Application of Intraoperative Neuromonitoring (IONM) of the Recurrent Laryngeal Nerve during Esophagectomy: A Systematic Review and Meta-Analysis

Background: recurrent laryngeal nerve palsy (RLNP) is a common and severe complication of esophagectomy in esophageal cancer (EC). Several studies explored the application of intraoperative neuromonitoring (IONM) in esophagectomy to prevent RLNP. The purpose of this study was to conduct a systematic review and meta-analysis to evaluate the value of IONM in esophagectomy for EC. Methods: an electronic of the literature using Google Scholar, PubMed, Embase, and Web of Science (data up to October 2022) was conducted and screened to compare IONM-assisted and conventional non-IONM-assisted esophagectomy. RLNP, the number of mediastinal lymph nodes (LN) dissected, aspiration, pneumonia, chylothorax, anastomotic leakage, the number of total LN dissected, postoperative hospital stay and total operation time were evaluated using Review Manager 5.4.1. Result: ten studies were ultimately included, with a total of 949 patients from one randomized controlled trial and nine retrospective case–control studies in the meta-analysis. The present study demonstrated that IONM reduced the incidence of RLNP(Odds Ratio (OR) 0.37, 95% Confidence Interval (CI) 0.26–0.52) and pneumonia (OR 0.58, 95%CI 0.41–0.82) and was associated with more mediastinal LN dissected (Weighted Mean Difference (WMD) 4.75, 95%CI 3.02–6.48) and total mediastinal LN dissected (WMD 5.47, 95%CI 0.39–10.56). In addition, IONM does not increase the incidence of aspiration (OR 0.4, 95%CI 0.07–2.51), chylothorax (OR 0.55, 95%CI 0.17–1.76), and anastomotic leakage (OR 0.78, 95%CI 0.48–1.27) and does not increase the total operative time (WMD −12.33, 95%CI −33.94–9.28) or postoperative hospital stay (WMD −2.07 95%CI −6.61–2.46) after esophagectomy. Conclusion: IONM showed advantages for preventing RLNP and pneumonia and was associated with more mediastinal and total LN dissected in esophagectomy. IONM should be recommended for esophagectomy.