Conformal Sphincter-Preservation Operation Versus InterSphincteric Resection on Anal Function in Low Rectal Cancer

The distal rectum is freed to the entrance of the internal and external sphincter space, and then an oblique resection line is designed under direct vision according to the tumor site and shape, ensuring that the distal and lateral margins are not less than 1 cm, and preserving the contralateral dentate line and the intestinal wall as much as possible, and the anastomosis is completed manually or with instruments.

Partial, subtotal, or total excision of the internal sphincter and/or a portion of the longitudinal rectal muscle, expansion of the distal rectal excision margin into the anal canal or to the anal verge, and completion of the colo-anal anastomosis manually or instrumentally.