Fecal diversions may be required on either a temporary or permanent basis for the management of a variety of pathologic conditions, including congenital anomalies, obstructive or inflammatory disorders, traumatic disruption of the intestinal tract, or gastrointestinal malignancy . The number of permanent diversions is decreasing because of medical and surgical advances.
Fecal diversions are commonly classified according to the segment of the bowel utilized (eg, sigmoid, colon, ileum) and/or surgical construction (eg, loop, end); both anatomic location and construction have an impact on management. Location of the ostomy (eg, whether it is proximal or distal to the ileocecal valve or proximal to the anus) tremendously impacts the type and volume of output (effluent). Ileostomies, cecostomies, and ascending colostomies typically produce >500 mL per day of output containing digestive enzymes, while descending/sigmoid colostomies produce stool that is formed and does not contain digestive enzymes [2,3]. Loop stomas are larger and somewhat more difficult to manage than end stomas. Any diversion involving retention of the distal bowel is normally accompanied by intermittent mucoid discharge from the anus.
The surgical principles of construction of an ostomy and the management of parastomal hernia complications are reviewed separately. (See "Surgical principles of ostomy construction" and "Parastomal hernia".)
A colostomy is performed when it is necessary to bypass or remove the distal colon, rectum, or anus, and it is either inadvisable or not feasible to maintain integrity of the bowel. If the distal rectum and anorectal sphincter mechanism are removed, the colostomy is permanent; if the sphincter mechanism is retained, there is the potential for restoration of continuity.
Temporary colostomy — A temporary colostomy can be performed on an emergency basis to decompress an obstructed or perforated distal colon. A temporary "diverting" colostomy can also be performed electively to permit healing of a fistulous tract or acute inflammatory process distal to the colostomy. In addition, a diverting colostomy is sometimes created for protection of a distal anastomosis when delayed healing is anticipated (such as an anastomosis involving irradiated tissue); however, the procedure now favored for protection of a distal anastomosis is a diverting ileostomy [4-6].