Expandable absorbable implants for breast reconstruction and augmentation

Abstract

Expandable absorbable implants have been developed that are suitable for breast reconstruction following mastectomy. The implants can be implanted in the vicinity of a tissue expander, for example, by suturing to the detached edge of the pectoralis major muscle to function as a pectoralis extender, and used to form a sling for a tissue expander. The implants, which permit tissue-ingrowth and slowly degrade, can be expanded in the breast using a tissue expander in order to form a pocket for a permanent breast implant. After expansion, the tissue expander can be removed and replaced with a permanent breast implant. The expandable implants help reduce patient discomfort resulting from tissue expansion, and avoid the need to use allografts or xenografts to create the pocket for the tissue expander. The expandable absorbable implant preferably comprises poly-4-hydroxybutyrate or copolymer thereof.

1 - 68 . (canceled) 
     
     
         69 . An expandable absorbable breast implant having a first layer of non-sacrificial struts arranged in a wavy pattern, wherein the first layer is sandwiched between a first layer of sacrificial struts and a second layer of sacrificial struts. 
     
     
         70 . The implant of  claim 69 , wherein the first layer comprises straight sacrificial struts, and wherein the second layer comprises straight sacrificial struts. 
     
     
         71 . The implant of  claim 69 , wherein the first layer of sacrificial struts extend along a first direction, wherein the second layer of sacrificial struts extend along a second direction, and wherein the first direction is different from the second direction. 
     
     
         72 . The implant of  claim 71 , wherein the first direction is perpendicular to the second direction. 
     
     
         73 . The implant of  claim 69 , wherein the first layer of sacrificial struts is arranged opposed to and spaced from the second layer of the sacrificial struts. 
     
     
         74 . The implant of  claim 69 , further comprising a second layer of non-sacrificial struts arranged in a wavy pattern, wherein the first layer of non-sacrificial struts extends along a first direction, and wherein the second layer of non-sacrificial struts extends along a second direction. 
     
     
         75 . The implant of  claim 74 , wherein the first direction is perpendicular to the second direction. 
     
     
         76 . The implant of  claim 69 , wherein the sacrificial struts comprise polymeric fibers, wherein the non-sacrificial struts comprise polymeric fibers. 
     
     
         77 . The implant of  claim 76 , wherein the polymeric fibers of the sacrificial and/or the non-sacrificial struts comprise poly-4-hydroxybutyrate or copolymer thereof. 
     
     
         78 . The implant of  claim 76 , wherein the sacrificial polymeric fibers are less oriented than the non-sacrificial polymeric fibers. 
     
     
         79 . The implant of  claim 76 , wherein the sacrificial polymeric fibers have lower weight average molecular weights than the non-sacrificial polymeric fibers. 
     
     
         80 . The implant of  claim 69 , wherein the implant has been sterilized using ethylene oxide, gamma-irradiation or electron beam irradiation. 
     
     
         81 . A method of using the implant of  claim 69 , wherein the implant is used for breast reconstruction, the method comprising the steps of:
 (i) implanting a tissue expander in the patient;   (ii) implanting the implant in the vicinity of the tissue expander;   (iii) expanding the tissue expander;   (iv) removing the tissue expander; and   (v) implanting a permanent breast implant in the patient.   
     
     
         82 . The method of  claim 81 , wherein the permanent breast implant is implanted into a pocket created by the tissue expander and optionally, wherein the breast implant is a saline breast implant or a silicon breast implant. 
     
     
         83 . The method of  claim 81 , further comprising breaking the sacrificial struts by expansion of a tissue expander before breaking the non-sacrificial struts. 
     
     
         84 . A method of forming the implant of  claim 69  comprising processing an unoriented or partially oriented absorbable polymer to form a lattice or mesh, wherein the lattice or mesh comprises the sacrificial struts and the non-sacrificial struts, wherein the sacrificial struts degrade faster than the non-sacrificial struts. 
     
     
         85 . The method of  claim 84 , wherein the implant is expanded using a tissue expander. 
     
     
         86 . The implant of  claim 69 , wherein the non-sacrificial strut layer zigzags between the first and second layers of sacrificial struts. 
     
     
         87 . The implant of  claim 76 , wherein the non-sacrificial polymeric fibers have an accordion structure that can be expanded when the sacrificial polymeric fibers are stretched or degraded. 
     
     
         88 . The implant of  claim 69 , wherein the implant expands when the sacrificial struts are elongated or degraded. 
     
     
         89 . The implant of  claim 69 , wherein the implant is knitted. 
     
     
         90 . The implant of  claim 69 , wherein the sacrificial struts have a smaller diameter than the non-sacrificial struts.