Benign Colonic Strictures.

Benign colonic strictures are a rare but important cause of large-bowel obstruction and are due to a variety of pathologies. Although resection remains the mainstay of treatment, alternate therapies such as dilation and stenting may be considered on a case-by-case basis once malignancy has been ruled out. The role of endoluminal stents in benign colonic strictures remains an area of evolving research.

The approach and urgency taken in the management of a patient presenting with a benign colonic stricture depends on the acuity and severity of the patient’s symptoms (see the Algorithm ). In patients presenting with acute obstruction from a presumed benign colonic stricture, initial management consists of intravenous fluid administration for resuscitation; nasogastric tube placement for gastric decompression if the stomach is distended; and correction of electrolyte abnormalities. In patients with evidence of complete obstruction, peritonitis, or perforation, emergent surgery is indicated. Surgical options include diversion with loop colostomy, resection of the strictured segment with end colostomy, or segmental colectomy with primary anastomosis with or without diverting loop ileostomy. Proximal diversion without resection fails to address the diagnostic uncertainty, but it may allay the patient’s condition and allow for further diagnostic evaluations. Additionally, on-table colonic lavage may be a useful tool that, while cumbersome, may allow for conversion of multistage procedures (eg, Hartmann’s) to a lesser-staged procedure in patients with inadequate mechanical bowel preparation. Operative approach and surgical management ultimately depend on patient presenting factors, as well as surgeon experience and preference. In stable patients with partial obstruction or chronic obstructive symptoms, a variety of therapeutic interventions may be considered, beginning with dilation. The technique of stricture dilation is dependent on the level of stricture with distal rectal strictures often amenable to digital and/or bougie dilation, at times performed at home by patients themselves. Endoscopic techniques include balloon dilation with or without intralesional steroid injection or electroincision 7 and, in rare cases, endoscopic stent placement. 1 Technical success of endoscopic balloon dilation in the treatment of anastomotic and benign inflammatory strictures is seen in greater than 73% to 100% of patients with good long-term clinical efficacy, although repeated dilations are frequently needed. 6 , 7 Long strictures (>2 cm), severe bowel angulation, and the inability to endoscopically reach the stricture are associated with technical failure or the need for repeat dilation. 7 Complications following balloon dilations occur in 2% of cases, and most commonly include perforation and bleeding. 7 Surgery is appropriate for strictures that are not amenable to or fail endoscopic treatment but should also be considered in patients if malignancy is a possibility or cannot be ruled out. In patients with continued passage of flatus, a more gradual preoperative bowel preparation regimen may improve tolerance and allow for elective resection. Colonic stents are commonly used in the management of malignant colonic obstruction, but their role in the management of benign strictures remains controversial. Studies have shown colonic stenting to be effective in temporizing obstruction as a bridge to surgery or as definitive treatment for benign strictures. 8 – 10 However, stent placement for benign causes represents only 3% of cases. 11 Technical success in stent placement is variable with some reporting high rates of failure, 12 whereas larger, more recent series have reported success rates above 72%. 8 , 9 In the largest series of patients to date, 22 of 23 patients presenting with acute obstruction secondary to benign causes were relieved of obstruction. 9 Four patients did not undergo subsequent colectomy; however, of the remaining patients that did, 16 (84%) were converted to an elective operation and 8 (42%) did not require a stoma after stent insertion. 9 Complications following stent placement have been reported in 38% to 62.5% of cases; stent migration was the most frequent complication, occurring in 9% to 40% of patients. 8 – 10 , 12 Overall, the rates of stent migration appear to be higher for benign stricture than for malignant strictures with migration occurring in 10% to 16% of malignant cases. 10 , 11

A significant proportion of benign strictures are incidentally discovered and asymptomatic. Symptomatic strictures are most often characterized by abdominal distension, but may present with chronic, intermittent large-bowel obstruction, constipation, and pain. Occasionally, patients may present with acute obstruction with abdominal pain, obstipation, and signs or symptoms of intravascular hypovolemia such as hypotension and tachycardia. In contrast to small-bowel obstructions, nausea and emesis are less common in colonic obstructions because a competent ileocecal valve (ICV) will limit proximal small-bowel distension. A competent ICV can contribute to the development of a closed-loop obstruction, as well, between the ICV and the obstructing stricture. A variable degree of abdominal distension may be present, and peritonitis may be seen in cases where severe colonic dilation has resulted in the development of colonic ischemia or perforation. Diagnostic evaluations in both the asymptomatic and acutely obstructed patient should be directed at identifying common causes of large-bowel obstruction including malignancy, volvulus, hernia, colonic pseudo-obstruction, as well as colonic stricture. Initial imaging studies include abdominal radiographs and CT scans of the abdomen and pelvis. Water-soluble contrast enemas may better identify the site of stricture and can provide important additional information including stricture length, severity, and any associated lesions. Colonoscopy is useful in both the diagnosis and treatment of benign strictures, but it is contraindicated in cases of peritonitis or complete obstruction because of the risk of perforation with further bowel distension. When performed, endoscopic interventions should include biopsy of strictures. Not uncommonly, diagnostic uncertainty remains after thorough evaluation and operative intervention is required to allow for pathological evaluation of the diseased segment.