Efficacy of Intraoperative Facial Nerve Monitoring in Parotidectomy: A Systematic Review and Meta‐Analysis (1970‐2025)
Bibliographic record
Abstract
OBJECTIVE: To assess the effectiveness of intraoperative facial nerve monitoring (FNM) in reducing immediate and permanent postoperative facial nerve weakness after primary parotidectomy. DATA SOURCES: PubMed-NCBI database, January 1970 to May 2025. REVIEW METHODS: 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. RESULTS: 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. CONCLUSION: 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.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.016 | 0.003 |
| Bibliometrics | 0.002 | 0.003 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".