Abstract:
An external breast prosthesis having a thin-walled outer shell and an air-filled interior cavity. The prosthesis is fabricated using a method and die set to form the two-part shell without internal supporting structure. The method provides a repeatable process which yields a prosthesis having durable air-tight seal between the anterior and posterior shell and a Class-A exterior surface which accurately replicates the visual and tactile characteristics of a human breast.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/255,910, filed on Oct. 29, 2009. The entire disclosure of the above application is incorporated herein by reference. 
     
    
     FIELD 
       [0002]    The present disclosure relates to a breast prosthesis and method of fabricating same, and in particular to an external air-filled breast prosthesis having a human-like appearance. 
       BACKGROUND 
       [0003]    This section provides background information related to the present disclosure which is not necessarily prior art. 
         [0004]    The use of prosthesis is well known for the purpose of replicating or augmenting anatomical features of the human body, and in particular the human breast. To be acceptable, a breast prosthesis must accurately replicate the size and shape of the anatomy, as well as the function of such anatomy. In addition, the prosthesis must be ergonomically compatible and comfortable for the wearer. 
         [0005]    The art is replete with various internal and external breast prostheses. In some instances, a relatively thin outer elastic shell is formed from an elastic silicone material. In these embodiments, the prosthesis is either made of solid silicon or the interior cavity of the prosthesis is filled with a material which provides internal support. Such filler materials may include various foams or other biocompatible fluids such as saline, silicone gel or natural triglyceride oils. These prostheses have a tendency to be heavy and/or inaccurate at replicating the form and function of the subject anatomy. 
         [0006]    Accordingly, there is a need the art to provide an external breast prosthesis with a thin outer shell formed of an elastomeric material and an interior air-filled cavity, as well as a method and die set for fabricating such an external breast prosthesis. 
       SUMMARY 
       [0007]    This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
         [0008]    As further set forth in detail below, this disclosure provides an external breast prosthesis having a thin-walled outer shell and an air-filled internal cavity. The prosthesis is fabricated using a process and die set which provides a two part shell including an anterior cup-shaped portion and a posterior backer which when assembled defines an air-tight cavity. The nipple structure of the prosthesis is formed with a rayon flocking material having a fleshy color consisting of various tints of red, purple and gold. The outer shell is formed of an elastomeric material, preferably an elastic silicone material which has been vacuum treated to remove air that would otherwise cause bubbles, pits or voids in the thin-walled prosthesis. This disclosure further provides a method and die set for fabricating the thin-walled air-filled prosthesis. 
         [0009]    Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       DRAWINGS 
         [0010]    The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
           [0011]      FIG. 1  illustrates a first mold assembly in which the anterior cup-shaped portion of the prosthesis is formed; 
           [0012]      FIG. 2A  illustrates a second molding assembly in a pre-assembled state with a thickened layer of elastic silicone material spread on the die plate; 
           [0013]      FIG. 2B  illustrates the second molding assembly shown in  FIG. 2A  with the die cavity placed on top of the die plate; 
           [0014]      FIG. 3  is an illustration of the breast prosthesis in its finalized form; and 
           [0015]      FIG. 4  is a flow chart setting forth the processing steps used in the fabrication of the breast prosthesis. 
       
    
    
       [0016]    Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
       DETAILED DESCRIPTION 
       [0017]    Example embodiments will now be described more fully with reference to the accompanying drawings. 
         [0018]    With reference now to the figures, an external breast prosthesis  10  having a thin-walled elastomeric shell  12 ,  16  with an air-filled interior cavity  18  is illustrated. In addition, the method and die set for fabricating this prosthesis is illustrated and described. With particular reference to  FIGS. 1-3 , the external breast prosthesis  10  includes a thin-walled anterior shell  12  having a perimeter edge portion  14  joined to a thin-walled posterior shell  16 . In this configuration the anterior shell  12  and posterior shell  16  are arranged to define an air-filled interior cavity  18 . The anterior shell  12  has a nipple/areola region  20  formed therein. As best seen in  FIG. 3 , the perimeter edge  14  of the anterior shell  12  is a chamfered perimeter edge  14  formed thereon which complements the edge defined by the posterior shell  16 . In particular, the perimeter edge  14  bisects the interface between anterior shell  12  and posterior shell  16  to form a mitered joint. As noted above, the prosthesis is fabricated with an elastomeric material, preferably an elastic silicone material. 
         [0019]    The breast prosthesis  10  is fabricated by injection molding the anterior shell  12  and then position forming the posterior shell  16  onto the anterior shell. The die sets  30 ,  50  used in this fabrication process sufficiently support the anterior shell  12  such that the prosthesis can be fabricated with an air-filled cavity and without internal support. In particular, a first mold assembly  30  as shown in  FIG. 1  includes a lower die  32  and an upper cover  34 . A series of pins  36  extend across the die separation surface and align the upper cover  34  with the lower die  32 . The lower die  32  has a generally concave die cavity  38  formed therein. The bottom region  40  of the die cavity  38  is shaped to replicate the nipple/areola region of a human breast. 
         [0020]    As presently preferred, the die cavity  38  is formed using a machining process which yields a Class-A exterior surface for the anterior shell  12  of the breast prosthesis  10 . In particular, the interior die cavity  38  is machined to a precision surface based upon 3-dimensional modeling data similar to the techniques utilized in fabrication of automotive body panels. The upper die cover  34  has a generally convex surface  42  which complements the concave surface  38  formed on lower die  32 . The convex surface  42  terminates at an angled annular surface  44  which defines the chamfered perimeter edge  14  on anterior shell  12 . A gate  46  is formed through upper die cover  34  and extends into the cavity formed between concave surface  38  and convex surface  42 . The gate  46  is coupled to an injection molding system  48  suitable for injecting an elastomeric material into the cavity. 
         [0021]    A second die assembly  50  is provided which includes the lower die cavity  32  used in the first die assembly  30  and a die plate  52 . The die plate  52  has a generally flat upper die surface  54  which may abut the perimeter edge  14  of the anterior shell  12  and extends inwardly towards the nipple/aerola region  20 . As shown in  FIG. 2B , the die cavity  32  is positionable into an abutting relationship with die plate  52  on a margin  56  which may be slightly relieved from the upper die surface  54 . Gates  58  are formed in the margin  56  of the die plate  52  and extend from the horizontal surface to the boundary  60  of the die plate  52  for directing excess elastomeric material away from the prosthesis  10  during fabrication. 
         [0022]    With reference now to  FIG. 4 , the fabrication process will be further explained. As presently preferred, a first mold cavity  32  is provided in an upright position with the concaved cavity facing upwardly. The nipple/areola region  20  of the breast prosthesis  10  is formed by depositing elastomeric material colored with pigments of red, purple and gold and mixed with rayon flocking fibers to simulate the color and texture of the nipple/areola region of a human breast. This material is permitted to partially cure. 
         [0023]    While the nipple/aerola region cures, the first mold cavity  32  is enclosed with a die cover  34  yielding a thin-walled cavity to define what will become the anterior shell  12 . Conventional injection molding process is used to inject elastomeric material into the first mold assembly  30  and form the anterior shell  12 . The anterior shell  12  is allowed to substantially cure, typically for approximately four hours. 
         [0024]    Once the anterior shell  12  is cured, the die cover  34  is removed from the die cavity  32  and the sprue  48  extending from the interior surface of anterior shell  12  is trimmed. A die plate  52  is provided with the upper surface  54  which is spread with a partially cured elastomeric material. In this regard, it is important that the elastomeric material be partially cured to a degree sufficient such that its viscosity will allow the elastomeric material to remain on the relatively flat horizontal surface  54  formed on die plate  52 . Alternatively, the die plate  52  may be provided with a seal or similar feature around the boundary  60  for confining the elastomeric material on the upper surface  54 . 
         [0025]    A layer of adhesive  62  is applied to the perimeter edge  14  of the anterior shell  12 . A suitable adhesive is selected to enhance adhesion and induce vulcanization or similar process in which the polymer molecules are linked to other polymer molecules by atomic bridges to form an air tight bond. While a vulcanization process in presently preferred, other acceptable processes such as similar thermostatic or thermoplastic processes may be utilized to achieve an air tight interface. 
         [0026]    Next, the die cavity  32  is rotated 180° from its position as shown in  FIG. 1  into an inverted position as shown in  FIGS. 2A and 2B . The die cavity  32  is then lowered on top of die plate  52  and aligned with pins  36  in a manner similar to that described with reference to  FIG. 1 . Sufficient adhesion exists between the anterior shell  12  and die cavity  32  to support the anterior shell  12  in the concave position above posterior portion  16 . The interior cavity  18  defined by anterior shell  12  and posterior portion  16  captures ambient air to create air-filled interior cavity  18 . The breast prosthesis  10  is allowed to fully cure, taking approximately three to six hours. 
         [0027]    Once fully cured, the die plate  52  is removed form the die cavity  32 . The breast prosthesis  10  is removed from die cavity  32 . The molded breast  10  may include some flash material extending from the perimeter regions which may be trimmed using conventional processes. The breast prosthesis  10  is then washed and talced to provide an acceptable tactile characteristic simulating that of the human skin. 
         [0028]    The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention.