The lifetime risk of surgery for complications of IBD ranges from 40 to 70 percent and the risk of surgical complications from 13 to 55 percent.
About one third of people with ulcerative colitis and up to three fourths of people with Crohn’s
disease will need surgery.
For ulcerative colitis, a patient may need removal of the entire colon, called a “total colectomy”. A total colectomy may be required even if a patient has severe disease in only one area of the colon, because removing only that area will not cure the disease, and it will return.
In Crohn’s disease, the most common area of the gut affected is bottom of the small intestine where it connects to the colon (at the “ileocecal valve”). This part of the gut is the most common area requiring removal by surgery (called an “ileocecal resection”).
 Source: Jan S et al. Variation in surgical outcomes for adolescents and young adults with inflammatory bowel disease. Pediatrics 2013;131, Suppl 1:S81-S89.