Clinical implications of anterolateral thigh flap shrinkage.

Objective: To evaluate anterolateral thigh flap shrinkage after elevation and to develop a predictive model for flap design.

Method: A prospective study was conducted in a university teaching hospital. The skin islands from anterolateral thigh flaps were outlined on a transparent sheet before and after the reconstruction procedure. Dimensions of the stretched flaps were also recorded. These three outlines were scanned and the surface areas computed and compared by tracing and use of AutoCAD. Age, sex, flap dimension, and flap thickness were investigated for association with flap shrinkage.

Results: Forty-five anterolateral thigh flaps harvested for head and neck soft tissue reconstruction after tumor resection were studied. Flap size ranged from 4 to 14 cm in width and 8 to 22 cm in length; flap area ranged from 30.6 to 151.0 cm. On average, the flaps shrunk by 25.0% (6.2%-52.6%), a highly significant change (P < .01). Flap width and thickness correlated with the reduction in flap size. The average stretched-flap area was 10.1% (0.4%-29.4%) less than the preflap area, a significant reduction (P < .01). The difference between stretched-flap and preflap areas was independent of all variables. We developed a predictive model using a stepwise multiple linear regression method with a coefficient of determination of 0.495.

Conclusions: Anterolateral thigh flaps shrink after harvesting, and flap width and thickness are significant contributing variables. These findings indicate that flap size must take shrinkage into account to ensure sufficient coverage.