Efficacy of intraoperative visual evoked potential amplitude reduction in predicting visual outcome after extended endoscopic endonasal resection of craniopharyngiomas

Abstract

OBJECTIVE Postoperative visual outcome is a major concern of neurosurgeons for patients with craniopharyngiomas. The current study aimed to investigate the value of visual evoked potential (VEP) amplitude reduction (N75-P100 and P100-N145) for predicting postoperative visual dysfunction (POVD) and refining current warning criteria for VEP monitoring. METHODS Data from 96 patients who underwent the extended endoscopic endonasal approach for craniopharyngiomas between October 2020 and November 2021 were retrospectively reviewed. VEP amplitude reduction ratios were calculated and compared between patients with POVD and those without. Subsequently, the critical threshold values of VEP amplitude reduction ratios for predicting POVD were obtained through receiver operating characteristic curve analysis. Finally, multivariate binary logistic regression analysis was applied to evaluate the effect of potential factors on the probability of experiencing POVD. RESULTS Both N75-P100 and P100-N145 amplitude reduction ratios were significantly higher in patients with POVD (p < 0.001 for both). The threshold value of the N75-P100 amplitude reduction ratio for predicting POVD was 51.76% with an area under the curve (AUC) of 0.816 (p < 0.001), while the threshold value of the P100-N145 amplitude reduction ratio was 38.80% with an AUC of 0.738 (p < 0.001). Both N75-P100 and P100-N145 amplitude reduction ratios were identified as independent predictors for POVD via multivariate analysis (p < 0.001 and p = 0.018, respectively). CONCLUSIONS Both N75-P100 and P100-N145 amplitude reduction ratios showed great potential to be indicators for POVD in patients with craniopharyngiomas. Regarding warning criteria for VEP monitoring, the authors recommend that both N75-P100 and P100-N145 amplitude reduction should be considered, with early warning criteria of a 50% reduction for N75-P100 amplitude and/or a 40% reduction for P100-N145 amplitude.