Soft tissue repair allografts and methods for preparing same

Abstract

Allografts for soft tissue repair, including breast reconstruction and other plastic surgery procedures, are disclosed. One allograft is made from decellularized dermal tissue and constitutes a collagen matrix having substantially uniform density and porosity. Another allograft is a hybrid bilayer tissue form that is made from decellularized dermal and adipose tissues. Methods for making both allografts are also disclosed.

We claim: 
     
         1 . A method for making an allograft dermal tissue form, comprising the steps of:
 providing a donor tissue including skin having (a) an epidermis, (b) a dermis underlying the epidermis, the dermis including a papillary dermis adjacent the epidermis, a reticular dermis distal to the epidermis, and a papillary-reticular dermis interface PRI between the papillary dermis and reticular dermis, and (c) a dermis-epidermis junction between the papillary dermis and epidermis; and a hypodermis adipose tissue underlying the reticular dermis RD, distal to the papillary-reticular dermis interface;   making a first cut into the reticular dermis at a first location distal the papillary-reticular dermis interface, and along a first plane substantially parallel to the papillary-reticular dermis interface;   removing the hypodermis from the reticular dermis along the first cut to form a first exposed surface on a remaining portion of the donor tissue;   making a second cut into the papillary dermis at a second location proximate the dermis-epidermis junction, and along a second plane substantially parallel to the papillary-reticular dermis interface and the first plane;   removing the epidermis, dermis-epidermis junction and a portion of the papillary dermis from the remaining portion of the donor tissue to form a second exposed surface on a remaining portion of the dermis opposite the first exposed surface, wherein the first and second locations are selected such that the remaining portion of the dermis constitutes a collagen matrix having substantially uniform density and porosity between the first exposed surface and the second exposed surface.   
     
     
         2 . The method of  claim 1 , wherein the papillary dermis has an upper portion immediately adjacent the dermis-epidermis junction and proximate the epidermis, and a structurally different lower portion distal the dermis-epidermis junction and epidermis and adjacent the reticular dermis, wherein the upper portion of the papillary dermis is the portion of the papillary dermis removed by said second removing step, and the remaining portion of the dermis includes the lower portion of the papillary dermis and at least a portion of the reticular dermis. 
     
     
         3 . The method of  claim 1 , further comprising the step of treating the remaining portion of the dermis. 
     
     
         4 . The method of  claim 3 , wherein said treating step includes decellularizing the remaining portion of the dermis. 
     
     
         5 . The method of  claim 3 , wherein said treating step includes cleaning the remaining portion of the dermis. 
     
     
         6 . The method of  claim 3 , further comprising the step of cutting the treated remaining portion of the dermis into sheets. 
     
     
         7 . The method of  claim 6 , wherein said cutting step is performed so that the sheets have a rectangular shape. 
     
     
         8 . The method of  claim 3 , further comprising the step of packaging the treated remaining portion of the dermis. 
     
     
         9 . The method of  claim 3 , further comprising the step of adding cells to the treated remaining portion of the dermis. 
     
     
         10 . The method of  claim 1 , further comprising the step of adding one or more biological substances to the remaining portion of the dermis. 
     
     
         11 . The method of  claim 1 , further comprising the step of adding one or more reinforcing elements to the remaining portion of the dermis. 
     
     
         12 . The method of  claim 1 , further comprising the step of chemically modifying the remaining portion of the dermis. 
     
     
         13 . An allograft dermal tissue form for use in surgical procedures, comprising a portion of dermal tissue having a first exposed surface formed by a first cut and a second exposed surface formed by a second cut opposite said first exposed surface, said portion of dermal tissue constituting a collagen matrix having substantially uniform density and porosity between said first exposed surface and said second exposed surface. 
     
     
         14 . The allograft dermal tissue form of  claim 13 , wherein said portion of dermal tissue includes a portion of a papillary dermis and at least a portion of a reticular dermis. 
     
     
         15 . The allograft dermal tissue form of  claim 14 , wherein said portion of said papillary dermis is a lower portion distal an epidermis and adjacent the reticular dermis, said lower portion being structurally different from an upper portion of said papillary dermis proximate the epidermis. 
     
     
         16 . The allograft dermal tissue form of  claim 13 , wherein said portion of dermal tissue is in sheet form. 
     
     
         17 . The allograft dermal tissue form of  claim 13 , wherein said portion of dermal tissue is in particulate form. 
     
     
         18 . The allograft dermal tissue form of  claim 13 , wherein said portion of dermal tissue is perforated, and thereby in mesh form. 
     
     
         19 . The allograft dermal tissue form of  claim 13 , further comprising cells. 
     
     
         20 . The allograft dermal tissue form of  claim 19 , wherein said cells include one or more of the group consisting of stem cells, fibroblasts, osteoblasts, myoblasts and keratinocytes. 
     
     
         21 . The allograft dermal tissue form of  claim 13 , further comprising one or more biological substances. 
     
     
         22 . The allograft dermal tissue form of  claim 21 , wherein said one or more biological substances are selected from the group consisting of platelet-rich plasma, bone marrow aspirate, demineralized bone particles or fibers other allograft tissue forms, and amnion tissue. 
     
     
         23 . The allograft dermal tissue form of  claim 13 , further comprising reinforcing elements. 
     
     
         24 . The allograft dermal tissue form of  claim 23 , wherein said reinforcing elements are absorbable fibers. 
     
     
         25 . The allograft dermal tissue form of  claim 23 , wherein said reinforcing elements are non-absorbable fibers. 
     
     
         26 . A method for forming an allograft hybrid bilayer tissue form, comprising the steps of:
 providing a donor tissue including a skin having (a) an epidermis and (b) a dermis underlying the epidermis, the dermis including a papillary dermis adjacent the epidermis, a reticular dermis distal to the epidermis, and a papillary-reticular dermis interface between the papillary dermis and reticular dermis; and a hypodermis adipose tissue underlying the reticular dermis;   making a cut into the reticular dermis at a location proximate the hypodermis, and along a plane substantially parallel to the papillary-reticular dermis interface; and   removing the hypodermis and a portion of the reticular dermis attached to the hypodermis to form said allograft hybrid bilayer tissue form such that said allograft hybrid bilayer tissue form includes both a dermal side and an adipose side.   
     
     
         27 . The method of  claim 26 , further comprising the step of adding cells to the allograft hybrid bilayer tissue form. 
     
     
         28 . The method of  claim 26 , further comprising the step of adding one or more biological substances to the allograft hybrid bilayer tissue form. 
     
     
         29 . The method of  claim 26 , further comprising the step of adding one or more reinforcing elements to the allograft hybrid bilayer tissue form. 
     
     
         30 . The method of  claim 26 , further comprising the step of chemically modifying the allograft hybrid bilayer tissue form. 
     
     
         31 . An allograft hybrid bilayer tissue form for use in surgical procedures, comprising a dermal side and an adipose side. 
     
     
         32 . The allograft hybrid bilayer tissue form of  claim 31 , wherein said dermal side includes a portion of a reticular dermis RD of a donor skin tissue. 
     
     
         33 . The allograft hybrid bilayer tissue form of  claim 32 , wherein said adipose side includes a hypodermis H underlying the reticular dermis RD of the donor skin tissue, and attached to said portion of a reticular dermis RD. 
     
     
         34 . The allograft hybrid bilayer tissue form of  claim 31 , wherein said allograft hybrid bilayer tissue form is in particulate form. 
     
     
         35 . The allograft hybrid bilayer tissue form of  claim 31 , wherein said allograft hybrid bilayer tissue form is perforated, and thereby in mesh form. 
     
     
         36 . The allograft hybrid bilayer tissue form of  claim 31 , further comprising cells. 
     
     
         37 . The allograft hybrid bilayer tissue form of  claim 36 , wherein said cells include one or more of the group consisting of stem cells, fibroblasts, osteoblasts, myoblasts and keratinocytes. 
     
     
         38 . The allograft hybrid bilayer tissue form of  claim 31 , further comprising one or more biological substances. 
     
     
         39 . The allograft hybrid bilayer tissue form of  claim 38 , wherein said one or more biological substances are selected from the group consisting of platelet-rich plasma, bone marrow aspirate, demineralized bone particles or fibers other allograft tissue forms, and amnion tissue. 
     
     
         40 . The allograft hybrid bilayer tissue form of  claim 31 , further comprising reinforcing elements. 
     
     
         41 . The allograft hybrid bilayer tissue form of  claim 40 , wherein said reinforcing elements are absorbable fibers. 
     
     
         42 . The allograft hybrid bilayer tissue form of  claim 40 , wherein said reinforcing elements are non-absorbable fibers.