INTRODUCTION

Despite recent advances in the medical treatment of ulcerative colitis (UC), colectomy is still required in some patients with medically refractory disease, poor tolerance of medications, or colitis-associated neoplasia (CAN). In a population study from Olmsted County, the cumulative probability of colectomy from the time of UC diagnosis was 13.1% at 5 years (95% confidence interval [CI]: 9.4–16.6%), 18.9% at 10 years (95% CI: 14.4–23.2%), and 25.4% at 20 years (95% CI: 19.8–30.8%). A metaanalysis of population-based studies reported a cumulative risk of colectomy in adult patients with UC of 4.4%, 10.1%, and 14.6%, respectively, with a trend of a decreased surgical rate as compared with pre “biological era.” There is a trend that the proportion of patients undergoing colectomy for CAN is increasing and the number of patients having surgery for the medically refractory disease is decreasing.

Restorative proctocolectomy (RPC) with ileal pouch-anal anastomosis (IPAA) has become a standard procedure for patients with UC or familial adenomatous polyposis (FAP) who require surgery. This complex reconstructive surgery has significantly improved patients’ quality of life (QoL). However, adverse sequelae often occur, potentially causing significant morbidities and adversely affecting patients’ QoL and surgical outcomes. The International Ileal Pouch Consortium (IIPC) and Global Interventional Inflammatory Bowel Disease (IBD) Group (GIIBDG) published a series of consensus guidelines in the diagnosis, classification, and management of ileal pouch disorders. The adverse sequelae or complications can be divided into five categories: (1) structural, (2) inflammatory, (3) functional, (4) neoplastic, and (5) systemic and metabolic. , Endoscopy or pouchoscopy plays a key role in the diagnosis and treatment of these complications. , In this chapter, normal anatomy and diseased conditions of the ileal pouch are discussed. The chapter is focused on pouch disorders amenable endoscopic therapy.

ANATOMY AND LANDMARKS

Various techniques are used to construct a pelvic pouch or IPAA. IPAA is fashioned by stapled anastomosis or hand-sewn anastomosis, with or without mucosectomy. Typically, the length of the anal transition zone (ATZ) is approximately 1 cm ( Fig. 36.1 ). The distance between the proximal edge of the ATZ and the staple line or suture line is the length of the cuff. The classic length of a well-constructed IPAA without mucosectomy is about 2 to 3 cm ( Fig. 36.2 ). The anastomosis should be patent and traversable to an endoscope without resistance. The best way to accurately assess the anastomotic stricture is digital and endoscopic examination while the patient is under sedation or monitored anesthesia care. The latter can minimize the component of anal spasms. Patients with or without mucosectomy can still have cuffitis or develop neoplasia. Routine surveillance pouchoscopy should include a biopsy of the cuff and ATZ. The anal column and dentate line should also be carefully examined during pouchoscopy as they are common origins for cryptoglandular fistulas, pouch vaginal fistula (PVF), and perianal fistulas.

Anal transition zone at the junction between the squamous and columnar epithelium in handsewn ileal pouch-anal anastomosis with mucosectomy.

Normal 2-cm-long cuff in stapled pouch-anal anastomosis without mucosectomy.

Common configurations are 2-limb, 1-“U-turn”- J- and 3-limb, 2-“U-turn” S-pouches, with the latter having a larger volume ( Fig. 36.3 ). The efferent limb of a J-pouch leads to the tip of the “J” or the dome of the pouch body, while the efferent limb of an “S” pouch is connected with the ATZ. The “normal” length of the pouch should be between 15 and 18 cm. The pouch body should be straight without axial or longitudinal twists. Some patients may have superficial or deep bleeding or nonbleeding ulcers along the vertical staple lines or suture lines of the pouch body. These ischemic ulcers with active bleeding or the stigmata of bleeding may cause hematochezia and iron deficiency anemia ( Fig. 36.4 ). Some may notice dislodged staples along the staple lines.

An S-pouch with a large capacity.

Vertical staple line in the J-pouch body with stigmata of low-grade bleeding.

The tip of the “J” of the J-pouch can be easily visualized by the identification of submucosal staples or sutures can be seen and the proximity of the nearby pouch inlet ( Fig. 36.5 ). Of note, the S-pouch does have the tip of the “J” structure. The presence or absence of the tip of the “J” has been used to differentiate the J-pouch from the S-pouch when the original operative note is not available. The tip of the “J” is prone to the development of inflammation, ulcers, or leaks, presumably being related to ischemia.

The tip of the “J” is sealed with staples, with a transmucosal view.

The pouch inlet is a structure between the pouch body and the prepouch ileum. The inlet should be widely patent, along with the patent tip of the “J” and vertical staple line, comprising an “owl’s eye” configuration ( Fig. 36.6 ). Distortion of the “owl’s eye” anatomy was found to be associated with a diseased pouch and a risk for pouch failure. Ulcers ( Fig. 36.7 ) and strictures ( Fig. 36.8 ) are common at the pouch inlet, resulting from ischemia, Crohn’s disease (CD), or the use of nonsteroidal antiinflammatory drugs (NSAID).

The owl’s eye configuration of a healthy J-pouch with one eye leading to the prepouch ileum and the other to the tip of the “J,” conjoined by a “beak” from the vertical staple line.

Circumferential ulcers at the pouch inlet from ischemia.

A pinhole stricture at the pouch inlet.

The term prepouch ileum normally describes the segment of the distal ileum between the pouch inlet and stoma closure site with a common length between 20 and 30 cm. Some investigators may use the prepouch ileum to designate the segment of the ileum proximal to the pouch inlet, including the segment above the stoma closure site. The prepouch ileum is prone to the development of inflammation (i.e., prepouch ileitis [PPI]) and strictures resulting from CD, ischemia, the use of NSAIDs, or concurrent autoimmune disorders ( Fig. 36.9 ).

Prepouch ileitis with ulcers.

The construction of diverting end or loop ileostomy is a part of staged IPAA. The stoma is closed by handsewn end-to-end anastomosis ( Fig. 36.10 ) or side-to-side anastomosis ( Fig. 36.11 ), with each having its pros and cons. It appears that end-to-end anastomosis carries a higher risk for anastomotic stricture and side-to-side anastomosis has a greater risk for a staple-line leak or luminal dilation (e.g., “pouch-over-pouch”), than their counterparts. PPI rarely involves the ileum proximal to the stoma closure site. Polypectomy, EMR, or endoscopic submucosal dissection (ESD) may be easier to perform in the pouch than in the cuff or ATZ. Submucosal fibrosis has made EMR or ESD difficult, particularly in the lesions in the cuff or ATZ. It has been recommended that mucosal biopsy be avoided in a lesion highly suspected of dysplasia and anticipated to have endoscopic resection, to reduce the risk of trauma-associated fibrosis.

End-to-end anastomosis at the loop ileostomy closure site.

Side-to-side anastomosis with ulcer, bleeding, and dislodged staples at the stoma closure site.

STRUCTURAL COMPLICATIONS

Structural complications of IPAA can be broadly categorized into obstruction, leaks, and bleeding.

Obstruction

The new classification of bowel obstruction in CD was proposed by the author. This classification system can be extrapolated to other IBD-associated bowel obstructions, including IPAA. Briefly, the classification system portrays the obstruction into (1) intraluminal (e.g., lumen-blocking polyps, prolapse, and bezoars), (2) intramural (e.g., ischemic secondary or anastomotic strictures or CD-associated primary strictures), or (3) extraluminal (e.g., adhesions, compression from masses, twisted pouch). For intraluminal strictures in CD, the GIIBDG also proposed a classification for CD strictures, based on the underlying disease, location, number, length, severity, and complexity. The GIIBDG also proposed a classification of IBD-associated strictures. The GIIBDG classification systems can be used to characterize ileal pouch strictures or obstruction.

Postoperative ileus at the acute phase may present a dilated pouch body and ileum. For persistent postoperative ileum, pouchoscopy may occasionally be performed to evaluate ischemia and placement of decompression ( Fig. 36.12 ).

Placement of a decompression tube via pouchoscopy in postoperative ileus.

The common locations of the intramural strictures are the anastomosis ( Fig. 36.13 ), pouch inlet ( Fig. 36.8 ), prepouch ileum ( Fig. 36.14 ), stoma closure site ( Fig. 36.15 ), and less often at the pouch body. Pouchoscopy is valuable to characterize the location, number, severity, and length of the stricture. In experienced hands, pouchoscopy may be used to differentiate inflammatory and fibrotic strictures. Some previously underappreciated factors may contribute to the formation and exacerbation of strictures, such as prolapse or intussusception or prolapse ( Fig. 36.16 ) or pedunculated polyps ( Fig. 36.17 ) of the bowel proximal to the stricture and clustering or dislodged staples at the anastomosis ( Fig. 36.18 ).

Anastomotic stricture.

Mild circumferential nonulcerated stricture at the prepouch ileum.

Stricture at the side-to-side anastomosis at the stoma closure site.

Pouch inlet stricture with prolapse of mucosa from the proximal prepouch ileum.

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