Classification of Strictures From Crohn’s Disease, Ulcerative Colitis, and Inflammatory Bowel Disease–Related Surgery

Introduction

Crohn's disease (CD) and ulcerative colitis (UC) are the two premier forms of inflammatory bowel disease (IBD). In the Montreal Classification System, CD was divided into non-stricturing/non-penetrating (B1), stricturing (B2), and penetrating (B3), based on clinical behavior. Stricturing disease is believed to result from persistent inflammation. CD-related strictures often lead to significant morbidities such as bowel obstruction and the development of fistula and abscess. In contrast, UC is characterized by the extent of colonic involvement with categories including extensive colitis, left-sided colitis, and proctitis. Despite being a “mucosal disease,” long-term UC can also cause strictures due to cancer, muscularis mucosae hyperplasia, and submucosal fibrosis possibly related to inflammatory cells. The inflammatory component of stricture may respond to corticosteroids or anti-tumor necrosis factor (TNF) therapy. On the other hand, there has been a concern that rapid tissue healing from anti-TNF therapy may result in or promote the formation of stricture.

CD-associated primary strictures have traditionally been treated with surgery, with bowel resection, stricturoplasty, or bypass. However, surgical therapies for both CD and UC are often associated with subsequent strictures at anastomosis sites. A Belgium team of investigators reported that strictures occurred at the surgical anastomosis or neoterminal ileum in 46% of patients after surgical intervention for CD. In patients with UC who underwent ileal pouch-anal anastomosis (IPAA), anastomotic strictures have been reported as occurring in 10%–40% of patients. The purported causes of anastomotic strictures included surgery-related ischemia, bacterial stasis, and high pressures within the intestine. Anastomotic strictures tend to recur, even after surgical resection and reanastomosis, and stricturoplasty.

The disease process of IBD is complex, which is further complicated by the use of medications and surgery-altered anatomy, the strictures in IBD patients represent a wide spectrum of phenotypes. Diagnosis and classification are important for proper management and improvement of short and long outcomes.