 Bowel resection may be performed to treat gastrointestinal cancer, bowel necrosis, severe enteritis, diverticular disease, Crohn's disease, endometriosis, ulcerative colitis, or bowel obstruction due to scar tissue.Other reasons to perform bowel resection include traumatic injuries and to remove polyps when polypectomy is insufficient, either to prevent polyps from ever becoming cancerous or because they are causing or threatening bowel obstruction, such as in familial adenomatous polyposis, Peutz–Jeghers syndrome, or other polyposis syndromes.Some patients require ileostomy or colostomy after this procedure as alternative means of excretion.