Evaluation of acellular dermal graft in sheet (AlloDerm) and injectable (micronized AlloDerm) forms for soft tissue augmentation. Clinical observations and histological analysis.

OBJECTIVES To evaluate the histological and clinical properties of (1) subdermally implanted acellular dermal graft (AlloDerm) sheets vs intradermal bovine collagen and (2) subdermally or intradermally injected micronized AlloDerm vs type I bovine collagen cross-linked with glutaraldehyde (Zyplast). PATIENTS Twenty-five adult patients testing nonallergic to bovine collagen. METHODS (1) Stacked disks of AlloDerm were implanted subdermally behind one ear, and bovine collagen was injected intradermally behind the other. The soft tissue augmentation caused by the implants was measured by digital photography at 1, 4, and 12 weeks, and biopsy specimens of each implant type were examined at 3 months after implantation. (2) Micronized AlloDerm was injected intradermally and subdermally in 2 different locations behind one ear, and bovine collagen was injected in the same manner behind the other. The soft tissue augmentation caused by the implants was measured by digital photography at the time of implantation and at 1 and 4 weeks after implantation. All implants were examined 1 month after implantation. RESULTS All patients tolerated both implants well. (1) AlloDerm implants retained a higher percentage of the original implant volume than Zyplast at 1 and 3 months after implantation. Histologically, AlloDerm implants were extensively invaded by host fibroblasts without any foreign body reaction. (2) Intradermally injected micronized AlloDerm implants retained a higher percentage of the original implant volume at 1 month after implantation than intradermal Zyplast. Histologically, micronized AlloDerm implants were extensively invaded by host fibroblasts without any foreign body reaction. No significant differences were noted between subdermally injected micronized AlloDerm and Zyplast. CONCLUSIONS The macroscopic and microscopic behavior of subdermally implanted AlloDerm sheets and subdermally and intradermally injected micronized AlloDerm was compared with intradermally injected Zyplast. AlloDerm sheet volume persisted to a significantly (P < .001) greater degree than bovine collagen during the first 3 months after placement. Clinically, intradermally injected micronized AlloDerm volume persisted to a significantly (P = .01, .04, and .01, respectively) greater degree than intradermal Zyplast or subdermal micronized AlloDerm or Zyplast. Histologically, micronized AlloDerm and AlloDerm are well tolerated at 1 and 3 months, respectively. Host tissue incorporation with fibroblast in-growth and collagen deposition is seen in both materials. AlloDerm and micronized AlloDerm hold promise for use in facial soft tissue augmentation.