[The management of size discrepancies in microvascular anastomoses]

Microvascular anastomosis is the main component of flap transfer and replantation surgery. The aim of this study was to evaluate size discrepancies encountered during microvascular surgery, techniques to handle the problems, and the results of anastomoses performed.

We evaluated 99 microsurgery operations (103 artery, 125 vein anastomoses) performed in 96 patients with respect to size discrepancy. These operations included free flap transfer (n=67), replantation (n=23), revascularization (n=6), and toe-to-hand transplantation (n=3). Size discrepancy was defined as the inequality of vessel diameters at a ratio of 1:1.5 or greater.

Size discrepancy was found in 32.5% (n=74) of 228 anastomoses, the most frequent being in vein anastomoses performed during free flap transfers. Simple discrepancies were dealt with by dilatation with the use of a jeweller's forceps in 14 anastomoses. In nine discrepancies exceeding 1:1.5, the oblique cut, fish mouth cut, and sleeve techniques were employed in four, three, and two anastomoses, respectively. End-to-side anastomosis was used in six patients in whom free flap transfer was carried out for extremity defects. The remaining 45 anastomoses were performed using a modification of the Xiu and Song's method. Venous grafts were used because of tension of the anastomosis and insufficient vessel lengths in three, eight, and three patients who underwent replantation, free flap transfer, and revascularization, respectively.

An appreciation of various techniques is essential to avoid discrepancy-related problems both during and following microvascular surgery.