The effect of tissue expansion on the random flap viability and wound tensile strength of previously irradiated rabbit skin.

Tissue expansion facilitates coverage of cutaneous defects both through the generation of additional skin surface area and by increasing random flap length/width viability factors. The opportunity to apply tissue expansion techniques to head and neck defects within previously irradiated skin fields continues to increase. To study the effect of tissue expansion on the cutaneous perfusion and wound-healing capacity of irradiation-damaged skin, rabbit scalps were subjected to 5 weeks of fractionated radiation followed at 4 months by prolonged tissue expansion. Standardized random flaps were then created and reset within the expanded skin and analyzed in parallel with nonirradiated and nonexpanded control animals. Flap viability as expressed by area and mean maximum length was determined at 10 days postwounding followed by determination of wound-breaking strength. Irradiated tissues demonstrated a significantly reduced flap viability that was significantly increased by expansion. However, tissue expansion-related increases in flap length exceeded those expressed as percent of total area surviving for irradiated animals. Tissue expansion resulted in significant increases in wound tensile strength only in nonirradiated animals. These findings suggest that, compared with controls, several of the benefits of tissue expansion are less appreciable in radiation-damaged skin.