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A distal loop ileostomy is used most commonly for temporary diversion of the gastrointestinal contents to protect a colonic anastomosis. When it is constructed with a dominant proximal limb, this ostomy provides nearly complete diversion of succus. The loop ileostomy has replaced the traditional right transverse colon loop colostomy in many circumstances because this loop is easier to construct and close. Additionally, the loop ileostomy has proven to be no more difficult for patients to manage than a proximal colostomy. A loop ileostomy, however, does not decompress the colon when the ileocecal valve is intact. In patients who require acute colon decompression, a loop colostomy will allow both colon decompression and colon preparation for a staged procedure.
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PREOPERATIVE PREPARATION
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Most patients undergoing emergency or complex operations on the colon are counseled by their surgeons about the potential need for an ostomy. If available, an enterostomal therapist should visit patients prior to surgery. The potential ostomy site should be marked with indelible ink (FIGURE 1). An ostomy is best placed near the lateral edge of the rectus muscle and sheath. It may be placed either above or below the umbilicus. The position chosen must take into consideration the span of the ostomy gasket such that it has a smooth, wide surface for adherence. The costal margin, indentation of the umbilicus, uneven scars, and skin folds will not allow secure placement of the ostomy gasket. In general, the beltline should be avoided, and the patient should both stand and sit with an appliance in place during this marking. In obese patients, exteriorization of a loop of bowel often can be challenging because of the thickness of the abdominal wall. Selecting an upper abdominal site where abdominal wall thickness is often lesser than lower abdomen often can circumvent this issue. Patients should be reassured about their ongoing care by the enterostomal therapist. Reading material and samples are often provided. If an enterostomal therapist is unavailable, the surgeon should make every effort to educate patients using written and pictorial aids.
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DETAILS OF THE PROCEDURE
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The anesthesia, position, and abdominal incision and exposure are determined by the colon operation being performed. Preoperative markings often need to be freshened periodically with a sterile marker during the course of a long operation. If this is not done, at the end of a protracted and difficult operation, the inked markings likely will be gone. On completion of the colon anastomosis and prior to closure of the abdomen, the ostomy site is revisited. The cut edge of the abdominal wall, namely the linea alba in the midline incision, is grasped with Kocher clamps and retracted to the central position it will occupy after closure. In patients with a thick abdominal wall, an additional clamp may be placed on the dermis to hold the abdominal wall in its usual alignment. A 3-cm circle ...