PURPOSE:Compare partial-thickness suture and stapled microvascular repairs(not including intima) with standard full-thickness repairs pioneered by Alexis Carrel. METHODS:32 end-to-end anastomotic repairs performed in rat femoral arteries <1mm. Group I: 13 full-thickness repairs, Group II: 19 extraluminal repairs (partial-thickness n=12, stapled n=7). Patency rates as well as histopathologic evaluation at one and three week harvests performed. Methylmethacrylate microvascular casts studied under electron microscopy. RESULTS: No statistical difference between intraluminal and extraluminal repairs. Patency rates between Groups I and II were 92% and 94% res-pectively. 100% patency seen with partial-thickness repair. Histology revealed localized inflammation to adventitia and media with endothelialization at one week in Group II. Anastomotic microcirculation did not originate from repaired artery in any of the groups. CONCLUSION: Patency rates with end-to-end anastomotic repairs using extraluminal techniques are comparable to standard full-thickness technique. Repairs that do not include the intima reveal focal inflammatory responses to the outer layers and more rapid endothelialization, while neighboring vessels perfuse the healing anastomosis.