Safety and Efficacy of the Stag Beetle Knife for the Management of Zenker’s Diverticulum: An Updated Systematic Review and Meta-Analysis

The stag beetle (SB) knife, a unique scissor-shaped device with rotating insulated monopolar blades, is increasingly used in the endoscopic management of Zenker's diverticulum (ZD). This systematic review and meta-analysis aimed to evaluate its overall safety, efficacy, and feasibility. A thorough search of electronic databases and conference abstracts was conducted until November 2023. Meta-analysis utilized the random-effects model, with I² (%) assessing heterogeneity. Subgroup analysis was based on sample size, employing the standard mean difference (SMD) and 95% confidence interval (CI) for continuous variables. Key outcomes included clinical success, recurrence rate, adverse events, and improvement in dysphagia score. Eight studies with 299 patients (60.5% males, mean age: 72.75±2.86 years, ZD size: 2.66±0.52 cm, and procedures lasted 23.06±10.00 min) were included. Clinical success was achieved in 86% (95% CI: 81-90; I²=0%) after 10.98 sessions, and 22.74% required multiple (up to four) sessions. The recurrence rate was 15% (95% CI: 11-20; I²=0%). Intraprocedural complications occurred in 9% (95% CI: 5-13; I²=29%), primarily minor bleeding (9.6%), micro-perforation (2%), odynophagia (1.3%), and fever (1.05%). Late-onset bleeding occurred in 3.2% after one week. Adverse events were conservatively managed, and subgroup analysis by sample size indicated a significant difference in mean sessions (p=0.02). Dysphagia scores showed significant improvement following treatment, with an SMD of -1.59 (95% CI: -2.27 to -0.91; p<0.01; I²=97%) over a mean follow-up of 22.23±11.47 months. The meta-analysis confirms the SB knife's success in ZD, displaying excellent safety and dysphagia improvement. However, further research is needed to define optimal patient cohorts and compare them with other management techniques.