Postoperative changes in blood flow in free muscle flaps: A prospective study

We used color Doppler ultrasound (US) to study postoperative changes in blo od flow in 10 non-innervated free latissimus dorsi (LD) muscle flaps transp lanted onto lower extremities. The peak, mean, and minimum velocities, resi stance index, and diameter of the pedicle, and the recipient and control ar teries were recorded preoperatively and on the 2nd, 5th, and 10th days afte r surgery. In the pedicle of the transplant, the peak and mean velocities i ncreased but not significantly during the follow-up. The minimum velocity v alue in the thoraco-dorsal artery was (mean +/- SD) 4 +/- 5 cm/sec preopera tively, and was in the leg 19 +/- 9 cm/sec (P < 0.05) on the 5th and 17 +/- 10 cm/sec (P < 0.05) on the 10th postoperative day. The preoperative value of the resistance index decreased from 0.92 +/- 0.12 to 0.79 +/- 0.08 on t he 10th postoperative day (P < 0.05). In the recipient artery, the peak (11 7 +/- 37) and mean (35 +/- 16 cm/sec) velocities increased significantly on the 5th postoperative day compared to the preoperative value (79 +/- 22 an d 14 +/- 6 cm/sec, respectively). The minimum velocity increased but not si gnificantly. The resistance index was preoperatively 1.23 +/- 0.09 and 0.88 +/- 0.16 (P < 0.05) on the 10th postoperative day. This prospective clinic al study demonstrates that blood flow in the pedicle and in the recipient a rtery of a free muscle flap increases after surgery. This phenomenon may be due to loss of vascular tone and decreased resistance after denervation. I ncreased blood flow helps to keep the microanastomosis open and also promot es wound healing.(C) 1999 Wiley-Liss, Inc.