Absolute indications for surgery are exsanguinating hemorrhage, perforation, and documented or strongly suspected carcinoma. Other indications for surgery are severe colitis with or without toxic megacolon unresponsive to conventional maximal medical therapy, and the patient with less severe, but medically intractable symptoms or intolerable steroid side effects.
There are no prospective randomized trials comparing medical treatment with surgery for any indication in ulcerative colitis, but three situations are absolute indications for surgery because continued medical therapy is doomed to failure and potentially fatal: exsanguinating hemorrhage, frank perforation, and documented or strongly suspected carcinoma, i.e., high grade dysplasia or low grade dysplasia in a mass lesion.
Massive hemorrhage in ulcerative colitis is due to diffuse mucosal ulceration. If the hemorrhage is exsanguinating or even persisting despite maximal medical therapy (see above), it is an indication for emergency surgery. If the patient’s condition permits, total proctocolectomy may be the most reliable procedure because a small group (approximately 12%) of patients may have continued hemorrhage from the retained rectal segment if only a subtotal colectomy is performed   . On the other hand, subtotal colectomy with preservation of the rectum for a future restorative procedure is an acceptable choice, so long as the small risks of further hemorrhage are appreciated and appropriately monitored.
Perforation, fortunately occurring in only 2-3% of hospitalized ulcerative colitis patients at tertiary referral centers  , is the most dreaded and most lethal complication of toxic colonic dilation. In a univariate analysis, perforation had a more adverse impact on survival than any other single clinical variable  . Moreover, it is essential to recognize that perforation can occur without being preceded by megacolon. The surgical procedure of choice in this setting is a subtotal colectomy with rectosigmoid mucous fistula or Hartmann’s closure  .
When colon cancer is identified, the need for surgery is obvious; similarly, the colonoscopic biopsy diagnosis of high grade dysplasia is often indicative of a concurrent or future cancer and is an indication for colectomy   . The finding of low grade dysplasia in a mass lesion  or a stricture not passable during colonoscopy   , especially in longstanding disease, are likewise often seen in conjunction with colon cancer and colectomy is advisable. The findings of low grade dysplasia in flat mucosa may also be an indication for colectomy because an analysis of 10 prospective series of dysplasia surveillance in 1225 patients found cancer at colectomy immediately after colonoscopic biopsy evidence of low grade dysplasia in 19% of patients  , whereas the 5-year predictive value of low grade dysplasia for either cancer or high grade dysplasia is as high as 54%   .
Other indications for surgery include the patient with severe colitis or toxic megacolon unresponsive to maximal intravenous medical therapy (see above). The patient with less severe but medically intractable symptoms, resulting in physical debility, psychosocial dysfunction, or intolerable steroid side effects, may also be best served by colectomy. However, uncontrolled series suggest that approximately two-thirds of these patients may achieve remission with the use of the immunosuppressive drugs azathioprine or 6-MP   .
Only rarely is surgery necessary to control the extraintestinal manifestations of UC. Likewise, patients with severe, progressive pyoderma gangrenosum, in whom the pyoderma activity parallels the activity of the colitis  , or with hemolytic anemia refractory to steroids and splenectomy, may benefit from colectomy   . By contrast, the course of primary sclerosing cholangitis is independent of the activity of the colitis and is not affected by colectomy.