Skull Base Neoplasms clinical trials at University of California Health

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.

Endonasal endoscopic approaches are an established treatment for suprasellar lesions compromising the optic nerves (ON). Surgery often involves dissecting tumors from the optic nerves and its blood supply, which can result in nerve damage and visual loss after surgery. To date, there are no reliable methods to monitor the optic nerve function during surgery and thus, post-surgical visual outcomes is unknown until the patients are fully awake after surgery for a visual exam. This delay in diagnosis prevents early therapeutic measures and can result in further harm to the ON. We have recently recognized that when ICG is routinely injected during these cases to check for patency of the big arteries the sub millimetric superior hypophyseal arteries supplying (SHA) the ON are also visible and that lack of visualization of these vessels is associated with worse visual deficits after surgery. Thus, ICG may be a tool to intraoperative predict visual outcomes after endonasal approach for suprasellar lesions and fill the nondiagnostic gap. This study will assess whether endoscopic ICG angiography before and after resection of suprasellar lesions can predict post-operative visual deficits. Successful completion will provide surgeons a novel tool to assess visual function during surgery. The ICG endoscopic angiograms suggested in this study are noninvasive and currently routinely performed at the end of surgery to check for patency of big brain arteries.