The real-time brain tissue oxygen saturation monitoring using a versatile red-green-blue camera in cerebrovascular surgery.

Background: Intraoperative monitoring plays a crucial role in reducing complications during neurosurgical procedures. However, effective methods to detect brain tissue viability changes due to blood flow alterations remain unsolved. Electrophysiological techniques, such as motor evoked potentials (MEPs), and fluorescent angiography using indocyanine green, are the primary methods for intraoperative assessment. Real-time intraoperative monitoring is essential for ensuring safe neurosurgical interventions. This study aims to develop a non-contact imaging system for brain tissue surface tissue oxygen saturation (StO2) using red-green-blue (RGB) imaging based on diffuse reflectance spectroscopy.

Methods: Twelve patients with cerebrovascular diseases who underwent craniotomy were included. Six patients had Moyamoya disease, while the remaining six had unruptured cerebral aneurysms. StO2 was monitored in all patients using an RGB camera during surgery.

Results: In Moyamoya disease cases, superficial temporal artery (STA)-middle cerebral artery bypass and encephalo-myo-synangiosis were performed. A significant increase in StO2 was observed after STA release, correlating with cerebral hyperperfusion syndrome as evaluated by ¹⁵O-Positron Emission Tomography scans 1 day post-surgery. In cerebral aneurysm cases, StO2 alterations were noted during internal carotid artery temporary occlusion, potentially impacting MEP outcomes. The effects of various intraoperative parameters on StO2 were evaluated.

Conclusion: Real-time monitoring of StO2 using a highly versatile RGB camera mounted on the side scope of any surgical microscope, regardless of model, is a promising approach for enhancing the safety and efficacy of neurosurgical interventions. By capturing real-time changes in tissue oxygenation, this method may aid in predicting postoperative complications and preventing ischemic events.