INTRODUCTION

Ileal pouch–anal anastomosis (IPAA) following proctocolectomy has become a preferred surgical approach for patients with medically refractory inflammatory bowel disease (IBD) such as ulcerative colitis (UC), indeterminate colitis (IC), colitis-associated neoplasia, or familial adenomatous polyposis (FAP). J-pouch is the most commonly constructed pouch, while other pouches including the “S-,” “W-,” “H-,” “T-,” and “K-” pouches are constructed in selected patients. Patients with restorative proctocolectomy and IPAA significantly improve their health-related quality of life. However, post-IPAA adverse sequelae were common, with a reported frequency as high as 60%, leading to pouch failure with pouch excision or permanent diversion in 4% to 12% of patients. Stricture was considered as one of the most common causes for pouch failure. ^, A large study including a total of 3707 patients with UC, IC, or Cron’s disease (CD) treated with IPAA who were followed up postoperatively with a median of about 7 years, formation of early-onset strictures after IPAA was seen in 5% of patients, and late-onset strictures were reported in 11% of patients. A separate study reported the 30-year accumulative probability of stricture being as high as 56%, 73%, and 75% in patients with a preoperative diagnosis of UC, IC, and Crohn’s colitis, respectively.

The diagnosis of strictures requires a combined assessment of clinical presentation, endoscopy, and imaging. ^, Clinical presentations primarily consist of abdominal pain, nausea, bloating, vomiting, malnutrition, dehydration, and dyschezia. Patients may also complain of postobstructive diarrhea. Furthermore, we need to be cautious about asymptomatic strictures, as there are discrepancies between the degree of symptomatology and the severity of objective findings on endoscopy and imaging. Endoscopy plays a key role in the diagnosis, differential diagnosis, and treatment of pouch strictures. It is important to evaluate and photo-document strictures with relevant common landmarks of ileal pouches. ^, Various imaging has also been used in the detection and characterization of pouch strictures including computed tomography (CT), computed tomography enterography (CTE), magnetic resonance imaging (MRI), magnetic resonance enterography (MRE), small bowel follow-through, barium defecography, and gastrografin enema (GGE). The role of ultrasound elastography in the characterization of pouch strictures remains to be defined.

The management of strictures consists of medical, endoscopic, and surgical therapies. Due to the nature of mechanical strictures, the role of medical management is often limited. Most studies were conducted among patients with CD of the pouch, including those with fibrostenotic CD of the pouch. In these case series, the improvement in symptoms, endoscopy, or imaging was not set as an outcome of the medical therapy. Furthermore, the currently available medical therapy does not seem to be effective in treating existing strictures, especially fibrotic strictures. However, adequate control of inflammation with proper medical therapy likely helps prevent or deter stricture formation. Therefore, it is recommended that medical treatment be used in conjunction with endoscopic or surgical therapies. Surgery is considered a more definitive treatment modality available in the treatment of ileal pouch strictures than medical and endoscopic therapies. The most commonly performed procedures include bowel resection with anastomosis, strictureplasty, pouch redo, and diverting ileostomy. Given the invasive nature, postoperative adverse events, and frequent postoperative recurrence, surgery is reserved as a last resort. The goal of endoscopic therapy has therefore been to release obstruction, improve symptoms, and avoid or space out the need for surgical intervention.

ETIOLOGIES AND CLASSIFICATIONS OF POUCH STRICTURES

Common causes for strictures in patients with the ileal pouch include anastomotic tension, surgery-associated tissue ischemia, pelvic sepsis, medications, and CD of the pouch. Surgery-related ischemia is a well-established factor contributing to the formation of strictures. These strictures often result from compromised blood flow or tension in the blood vessels. Therefore, obese patients or those with short mesentery were found to have a higher risk for postsurgical complications including chronic pouchitis, anastomotic leaks, strictures, and even pouch failure, than controls. On the other hand, anastomotic strictures have been reported to be more prevalent in hand-sewn anastomosis, and these strictures are often long and narrow. ^, The size of the stapler used did not affect the risks. Fibrotic strictures are also associated with intraoperative or postoperative complications such as pelvis abscess or fistula that lead to dense scarring and tight strictures. Although the formation of a stricture is primarily a consequence of the inflammatory process, proposed risk factors included medication use such as antitumor necrosis factor (TNF) and nonsteroidal anti-inflammatory drugs (NSAIDs). ^{, ,}

Strictures are also found to be associated with CD of the pouch. Precolectomy evaluation and exclusion of CD may help reduce the frequency of CD in the pouch. However, de novo CD of the pouch can develop weeks, months, or even years after IPAA. ^, The diagnosis of CD of the pouch can be challenging. The International Ileal Pouch Consortium has published a consensus guideline in the diagnosis and classification of ileal pouch disorders. A diagnosis of Crohn’s disease of the pouch is made based on a combined assessment of clinical, endoscopic, histologic, and imaging features. In the consensus guidelines, the presence of the following feature(s) suggests a diagnosis of de novo CD of the pouch, irrespective of precolectomy diagnosis of CD: (1) noncaseating, non-crypt-rupture-associated granulomas on intestinal biopsy of the prepouch afferent limb, pouch body, or cuff; (2) segmental or skip lesions (such as longitudinal ulcers) or strictures in the pouch or small bowel; (3) late development of fistulas or abscess (6–12 months after stoma closure); and (4) prepouch ileitis. CD of the pouch can be classified into inflammatory, fibrostenotic, or fistulizing phenotypes modified from the Vienna Classification and Montreal Classification. ^, CD of the pouch, especially fibrostenotic and fistulizing phenotypes, is strongly associated with an increased risk of pouch failure.

The distinction between etiologies of strictures can be difficult. A persistent stricture after the discontinuation of NSAIDs or an isolated stricture of the anastomosis in the absence of fistulae or mucosal inflammation favors a diagnosis of surgical ischemia-related stricture. Response of inflammatory strictures to anti-inflammatory agents including biologics may suggest a diagnosis of CD of the pouch.

In addition to intrinsic strictures, luminal narrowing or obstruction can result from extrinsic factors, such as afferent limb syndrome (ALS) and efferent limb syndrome (ELS), pouch prolapse, pouch horizontal folding, and twisted pouch, collectively named floppy pouch complex. ^{, ,} ALS refers to the condition in which the prepouch ileum is sharply angulated at the inlet or is trapped between the sacrum and pouch body posteriorly. ELS is the condition that results from bending of the long efferent limb in patients with S pouches or angulation between the pouch body and a long rectal stump in the J-pouch. Both ALS and ELS are more commonly seen in patients with S-pouches than those with J-pouches. In these conditions, intrinsic changes are often not observed in endoscopy. ^, Last but not least, pouch bezoars are occasionally associated with strictures as well, especially in those with continent ileostomies.

No uniform classification of pouch strictures has been established. However, different methods have been used to classify and describe the characteristics of the strictures. Our group has previously summarized a proposed classification ( Table 14.1 ). Pouch strictures can be classified into: (1) primary ( de novo stricture) or secondary (anastomotic strictures) according to the etiology; (2) strictures at the anus, anastomotic, pouch body, inlet, afferent limb, or ileostomy closure site, based on the location; (3) single or multiple strictures based on the number; (4) into short or long strictures based on the length; and (5) simple versus complex strictures.

ENDOSCOPIC BALLOON DILATION

Indications

There have been controversies about treating asymptomatic strictures, but most believe that all symptomatic patients with pouch strictures should be treated, as outlined by the consensus guideline from the Global Interventional IBD Group. The treatment modalities include medical, endoscopic, and surgical approaches. Endoscopic therapies have emerged as valid treatment options. The efficacy and safety of EBD in pouch strictures have been described in multiple studies ( Table 14.2 ) and EBD has become an important treatment modality for IBD strictures in the pouch or nonpouch patients. EBD is overall effective and safe in treating ileal pouch strictures, irrespective of their locations. With the use of a guidewire and/or fluoroscopy, even angulated and tight stricture may be dilated. Better outcomes are often observed in patients with single, short (<4–5 cm), and straight strictures. ^, Before the endoscopic intervention, cross-sectional imaging and/or GGE should be obtained to guide the treatment.

Table 14.2

Published Studies on Endoscopic Balloon Dilation

Study	Patients	Follow-up (years)	Length of Stricture (cm)	Location of Strictures	Crohn’s Disease of the Pouch	Technical Success/ Endoscopic Improvement	Symptomatic Improvement	Pouch Failure	Major Adverse Event
Shen et al.	19	0.5	1	Inlet: 14 Outlet: 14	57.9%	NA	NA	5/10/25 years: 3%, 9.4%, 14.1%	0
Shen et al.	150	9.6	1 (0.5–1.25)	Inlet: 63.4% Outlet: 46.6% Afferent limb: 16.8% Body: 1.5% Loop ileostomy: 3.1%	41.3%	97.8%	80.3%	12.7%	Perforation: 0.49% Bleeding: 0.98%
Wu et al.	151	4.1	1.2 ± 0.6	Inlet: 96 Outlet: 73 Afferent limb: 29 Body:2	37.7%	NA	NA	12.6%	Perforation: 2 Bleeding: 4 Total of 3 patients (2%)
Lan et al.	160	3.6	2.0 (1.0–2.0)	Inlet and afferent limb: 100%	25%	100%	42.3%	5.6%	Perforation: 0.8%
Fumeryet al.	20	3.0	–	Inlet: 8.6% Outlet: 87% Afferent limb: 4.3%	30%	98%	95%	Pouch surgery: 5%	0

Table 14.3

Published Studies on Endoscopic Stricturotomy/Stricturoplasty

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