Endoscopic and Conservative Management of Symptomatic Lemmel Syndrome: A Systematic Review and Patient-Level Synthesis

Background. Lemmel syndrome is obstructive jaundice or pancreaticobiliary ductal dilatation caused by extrinsic compression from a periampullary duodenal diverticulum, without choledocholithiasis or periampullary neoplasm. Management is not standardised, and no patient-level synthesis of outcomes exists. Methods. We searched PubMed, Embase, and the Cochrane Library for adults with symptomatic Lemmel syndrome reporting management and outcome, synthesised at patient level with exact Clopper–Pearson confidence intervals. Co-primary outcomes were ERCP technical success and durable endoscopic success, defined as resolution without surgical or percutaneous rescue; recurrence-free survival was estimated using Kaplan–Meier analysis. Results. Twenty-six studies reporting 46 patients were identified; one diagnostic series and one non-qualifying patient were excluded, leaving 26 patients from 24 reports. ERCP was attempted in 16 patients (61.5%), with technical success in 14 (87.5%) and endoscopic success in 12 (75.0%); four (25.0%) required rescue. One bleeding event occurred (6.3%); no pancreatitis, perforation, or death was reported. Among 20 patients with follow-up, three recurrences occurred; Kaplan–Meier recurrence-free survival was 93.3% at one month, 85.6% at 1.84 months, and 73.3% at six months. Conclusions. Endoscopic therapy achieves technical success, though one in four require rescue. Kaplan–Meier analysis estimated 26.7% recurrence by six months; prospective registry data with longer follow-up are needed.