Haemodynamic changes in the fingers after free radial forearm flap transfer: a prospective study using SPP

Harvesting the radial forearm flap may cause circulatory problems in the donor arm. To investigate the influence on donor hands after radial forearm flap harvesting, we assessed the process of circulatory changes prospectively by measuring skin perfusion pressure (SPP) that is clinically useful in detecting vascular lesions. The records of 17 patients (14 men and 3 women aged 59.7+/-11.8 years) who had undergone free radial forearm flap transfer for head and neck reconstruction, between December 2005 and April 2007, were analysed. SPP in the thumb (finger I), the middle finger (III) and the little finger (V) was measured in the 17 patients preoperatively and 1 month and 3, 6, 9 and 12 months postoperatively. All statistical tests were two sided, with a significance level defined as p<0.05. Preoperatively, baseline SPP was more dominant in finger I than in finger V. Postoperatively, SPP changed significantly in both fingers, while it showed no change in finger III and tended to be higher in finger I than in the other two. Harvesting the free radial forearm flap reduces skin perfusion in the fingers of the donor arm and, we assume, leads to a re-distribution of blood flow to the fingers, with the residual ulnar artery still supplying more blood flow to finger I than to finger V. This suggests the presence of an autoregulating mechanism whereby blood perfusion to the fingers is controlled by the physiological demands of individual fingers.