Advantage of Using Intraoperative Visual Evoked Potentials to Preserve Visual Function During Surgical Procedures Near the Optical Pathways

This genuine optimised monitoring in France, set up in association with Metrovision company, should help increasing intraoperative VEP reliability as a monitoring tool for visual pathways function.

In this study, we assess the predictive value of relevant intraoperative variations of VEP (more than 50% variation of latency and amplitude) on the visual prognosis at six months after surgery The visual assessment consisting of a visual field, a visual acuity, and the performance of pattern transient VEP, will be performed by an ophthalmologist before surgery, and at three and six months after surgery. An electroencephalogram with photostimulatory lighting will be used in pre-operative and will validate the absence of photo-induced epilepsy risk.

During the intervention, VEPs associated to an electroretinogram will be performed by a neurosurgeon trained to the use of these tools by Metrovision company:

• Under general anaesthesia, but before any surgery.
• During the surgery, at predetermined surgical times (while performing the craniotomy or the sphenoid opening, at various times during the perioptic lesion dissection, after the lesion resection, when closing).

Inclusion criteria

• Patients with lesion compressing or near the optical pathways

Exclusion criteria

• Patients with photic epilepsy