Optic Nerve Stimulation for Skull Base Tumors

Assessing the function of the optic nerve is paramount during various neurosurgical procedures. Effective optic nerve monitoring has remained elusive as Visual Evoked Potentials (the current existing tool) provides only diffuse and delayed assessment of nerve function. Here, the investigators propose a prospective study involving adult patients (aged 18 years and older) undergoing endonasal or open cranial approaches around the optic nerves, who will receive pre- and post-operative visual evaluations. During surgery, the optic nerve and chiasm will be stimulated, and the response will be recorded in both eyes and the occipital cortex via skin electrodes. The investigators aim to utilize anterograde optic nerve microstimulation to assess the nerve's integrity during open and endoscopic cranial approaches. Electrophysiological readings will be acquired, as is routine in the operating room, by our team of experts, and intraoperative findings will be correlated with post- surgical clinical outcomes. Our objective is to utilize existing technology in the operating room to safely and effectively monitor optic nerve function during surgery.