List of Abbreviations
Argon plasma coagulation
Endoscopic balloon dilation
Endoscopic mucosal resection
Endoscopic submucosal dissection
Inflammatory bowel disease
Ileal pouch-anal anastomosis
Nonsteroidal antiinflammatory drugs
Rectal vaginal fistula
Patients with inflammatory bowel disease (IBD) are prone to the development of disease-related (primary) or surgery-related (secondary) strictures. Medical therapy has a limited role in the treatment of fibrotic stricture. Endoscopic balloon dilation (EBD) has become a part of standard therapy for IBD patients with the primary or secondary stricture, in place of or in conjunction with surgical therapy. EBD has been shown to be effectively and safely performed in experienced hands and has been proven to avoid or postpone the need for surgical intervention for strictures. However, the recurrence of stricture after EBD is common and patients who failed EBD therapy then underwent surgical treatment had a higher risk for surgical complications than those having upfront surgery. On the other hand, surgical resection or strictureplasty for IBD-related strictures also has issues with postoperative recurrence of stricture, along with surgery-related complications. This author’s team has been actively seeking alternatives for EBD and surgical therapy for refractory or recurrent IBD strictures. Naturally, endoscopic stricturotomy (ES) with electroincision or electrocauterization, which have been used in strictures in the biliary system or upper gastrointestinal (GI) track, became the valid candidate procedure. There are limited published data on the techniques in the literature. The rationale, principles, and techniques described in this chapter are largely based on the author’s own experience.
The Rationale for Endoscopic Stricturotomy
This author feels that ES is more effective than EBD for IBD-related strictures, while bearing the similar safety profile. However, ES has advantages and disadvantages as compared with IBD.
Advantages of Endoscopic Stricturotomy
ES appears to be more effective in treating IBD strictures ( Fig. 14.1 ). The effect of EBD is dependent on its radial force, while bougie dilation relies on a shear force. Both EBD and bougie dilation is easier to perform than ES. However, the main limitations of EBD and bougie dilation are: (1) no control on depth of treatment; (2) no control on the topographical location in the circumference of stricture of the tear; (3) poor response of long or spindle-shaped strictures to EBD; and (4) discomfort during the treatment in the distal rectal or anal strictures. Due to those inherent limitations, EBD or bougie dilation may have a higher risk for iatrogenic or nonintended barotrauma to adjacent organs, such as the vagina (rectal vaginal fistula or pouch-vaginal fistula) and bladder (rectal vesicular fistula or pouch-vesicular fistula). The endoscopist should take an extreme precaution when performing EBD of the strictures in the distal rectum, distal pouch, anus, or anastomosis in the area, particularly in female patients. For female patients, the balloon size may be smaller (e.g., 16–18 mm) than that of male patients (18–20 mm), for the concern of the iatrogenic development of rectovaginal fistula or pouch-vaginal fistula.
The main advantages of ES over EBD and bougie dilation are endoscopist’s full control of depth and topographical location of the therapy. There are vulnerable areas in the gut with a high risk of detrimental consequences should procedure-associated perforation occur. For example, the injury to anterior wall of the distal rectum or distal ileal pouch with adjacent organs such as vagina, prostate, and bladder may lead to a fistula to the organ ( Fig. 14.2 ). For intestinal strictures undergoing endoscopic therapy, iatrogenic injury, if happens, can result in free perforation with peritonitis or perforation into mesentery with mesentery abscess. The adverse outcome for mesenteric abscess is usually worse than peritonitis. The pattern of iatrogenic injury is out of endoscopist’s control when performing EBD. In contrast, endoscopist should be able to identify and intentionally avoid those vulnerable locations when performing ES. During the ES, the endoscopist is able to deliver the therapy to the designed spot of treatment, intentionally avoiding the areas vulnerable for the iatrogenic injury, such as the anterior wall of the rectum or ileal pouch ( Fig. 14.2 ) and mesenteric site of ileocolonic anastomosis. To ensure a safe procedure for the stricture in the distal bowel, ES needs to be performed along the posterior wall which is next to the presacral space.
EBD exerts an even radial force to the circumference of the bowel stricture, with the assumption that the stricture is symmetric in both longitudinal axis and radial plane. The “ideal” stricture lesions for EBD are web-like ones occupying whole circumference of the bowel lumen, such as some of nonsteroidal antiinflammatory drug stricture and Schatzki ring of the distal esophagus. However, strictures in patients with IBD are often asymmetric, along the longitudinal axis or radial plane. For example, stricture at the ileocolonic anastomosis is asymmetric along the longitudinal axis, as the one side of the anastomosis is the small bowel (thinner) and other side is the large bowel (thicker). The primary, disease-related stricture can be asymmetric on the radial plane. In this author’s experience, those asymmetric strictures are prone to the development of perforation from EBD. In this setting, ES provides a safer alternative, with its therapeutic target aimed properly. Patients who are on long-term therapy with biological agents may develop spindle-shaped stricture, with overlying normal mucosa and vulnerable fibrosis tissue underneath. EBD therapy can be risky, as it can easily cause perforation. In this setting, ES may be feasible and preferred, as the endoscopist may control the depth of electric incision ( Fig. 14.3 ).
The development of ES in IBD stricture and its evolution is based on the assumption as well as clinical experience that this treatment modality is more effective than EBD. Although there are no published randomized controlled trials, our historic cohort study has demonstrated that endoscopic needle knife (NK) or isolated-tip (IT) knife ( Fig. 14.4 ) electroincision appeared more effective than EBD in treating IBD- and non-IBD lower GI strictures with comparable safety.
Limitations of Endoscopic Stricturotomy
In contrast to the mucosal layer for endoscopic mucosal resection (EMR) and submucosa layer for endoscopic submucosal dissection (ESD) in endoscopic therapy for dysplasia, there are no published data, consensus, or guideline on the depth of therapy, for example, mucosa, muscularis mucosae, submucosa, or muscularis propria, due to the complex structure in strictured bowel. The 5-layer structure of bowel wall is often disrupted in strictured area in patients with CD and the fibrosis process is often transmural ( Fig. 14.5 ). The goal of endoscopic therapy for the stricture is to keep the full patency of bowel lumen. After a successful endoscopic therapy, the endoscopic should pass the scope without resistance. In patients with EMR or ESD therapy, the incidental incision to the level of muscularis propria may harbinger an on-site or subsequent perforation and a proper rescuing procedure may be indicated. This may not be the case for EBD or ES, as fibrotic tissue is often intervened with the muscularis mucosae, submucosa or muscularis propria.