Loop Colostomy

Surgical stomas are constructed to connect a body cavity to the outside and are named according to their anatomic location—for example, colostomy, ileostomy, or urostomy. A colostomy is a surgical procedure by which a stoma is constructed through exteriorization of the large intestine.

A colostomy can be constructed as a loop colostomy or as an end colostomy. A loop colostomy is defined as a stoma in which the entire loop of colon is exteriorized and both the proximal limb and the distal limb open into the common stoma opening and are not transected. An end colostomy is created from the proximal end of the colon; the distal end can be stapled or sewn shut and remains as a blind pouch, or it can be exteriorized separately.

This article focuses on the surgical techniques for constructing a loop colostomy.

Loop colostomies are usually temporary and are generally constructed in preference to end colostomies whenever the colostomy is intended to be reversed at a later date. Compared with takedown of an end colostomy, local takedown of a loop colostomy is associated with a shorter average hospital stay, less intraoperative blood loss, and a lower complication rate.[1]

The main indications for loop colostomies are as follows:

• To relieve distal obstruction ^[2] (mainly as a palliative procedure)—for example, in the case of obstructing  rectal cancer ^{[3, 4]}
• To divert fecal load from a newly performed distal anastomosis

Imprecise location of the stoma site can be a source of extensive morbidity and patient dissatisfaction in the postoperative period. The goal of preoperative marking of the stoma site is to provide an opening that allows easy placement of an ostomy appliance that can be maintained with an adequate seal for up to 5-7 days. An enterostomal nurse aims for marking a stoma that is preferably away from the umbilicus, skin creases, and bony prominences.

Key points in the marking of the location are as follows:

• The patient should be awake
• The site is evaluated with the patient supine, sitting, and bending; this will allow choice of the optimal location for facilitating subsequent care
• The site is marked with permanent ink before the surgical preparation to ensure that the marking is not displaced and to avoid anatomic distortion when the abdomen is opened
• In patients who have undergone multiple previous abdominal surgical procedures, computed tomography (CT) of the abdomen may be useful for helping determine the best location for the colostomy
• As a rule, in an individual with an average body mass index (BMI), the most common location is through the infraumbilical fat roll; in an obese individual with a pannus, the stoma is located in the upper abdomen, away from skin creases, where the skin is flat

Surgical approaches to the creation of a loop colostomy (see the images below) are categorized as follows:

• Open
• Laparoscopic
• Trephine- or colonoscopy-assisted

Construction of loop colostomy.

Construction of loop colostomy.

Overall, the surgical techniques available for constructing a loop colostomy have evolved greatly over the past decade. It is important to emphasize that although loop colostomy is a relatively simple procedure, it is considered a temporary one, and the goal is to reverse it at a later date.

Clinical practice guidelines for ostomy surgery have been developed by the American Society of Colon and Rectal Surgeons (ASCRS).[5]

Preoperatively, the location of the stoma site is marked.

A standard midline incision is made. The colon is mobilized from its attachments sharply. The adjacent flexure may be mobilized, if necessary, to permit the colon to reach the abdominal wall.

After adequate mobilization of the colon, a 4- to 5-cm transverse incision is made in the right or left upper quadrant over the rectus muscle where the stoma was preoperatively marked. The incision is then dissected down to the level of the fascia, which is divided in the same fashion.

After retraction of the fascia, the rectus muscle is exposed. The lateral edge of the rectus muscle may have to be divided with an electrocautery. The posterior rectus sheath is then exposed and divided to afford entry into the peritoneal cavity.

A mesenteric window is constructed between the marginal artery and the mesenteric border of the bowel to avoid compromise. The loop of bowel is delivered through the transverse skin incision, with care taken to ensure that no tension is placed on the bowel loop. The fascial opening should be wide enough to accommodate the bowel and one finger.

A skin bridge may be used to provide additional support to the posterior wall of the colon. The midline abdominal wound is closed before the stoma is matured.

A transverse semilunar incision is made along the length of the loop of colon. The incision should be long enough to allow visualization of the posterior wall of the colon.

The loop colostomy is then matured so that the proximal and distal limbs are separated. Full-thickness 3-0 polyglactin sutures are placed from the bowel wall to the dermis. The stoma is then fitted with an ostomy appliance.

If a supporting bridge or rod was used, it can be removed in 4-5 days. If concerns about poor healing exist, the bridge can be left in place for a longer period.

It should be kept in mind that several studies have found routine support rod use to yield a significant increase in postoperative complications.[6, 7]

No standard technique for performing a laparoscopic colostomy exists, but the basic principles are similar to those of an open loop colostomy.

A laparoscopic approach to colostomy construction was first described in the early 1990s,[8, 9]  and modifications of the initially described technique have been developed.[10, 11]  The laparoscopic approach has certain general advantages over the open approach, which have been well described in the laparoscopic surgery literature. The construction of the stoma is performed as in an open loop colostomy.

Points to be kept in mind for the laparoscopic approach include the following:

• A supraumbilical 5 mm trocar is inserted under direct vision; through that trocar, the authors establish pneumoperitoneum
• The authors typically place two more 5-mm trocars, one supraumbilical and the other in the right lower quadrant, if a sigmoid loop colostomy is planned; they almost never perform transverse loop colostomies
• The bowel is mobilized with the goal of obtaining adequate length to reach (without tension) the abdominal wall at the site of the premarked stoma
• Advantages of the laparoscopic approach include minimized postoperative ileus; oral intake starts on postoperative day 1
• Smaller incisions, which are often distant from the stoma site, minimize wound complications and also facilitate the fitting of ostomy appliances

A loop colostomy can also be fashioned with the assistance of colonoscopy.[12, 13]

For a standard sigmoid colostomy, the patient is positioned in the lithotomy position. Complete bowel preparation is preferred. The stoma site is marked preoperatively in the standard fashion.

A flexible sigmoidoscope or an adult colonoscope can be used for identification of the distal limb of the colon to be used for the colostomy. The stoma site is prepared in the same fashion as in open and laparoscopic approaches (see above). The distal limb of the colon is identified through endoscopic illumination or endoscopic insufflation of air.

The colon is then gently exteriorized through the skin incision. A skin bridge may be used to prevent it from retracting back into the abdomen.

The loop colostomy is matured by using the same technique described for the open and laparoscopic approaches (see above).

The advantages of trephine colostomy over open colostomy include the following:

• It can be performed with local anesthesia
• The operating time is shorter
• The requirement for narcotic pain medications postoperatively is reduced

Limitations include the following:

• Problems with retraction of the stoma are more likely, probably related to inadequate mobilization of the mesentery
• Visualization is limited, especially in patients with extensive adhesions

The techniques for laparoscopic-assisted trephine loop colostomy have not been standardized. The procedure can be performed either with the gasless laparoscopic approach or with the use of pneumoperitoneum.

A colonoscope or a sigmoidoscope can be used as described above to identify the distal limb of the colon. A single incision is made in the premarked stoma site. A camera is used to aid with visualization and mobilization of the segment of bowel. Abdominal wall retraction is obtained with standard body wall retractors. The distal limb is identified with endoscopic guidance and brought out through the skin incision. The colostomy is matured as described above.

In a systematic review of 18 randomized controlled trials (N = 1009), Malik et al reporting on stoma-related complications in adults with loop colostomies, end colostomies, and loop ileostomies.[14] The incidence of such complications ranged from 2.9% to 81.1%; peristomal skin complications and parastomal hernia were the most common. Morbidity was highest in the end colostomy group, followed by the loop colostomy group and then by the loop ileostomy group. The high level of detection bias and heterogeneity between studies limited the accuracy with which the true incidence of each stoma-related complication could be determined.