Endoscopic approaches to gastrointestinal (GI) perforations, leaks, and fistulas remain in an early stage of development in Mongolia. However, with recent advances in equipment and endoscopic skills, minimally invasive closure techniques have rapidly gained ground. Among these, the Over-the-Scope Clip (OTSC) system has emerged as a key innovation, enabling effective closure of small defects and reducing the need for surgical re-intervention.

A retrospective review was conducted of 30 patients treated with the OTSC system between 2024 and 2025 in six tertiary centers across Mongolia (Brilliant Hospital, NCCD, MCH, MNUMS Hospital, And-Med, and Mungun Guur). Indications included post-surgical leaks, perforations (post-ESD, post-ERCP, or postoperative), fistulas, and foreign body–related defects. Two pediatric cases (aged 1 and 8 years) were successfully treated using OTSC mini.

The overall technical success rate was 90%, and all OTSC applications achieved complete closure. Two patients died from underlying systemic disease unrelated to the endoscopic procedure. The majority of cases (≈60%) involved post-surgical leaks, most frequently in the esophagus and duodenum. The procedure was found to be simple, quick to learn, and technically feasible, even in limited-resource settings, providing a practical alternative to surgery.

The introduction of OTSC in Mongolia represents a major step forward in endoscopic management of GI complications. This technique offers a safe, effective, and minimally invasive solution for perforations and leaks, especially after esophago-jejunal or duodenal anastomoses. These early multicenter results demonstrate the growing capability of Mongolian endoscopists to manage complex GI defects endoscopically and highlight the expanding role of OTSC as a standard therapeutic tool in the region.