colectomy

Colectomy refers to the surgical removal of part or all of the colon and is a key management strategy in both benign and malignant colonic disease. Indications include colorectal adenocarcinoma (oncologic resection with lymphadenectomy), complicated diverticulitis (perforation, abscess, fistula, recurrent attacks), inflammatory bowel disease refractory to medical therapy (ulcerative colitis is curable with total proctocolectomy; Crohn's disease recurs so segmental resection is favored), toxic megacolon, ischemic colitis with necrosis, volvulus, familial adenomatous polyposis (prophylactic colectomy), and large bowel obstruction.

Types: Right hemicolectomy (cecum, ascending colon, hepatic flexure) for right-sided cancers; left hemicolectomy (splenic flexure to sigmoid) for left-sided lesions; sigmoidectomy for sigmoid disease (e.g., diverticulitis); subtotal colectomy (most of colon, sparing rectum) often used in fulminant colitis; total proctocolectomy (colon + rectum) curative for ulcerative colitis and FAP, often followed by ileal pouch-anal anastomosis (IPAA) or permanent ileostomy.

Surgical principles include ensuring adequate margins, proper blood supply preservation (SMA vs IMA branches), lymph node dissection for cancer staging, and decision between primary anastomosis vs. diversion (colostomy/ileostomy) based on patient stability, contamination, and nutritional status (e.g., Hartmann procedure for perforated diverticulitis with fecal peritonitis).

Complications include anastomotic leak, surgical site infection, ileus, short bowel syndrome (with extensive resection), bleeding, and long-term issues like pouchitis after IPAA. Understanding colectomy is essential for USMLE questions on management algorithms for colorectal cancer, IBD, and diverticulitis, as well as complications tested in surgery/GI blocks.