Intraoperative hemodynamic evaluation of the radial and ulnar arteries during free radial forearm flap procedure

The purpose of this prospective study was to assess the blood flow of the radial and ulnar arteries before and after radial forearm flap raising. Twenty-two patients underwent radial forearm microvascular reconstruction for leg soft tissue defects. Blood flow of the radial, ulnar, and recipient arteries was measured intraoperatively by transit-time and ultrasonic flowmeter. In the in situ radial artery, the mean blood flow was 60.5 +/- 47.7 mL/min before, 6.7 +/- 4.1 mL/min after raising the flap, and 5.8 +/- 2.0 mL/min after end-to-end anastomosis to the recipient artery. In the ulnar artery, the mean blood flow was 60.5 +/- 43.3 mL/min before harvesting the radial forearm flap and significantly increased to 85.7 +/- 57.9 mL/min after radial artery sacrifice. A significant difference was also found between this value and the value of blood flow in the ulnar and radial arteries pooled together ( P < 0.05). The vascular resistance in the ulnar artery decreased significantly after the radial artery flap raising (from 2.7 +/- 3.1 to 1.9 +/- 2.2 peripheral resistance units, P = 0.010). The forearm has a conspicuous arterial vascularization not only through the radial and ulnar arteries but also through the interosseous system. The raising of the radial forearm flap increases blood flow and decreases vascular resistance in the ulnar artery.