Novel methods for generating fractional epidermal micrografts.

Epidermal suction blister grafts are an effective treatment for chronic wounds or vitiligo, but this treatment is time consuming and limited to small areas. To compare two novel strategies to create fractional epidermal grafts. Epidermal blisters were raised from fresh human skin ex vivo at 38-40 °C, with suction of 380-510 mmHg. In Strategy 1, a 1-cm blister was micromeshed into approximately 500 pieces, transferred to elastic adhesive dressing, then pneumatically expanded to approximately nine times the original blister area. In Strategy 2, a 25-cm(2) array of 100 small blisters was raised, simultaneously harvested and captured directly onto an adhesive dressing. Measurements were taken for the pneumatic expansion limit, the release of microblisters upon hydration of the dressing adhesive, light microscopy, epidermal cell viability and positive L-3,4 dihydroxyphenylalanine melanocyte presence in blisters. Both strategies yielded viable fractional epidermal microblister arrays, carried on a dressing for transfer to graft recipient sites. The microblisters were gradually released upon hydration of the dressing adhesive. Strategy 2 has major advantages as only small blisters are made at the donor site, skilful dissection and physical expansion are not required and the strategy can be scaled to create large-area grafts. Strategy 2 is the more practical method for fractional epidermal micrografting to treat larger lesions with less donor-site trauma and has recently been commercialized.