Biofragmentable bowel anastomosis ring: comparative efficacy studies in dogs.

Three studies were conducted in a total of 178 dogs to determine the efficacy of a biofragmentable bowel anastomosis ring (BAR) composed of polyglycolic acid and 12.5% barium sulfate. Wound strength and healing of BAR, suture, and staple colonic anastomoses were compared for intervals of up to 1 year. The effect of systemic steroid treatment and BAR size on anastomotic wound strength and healing was also studied. The BARs fragmented at a mean time of 15.06 days postoperatively and were passed in the feces without injury. Wound strength was determined by measurements of the pressure required to burst the anastomosed colonic segment and measurements of the tension required to break 10 mm wide longitudinal strips of the anastomosed segment. The studies demonstrated that wound strength had progressed to a point where continued mechanical support (with sutures or staples) was no longer required by 14 days in both nontreated and steroid-treated dogs. Gross healing evaluations at 21 days and beyond showed no differences due to anastomotic method. Microscopic evaluations suggested that residual granulation tissue was less at the sites of BAR asastomoses than at sites of suture or staple anastomoses at the 1-year interval, suggesting that healing may be better with BAR than with standard methods of colon anastomosis.