The effect of twisting on perforator flap viability : An experimental study in rats

Perforator flaps increasingly find acceptance and use in the field of reconstructive surgery due to their decreased donor-site morbidity and increased like-tissue coverage. Nevertheless, they are more prone to vascular compromise, especially when the meticulous technique they require is not employed. Pedicle twisting is a condition occasionally encountered in flap procedures, sometimes inadvertently, sometimes inevitably. In this study, circulatory comprise induced by twisting of the pedicle on a true perforator flap in a rat model is investigated.Thirty-eight Wistar-Albino rats were randomized into 4 groups, and cranial epigastric artery true perforator flaps were elevated on a single perforator. The flaps were returned as they were in the control group (n = 9), and with 90 degrees , 180 degrees , and 270 degrees of torsion in groups 2 (n = 9), 3 (n = 10), and 4 (n = 10), respectively. The flaps were evaluated by their flap survival area, weight, and histopathological appearance by the end of the first week. The mean flap survival ratios for groups 1, 2, 3, and 4 were 97.78 +/- 4.41%, 72.22 +/- 44.10%, 73.50 +/- 30.46%, and 30 +/- 30.18% (mean +/- SD), respectively. The degree of degenerative changes in group 4 was found to be statistically significant (P < 0.016).Our histopathological examinations indicate that vascular compromise was moderate in group 3 and severe in group 4. Our findings suggest that under normal conditions, the pedicle of a true perforator flap must not be twisted more than 180 degrees .