Ischemia and intersecting stapling: the Achilles’ heel of problematic low rectal anastomoses

Abstract

It is well known that low rectal anastomoses are associated with an increased number of anastomotic leaks, even if well-established principles of bowel anastomosis are strictly adhered to, such as avoiding tension of adapting tissues, preserving adequate tissue vascularization and ensuring the anastomosis watertight, with potentially disastrous consequences for patients. Although many risk factors related to anastomotic disruption have been identified, the mechanisms leading to stapling line failure for low rectal anastomoses have not yet been well defined. Colonic J-pouch construction after low anterior resection is now common practice because of the larger capacity of the J-pouch and the improvement in anorectal function in the early postoperative period. This procedure involves two longitudinal enterotomies on the same segment of the intestinal wall. A bowel wall bridge flap is then formed and the blood perfusion of the flap will inevitably be further compromised, which may contribute to leakage of the pouch-anal anastomosis, fistula formation, and stricture at the pouch-anal anastomosis (Fig. 1). It is a common precept from anatomy that no double-parallel longitudinal incisions should be made on the same segment of the intestinal wall. An incomplete staple line may be created when crossoverlap stapling is used after a double-stapling technique. Staples being driven into other staples may be one of the potential adverse events related to the double-stapling technique. When a double-stapling technique is adopted and the staples of the second circular stapler are driven into tissue under the pressure created by closing the stapler, some of the staples will hit the B-formed staples made by the former linear stapler and will never reach the anvil or will fail to completely puncture the tissue, especially in tangential or acute angle cross-overlapping stapling (Fig. 2a–c). The current thickness of the titanium wire used for staples is normally 0.2–0.3 mm. The probability that staples will strike other staples is low, even if the original staples have been buckled or bent into the final B shape, although this adverse event has not been proven by experiments. Therefore, in our opinion, intersecting staple lines should be used as sparingly as possible, and if they must be used, they should be placed at right angles to