Abstract:
An improved breast implant prosthesis provides fastening components to anchor the implant to retroglandular or retromuscular tissue and secure the implant in place. Location markers are also provided to ensure correct orientation of the prosthesis during the augmentation mammaplasty procedure and provide postoperative orientation information without the use of invasive procedures.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to an improved implantable breast prosthesis and, in particular, to an implantable breast prosthesis that may be anchored in place in a body cavity to reduce postoperative movement of the implant and provide an indication of the orientation of the prosthesis. 
     Breast prostheses are known which are designed to be implanted behind the breast for reconstruction or augmentation of the mammary gland. These prostheses are made up of an elastomeric envelope or shell delimiting a hermetically closed space which is filled with saline solution, silicone gel or other suitable filling material. Typically, a small periareolar, inframammary, transaxillary, or periumbilical incision is made in the patient and a retroglandular or retropectoral pocket is formed into which the breast prosthesis is inserted. The implant is filled with saline solution or other suitable filling material to a specified volume. The physician verifies the correct orientation of the prosthesis before closing the incision. 
     A postoperative problem may occur if the implant becomes dislodged from its original placement, creating a noticeable breast deformity. This deformity has been detected in women both within the immediate and long-term postoperative period. Additionally, there is currently no means to diagnose whether the implant has become malpositioned at any time after surgery. 
     Another difficulty with anatomically shaped breast prostheses is correctly orienting the prosthesis once it has been inserted in the retroglandular or retropectoral pocket. Typically a tab is attached to the posterior surface of the prosthesis in the six o&#39;clock position to provide a way for the physician to correctly position the prosthesis within the pocket. However, when a transaxillary incision is used to insert the prosthesis, the surgeon is not able to reach the tab to verify correct placement of the implant and must rely on visual inspection to ensure the proper orientation of the implant. 
     SUMMARY OF THE INVENTION 
     It is therefore the primary object of the present invention to provide an improved breast prosthesis that may be anchored to retroglandular or retromuscular tissue to restrict postoperative movement of the implant. 
     Another important object of the present invention, as aforesaid, is to provide an improved breast prosthesis with markers to aid the physician in correctly placing the prosthesis during surgery. 
     Still another important object of the present invention is to provide an improved breast prosthesis with markers to determine postoperative orientation of the prosthesis. 
     Yet another important object of the present invention is to provide an improved breast prosthesis with radiopaque markers to determine postoperative 3-dimensional orientation of the prosthesis. 
     These and other objects of the present invention are achieved by providing an improved breast prosthesis having a fastening member secured to the posterior of the flexible shell of the prosthesis which is capable of receiving and holding a suture to secure the prosthesis to the patient&#39;s retroglandular or retromuscular tissue. Upper and lower markers on the posterior surface of the flexible shell provide tactile and visual indicators to positively orient the prosthesis during the implantation procedure, as well as reconfirm to the surgeon the implant shape (i.e. round or anatomical). Radiopaque markers provide postoperative location information using standard X-ray equipment to positively determine the 3-dimensional orientation of the implant without use of a surgical procedure. 
     Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, an embodiment of this invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevational posterior illustration of an anatomical breast implant incorporating the improvements of the present invention; 
     FIG. 2 is a vertical cross-sectional illustration of the anatomical breast implant of FIG. 1; 
     FIG. 3 is an elevational posterior illustration of a symmetrical breast implant incorporating the improvements of the present invention; 
     FIG. 4 is a vertical cross-sectional illustration of the symmetrical breast implant of FIG. 3; 
     FIG. 5 is an elevational posterior illustration of a modified form of the implant of FIG. 1; 
     FIG. 6 is an elevational posterior illustration of a modified form of the implant of FIG. 3; 
     FIG. 7 is an elevational view of fastening members combined with a reinforcement ring; 
     FIG. 8 is an elevational posterior illustration of another modified form of the implant of FIG. 1; 
     FIG. 9 is an elevational posterior illustration of another modified form of the implant of FIG. 3; 
     FIGS. 10-12 are enlarged, diagrammatic cross-sectional illustrations of the fastening material; 
     FIG. 13 illustrates a breast deformity caused by a breast implant that has rotated about a vertical axis and out of the original placement; 
     FIG. 14 illustrates a breast deformity caused by a breast implant that has rotated about a horizontal axis and out of the original position; 
     FIG. 15 is an illustration showing various incision locations; 
     FIG. 16 is a cross-sectional illustration showing an anatomical breast implant anchored to the pectoral muscle fascia by a suture through the lower fastening member; and 
     FIGS. 17-20 illustrate upper and lower sutures for retroglandular and retropectoral placements of a breast implant. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Turning more particularly to the drawings, an anatomical breast prosthesis of the present invention is generally indicated by reference numeral  20  in FIGS. 1-2, and a symmetrical breast prosthesis is generally indicated by reference numeral  20   a  in FIGS. 3-4. Prosthesis  20  comprises an outer shell  22 , an upper fastening member  24 , a lower fastening member  26 , an upper marker  28  with two tactile buttons and a lower marker  30  with one tactile button. It should be understood that the difference in the prostheses illustrated in FIGS. 1 and 3 is simply the shape of the outer shell  22  and  22   a  and the number of upper tactile buttons indicated by  28  and  28   a.  Corresponding components in the prosthesis of FIGS. 3 and 4 are designated by the same reference numerals with the addition of the “a” notation. 
     Outer shell  22  is made of a flexible biocompatible material such as room temperature vulcanized silicone, Silastic®, high temperature vulcanized silicone or other material suitable for implanting. Outer shell  22  presents an interior area  32  for containing a suitable filling material such as saline solution, silicone gel, or other material. Outer shell  22  has an anterior area generally indicated by reference numeral  34  and a posterior area generally indicated by reference numeral  36 . Outer shell  20   a  is likewise constructed. 
     Fastening members  24  and  26  are made of a flexible biocompatible material that is capable of receiving and holding a suture. Fastening members  24  and  26  may be generally rectangularly shaped as illustrated in FIGS. 1,  3 ,  5  and  6  and in radial alignment in the opposed twelve o&#39;clock and six o&#39;clock positions. The inner end portion of fastening members  24  and  26  are each bonded or otherwise secured to posterior area  36  thereby presenting free ends  25  and  27  illustrated in FIG.  2 . 
     Markers  28  and  30  provide both visual and tactile orientation information to assist the surgeon in correctly orienting the prosthesis  20  when placed in a body cavity. Because anatomical breast prosthesis  20  illustrated in FIG. 1 is asymmetrical, marker  28  is comprised of two semi-spherical buttons that permit the surgeon to determine correct orientation of prosthesis  20 . Additionally, a twin-buttoned marker will allow quick confirmation by the surgeon that a deflated implant is indeed an asymmetrical style since both the asymmetrical and symmetrical implants tend to appear similar when deflated. When prosthesis  20  is correctly oriented, the two buttons of marker  28  are in the twelve o&#39;clock position at the top of the breast cavity. Likewise, marker  30  is comprised of a single semi-spherical button that permits the surgeon to correctly orient the prosthesis  20  such that marker  30  is in the six o&#39;clock position at the bottom of the breast cavity. As illustrated in FIG. 3, the orientation of symmetrical breast prosthesis  20   a  is not important as either marker  28   a  or  30   a  may be located in either the twelve o&#39;clock or six o&#39;clock position within the posterior breast cavity with identical results. 
     A reinforcement ring  38  illustrated in FIGS. 5-6 may be used to provide additional strength to shell  22  where fastening members  24  and  26  are bonded to posterior area  36 . Reinforcement ring  38  may be bonded over the interior ends of fastening members  24  and  26  to form a laminate to secure fastening members  24  and  26  to shell  22  or fastening members  24  and  26  may be bonded to the exterior surface of reinforcement ring  38 . As illustrated in FIG. 7, the reinforcement ring  38  and fastening members  24  and  26  may be made from the same piece of material and bonded to posterior area  36  of shell  22 . 
     In another embodiment illustrated in FIGS. 8 and 9, fastening member  40  is ring-shaped and bonded to posterior area  36  of shell  22  around the inner portion of the ring under reinforcement ring  38  leaving the outer portion of the fastening ring  40  free. It should be understood that fastening ring  40  may be bonded to posterior area  36  without reinforcement ring  38 . 
     Markers  28 ,  30 ,  28   a  and  30   a  may be made from a biocompatible material such as Silastic® or a harder plastic or from a radiopaque material. The same is true for fastening members  24  and  26 . A radiopaque material such as aluminum, barium, stainless steel, or other suitable material may be embedded in markers  28  and  30  to provide a means to determine the 3-dimensional orientation of the prosthesis once it has been implanted using a common X-ray imaging system, an ultrasound system, or a computerized temography for example, or other noninvasive means. 
     Fastening members  24  and  26  and fastening ring  40  may consist of a single high strength biocompatible material that is capable of receiving and holding a suture or may be constructed of a reinforced material. Additionally, fastening members may be radiopaque to provide 3-dimensional orientation information as described hereinabove. In the preferred embodiment fastening members  24  and  26  and fastening ring  40  are constructed of Dacron® reinforced Silastic®. The Dacron® layer  41  may be embedded in the Silastic®  43  as shown in FIG. 10, along the upper (or lower surface) as shown in FIG. 11, or along both upper and lower surfaces for added strength as shown in FIG.  12 . The locations of the Dacron®  41  or other reinforcing material within the host material such as Silastic® as shown in FIGS. 10-12 are exemplary only. Other materials or combination of materials and placements may be used to achieve the same or similar results. 
     FIGS. 13 and 14 illustrate problems that have occurred in prior art breast implants. As illustrated in FIG. 13, an anatomical breast implant  42  may turn or rotate about its vertical axis indicated by direction arrow  44  resulting in a noticeable breast deformity  46 . The same problem may occur with a prior art symmetrical breast prosthesis. 
     As illustrated in FIG. 14, an anatomical breast implant  42  is shown rotated about its horizontal axis indicated by direction arrow  48  resulting in a noticeable breast deformity  50 . It should be understood that breast implant  42  may rotate about any axis and is not limited to the two examples shown in FIGS. 13 and 14. 
     Referring to FIGS. 15-20, three common incision regions are shown (FIG. 15) which include transaxillary  52 , periareolar  54 , inframammary  56  and periumbilical  57  incisions. The skin incision is made through the dermis  58  of a breast generally indicated at  59 , using a scalpel (not shown), and electrocautery (not shown) is then used to incise into the breast tissue  60 . The dissection through the breast tissue proceeds either straight posteriorly or by beveling forty-five degrees toward the chest wall  62  which overlaps ribs  64 . When the fascia of the pectoralis major muscle  66  is reached, the breast tissue  60  is mobilized off of the pectoralis major muscle  66  if development of a retroglandular pocket  68  is sought. Pocket  68  is precisely formed between the pectoralis major muscle  66  and the breast tissue  60 . 
     Breast implant  20  is inspected for defects and the type of breast implant, anatomical  20  or symmetrical  20   a  is verified by checking the number of buttons  28  and  28   a,  then inserted through the incision into the pocket  68 . If a periareolar  54  or an inframammary  56  incision is used, implant  20  will be oriented such that the surgeon can feel marker  30  in the six o&#39;clock position toward the bottom of breast  59 . With breast implant  20  properly positioned, a suture  70  is located through fastening member  26  or  26   a  into pectoralis major muscle fascia  66  to anchor implant  20  in place. A figure eight suture  70  or other known stitch may be used. If a transaxillary  52  incision is used, implant  20  will be oriented such that the surgeon can feel marker  28  in the twelve o&#39;clock position toward the top of breast  59 . Thus, because of the tactile difference in markers  28  and  30  for an anatomical implant  20 , the surgeon can readily distinguish between the top and the bottom of implant  20  for correct orientation. 
     When performing a retropectoral augmentation (FIGS.  17  and  19 ), the pectoralis major muscle  66  is lifted up to provide access to the chest wall  62  and form a pocket  72  therebetween. The breast implant  20  is inserted into pocket  72  through the incision and oriented such that marker  30  is in the six o&#39;clock position for a periareolar  54  or inframammary  56  incision. If a transaxillary  52  incision is used, breast implant  20  is oriented such that marker  28  is in the twelve o&#39;clock position toward the top of breast  59 . A single figure eight suture  70  is located through lower fastening member  26  (FIG. 19) or upper fastening member  24  into chest wall  62  to lock implant  20  in place. 
     FIGS. 18 and 20 illustrate a retroglandular augmentation mammoplasty utilizing a symmetrical implant  20   a.  A suture  70  is placed through upper fastening member  24   a  into pectoralis muscle fascia  66  through a transaxillary incision  52  (FIG.  18 ). A suture  70  is placed through lower fastening member  28   a  into pectoralis muscle fascia  66  through a periareolar  54  or an inframammary  56  incision (FIG. 20) to secure breast implant  20   a  in place. For a symmetrical breast implant, there is no difference in orientation about the horizontal axis, thus markers  28   a  and  30   a  are identical. 
     For larger implants, it may be desirable to anchor implant  20  to pectoralis muscle fascia tissue  66  or chest wall tissue  62  in more than one location such as the ten o&#39;clock and four o&#39;clock positions for added stability and security. Fastening member  40  (FIGS. 8 and 9) may be utilized to provide alternative anchor points for one or more sutures and to provide the surgeon with alternative more convenient or physiologically stable anchor points. 
     Postoperatively, radiopaque markers  28  and  30 , or radiopaque fastening members  24  and  26 , provide orientation information on an X-ray image or other non-invasive imaging system to determine if breast implant  20  has shifted or moved from its original implanted position due to trauma to the chest area, for example trauma sustained in an automobile accident, or a routine mammography. The physician may readily determine if a breast deformity is caused by a displaced implant  20  or for some other reason. 
     It is to be understood that while certain forms of this invention have been illustrated and described, it is not limited thereto, except in so far as such limitations are included in the following claims.