Benign anastomotic stricture of the rectum complicated by metal stent insertion: Salvage by placement of a biodegradable polydioxanone stent

Abstract

Introduction

Benign strictures of the gastrointestinal (GI) tract can severely impair a patient’s quality of life and may present a formidable management challenge. Stenting intuitively offers a better chance of remodeling the stricture, compared to the short-term disruption achieved by pneumatic dilatation. Permanent insertion of a metal stent is contraindicated, although temporary stenting with fully covered removable stents can be performed.1 In Europe, a single type of biodegradable stent—the SX-Ella biodegradable (BD) stent (Ella-CS, Hradec Kralove, Czech Republic)—is commercially available (Fig. 1). However, it is only licensed for benign esophageal strictures. They have been used off-label successfully for the temporary treatment of benign and malignant strictures throughout the GI tract,2–7 and they show promising results in treating anastomotic rectal strictures.8,9

SX-Ella BD stents are braided from a polydioxanone mono-filament in a conventional fashion. The stents are radiolucent with seven radiopaque markers. SX-Ella BD stents need to be loaded by hand into the delivery system prior to use (at which point significant elongation occurs, as seen with braided metal stents). The stents are available in diameters of 18–25 mm and lengths of 60–135 mm (Fig. 1). The 28 Fr delivery system is designed for use in the esophagus and the tortuous access route requires an ultra-stiff guide wire. The manufacturer reports that the radial expansion force of an 18-mm diameter BD stent is approximately 62% of the force exerted by the Wallflex nitinol stent (Boston-Scientific, St. Albans, UK) (166 g vs. 269 g, respectively); the force of the BD stent is also reduced in larger sizes. The radial force is maintained 6–8 weeks, after which the stent starts to weaken. Biodegradable stents begin to disintegrate after 3 months and usually have disappeared after 4 months. This process is accelerated in an acidic environment. The cost of biodegradable stents and metal stents are comparable.

Case report

After neoadjuvant radiotherapy and a curative anterior resection of a T3 rectal tumor, a 53-year-old man developed an anastomotic stricture. This was confirmed by endoscopy and a barium enema (Fig. 2). The stricture prevented reversal of the defunctioning ileostomy.

Balloon dilatation failed to achieve long-term patency. A Wallflex stent (Boston Scientific, St Albans, UK) was inserted at a local hospital. Despite the combined use of endoscopic and fluoroscopic guidance, the stent was unfortunately deployed below the stricture because the guide wire had not crossed the lesion (Fig. 3). Fifteen months after the insertion of the metal stent, the patient was referred to the supraregional cancer center for the insertion of a biodegradable stent. An attempt to remove the metal stent by endoscopy was only partially successful because an uncovered stent had been used.

The institutional review board approved the procedure. The patient provided consent for the off-label use of the BD stent.

Under sedation with fentanyl and midazolam and using fluoroscopic guidance, the stricture was crossed with a straight hydrophilic wire (Terumo, Prescot, UK) and a 6 Fr biliary manipulation catheter (Cook, Hitchin, UK). After the stricture was outlined with water-soluble contrast medium, a 25 mm × 60 mm uncovered esophageal Ella BD stent was inserted over an ultra-stiff back-up Meier wire (Boston Scientific, St. Albans, UK) and deployed without difficulty (Fig. 4A, B). Residual strands of wire from the original stent were embedded in the rectal mucosa. Limited balloon dilatation to 12 mm was performed in consideration of posttreatment fibrosis and the surrounding nitinol wires.

Computed tomography (CT) scans on the same day showed the stent in good position with 60% stent expansion (Fig. 5). The patient made an uneventful recovery. His ileostomy was reversed 3 months later. After 4 months, the BD stent had dissolved and the anastomosis allowed the passage of a colonoscope. Eighteen months after the BD stent insertion, the patient had minor rectal seepage and occasional spasmodic abdominal pain, but declined any further assessment or intervention.

Discussion

Biodegradable stents allow temporary stenting without the need for a removal procedure. These stents achieve symptom relief—at least, while in situ. Permanent patency in benign esophageal strictures may not be achieved, even by repeated stent insertion.10 However, initial results with short fibrotic strictures (e.g., surgical anastomoses) are promising. This suggests that strictures of different etiologies may respond in a different fashion.

BD stents have a lower expansion force than metal stents and lack the superelastic properties of nitinol. However, no data exist on the minimum force that is indeed required for sufficient stricture dilatation. In our patient, we assumed that perirectal fibrosis from previous radiotherapy and the surrounding remnant of the metal stent would prevent adequate stent expansion. Limited dilatation to only 50% of the stent diameter was performed to minimize the risk of perforation. As with metal stents, expansion is a process that often takes several days. Balloon dilatation should only be performed if a delivery system cannot be passed or if dilatation is needed in a particularly hostile environment. However, balloon dilatation can always be performed at a later time if stent expansion proves clinically insufficient.

A degree of hypertrophic mucosal overgranulation from direct irritation is common while a BD stent is in place and cases of stent obstruction have been reported.11,12 However, this is rarely a problem clinically and, more importantly, it seems reversible after the stent has dissolved.

In conclusion, the off-label use of BD stents in the colon may be considered in patients with anastomotic strictures for whom attempts at conventional dilatation have failed. Their application in other pathologies such as diverticular or ischemic stricture has yet to be evaluated.

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