The Predictive Role of Intraoperative Visual Evoked Potentials in Visual Improvement After Endoscopic Pituitary Tumor...

With the advent of extensive endoscopic approaches for pituitary tumors, there has also been an increase in surgery for larger and more complex tumors. Intraoperative manipulation during endoscopic resection of sellar tumors poses potential risk in postoperative visual function in this tumor population. This study proposes a method of accurate intraoperative monitoring of visual evoked potentials (VEPs) and its role in predicting visual function outcomes.

Intraoperative VEPs were monitored for 42 resections from a single surgical team, with average tumor size of 2.84 cm. Changes in VEP amplitude and latency in excess of 50% were considered significant. Preoperative and postoperative visual information was obtained from ophthalmology and hospital records, along with patient demographics, comorbidities, and tumor characteristics.

Patients were stratified as experiencing deteriorations in VEPs that did not restore to baseline (n = 4), deteriorations in VEPs that did restore to baseline (n = 6), no change in VEPs (n = 31), and improvement in VEPs (n = 1). Correlation between VEP changes and postoperative visual fields was measured through univariate ordered logistic regression. Improved intraoperative VEP measurements were associated with odds ratio (OR) of visual field improvement of 3.15 (95% confidence interval, 1.15-8.59). Specifically, changes in VEP amplitude were positively associated with visual field improvement with OR of 4.35 (OR, 1.29-14.7). No association was observed between VEPs and other patient or tumor characteristics.

Changes in VEP amplitude during endoscopic sellar tumor resection correlate with postoperative visual function. Intraoperative VEP monitoring can serve an important role in preventing postoperative visual field loss.