FATE OF FREE-FLAP MICROANASTOMOSIS DISTAL TO THE ZONE OF INJURY IN LOWER-EXTREMITY TRAUMA

The decision to perform free flap microanastomosis to clearly uninjure d vessels proximal to the zone of injury for lower extremity reconstru ction must be weighed against the anatomic and technical difficulties of performing such an anastomosis. Preserved blood flow through vessel s traversing the zone of injury has been shown. The records of all pat ients who underwent lower extremity reconstruction with microvascular free flaps at NYU Medical Center and Bellevue Hospital Center from Jan uary 1979 through August 1995 were reviewed. Patients with free flap m icroanastomoses distal to the zone of injury were compared with those with proximally based anastomoses. The group of patients was subdivide d further into acute (1-21 days), subacute (22-60 days), and chronic ( greater than 60 days) reconstruction groups. Of 451 microvascular free flaps, 35 were performed with recipient vessels distal to the zone of injury. Time interval from injury to coverage ranged from 24 hours to 57 years. Of 35 distally based flaps, 33 (94 percent) were successful and 5 required reoperation (14 percent). There was a similar incidenc e of thrombotic complications throughout all after-injury phases. Of 4 16 free flaps performed with microanastomoses to vessels proximal to t he zone of injury, 388 (93 percent) were successful and 62 (15 percent ) required reoperation. There was no significant difference (P > 0.05) in outcome between distal and proximal anastomoses and no significant difference (p > 0.05) in rates of reoperation. Timing of operation af ter injury had no bearing on outcome. Distally based microvascular fre e flaps anastomoses may he technically less difficult with rates of su rvival equal to those of proximally based flaps. The consideration and use of microanastomoses distal to the zone of injury are encouraged i n selected patients.