The predictive value of intraoperative facial motor evoked potentials in cerebellopontine angle tumor surgery.

Objective: Our aim is to explore the value of intraoperative facial motor evoked potentials (FMEP) for facial outcomes in cerebellopontine angle (CPA) tumor surgery to provide an evidence-based consensus standard for future clinical practice and prospective studies.

Methods: Electronic databases were searched from inception to June 2023. Study quality was assessed with the QUADAS-2 tool. Bivariate and random-effects models for meta-analysis and meta-regression generated summary receiver operating characteristic curves (ROC) and forest plots for estimates of sensitivity and specificity.

Results: We included 17 studies (1,206 participants). Sensitivity was lower in the immediate (IM) post-operative (0.76, 95% CI 0.65-0.84) compared to follow-up (FU) period (0.82, 95% CI 0.74-0.88) while specificity was similar in both groups (IM, 0.94, 95% CI 0.89-0.97; FU, 0.93, 95% CI 0.87-0.96). Data driven estimates improved FMEP performance but require confirmation from future studies. Amplitude cutoff criteria and studies that scored new deficits as worse than House-Brackmann (HB) grade 2 yielded best sensitivities.

Conclusions: FMEP demonstrated statistically significant accuracy for facial function monitoring. Implementation of FMEPs varied widely across studies.

Significance: Our study is the first systematic review with meta-analysis to demonstrate that intraoperative FMEP is valuable in CPA tumor surgery for facial outcomes. Meta-regression identified the methods that were most useful in the application of FMEPs.