to the shell. In some examples, an adhesive can be applied to the shell before introducing a filler material into a cavity defined by the shell. For example, a silicone adhesive matching the dimensions of an opening resulting from the molding process can be applied and vulcanized to seal the adhesive in the shell. Optionally, the shell can be leak-tested to confirm that the adhesive has been securely bonded. The adhesive can then be cured, for example, with heat and/or pressure. A suitable filler material, for example, silicone gel, can be introduced into the shell, such as by injection through the adhesive. In some examples, the filler can be introduced into the shell at 100% or less of the nominal volume defined by the mold (e.g., the mandrel head) in order to achieve the desired final shape.

[0063] Before or after the introduction of the filling, the process may include introducing a UDI, for example, a transponder, into the implant. For example, the transponder may be placed inside the shell before affixing the adhesive to the shell, after affixing the adhesive to the shell but before injecting a filling, or after injecting a filling into the shell cavity. The transponder may be heavier than the filling, so that the transponder falls by gravity to rest on the inner surface of the shell, the transponder being mobile through the filling before the filling cures. The implant may optionally be vacuum tested, for example, to remove air bubbles, and then the implant may be sealed. For example, the filling hole in the adhesive may be closed with a suitable adhesive, such as a curable silicone-based adhesive.

[0064] Finally, the filling can be cured, for example, in a gel curing cycle. The implant can be placed in a cavity of a substrate, such as a curing cup having a concave surface to receive the implant, in order to maintain symmetrical shape (e.g., symmetry of posterior and anterior apices) during the curing process. In some examples, the substrate may comprise a heat-resistant material, such as a ceramic. The implant can then be inspected for quality (to identify and discard defective implants).

[0065] Non-limiting examples of implants according to the description presented include the following:

[0066] In at least one instance, the implant is a round body contour implant comprising a silicone shell and silicone gel filling, wherein the shell includes an adhesive at or near a posterior or anterior apex of the shell. The adhesive may be generally circular in shape and have a diameter of about 25 mm to about 30 mm, such as about 26 mm, about 27 mm, about 28 mm, or about 29 mm. The implant may have three planes of symmetry, for example, around the xy plane (posterior side symmetrical to the anterior side), around the xz plane (left side symmetrical to the right side), and around the yz plane (upper portion symmetrical to the lower portion).

[0067] In at least one instance, the implant is a round body-contouring implant comprising a silicone shell and silicone gel filling, wherein the shell includes an adhesive at or near a posterior or anterior apex of the shell. The adhesive may be generally circular in shape and have a diameter of about 15 mm to about 25 mm, such as about 16 mm, about 17 mm, about 18 mm, about 19 mm, about 20 mm, about 21 mm, about 22 mm, about 23 mm, or about 24 mm. The implant may have three planes of symmetry, for example, around the xy plane (posterior side symmetrical to anterior side), around the xz plane (left side symmetrical to right side), and around the yz plane (upper portion symmetrical to lower portion).

[0068] In at least one instance, the implant is a round body contour implant comprising a silicone shell and silicone gel filling, wherein the shell includes an adhesive that is not centered on the posterior or anterior apex of the shell. That is, the adhesive is located between an apex and the equator of the implant, for example, the adhesive having a shorter distance from the equator of about 3 mm to about 7 mm, such as about 3.5 mm, about 4 mm, about 4.5 mm, about 5 mm, about 5.5 mm, about 6 mm, or about 6.5 mm between the adhesive and the equator. For example, the adhesive may generally be circular in shape and have a diameter of about 25 mm to about 30 mm, such as about 26 mm, about 27 mm, about 28 mm, or about 29 mm, or a diameter of about 15 mm to about 25 mm, such as about 16 mm, about 17 mm, about 18 mm, about 19 mm, about 20 mm, about 21 mm, about 22 mm, about 23 mm, or about 24 mm. The implant may have three planes of symmetry, for example, around the xy plane (posterior side symmetrical to the anterior side), around the xz plane (left side symmetrical to the right side), and around the yz plane (upper portion symmetrical to the lower portion).

[0069] In at least one instance, the implant is a round body contour implant comprising a silicone shell and silicone gel filling, wherein the shell includes an adhesive that is not centered on the posterior or anterior apex of the shell. That is, the adhesive is located between an apex and the equator of the implant, for example, the adhesive having a shorter distance to the equator of about 10 mm to about 40 mm, such as about 15 mm to about 25 mm, for example, about 18 mm, about 18.5 mm, about 19 mm, about 19.5 mm, about 20 mm, about 20.5 mm, about 21 mm, about 21.5 mm, or about 22 mm between the adhesive and the equator. For example, the adhesive may generally be circular in shape and have a diameter of approximately 25 mm to approximately 30 mm, such as approximately 26 mm, approximately 27 mm, approximately 28 mm, or approximately 29 mm, or a diameter of approximately 15 mm to approximately 25 mm, such as approximately 16 mm, approximately 17 mm, approximately 18 mm, approximately 19 mm, approximately 20 mm, approximately 21 mm, approximately 22 mm, approximately 23 mm, or approximately 24 mm. The implant may have three planes of symmetry, for example, around the xy plane (posterior side symmetrical to the anterior side), around the xz plane (left side symmetrical to the right side), and around the yz plane (upper portion symmetrical to the lower portion).

[0070] The following examples are intended to illustrate the present description without, however, being limiting in nature. It is understood that the present description encompasses additional modalities consistent with the previous description and the following examples.

EXAMPLES Example 1

[0071] Several implants, including four breast implants (A, B, C, and D) and an inflatable tissue bisector (E), were prepared according to Table 2. The penetration value (1/10 mm) of the silicone gel used for the AD breast implants ranged from 10 to 60, where higher penetration values correspond to lower viscosity characteristics. Table 2

[0072] Photographs of breast implants A-D (lateral views) are shown in Fig. 5. Implants A-C had flat posterior surfaces and lacked symmetry around the xy plane (around their equators). In comparison, implant D according to the present description had symmetrical posterior and anterior surfaces. The viscosity of the silicone gel used for implant D allowed the gel to respond to gravity and maintain symmetry provided by the implant shell shape.

[0073] Any aspect or feature in any embodiment may be used with any other embodiment presented herein. It will be apparent to those skilled in the art that various modifications and variations may be made to the implants, implant features, and processes described without departing from the scope of the description. Other embodiments will become apparent to those skilled in the art from consideration of the specification and practice of the description described herein. The specification and examples are intended to be considered merely illustrative.

Claims (11)

1. Medical implant (100, 200, 300, 320, 340) which is a breast implant, characterized in that it comprises: an anterior side (104, 204) having a first apex (304, 324, 344); a posterior side (106, 206) having a second apex; an equator (102, 202, 306, 326, 346) separating the anterior side (104, 204) from the posterior side (106, 206) to allow for similar or equal projection at the first and second apices; wherein the implant comprises a shell and a filling within a cavity formed by the shell, wherein the filling is in the form of a fluid with viscosity or penetration value suitable to simulate the movement of natural breast tissue and has been introduced into the cavity so as to completely fill the cavity; wherein the the shell and the filling each comprise a biocompatible material; wherein the implant comprises at least two planes of symmetry; and wherein one of the at least two planes of symmetry corresponds to an equator of the implant, with one posterior side of the implant being symmetrical with respect to the equator with respect to an anterior side of the implant. 2. Medical implant (200), according to claim 1, characterized in that the implant has three planes of symmetry. 3. Medical implant (200), according to claim 1, characterized in that the equator (202) corresponds to an xy plane; the second plane of symmetry corresponds to an xz plane, which defines the left and right sides (208), 210) of the implant; and in that the implant (200) does not exhibit symmetry with respect to a yz plane, which defines the upper and lower sides (212, 214) of the implant (200). 4. Implant (100), according to claim 1, characterized in that the implant has a round shape. 5. Implant (100), according to claim 1, characterized in that the implant has an oval shape. 6. Implant (100), according to claim 1, characterized in that the implant has a teardrop shape. 7. Method for manufacturing the implant (100) as defined in any one of claims 1 to 6, characterized in that preparing the implant shell comprises: applying a first silicone dispersion to a mold surface to form at least one first layer of the shell; and applying a second silicone dispersion to at least one first layer to form at least one second layer, wherein the at least one second layer is a low diffusion barrier layer; wherein the second silicone dispersion comprises a colored silicone elastomer that includes a dye or a pigment, and the first silicone dispersion does not include a dye or a pigment. 8. Method according to claim 7, characterized in that the second silicone dispersion comprises from about 0.01% to about 0.05% by weight of the colored silicone elastomer, relative to the total weight of the second silicone dispersion, optionally wherein the colored silicone elastomer is blue, green, yellow, pink, orange or purple. 9. Method according to claim 7 or 8, characterized in that it further comprises removing the mold casing and inverting the casing, optionally wherein one surface of the mold is textured with surface features on the order of nanometers to micrometers, so that an outer surface of the casing, when inverted, is textured. 10. A method, according to any one of claims 7 to 9, characterized in that it further comprises heating the implant to cure a filling gel disposed within a cavity of the housing, in which the implant is placed on a substrate, such as in a cavity of a substrate, during heating to maintain a symmetrical shape of the implant. 11. Mold used in the method, as defined in any one of claims 7 to 10, for manufacturing the implant, characterized in that the mold is a mandrel comprising a head and a handle, the head being offset relative to the handle and having a symmetrical shape having at least two planes of symmetry corresponding to the at least two planes of symmetry of the implant, optionally wherein the head has a textured surface.