Evaluation of unmeshed and 1:1 meshed AlloDerm bolsters for stapled rectal anastomoses in a porcine model.

INTRODUCTION The major morbidity of colorectal anastomoses is leaks. The concept of staple-line reinforcement is a growing area of interest. In this study, we evaluated the feasibility and effect of utilizing AlloDerm to bolster end-to-end stapled rectal anastomoses in a porcine model. METHODS A total of 30 female 45-kg domestic pigs were studied, and each served as its own control by creating a bolstered and unbolstered anastomosis in each animal. All anastomoses were created with a 29-mm end-to-end stapling device. Bolstered anastomoses were randomized to proximal and distal positions along the rectum, and each rectorectal anastomosis was separated by an average of 10 cm. In 20 pigs, an unmeshed bolster of a 0.5-0.7-mm thickness was used. The remaining 10 pigs had a 1:1 meshed bolster that was 0.34-0.51 mm thick. The animals were survived for 14 days. Barium enemas were then performed and the two anastomotic sites harvested, and each anastomosis underwent burst testing. The internal diameter of each anastomosis was measured and a biochemical analysis was performed for matrix metalloproteinase (MMP), elastin and collagen content. RESULTS The unmeshed bolstered anastomoses burst fewer times than the unbolstered anastomoses (P=0.004) and had higher burst pressures (P=0.023), though their anastomotic circumferences were smaller (P=0.007). Meshed bolsters offered no strength advantage to anastomoses and were significantly (P=0.009) smaller than unbolstered anastomoses in the same animal. No difference in elastin, collagen, or MMP content was observed between bolstered and unbolstered groups. No animals had clinical or radiographic leaks. CONCLUSIONS The routine use of unmeshed and 1:1 meshed AlloDerm bolsters is safe and does not appear to inhibit healing in elective colorectal surgery on healthy subjects. AlloDerm may have a role as a tissue bolster in select patients who are more prone to develop anastomotic leaks.