Implantation and expansion of split-thickness skin grafts: a new source of prefabricated pedicle flaps and grafts.

Abstract

The objective of this study was to determine whether a split-thickness skin graft can be implanted deep to the skin and whether it can be expanded. We also wanted to find out whether this implanted and expanded split-thickness skin graft can be used as a new source of skin grafts and as a pedicle flap. A tissue expander mounted on a Dacron sheet backing was specially designed for this experiment. Six female Hanford minipigs weighing 20 to 25 kg were operated on in three stages. In stage one, a split-thickness skin graft 0.03 in thick was harvested from the back, placed dermal side out over the expander, and sutured to the Dacron backing. The expander with the overlying split-thickness skin graft was then implanted deep to the panniculus carnosus muscle. Daily expansion was started 2 weeks after implantation to obtain a total volume of 1300 to 2500 cc. In the second stage, performed 4 to 6 weeks after implantation, the skin over the expander was elevated superficial to the panniculus carnosus muscle as a ventrally based flap, and the panniculus carnosus muscle was next elevated as a dorsally based flap lined on its deep surface with the implanted/expanded skin. Full-thickness skin grafts obtained from this implanted/expanded skin and from normal skin were transplanted to two 3 x 3 cm skin defects. The panniculus carnosus muscle implanted/expanded skin flap was then turned 180 degrees and sutured to a dorsally created skin defect. In the third stage, 4 weeks later, we noted the quality, texture, and appearance and obtained punch biopsies from normal skin, normal skin graft, implanted/expanded skin graft, and panniculus carnosus muscle implanted/expanded flap for histopathologic examination. All skin grafts "took" well, survived implantation, and were expanded successfully. The initial surface area of implanted split-thickness skin graft showed a net increase of 8 to 193 percent (mean percentage net increase 90 percent). This implanted/expanded skin also was retransplanted successfully to a skin defect. In all six minipigs, a skin-lined panniculus carnosus muscle implanted/expanded skin flap was constructed and survived transfer to an adjacent skin defect. The smallest flap of panniculus carnosus muscle implanted/expanded skin measured 10 x 12 cm and the largest 12 x 28 cm (mean surface area 228 cm2).