Endoscopic Corrective Procedures for Kock Pouch- and Barnett Pouch-related Problems and Complications

Abbreviations

BCIR

Barnett continent intestinal reservoir

BMI

body mass index

CI

continent ileostomy

CD

Crohn’s disease

EBD

endoscopic balloon dilation

ECF

enterocutaneious fistula

ESt

endoscopic stricturotomy

FAP

familial adenomatous polyposis

IBD

inflammatory bowel disease

IPAA

ileal pouch-anal anastomosis

IQR

interquartile range

QoL

quality of life

UC

ulcerative colitis

VCE

video capsule endoscopy

Introduction

Patients with medically refractory ulcerative colitis (UC), colitis-associated neoplasia, or familial adenomatous polyposis (FAP) would need colectomy. While restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) is a preferred surgical option for these patients, some patients may not be candidates for IPAA, mainly due to the presence of structural or functional anal sphincter function or anatomical reach issues with mesenteric tension for pouch-anal anastomosis. Continent ileostomy (CI) may be offered to these patients. CI may be attempted in some patients who failed pouch due to certain structural or neoplastic disorders, such as pouch vaginal fistula, pouch prolapse, and dysplasia of the cuff or anal transition zone.

There are two forms of CI: Kock pouch and less commonly performed Barnett Continent Intestinal Reservoir (BCIR). While patients with CI have improved quality of life (QoL), structural, inflammatory, and functional adverse sequelae can occur, requiring medical and sometimes surgical intervention. Endoscopy plays an important role in the diagnosis and management of these disorders.

Anatomy and Endoscopic Landmarks of Continent Ileostomy

The Global Interventional IBD Group has published a consensus guideline on the endoscopic evaluation of surgically altered bowel in IBD, including patients with a continent ileostomy. Kock (K) pouch is the most common form of CI that was first devised by Nils Kock in 1969. While the popularity of the K-pouch has been overtaken by IPAA since the 1980s, it remains a valuable surgical treatment option for selected patients who are not candidates for IPAA or for those who failed IPAA. The main advantage of the K-pouch over traditional Brooke ileostomy is the avoidance of an external appliance. Structures of a Kock pouch consist of the prepouch ileum, pouch inlet, pouch body, nipple valve, exit conduit ( Fig. 38.1 ), and stoma. While the nipple valve is the main anatomic structure that preserves the continence, it is a common location for the development of structural complications.

BCIR is a variant of the Kock pouch where a loop of the small bowel collar is wrapped around the pouch outlet to augment the continence of ileostomy ( Fig. 38.2 ).

The main indications for CI are patients who are not candidates for pelvic ileal pouches usually due to structural or functional disorders of the anal sphincters; some who failed pelvic pouches; or those who are not satisfied with a conventional ileostomy. Patients with IPAA carry a significant risk for structural, inflammatory, or functional complications, and some of them may lead to pouch failure with pouch excision, pouch revision, or permanent diversion. It is reported that approximately 5% to 15% of patients with IPAA failed the pouch. ^, A conversion of a failed J- or S-ileal pouch to a CI may be performed in highly selected patients, using the existing functioned pelvic pouch body, or constructing with a new segment of the small bowel. A historical cohort study of 64 patients with salvage Kock pouches failed J- or S-pouches with underlying diagnoses of UC (N = 44, 69%) or CD with perianal disease (N = 13, 20%) showed the reuse of preexisting pelvic pouches in 16 (25%) patients. During a median follow-up of 5 years, pouch dysfunction, complications, and pouch revision were reported in 50%, 61%, and 45% of patients, respectively. Nonetheless, the retention rate of the Kock pouch was 95% during a median pouch survival of 4.2 years (range, 1–19).

The contradictions for the construction of CI are small bowel CD, CD of the preexisting pouch body, limited small bowel reserve, obesity, and significant comorbidities. Handelsman et al. reported 95 patients with Kock pouch surgery for IBD and found that all 8 patients with a precolectomy diagnosis of CD or indeterminate colitis developed serious complications of CI. In contrast, 17 (20%) of 87 patients with precolectomy diagnosis of UC developed complications.

Diagnosis of Disorders of Continent Ileostomy

Structural, inflammatory, and functional disorders of the IPAA can also occur in patients with CI. Adverse systemic or metabolic consequences can be seen in these with CI. Fortunately, pouch neoplasia is extremely rare in patients with CI.

The nipple valve of a Kock pouch is the most common location for complications including valve slippage, prolapse, angulation, stenoses, and fistulas. In a study of 31 patients with K-pouches for more than 10 years, 26 (84%) were found to have nipple valve slippage. Nipple valve slippage can be partial or total, leading to difficult intubation or pouch incontinence. Obesity or excessive weight gain is a common risk factor for nipple valve slippage. Obesity or weight gain is a major risk factor for nipple valve slippage.

Stenoses ( Figs. 38.3 and 38.4 ) and fistulas ( Figs. 38.5 and 38.6 ) can also occur in the stomal skin, pouch body, inlet, and prepouch afferent limb. Causes of strictures vary from tissue contraction, the use of nonsteroidal anti-inflammatory drugs, infection, and ischemia to CD. Patients with stricture may present with difficult intubation, abdominal pain, bloating, nausea, vomiting, or weight loss. Floppy pouch complex that is common in patients with IPAA ( Fig. 38.7 ) is rare in patients with Kock pouches. Bezoars or foreign bodies (such as capsule endoscopes) may be present in the lumen of CI, which can cause symptoms.