CHAPTER 98 The colon is the distal continuation of the gastrointestinal (GI) tract, extending from the ileocecal valve to the distal anal canal. It measures 4.5 to 6 feet in length and functions to reabsorb sodium and water and to provide temporary storage for enteric wastes. Operating on the colon mandates knowledge of its segmental blood supply. The right colon is supplied by the ileocolic and right colic branches of the superior mesenteric artery. The hepatic flexure to midtransverse colon is supplied by the middle colic artery. The distal transverse, splenic flexure, and descending and sigmoid colon are perfused by the left colic and sigmoidal branches of the inferior mesenteric artery. The region of the splenic flexure is known as a “watershed” area of marginal arterial supply, requiring extra caution during surgery. In addition, the ascending and descending colon have retroperitoneal attachments that must be divided during mobilization. Areas of the colon most susceptible to injury during gynecologic procedures are the cecum, the sigmoid colon, and the rectum. Primary repair of injuries to the cecum and proximal sigmoid colon without prior bowel preparation can be performed if soilage is minimal and the mesentery is not involved. Seemingly minor injuries to the mesentery can result in delayed ischemia with transmural infarction and perforation of the affected segment. In addition, there should be no hemodynamic shock or more than 1 L of blood loss from the primary procedure. The repair is performed in a manner similar to that previously described for small bowel injuries—interrupted 3-0 silk suture closure in a transverse fashion so as not to encroach on the lumen. Copious field irrigation with normal saline should follow. A 5% to 7% incidence of postoperative localized abscess is reported. This is often amenable to percutaneous drainage. Injuries of the distal sigmoid colon and rectum without previous bowel preparation are best treated with repair of the injury as described, but with proximal division of the colon and end sigmoid colostomy construction. If the injury involves the mesentery and there is a question of bowel viability, it is always safest to divide the colon distal to the point of injury using a gastrointestinal anastomosis (GIA) stapling device (Fig. 98–1A). Then, the proximal limb is brought out through the abdominal wall as a colostomy. Some degree of judgment is required in managing these injuries, and when available, an experienced general surgeon’s assistance should be obtained.
Colon Repair/Colostomy Creation