title: Assessing the long-term retention and permanency of acellular cross-linked porcine dermal collagen as a soft-tissue substitute.
abstract: BACKGROUND
  Acellular porcine dermis has been used as a soft-tissue substitute in Europe since 1998 and in the United States since 2000. Processing renders the composite acellular, reducing antigenicity and crosslinking the dermal collagen. The purpose of this study was to determine the long-term histologic response of this material to the transfer into a subcutaneous soft-tissue location in an in vivo mouse model.
  
  
  METHODS
  A total of 24 mice (ICR strain) underwent an initial procedure transplanting a segment of acellular porcine dermis into a dorsal subcutaneous pocket. The implants were examined for qualitative characteristics including rigidity, migration, inflammation, and healing response. Composites of skin, subcutaneous tissue, implant, and underlying muscle were harvested for histologic evaluation. The specimens were analyzed for inflammatory response, degree, and character of tissue incorporation and degree of implant resorption.
  
  
  RESULTS
  One of the 24 animals studied experienced extrusion of the implant. The remaining 23 implants persisted within their respective hosts until the time the animals were killed. The volume and weight of all of the implants remained unchanged from the preoperative to postoperative measurements. Dystrophic calcification and bone formation was seen at 12 months.
  
  
  CONCLUSIONS
  The results do not suggest characteristics optimal for implants used in soft-tissue augmentation for the purpose of aesthetics. The porcine dermis would appear from these results to be better suited for situations that require strength and permanence of the implant.
authors.affiliation: Division of Plastic and Reconstructive Surgery, The Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Texas, USA.
authors.forename: Pat
authors.initials: P
authors.lastname: Kelley
authors.forename: Kyle
authors.initials: K
authors.lastname: Gordley
authors.forename: Stephen
authors.initials: S
authors.lastname: Higuera
authors.forename: John
authors.initials: J
authors.lastname: Hicks
authors.forename: Larry H
authors.initials: LH
authors.lastname: Hollier
mesh_terms: D000818:Animals; D003094:Collagen; D008422:Materials Testing; D051379:Mice; D008813:Mice, Inbred ICR; D019736:Prostheses and Implants; D017768:Skin, Artificial; D013552:Swine
chemical_list: D003094:Collagen