Abstract:
A surgically implantable prosthetic device includes a first shell having an exterior surface, an interior surface, and enclosing a lumen, wherein the lumen enclosed by the first shell is able to accommodate a first fluid therein. The prosthetic device further includes a second shell having an exterior surface, an interior surface, and enclosing a lumen, wherein the lumen enclosed by the second shell is able to accommodate a second fluid therein. One or more fitted shells arranged adjacent to and in a graduated relation to each other are situated between the exterior surface of the second shell and the interior surface of the first shell. The one or more shells include an innermost fitted shell and an outermost fitted shell, wherein the innermost fitted shell is adjacent to the exterior surface of the second shell and the outermost fitted shell is adjacent to the interior surface of the first shell.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to surgically implantable prosthetic devices and, more specifically, to mammary prostheses. 
     2. Description of Related Art 
     It has become a practice in the field of surgery to place a prosthetic implant in various areas of the body under any one of various conditions. In cases where cancerous, precancerous, or other abnormal or damaged tissue has been removed, the prosthetic implant is often used as a replacement for the removed tissue and its purpose is to retain the original body contour. An implant of this character provides physical support for the surrounding body tissue, and by filling any voids that are created by the removal of the body tissue preserves the normal outward appearance and feel of the body. Prosthetic devices have also been used to enhance or augment the appearance of body parts. 
     Breast prostheses have long been used for breast augmentation and for reconstructive surgery following a mastectomy. The prostheses are available in numerous sizes and shapes including teardrop, round, low profile, and high profile. Usually, breast prostheses are implanted via a small inframammary or peri-aerolar incision into a pocket dissected deep to the patient&#39;s own breast tissue in front of the pectoral muscle. In certain situations, the prosthesis may be placed behind the various chest muscles. 
     Some prosthetic devices have utilized an outer shell or envelope which is filled with a silicone gel, a saline solution, or other liquid, such as an oil or polymer. Other breast prosthetic devices have utilized an envelope which is filled with a combination of silicone gel and saline solution in separate compartments. Prior art silicone gel devices have tactile properties similar to normal tissue, but suffer from certain disadvantages. First, some silicone may bleed through the envelope and migrate into the tissue. Second, rupture of the envelope of a silicone gel implant is difficult for a patient to detect. Third, silicone gel from a ruptured implant may cause an undesirable tissue response. 
     Some breast prosthetic devices have utilized an outer shell or envelope which is filled with a saline solution. The prior art saline solution filled prosthetic devices suffer from certain disadvantages and lack the proper appearance and tactile properties due to several factors. First, the saline solution displaces too quickly to give the proper tactile properties. Second, the ease of displacement of the saline solution can create a “fluid wave” in the implant presenting an unnatural look of the prosthetic device. Third, when the saline solution displaces from one area of the implant, the lack of volume in that area may result in visible wrinkling of the envelope. Fourth, the outer shell or envelope can fold upon itself, causing an area of wear (e.g., fold flaw), leading to failure and deflation. 
     There are breast prosthetic devices utilizing an outer envelope, wherein the envelope contains baffle forming material. The baffle forming material fills at least a portion of the outer envelope, while the remainder of the outer envelope is filled with a fluid, such as saline solution. The baffle forming material may or may not be attached to the outer envelope. The drawback to such prior art baffle forming material is that such material does not match the single layer structure, geometry, proportions, etc., of the outer envelope, thereby resulting in wrinkling and folding of the implant due to the uncontrolled position of the baffle forming material. Additionally, some of the prior art baffle material can be felt through the implant, resulting in an unnatural feel to the implant. 
     The object of the present invention is to overcome some of the drawbacks of the prior art implants. It is desirable to construct a surgically implantable prosthetic device which may be filled with saline and/or other fluids and which has the appropriate tactile feel, appearance, and other characteristics found in a human breast. Specifically, the present invention controls the position of the baffle forming material within the lumen with either minimum or no attachment points. 
     SUMMARY OF THE INVENTION 
     Briefly, according to the present invention, there is provided a surgically implantable prosthetic device, comprising an outer shell having an exterior surface, an interior surface, and enclosing an outer lumen or cavity, wherein the outer lumen is able to accommodate a first fluid therein. The prosthetic device further comprises an inner shell having an exterior surface, an interior surface, and enclosing an inner lumen or cavity, wherein the inner lumen is able to accommodate a second fluid therein. Additionally, the prosthetic device has one or more fitted shells situated between the exterior surface of the inner shell and the interior surface of the outer shell. The fitted shells are adjacent to each other and are arranged in a graduated manner, more specifically, a smaller shell is contained within a successive larger shell. 
     Both the outer lumen of the outer shell and the inner lumen of the inner shell may be filled with a fluid. The fluid is able to move within the outer lumen and envelop the fitted shells. A saline solution would be an appropriate choice for use as the fluid. Saline refers to any electrolyte combination together with water, however, the invention is not limited solely to the use of saline. Other fluids may be utilized such as, for example, organic polymers or protein fluids; furthermore, certain gases may possibly be utilized as substitutes for fluids. Lubricating agents may be added to the saline. 
     The prosthetic device utilizing saline or the like provides a safe and harmless prosthetic implant. If the outer shell is ruptured or compromised in any fashion, the saline is safely absorbed into the body tissue. Furthermore, the patient would observe the decrease in volume of the implant and quickly come in for a replacement. This quick indication of implant failure decreases the chance that there would be time for tissue to grow into the implant material after implant rupture due to lack of discovery. 
     The outer lumen and/or the inner lumen may be pre-filled prior to implantation or, alternatively, may be first implanted and then filled with the fluid. One or more valves may be provided for the filling of the outer lumen, which includes the spaces between the fitted shells, and the inner lumen. 
     The arrangement of the lumens, the fitted shells, and the inner and outer shells decreases the displacement rate of the fluid. This restriction of the ability of the fluid to move inside the outer lumen improves the desired tactile characteristics of the implant and reduces the “fluid wave” effect of the implant. Furthermore, this fitted shell arrangement prevents wrinkling, folding, or bunching together of the baffle material within the implant. Additionally, the outer shell is supported, feels smooth externally, and does not fold upon itself to create wear points. 
     These and other advantages of the present invention will be understood from the description of the desirable embodiments, taken with the accompanying drawings, wherein like reference numerals represent like elements throughout. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross-sectional side view of an implant, in accordance with the present invention; 
     FIG. 2 is a cross-sectional side view of the implant of FIG. 1, according to a first alternative embodiment of the present invention; 
     FIG. 3 is a cross-sectional side view of the implant of FIG. 1, according to a second alternative embodiment of the present invention; 
     FIG. 4 is a cross-sectional side view of the implant of FIG. 1, according to a third alternative embodiment of the present invention; and 
     FIG. 5 is a side perspective view of an alternative embodiment fitted shell of the implant of FIG.  1 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     For purposes of the description hereinafter, the spatial or directional terms, such as “inner”, “outer”, “top”, “bottom”, “central”, and derivatives thereof, shall relate to the invention as it is oriented in the drawing figures. However, it is to be understood that the invention may assume various alternative variations, except where expressly specified to the contrary. It is also to be understood that the specific apparatus illustrated in the attached drawings and described in the following specification is simply an exemplary embodiment of the present invention. Hence, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered as limiting. 
     Implant  10   a , a first alternative embodiment implant  10   b , a second alternative embodiment implant  10   c , and a third alternative embodiment implant  10   d , according to the present invention, are illustrated in FIGS. 1-4. The implant  10   a  is particularly adapted for use as a surgically implantable mammary prosthesis. The implant  10   a  includes an outer shell  12  enclosing a lumen or a cavity, an inner shell  14  enclosing a lumen or a cavity, and one or more generally dome-shaped fitted shells, e.g., a first fitted shell  16   a , a second fitted shell  16   b , a third fitted shell  16   c , and a fourth fitted shell  16   d . In a particularly desirable embodiment, with reference to the implant  10   a  as it is oriented in the drawings, the dimensions of the outer shell  12  and the inner shell  14  are defined by a diameter measurement and a projection measurement. The diameter measurement is representative of the width of the implant  10   a  at its widest point and the projection measurement is representative of the height of the implant  10   a  at its tallest point. In this desirable embodiment, the diameter measurement of the implant  10   a  is greater than the projection measurement of the implant  10   a . Thus, the implant  10   a  is substantially oval-shaped, elliptical-shaped, or parabolic-shaped. The first alternative embodiment implant  10   b  and the second alternative embodiment implant  10   c  are similar in form and function as the implant  10   a , except for the differences explicitly discussed herein. 
     With reference to FIG. 1, the outer shell  12  defines an outer lumen  20  and includes an exterior surface  22  and an interior surface  24 . The outer shell  12  may include a valve  26  that bridges a portion between the exterior surface  22  and the interior surface  24  of the outer shell  12 . The valve  26  may be placed along various areas of the outer shell  12 . The valve  26  allows for filling of the outer lumen  20  of the outer shell  12  with a fluid after the manufacture of the implant  10   a , either before or after implantation into a patient. The fluid is preferably a saline solution, yet it is to be understood that the term fluid may refer to both gaseous and liquid fillers or any combination thereof including, but not limited to, electrolyte and organic solutions. The valve  26  also allows for the controlled removal of the fluid without damaging or destroying the implant  10   a . Alternatively, the outer lumen  20  may be manufactured as a pre-filled and completely sealed member (not shown), and therefore, not require a valve  26  for the outer lumen  20 . 
     The outer shell  12  is preferably constructed of a non-porous, flexible, biocompatible material, such as silicone elastomer. The outer shell  12  has a wall of sufficient thickness to provide structural integrity to retain fluids while achieving the desired flexibility and malleability of the implant  10   a . The outer shell  12  is substantially oval-shaped, with the top of the implant  10   a  having a convex shape, as oriented in the drawings. Thus, the shape of the implant  10   a  is defined by the overall external shape of the outer shell  12 . In an exemplary embodiment, the enclosed volume within the outer shell  12  is 375 cc. Therefore, the outer shell  12  may accommodate say 375 cc of volume-displacing material, e.g., fluid and fitted shells. It is to be understood that various other volumes of shells  12  may be utilized. 
     The inner shell  14  defines an inner lumen  30 , and includes an exterior surface  32  and an interior surface  34 . The inner shell  14  is smaller than the outer shell  12  in that the diameter measurement and/or the projection measurement are less than that of the implant  10   a . The inner shell  14  is also substantially oval-shaped. In an exemplary embodiment, the enclosed volume of the inner shell  14  is 250 cc. The inner shell  14  is situated within the outer lumen  20  of the outer shell  12 , in a relatively central position with respect to interior surface  24  of the outer lumen  20 . Similar to the outer shell  12 , the inner shell  14  may include a valve  36 . The valve  36  bridges the exterior surface  32  and the interior surface  34  of the inner shell  14 , as well as the exterior surface  22  and the interior surface  24  of the outer shell  12 . The valve  36  allows for filling of the inner lumen  30  of the inner shell  14  with the fluid after the manufacture of the implant  10   a , either before or after implantation into a patient. The valve  36  also allows for the controlled removal of fluid without damaging or destroying the implant  10   a . Alternatively, as shown in FIG. 2, the inner lumen  30  may be manufactured as a pre-filled and completely sealed member and, therefore, not requiring the valve  36 . Thus, the first alternative embodiment implant  10   b  includes the valve  26  to fill the outer lumen  20 , but does not include the valve  36 . 
     Returning to FIG. 1, once implanted, the top of the implant  10   a  faces away from the chest wall of a patient. Thus, if the implant  10   a  is not pre-filled, it is desirable to have the valve  26  for the outer lumen  20  and the valve  36  for the inner lumen  30  situated near the top of the implant  10   a . This allows the implant  10   a  to be easily filled after it has been implanted in the patient. Otherwise, if the implant is filled by a surgeon prior to implantation, the valves  26 ,  36  may be situated along other areas of the exterior surface  22  of the outer shell  12 . 
     One or more fitted shells are situated within the outer lumen  20  of the outer shell  12 . It is to be appreciated that there exists an optimal number of fitted shells for effectively achieving the objects of the present invention. The optimal number of shells, which would be apparent to one having ordinary skill in the art, is based upon the characteristics of the implant, e.g., the needs of the patient, the dimensions of the implant, the type of fluid used, etc. Each fitted shell may be formed from a flexible, biocompatible material, such as silicone elastomer, having similar construction in shape as that of the inner shell  14  or the outer shell  12 . It is to be understood that the fitted shells may be of varying thicknesses in different areas, relative to each other and relative to the inner shell  14  and the outer shell  12 . Desirably, the fitted shells are to be as thin as possible, so as to minimize any bulk within the implant  10   a . Furthermore, the fitted shells may either be porous or non-porous. 
     In the desirable embodiment, as depicted in FIG. 1, the implant  10   a  includes four fitted shells: the first fitted shell  16   a , the second fitted shell  16   b , the third fitted shell  16   c , and the fourth fitted shell  16   d , although it is to be understood that any number of fitted shells may be utilized. Each fitted shell  16   a - 16   d  includes an exterior surface  38   a - 38   d  and an interior surface  40   a - 40   d , respectively. The primary difference between each fitted shell  16   a - 16   d  and the outer or inner shells  12 ,  14  is that each fitted shell  16   a - 16   d  has a portion cut out, thereby forming fitted shell openings  42   a - 42   d  in fitted shells  16   a - 16   d , respectively. The dimensions of each fitted shell are also defined by a diameter measurement and a projection measurement. The diameter measurement is representative of the length of the fitted shell at its widest point and the projection measurement is representative of the height of the fitted shell at its tallest point. 
     If more than one shell is utilized, as depicted in FIG. 1, then the fitted shells  16   a - 16   d  are contained within each other. Thus, it is preferable that the sizes of the fitted shells  16   a - 16   d  be graduated, in that either the diameter measurement, the projection measurement, or both the diameter and projection measurements of each fitted shell are incrementally larger or smaller than the preceding or successive fitted shells, respectively. For example, in an exemplary embodiment, the unenclosed volume measurements of the fitted shells  16   a - 16   d  are 350 cc, 325 cc, 300 cc, and 275 cc, respectively, with the fitted shells  16   a - 16   d  spaced between 0 cm and 1.0 cm apart from each other. The resultant graduated arrangement occupies the outer lumen  20  of the outer shell  12  with the inner shell  14  enveloped by the fitted shells  16   a - 16   d . It is to be understood that some of the fitted shells  16   a - 16   d  may be the same size as each other and therefore, not necessarily embody a graduated arrangement. The fitted shell openings  42   a - 42   d  are sized such so as to prevent the inner shell  14  from moving through the fitted shell openings  42   a - 42   d . Thus, the fourth fitted shell  16   d , having the smallest volume measurement, is adjacent to the exterior surface  32  of the inner shell  14  and the first fitted shell  16   a , having the largest volume measurement, is adjacent to the interior surface  24  of the outer shell  12 . The second fitted shell  16   b  and the third fitted shell  16   c  are situated between the first fitted shell  16   a  and the fourth fitted shell  16   d  according to their volume measurements. Specifically, the second fitted shell  16   b  is adjacent to the first fitted shell  16   a  and the third fitted shell  16   c  is adjacent to the fourth fitted shell  16   d . This graduated arrangement creates a space between each of the fitted shells and a space between both the inner and outer shells and the fitted shells. Thus, a space  44  is between the first fitted shell  16   a  and the second fitted shell  16   b , a space  46  is between the second fitted shell  16   b  and the third fitted shell  11   c , and a space  48  is between the third fitted shell  16   c  and the fourth fitted shell  16   d . Similarly, a space  50  is between the outer shell  12  and the first fitted shell  16   a  and a space  52  is between the inner shell  14  and the fourth fitted shell  16   d.    
     Insertion of the fluid into the outer lumen  20  of the outer shell  12  causes the fluid to fill the outer lumen  20  and to also envelop the fitted shells  16   a - 16   d  by flowing into the spaces  44 ,  46 ,  48 ,  50 , and  52 . The shape, size, and graduated arrangement of the fitted shells  16   a - 16   d  result in the fitted shells  16   a - 16   d  maintaining their relative positions within the outer shell  12  and prevent the fitted shells  16   a - 16   d  from wrinkling, folding, or bunching together, which would otherwise be felt as a bulge through the outer shell  12 . In conjunction with the inner shell  14  filled with the fluid, this combination provides the implant  10   a  with the simulated static and dynamic characteristics of natural breast tissue. Consequently, a breast reconstructed or enhanced with either the implant  10   a  or the alternative embodiment implant  10   b  will feel like a natural breast and will approximate the movement and feel of the natural breast. 
     With reference to FIG.  3  and with continuing reference to FIGS. 1 and 2, the second alternative embodiment implant  10   c  includes an alternative fitted shell arrangement  54 . The alternative fitted shell arrangement  54  performs the same function as the graduated arrangement of the fitted shells  16   a - 16   d  in both the implant  10   a  and the first alternative embodiment implant  10   b . The difference in the second alternative embodiment implant  10   c  is that the alternative fitted shell arrangement  54  provides more room for the inner shell  14  within the top and bottom of the outer lumen  20 . This is accomplished by having graduated diameter fitted shell openings for each fitted shell as well as having fitted shell openings at the bottom of one or more of the fitted shells. It is to be understood that each of the fitted shells may or may not have two graduated diameter fitted shell openings. Furthermore, it is to be understood that the fitted shells in the alternative fitted shell arrangement  54  maintain their relative positions within the outer shell  12 , thereby still effectively achieving the objects of the present invention. 
     With reference to FIG.  4  and with continuing reference to FIG. 1, FIG. 4 serves to illustrate a third alternative embodiment implant  10   d , wherein the valve  36  is situated at the bottom of the implant  10   d . The valve  36  of FIG. 4 performs the same function as the valve  36  in the implant  10   a  of FIG. 1, yet is placed in a different area of the implant  10   d . Still, other embodiments resulting in various placements of valves  26  and  36  may occur to those of ordinary skill in the art. 
     With reference to FIG.  5  and with continuing reference to FIG. 1, FIG. 5 depicts a side perspective view of an alternative embodiment fitted shell  56  of the implant  10   a . Each alternative embodiment fitted shell  56  may have the same shape and construction as the fitted shells  16   a - 16   d , and may assume a graduated arrangement within the outer lumen  20  of the outer shell  12 . Each alternative embodiment fitted shell  56  is different in that the shell  56  includes one or more perforations  58  that allow the fluid to pass through and/or between any other of the alternative embodiment fitted shells  56 . Desirably, the perforations  58  are implemented as cut slits circumferentially and outwardly extending from the top to the bottom of the alternative embodiment fitted shell  56  and/or as cut slits radially situated at the edge of the alternative fitted shells  56 . 
     It is to be understood that the implant  10   a  and any other alternative embodiment implants may be of various sizes and configurations. The diameter measurement and the projection measurement of the outer shell  12  and the inner shell  14  may vary in differently sized alternative embodiments. These alternative embodiments may represent various sizes, shapes, or proportions of implants available to the patient. Furthermore, the dimensions of the implant  10   a  may also be different depending on the number of fitted shells and the size of each fitted shell within the implant  10   a . Additionally, the outer shell  12 , the inner shell  14 , both the outer shell  12  and the inner shell  14 , or neither the outer shell  12  nor the inner shell  14  may be pre-filled with the fluid by a manufacturer of the implant  10   a . Thus, shells that are not pre-filled require the valve to be incorporated therein. 
     The above invention has been described with reference to the preferred and alternative embodiments. Obvious modifications, combinations, and alterations will occur to others upon reading the preceding detailed description. It is intended that the invention be construed as including all such modifications, combinations, and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.