Ex vivo and in vivo evaluation of a modified interrupted Lembert pattern for small intestinal anastomoses in horses

Objective: To compare single-layer anastomoses (modified continuous Lembert [mod-CL] and modified-interrupted Lembert [mod-IL]) and a 2-layer simple continuous anastomosis (2 L; seromuscular and mucosal) for jejunojejunal anastomoses in equine cadavers and to compare ex vivo to in vivo time to complete the anastomosis and stoma size with a mod-IL pattern. Study design: Measurements in jejunum from cadaver and anesthetized horses. Animals: Ten live horses and 18 equine cadavers. Methods: Time to complete anastomosis, bursting pressures (BP), leakage sites, and anastomotic index (size ratio of anastomotic lumen to control lumen) were recorded. Time to completion and lumen size were compared between in vivo and ex vivo mod-IL patterns. Results: The mod-CL pattern was fastest (8.44 +/- 1.30 min, p < .05), and the 2 L pattern was slower (17.07 +/- 2.0 min) than the mod-CL and mod-IL (p < .05). The anastomotic index exceeded 100 and did not differ between patterns. Segments reached higher bursting pressures when anastomosed with mod-IL (145.94 +/- 24.18 mm Hg) than mod-CL (p < .05). In vivo closure was approximately 8 minutes slower than ex vivo, and with a smaller anastomotic index. Conclusions: All anastomoses increased lumen size over control segments. Lumen size after placement of a mod-IL was greater ex vivo than in vivo, and completion was slower in vivo than ex vivo. Clinical significance: Slower and smaller anastomoses should be anticipated in vivo compared to ex vivo results. Anastomoses with a mod-IL pattern appear clinically advantageous, producing a comparable lumen size in less time than 2 L.