Colostomy

Basic Types

A colostomy is an anastomosis fashioned between the colon and skin of the abdominal wall. Colostomies may be temporary or permanent, depending on the disease and conditions for which they are created. However, appropriate planning and careful technical considerations should be given to the creation of any colostomy, because history has shown that even colostomies intended to be temporary may prove to be permanent in a significant number of patients.

A colostomy may be indicated to divert colonic contents temporarily from a pathologic process in the distal colon or rectum, such as an obstructing rectal cancer or phlegmon of the sigmoid colon associated with diverticulitis. Such a colostomy is usually a loop colostomy using the transverse colon. Other circumstances are more appropriately treated by an end colostomy, in which the end of the sigmoid or, more commonly, descending colon is fused with the skin of the abdominal wall. An end colostomy is an essential component of an abdominal perineal proctectomy performed for rectal cancer. Resection of the sigmoid colon with closure of the rectal stump and fashioning of a descending colon is usually referred to as Hartmann's operation ( Figure 29-1-1 ). This may be a useful approach for patients with diverticulitis and some patients with rectal cancer.

An ileostomy is the union of the ileum to the skin of the abdominal wall. As described for colostomy, an ileostomy may also be fashioned as a loop or an end stoma. A temporary loop ileostomy may be fashioned to protect a distal anastomosis, such as a coloanal anastomosis in a patient who has received preoperative chemoradiation for rectal cancer, or to protect an ileal pouch anal anastomosis in a patient treated with restorative proctocolectomy for ulcerative colitis. An end ileostomy is required if the colon and rectum must be removed and the anal sphincter cannot be preserved. The most common indication for a permanent end ileostomy is Crohn's disease with severe involvement of the anorectum.

A urinary conduit is one method of compensating for the loss of or severe malfunction of the urinary bladder. Construction of a urinary conduit involves isolation of a segment of intestine, usually ileum, with restoration of the continuity of the remaining intestine. One end of the conduit is brought onto the abdominal wall as a stoma and the other end is closed. The ureters are implanted into the intestinal pouch, which serves as a conduit for the excretion of urine. Significant advances in techniques of bladder reconstruction have made the use of the ileal urinary conduit less frequent than in the past few decades.

Physiologic Considerations and Practical Implications