Efficacy of Intraoperative Facial Nerve Monitoring in Parotidectomy: A Systematic Review and Meta-Analysis (1970-2025).

Abstract

To assess the effectiveness of intraoperative facial nerve monitoring (FNM) in reducing immediate and permanent postoperative facial nerve weakness after primary parotidectomy. PubMed-NCBI database, January 1970 to May 2025. A systematic review and meta-analysis were performed in accordance with PRISMA guidelines. Eligible studies compared primary parotidectomy performed with versus without FNM and reported outcomes as House-Brackmann grade ≥2. Two reviewers independently extracted study characteristics and outcomes. Study quality was assessed with the Newcastle-Ottawa Scale. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated; random-effects models were used when heterogeneity (I²) exceeded 30%. Number needed to monitor (NNM) was calculated for significant endpoints. Ten studies (n = 1047; 568 FNM, 479 control) met inclusion criteria. FNM was associated with nearly halved odds of immediate postoperative weakness (OR = 0.49; 95% CI, 0.35-0.67; P < .01; I² = 20.2%), corresponding to an NNM of 7. Permanent weakness was also associated with a significant reduction (OR = 0.49; 95% CI, 0.30-0.81; P < .01; I² = 12.9%), with an NNM of 11. Included studies were of moderate-to-high quality (NOS 6-8/9), though domain-level biases, particularly lack of blinding and incomplete confounder adjustment, were common. No significant publication bias was detected. Intraoperative FNM during primary parotidectomy was associated with reduced immediate and permanent postoperative dysfunction. These results, which extend beyond prior meta-analyses limited to immediate outcomes, support routine adoption of FNM as an adjunct to optimize nerve preservation and reduce morbidity.