Intraluminal Duodenal Diverticulum: Double Barrel Lumen Treated With Water Immersion Septotomy And Endoscopic Mucosal Resection

INTRODUCTION: Intraluminal duodenal diverticulum (IDD) is a rare congenital condition caused by incomplete recanalization of the foregut. Surgical diverticulotomy was historically used to treat patients with symptomatic IDD. Underwater septotomy and endoscopic mucosal resection (EMR) present a minimally invasive approach to relieve an obstructing IDD lesion. Our case report demonstrates effective management of IDD with underwater septotomy and EMR. CASE DESCRIPTION/METHODS: A 78-year-old male presented with progressive chronic post-prandial nausea and bloating associated with early satiety and substernal heartburn that was only moderately relieved with proton pump inhibitor therapy. Initial esophagogastroduodenoscopy (EGD) revealed post-bulbar duodenal stricture and symptoms persisted following balloon dilation. Repeat EGD showed IDD with double barrel lumen of the duodenal mucosa. Due to persistent symptoms, the decision was made to intervene on the obstructive IDD. The IDD was visualized in the second part of the duodenum. The obstructing lesion was tented back to visualize the septum, which was injected with saline-methylene blue lifting agent. Initial limited EMR was performed via snare excision to debulk diverticular tissue. Next, underwater septotomy was performed with a 20-mm snare tip. EMR of the lesion was then completed and the lesion was removed by snare. The mucosal defect closed with six endoscopic clips to achieve hemostasis. The next day, the patient developed gastrointestinal bleeding due to a visible vessel and hemostasis was again achieved with 7 French gold probe cautery and one additional endoscopic clip. DISCUSSION: Underwater septotomy and EMR successfully relieved obstruction due to IDD. Snare tip for septotomy was an effective alternative to needle knife and preserved resources by employing tools already being used for EMR. Underwater approach allowed for clear visualization due to minimal electrosurgical smoke production and potentially reduced risk of perforation compared to insufflation. This case highlights the use of underwater septotomy and EMR as minimally invasive management for obstructing IDD lesions.