Division of a single free flap in multiple digit reconstruction.

[BACKGROUND] Single free flaps are a commonly used reconstructive method for multiple soft tissue defects in digits. We analyzed the flap size, division timing, and degree of necrosis in cases with various types of flap division.

[METHODS] We conducted a retrospective review of the medical charts of patients who had undergone single free flap reconstruction for multiple soft tissue defects across their digits from 2011 to 2020. The flap types included were the lateral arm free flap, venous forearm free flap, thenar free flap, hypothenar free flap, anterolateral thigh free flap, medial plantar free flap, and second toe pulp free flap. Flap size, anastomosed vessels, division timing, and occurrence of flap necrosis were retrospectively investigated and then analyzed using the t-test.

[RESULTS] In total, 75 patients were included in the analysis. The success rate of the free flaps was 97.3%. All flaps were successfully divided after at least 17 days, with a mean of 47.17 days (range, 17-243 days) for large flaps and 42.81 days (range, 20-130 days) for the medium and small flaps (P=0.596). The mean area of flap necrosis was 2.38% in the large flaps and 2.58% in the medium and small flaps (P=0.935). Severe necrosis of the divided flap developed in two patients who had undergone flap division at week 6 and week 34.

[CONCLUSIONS] In cases where blood flow to the flap has been stable for more than 3 weeks, flap division can be safely attempted regardless of the flap size.