In an adult patient with a chronic esophageal fistula ≤2 cm following sleeve gastrectomy or gastric bypass that has failed conservative management for 4–6 weeks, what is the role of the Ovesco over‑the‑scope clip (OTSC) for closure?

Role of Ovesco Clip for Chronic Esophageal Fistula Post-Bariatric Surgery

For chronic esophageal fistulas ≤2 cm following bariatric surgery that have failed 4–6 weeks of conservative management, Ovesco over-the-scope clips (OTSC) should NOT be used as monotherapy; instead, fully covered self-expanding metal stents (SEMS) providing a snug fit with proximal fixation represent the preferred endoscopic approach, as OTSC and through-the-scope clips alone are usually not effective for established fistulas. 1

Why OTSCs Fail in Chronic Fistulas

The fundamental problem with OTSC use in chronic fistulas is tissue quality and pathophysiology:

• Fibrotic and inflamed tissue surrounding chronic fistulas prevents adequate clip purchase and compression, leading to high failure rates 2
• Poor tissue integrity from ischemia and inflammation at the fistula site makes the tissue unable to hold clips effectively 3
• Chronic defects (>30 days) have significantly lower success rates with OTSC compared to acute perforations 4, 5

In one retrospective series, OTSC technical success in chronic settings was only 50% with long-term clinical success of just 37%, compared to 100% success in acute perforations 5. Another study specifically noted that "OTSCs were less effective in cases of chronic defects" 5.

When OTSCs Can Be Considered

OTSCs demonstrate excellent efficacy in specific scenarios that do NOT match your clinical question:

• Acute perforations recognized during or immediately after endoscopy (≤72 hours), where success rates reach 85-100% 1
• Fresh leaks within days of surgery where tissue edges remain viable 1
• Defects 1-2 cm in size in the acute setting 1

The systematic review by Bartell demonstrated that OTSC failures occurred mainly with defects >2 cm and closure attempts >72 hours after perforation 1.

Recommended Approach for Chronic Post-Bariatric Fistulas

Primary strategy: Fully covered SEMS with fixation

• Place a fully covered stent providing a snug fit to seal the fistula 1
• The SEMS diameter should be slightly wider than the natural esophageal diameter to seal without expanding the defect 1
• Fix the stent proximally using endosuturing or a stent-fixing device to prevent migration, as there is no stricture to anchor the stent 1
• This approach allows closure by secondary intention, though it results in a longer clinical course than primary closure 1

Alternative/salvage strategy: Endoscopic vacuum-assisted closure (EVAC)

• EVAC should be considered for fistulas that fail SEMS placement 1
• One case series demonstrated successful closure of a chronic gastric fistula after bariatric surgery that had failed both OTSC and SEMS, requiring 9 sponge exchanges over 35 days 6
• EVAC achieves 90% healing for anastomotic leaks and 96% closure for esophageal perforations at median 17-day therapy duration 1

Critical Pitfalls to Avoid

Do not attempt OTSC monotherapy in chronic fistulas:

• The fibrotic tissue will not hold the clip adequately 2
• Failed OTSC attempts do not preclude subsequent therapy, but delay definitive treatment 2

Address downstream stenosis:

• Evaluate for gastric stenosis or anastomotic stricture creating elevated intraluminal pressures that perpetuate the fistula 3
• Failure to address downstream obstruction will cause persistent leak regardless of closure method 3

Recognize SEMS limitations:

• Fully covered SEMS do not provide a watertight seal—oral contents can pass alongside the stent 3
• Monitor for stent migration (high risk without stricture to anchor), tumor ingrowth/overgrowth, and food bolus obstruction 7

Plan for nutritional support:

• Maintaining adequate nutrition through oral intake alone is extremely difficult even with successful fistula closure 7
• Strongly consider percutaneous gastrostomy tubes for fluid and caloric support 7

Expected Outcomes

With appropriate SEMS placement for chronic fistulas:

• Successful closure improves quality of life scores significantly (p<0.001) 7
• Patients with successful closure have better survival (15 weeks) versus incomplete closure (6 weeks, p<0.05) 7
• Approximately 21% experience fistula recurrence requiring second intervention 7
• Late morbidity occurs in ~25% of patients 7