Intraoperative hemodynamic evaluation of the latissimus dorsi muscle flap: a prospective study.

The aim of this study was to assess intraoperatively the hemodynamic changes in the donor vessel of free latissimus dorsi (LD) flap before and after denervation and to analyze flow changes after flap transfer. Twenty-seven patients underwent LD muscle microvascular reconstruction for lower-limb soft tissue defects. Measurements of blood flow were performed intraoperatively by using a 2- to 5-mm probe ultrasonic transit-time flowmeter around the dissected vessels. Registrations were made in the thoracodorsal artery before and after harvesting the flap, after compressing and cutting the motor nerve, and after anastomosis. Mean blood flow of in situ harvested thoracodorsal artery as measured intraoperatively by transit-time flowmeter was (mean ± standard deviation) 16.6 ± 11 mL/min and was significantly increased after raising the flap to 24.0 ± 22 mL/min (p <0.05); it was 25.6 ± 23 mL/min after compressing the motor nerve and was significantly increased after cutting the motor nerve to 32.5 ± 26 mL/min (p <0.05). A significant increase of blood flow to 28.1 ± 19 mL/min was also detected in the thoracodorsal artery after flap transplantation with end-to-side anastomosis (p <0.05). Vascular resistance in the thoracodorsal artery significantly decreased after flap raising and anastomosis (from 7.5 ± 3.4 to 4.0 ± 1.9 and to 4.5 ± 2.4, respectively, p <0.05). LD flap harvesting increases blood flow and decreases resistance in the thoracodorsal artery, especially after denervation.