The healing process in high and low anterior resection of the rectum. A comparative study in the pig, using stapling devices.

The reason for the higher leakage frequency after low anterior resection compared with high resection is unexplained. With the development of stapling devices, we have a unique opportunity to investigate anastomotic healing during standardized conditions. In female pigs, six in each group, a high anterior resection was performed by resection of a 5-cm colon segment, 10 cm above the peritoneal fold, and low anterior resection was performed after resection of a 5-cm segment at the peritoneal fold and downward. Differences in healing parameters, i.e., blood flow, breaking strength, and radiologic and histologic appearance between low and high anterior resection, were evaluated. Two leakages occurred after low and none after high anterior resection. The anastomotic index was 0.37 (high) and 0.26 (low) (P less than 0.05). The breaking strength was higher in low resections; this might be due to the thicker wall. There were no differences in blood circulation between high and low anastomoses, but the blood flow was significantly higher in the anastomotic area in both groups. This is probably due to the inflammatory reaction taking place in the healing anastomoses. This study, performed in a standardized fashion with a stapler adjusted to wall thickness and size of the intestine, cannot, on the basis of microcirculation, explain why leakage is more common in lower anastomoses.