28 TRAUMA TO THE COLON AND RECTUM
W. Andrew Lawrence M.D., Jon M. Burch M.D.

COLON TRAUMA

1. How do most colon injuries occur?

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Nearly all (> 95%) colon injuries are caused by penetrating trauma from gunshot, stab, iatrogenic, or sexual injury. Blunt colonic trauma is rare and usually results from seat belts during motor vehicle accidents.

2. How are colon injuries diagnosed?

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They are usually diagnosed during laparotomy for penetrating trauma. For patients in whom the need for laparotomy has not been established, chest and upright abdominal radiographs assess free air and detect the location of penetrating objects. Triple-contrast computed tomography (CT) or soluble-contrast radiographs (followed by barium, if necessary) can diagnose retroperitoneal colon injuries. White blood cells or fecal material in diagnostic peritoneal lavage (DPL) is highly suggestive of a bowel injury.

3. How are colon injuries graded?

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* Grade I-contusion hematoma without devascularization; or partial-thickness laceration
* Grade II-laceration < 50% circumference
* Grade III-laceration > 50% circumference
* Grade IV-transection of the colon
* Grade V-transection with segmental tissue loss

4. What are three surgical options for managing a colon injury?

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1. Primary repair: suturing of simple sidewall perforations or resection and primary anastomosis for more complex injuries
2. Colostomy: injured colon is exteriorized as a loop colostomy or the injured area is resected and an end ileostomy or proximal colostomy is formed
3. Exteriorized repair: a repaired perforation or anastomosis is suspended on the abdominal wall. If the suture line does not leak after 10 days, it can be returned to the abdominal cavity under local anesthesia. If the repair breaks down, it is treated like a loop colostomy.

5. What are the advantages and disadvantages of each of these options?

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1. Primary repair is desirable because definitive treatment is carried out at the initial operation and the patient is spared the morbidity of a colostomy and its reversal. The disadvantage is that suture lines are created in suboptimal conditions, so leakage may occur.
2. Proximal colostomy avoids an unprotected suture line in the abdomen but requires a second operation to close the colostomy. Stomal complications, including necrosis, stenosis, obstruction, and prolapse, may occur.
3. Exteriorized repair is similar to colostomy formation in that it avoids formation of an intraperitoneal suture line. Unfortunately, many patients require a colostomy closure, and stomal complications similar to those of colostomies may occur.

6. How are most patients with colon injuries surgically managed?

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Primary repair is safe and effective in essentially all patients with colon trauma. Handsewn and stapled anastomoses have equal complication rates.
KEY POINTS: SURGICAL MANAGEMENT OF COLON INJURIES

1. Primary repair is safe.
2. Handsewn and stapled anastomoses have equal complication rates.
3. A preoperative dose of antibiotic therapy, to be continued for 24 hours, is advantageous.

7. How should the surgical incision and penetrating wound be managed?

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Wounds should be left open (for delayed primary closure) to decrease the incidence of wound infection and fascial dehiscence.

8. What complications are associated with colonic injury and its treatment?

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* Wound infection (≤ 65% if the skin incision is closed primarily; do not be tempted to close a dirty incision)
* Intraabdominal abscess (20%)
* Fascial dehiscence (10%)
* Stomal complications (5%)
* Anastomotic leak (5%)
* Mortality (6%)