Soft tissue repair allografts and methods for preparing same
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.
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,
the papillary dermis including a first portion immediately adjacent the dermis-epidermis junction and proximate the epidermis, the first portion containing a first collagen matrix, and a structurally different second portion distal the dermis-epidermis junction and epidermis and adjacent the reticular dermis, the second portion containing a second collagen matrix, wherein the first collagen matrix is more densely packed than the more open second collagen matrix; 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 consisting of at least a portion of the reticular dermis on a remaining portion of the donor tissue;
making a second cut into the first portion of 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 first portion of the papillary dermis from the remaining portion of the donor tissue to form a second exposed surface consisting of the second portion of the papillary dermis on a remaining portion of the dermis opposite the first exposed surface, wherein the first and second locations are selected to produce an allograft dermal tissue form that includes the second portion of the papillary dermis and at least a portion of the reticular dermis, essentially lacks an epidermis, a dermis-epidermis junction a first portion of papillary dermis and a hypodermis, and constitutes a collagen matrix having uniform density and porosity between the first exposed surface and the second exposed surface.
2. The method of claim 1 , further comprising the step of treating the allograft dermal tissue form.
3. The method of claim 2 , wherein said treating step includes decellularizing the allograft dermal tissue form.
4. The method of claim 2 , wherein said treating step includes cleaning the allograft dermal tissue form.
5. The method of claim 2 , further comprising the step of cutting the treated allograft dermal tissue form into sheets.
6. The method of claim 5 , wherein said cutting step is performed so that the sheets have a rectangular shape.
7. The method of claim 2 , further comprising the step of packaging the treated allograft dermal tissue form.
8. The method of claim 2 , further comprising the step of adding cells to the treated allograft dermal tissue form.
9. The method of claim 1 , further comprising the step of adding one or more biological substances to the allograft dermal tissue form.
10. The method of claim 1 , further comprising the step of adding one or more reinforcing elements to the allograft dermal tissue form.
11. The method of claim 1 , further comprising the step of chemically modifying the allograft dermal tissue form.