Abstract:
A breast implant is provided which includes a filling, or core having a lower overall density relative to silicone gel-filled or saline-filled implant. The core may be a composite including flexible, bodies, for example, air-containing, or gas-containing, bodies, and a gel medium between or around the bodies.

Description:
CROSS-REFERENCE 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 14/695,285, filed on Apr. 24, 2015 which claims priority to, and the benefit of, U.S. Provisional Patent Application Ser. No. 61/984,660, filed on Apr. 25, 2014, the entire disclosure of which is incorporated herein by this specific reference. 
     
    
       [0002]    The present invention generally relates to implantable prosthetic devices and specifically relates to implantable prosthetic devices, for example, breast implants, of reduced weight. 
         [0003]    Reconstructive and cosmetic surgery using prosthetic implants is a common practice. For example, reconstructive breast surgery is commonly practiced to allow reconstruction of a woman&#39;s breast that was affected by procedures such as mastectomy. Cosmetic breast surgery has also become available to amend the appearance of a woman&#39;s breast, for example by adding an implant to increase the size of the breast, to correct asymmetries, change shape and fix deformities. 
         [0004]    For reconstructive and cosmetic surgery, a breast implant is required to be able to provide a specific three-dimensional shape and maintain that shape for many years, typically for at least ten years, from which the implant is introduced into the breast. The implant is also required to provide the implanted breast with the feel of a natural human breast. 
         [0005]    Conventional breast implants typically comprise an outer shell or envelope typically formed from cured silicone elastomer. The shell can be single or multi layered, and can be smooth or textured. The shell, being in the form of an envelope or pocket, encloses or contains a core or filling, usually silicone gel or saline. A saline filling can be contained in the shell before surgery, or may be introduced into the shell during or after surgery. Silicone gel implants typically are implanted in their fully completed form. 
         [0006]    A typical conventional breast implant may weigh between 50 to 1000 grams, depending of course on the volume and the type of material from which is it is made. However, commercially available breast implants, whether filled with silicone gel or saline, generally have an overall product specific gravity close to one, similar to the specific weight of the natural breast tissue. 
         [0007]    Nevertheless, natural breast tissue is a live tissue undergoing a common natural lifecycle just as any other tissue within the body, while a breast implant is “dead weight” contained by body tissue. Both natural breast tissue and breast implants are subjected to forces of gravity. The most common response of both natural breast tissue and breast implants to gravitational force over time is sagging and pulling of the skin and overlying tissue structures. Unfortunately, the rate of sagging may be enhanced in implanted breasts. 
         [0008]    Some breast implant patients may experience other undesirable consequences related to the weight of the implants. Such problems include excess ptosis of the breasts, tissue atrophy, prominence of the implant through breast tissue, back pain, and/or formation of striae on the skin. Reconstructive surgery patients may be especially prone to such problems when much of the natural supporting breast tissue may have been removed as a result of a mastectomy procedure, leaving less tissue to cover and support an underlying implant. For these patients, a lighter weight implant would be especially desirable. 
         [0009]    A variety of products and methods have been proposed to produce a lighter weight breast implant. Shaw, U.S. Pat. No. 4,380,569 discloses the use of hollow glass spheres, which are added to a silicone gel fillers to reduce the overall density, and therefore the weight, of a breast implant. Govrin-Yehudian, U.S. Pat. No. 7,988,731 discloses a double lumen-type breast implant having with materials of differing densities. Schuessler, U.S. patent application Ser. No. 13/327,038, describes a flexible, collapsible prosthesis made of a cellular material. U.S. Pat. No. 5,658,330 to Carlisle, et al. describes a molded foam implant. 
         [0010]    Various proposals in the art have been directed at reducing the weight of breast implants while maintaining a natural look and feel. However, there is still a great need for an improved, lighter weight breast implant. 
       SUMMARY 
       [0011]    The present invention provides a prosthetic implant, for example, a breast implant which has a reduced weight relative to conventional gel or saline implants, and which also has natural look and feel when implanted. 
         [0012]    The implant generally comprises a shell, which may be a conventionally made cured silicone elastomer, and a core, contained within the shell. The core of the present implants has a lower overall density relative to silicone gel or saline. In one aspect, the core comprises a composite material. More specifically, the core may comprise a hollow body or bodies, for example, air-containing, or gas-containing, bodies, and a medium between or around the bodies. The medium may comprise a silicone gel, for example, a fluid silicone gel or a cohesive silicone gel, which surrounds the bodies. 
         [0013]    As used within the scope of the present disclosure, the hollow bodies are considered to be bodies having at least one void or cavity enclosed by a solid material. Hollow bodies include bodies having one of multiple cavities, such as micro-cavities, as well as bodies having cavities of tens of millimeters or greater in size. In some embodiments, the bodies, overall, have a specific gravity of less than 1. Preferably, the bodies provide a lightness to the implant relative to an otherwise identical saline or silicone gel-filled implant not comprising or including the one or more hollow bodies. 
         [0014]    In one aspect, the hollow bodies are extruded or molded bodies, for example, made of a polymer such as a silicone-based polymer, for example, a medical grade, cured silicone polymer. The bodies are constructed with voids or cavities. The voids or cavities contain a gas, for example, air, or other suitable gas or gaseous medium. The bodies may have very thin walls or small diameters or cross sections, and may generally be flexible, soft and pliable. 
         [0015]    In one embodiment, the bodies comprise tubing, for example, silicone tubing. The tubing may have an outer diameter of about 1 mm to about 10 mm, more preferably from about 2 mm to about 5 mm. The tubing is flexible and compressible providing an additional compliance and softness to the device. In some embodiments, the breast implant includes a single continuous length of tubing. In other embodiments, a breast implant includes tubing comprising a plurality of separate lengths of tubing. Each end of the tubing, or segments of the tubing, may be tied off or plugged closed in order to contain the air (or other gaseous) medium within the hollow bore of the tubing, and not allow ingress of the fluid medium portion of the core. 
         [0016]    The fluid medium in which the bodies are contained may be air, saline or other aqueous medium, or gel, for example, silicone gel, for example, cohesive silicone gel. The implant could be constructed as a single lumen, or as a double lumen. 
         [0017]    The hollow bodies may be in the form of other extruded shapes having voids, for example, closed cells, for containing air or other gas. 
         [0018]    In some embodiments, a breast implant is provided comprising a shell, a core or filling enclosed by the shell, and the filling comprising a gel medium and a plurality of gas-containing bodies. The filling has a relatively higher concentration of gas-containing bodies in at least one region of the filling relative to another region of the filling, thereby providing an implant having a variable density. In some embodiments, gas-containing bodies are tubes, and the tubes are more highly concentrated in a posterior portion of the implant than in an anterior portion of the implant. 
         [0019]    Each and every feature described herein, and each and every combination of two or more of such features, is included within the scope of the present invention provided that the features included in such a combination are not mutually inconsistent. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    The present invention may be better appreciated, and its aspects, advantages and features better understood, with consideration given to the following Detailed Description and Drawings in which: 
           [0021]      FIG. 1  is a cross-sectional view of an implant in accordance with an embodiment of the invention; 
           [0022]      FIG. 2  is a perspective view of a single hollow body component of the implant shown in  FIG. 1 ; 
           [0023]      FIG. 3  is a perspective view of a plurality of hollow bodies which may be used as an alternative to the single hollow body component shown in  FIG. 2 ; 
           [0024]      FIG. 4  is a cross sectional view of the hollow body component shown in  FIG. 2 . 
           [0025]      FIGS. 5 and 6  show, respectively, two different alternative cross-sectional shapes for hollow body components such as shown in  FIG. 2 ; 
           [0026]      FIGS. 7, 8 and 9  show respectively, cross-sections of three other hollow body components; 
           [0027]      FIG. 10  is a perspective view of yet another hollow body component of an implant of the present invention; 
           [0028]      FIGS. 11 and 12  are cross sectional views of additional breast implants in accordance with different embodiments of the invention; 
           [0029]      FIG. 13  is a cross-sectional view of an implant in accordance with yet a still further embodiment of the invention; 
           [0030]      FIG. 14  is a perspective view of yet another hollow body component of an implant of the present invention; 
           [0031]      FIG. 15  is an illustration showing arrangement of multiple hollow bodies shown in  FIG. 14 ; and 
           [0032]      FIG. 16  shows yet another embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0033]    Turning now to  FIG. 1 , a breast implant  10  in accordance with one embodiment, is shown in simplified form, in a breast  12 . The implant  10  generally comprises a shell  14  and a filling  16  enclosed by the shell  14 . The filling  16  comprises at least one flexible hollow body  18  and a medium  20  containing the body  18 . 
         [0034]    As shown in  FIG. 2 , the body  18  may comprise an elongated body, for example, in the form of a tube  22 . The tube  22  may be sealed for example with appropriate structure  23  in such a manner such the medium  20  (not shown in  FIG. 2 ) does not enter the hollow cavity or bore  24  of the tubing  18 . 
         [0035]    Turning back to  FIG. 1 , the medium  20  may be any suitable fluid medium, for example a liquid medium, for example, saline or other suitable biocompatible liquid medium. 
         [0036]    In some embodiments, the medium  20  is a gel, for example a silicone gel, for example a fluid silicone gel or, alternatively, a more stable, firm silicone gel, such as a substantially non-flowable silicone gel, also sometimes referred to in the industry as a “form stable gel.” Such gels are known in the breast implant art and thus will not be described in greater detail herein. 
         [0037]    As shown, the implant  10  could be constructed with multiple lumens, for example, as a double lumen implant. For example, shell  14  may make up an outer lumen  26  that encloses an inner lumen  28 , which contains the filling  16 . Between the outer lumen  26  and inner lumen  28  may be disposed a silicone gel  30 , or other suitable medium such as saline, which at least partially surrounds the inner lumen  28 . 
         [0038]    Tubing  22  may be made of a soft molded, for example, extruded material, such as a soft silicone or other biocompatible polymeric material. 
         [0039]    In some embodiments, tubing  22  has an outer diameter of between about 1 mm and about 10 mm, for example, between about 2 mm and about 5 mm. Tubing may have an outer diameter of, for example, about 1 mm, about 2 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm, or greater. Tubing  18  may have a wall thickness of between about 0.5 mm and about 4 mm, for example, about 1 mm, about 1.5 mm, about 2 mm, about 2.5 mm, about 3 mm, about 3.5 mm, about 4 mm, about 4.5 mm, or about 5 mm, or greater. Bore  24  may have a diameter of, for example, about 0.5 mm and about 4 mm, for example, about 1 mm, about 1.5 mm, about 2 mm, about 2.5 mm, about 3 mm, about 3.5 mm, about 4 mm, about 4.5 mm, or about 5 mm, or greater. 
         [0040]    In some embodiments filling  16  comprises, or consists essentially of, a single strand of tubing  22 . 
         [0041]    In other embodiments, tubing  22  may be in the form of, or comprise, a plurality of separate tubing segments  22 ′, such as shown in  FIG. 3 . For example, filling  16  may comprise up to about 10, about 20, about 30, about 40, about 50, about 100, or more tubing segments  22 ′. 
         [0042]    Various exemplary cross sectional shapes of tubing  22  are shown in  FIGS. 4-6 .  FIG. 4  shows cylindrical tubing  22  with outer diameter D and inner diameter d defining bore  24 .  FIG. 5  shows tubing  22   a  having a somewhat star shaped cross section defined by a number of ridges, in this embodiment, eight ridges  32 . Other cross sections are contemplated, for example, tubing  22   b  having a rectangular cross section, such as shown in  FIG. 6 , defined by planar portions  34  and intermediate concave portions  36 . 
         [0043]    Still other tubing configurations are contemplated, for example, tubing  22   c ,  22   d  and  22   e  shown in  FIGS. 7-9 , respectively. These configurations are structured to reduce the chance, or to prevent the tubing structure from collapsing. 
         [0044]    For example, tubing  22   c , shown in  FIG. 7 , includes wall  37  and divisor portion  38 , separating bore  24  into separate bores  24   a  and  24   b . Divisor portion  38  prevents tubing  22   c  from collapsing under pressure and maintains shape integrity of tubing  22   c.    
         [0045]    Tubing  22   d , shown in  FIG. 8 , is in the form of a multilayered tubing, for example, a two-layered tubing, including a first material  40 , for example, silicone, and a second material  42 , for example, a fluoropolymer. Tubing  22   d  may be in the form of a sealed body containing air or other gaseous component in a cavity defined by tubing material  40 . Advantageously, second material  42  is a material that substantially or completely prevents diffusion of air (or other gaseous component) out of the tubing  22   d , thereby preventing collapse and maintaining integrity of tubing  22   d.    
         [0046]    Still further, tubing  22   e , shown in  FIG. 9 , is in the form of a cord  47  having voids  46 , instead of the bore  24  of some of the earlier described embodiments. The cord may be an extruded foam material for example, an extruded silicone foam. The foam is preferably a closed-cell foam. 
         [0047]    Turning now to  FIGS. 10 and 11 , a breast implant  110  is shown, which may be substantially the same as implant  10 , except that instead of tubing  22 , hollow bodies  18  are in the form of members  50 , for example, foam-like members  50  having voids  52 , preferably closed voids  52  which contain a gas such as air. Members  50  may have any suitable shape, for example, a cylindrical shape such as shown in  FIG. 10 , and may be made of a foam or sponge-like material  54  that is substantially impermeable by medium  20 . For example, in some embodiments, material  54  may be a cured silicone material and medium  20  may be saline. Members  50  may have an outer diameter of about 1 mm to about 10 mm, for example, between about 2 mm to about 5 mm, and a length of about 1 mm to about 10 mm, for example, between about 2 mm to about 5 mm. Members  50  may be present in the implant in a sufficient number, depending on the size or shape of members  50 , to provide the desired volume and firmness to implant  110 . For example, members  50  may be present in implant  110  in a quantity of about 100, about 1000, about 10,000, or about 100,000 members, for example. 
         [0048]    Members and segments  50  may be sized and shaped such that in plurality, they form a pliable, fluid filler material, such as shown in  FIG. 11 . 
         [0049]    Implant  210 , in accordance with another embodiment shown in  FIG. 12 , may be substantially the same as implant  110 , except that it is a single lumen implant rather than a double lumen implant. 
         [0050]    Turning now to  FIG. 13 , yet another implant  310  in accordance with the invention is shown. 
         [0051]    Implant  310  may be substantially the same as implant  10 ,  110 , or  210  except that the hollow bodies  18  are in the form of members  82  having a somewhat tetrahedral shape which enable them to flow, as a whole, and not become packed together, such as shown in  FIG. 15 . En masse, the members  82  provide a filling of breast implant  310  having a somewhat fluid movement, providing a desired pliable, natural feel and flexibility to the implant  310 . 
         [0052]    The members  82  may include enlarged ends  84 , for example, spherical ends, that provide for separation between adjacent members  82 . Stem regions  86  connecting enlarged ends  84  provide flexibility and interior space for the medium  20  between members  82 . In one embodiment, the tetrahedron shaped members  82  have a maximum dimension of between about 10 mm to about 300 mm, for example, between about 50 mm to about 250 mm, for example, between about 100 mm to about 200 mm. 
         [0053]      FIG. 16  shows yet another embodiment of the invention, in the form of a breast implant  410  having regions of different densities formed by different concentrations of members  22  in the medium  20 . For example, implant  410  includes shell  14  forming an envelope containing medium  20  for example, a silicone gel filler medium  20 , and members  22 , (and/or members  22   a ,  22   b ,  22   c ,  22   d , or any other members described herein) that are concentrated in certain regions of the implant  410 , thus providing a less dense or “lighter” region in the areas having the highest concentration of members  22 , and a more dense, or heavier, region in areas having a lower concentration of members  22 . This concept provides an implant having a desired variable feel or firmness and/or shape retention, for example, an implant having a softer anterior and a firmer anterior, or vice versa. This may be accomplished, for example, by positioning the implant  410  during curing of the filler medium  20 , such that the members  22 , which are buoyant in a substantially liquid, uncured silicone gel, will migrate to and become concentrated in a desired area of the implant  410 . In the embodiment shown, for example, the members  22  are more concentrated in a posterior region  92  of the implant  410 , and relatively less concentrated in an anterior region  94  of the implant  410 . 
         [0054]    In some embodiments, multiple gel fills and curing process steps can be used to position and concentrate the members  22  where desired in the implant  410 , thus creating zones of different densities and feel without the need for a second shell or double lumen design. 
         [0055]    While this invention has been described with respect to various specific examples and embodiments, it is to be understood that the invention is not limited thereto and that it can be variously practiced within the scope of the invention.