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Updated: Mar 31, 2026
Simultaneous Recording of Electroretinography and Visual Evoked Potentials in Anesthetized Rats
Published on: July 1, 2016
Intraoperative visual evoked potentials and electroretinographic monitoring during endoscopic transsphenoidal surgery
Chady Omara1,2, Jeremi Chabros1, John L Kilgallon1
1Department of Neurosurgery, Computational Neurosciences Outcome Center (CNOC), Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
Introduction:
Continuous monitoring of visual function during endoscopic transsphenoidal surgery (ETS) may help prevent damage to the optic apparatus, but the efficacy and feasibility of measuring a visual evoked potential (VEP) remains poorly understood.
Research Question:
What is the feasibility, safety, and clinical utility of combined VEPs and electroretinography (ERG) monitoring during ETS?
Material And Methods:
A database of 61 patients (122 eyes) receiving ETS was analyzed. VEPs were classified as robust or non-robust at baseline, with robustness defined by a consistent VEP morphology at start of surgery. A generalized linear-mixed model (GLMM) identified predictors of VEP robustness. Intraoperative VEP changes, effects of sevoflurane anesthesia, complications, and postoperative visual outcomes were assessed.
Results:
Of 122 eyes, 88 had robust ERGs, of which 68/88 (77%) exhibited robust VEPs. The Oz-Cz scalp channel was the most reliable for interpreting VEPs. The GLMM revealed preoperative visual deficits significantly predicted VEP robustness (p=0.034), while age, sex, tumor size, and chiasmal compression were not predictive. Intraoperative VEP loss during fat graft placement was observed in three patients (six eyes) and resolved after graft removal, without postoperative visual deficits. Sevoflurane anesthesia induced transient loss of intraoperative VEP signal in 71% of cases. No complications related to the monitoring procedure occurred, and no new visual deficits were observed postoperatively in patients with robust baseline signals.
Discussion And Conclusion:
VEP monitoring was feasible and safe, while providing real time-feedback that enabled corrective surgical maneuvers during critical steps. Careful patient selection and anesthesia management are essential to maximize efficacy of monitoring and potential clinical benefit.
