Anal Sphincter Complex Preservation

Abstract

To save the sphincter, understanding the anatomy of anal sphincter complex is essential. The anal canal extends from the level of the levator ani muscle to the anal verge. The muscularis propria of the rectum is consisted of the inner circular and outer longitudinal smooth muscle layer. The internal and external sphincters together can maintain anal continence. Intersphincteric groove lies between the subcutaneous external anal sphincter and the internal anal sphincter. This is one of the landmarks for intersphincteric resection. In the middle and low rectal cancer, total mesorectal excision should be performed. For distal rectal cancer, a 1-cm distal margin may be acceptable. To avoid positive circumferential resection margin, the surgeons should follow the principles of total mesorectal excision and perform en bloc resection of contiguous tissues when clinically indicated.