Microvascular anastomoses in irradiated vessels: a comparison between the Unilink system and sutures.

A new mechanical device (the Unilink system) was compared to conventional suture anastomoses in irradiated microvessels. Twenty rabbits received a single radiation dose of 20 Gy from a 7-MeV electron source through an anterior neck field. One and 6 months following irradiation, the carotid arteries and facial veins were divided and anastomosed on one side with the Unilink system and on the other side with suture technique. At sacrifice 4 weeks postoperatively, all vessels were evaluated for patency and histologic changes associated with radiation and anastomotic trauma. Histology disclosed severe radiation changes. Also, intimal hyperplasia was consistently found at the anastomotic sites in the arteries, while it was totally absent in the venous anastomoses. Occlusive thrombosis was found in two arteries, one anastomosed with the Unilink system and one sutured. Two other arteries, one from each group, had subtotal occlusions at the anastomotic site. No occlusions occurred in any of the venous anastomoses. The overall patency in this study was 97.5 percent, with no difference between the two techniques.