Monitoring Cerebral Oxygenation During Complex Neurosurgical Procedures

Near-infrared cerebral oximetry gives a noninvasive, continuous estimate of regional cerebral oxygen saturation and is an increasingly common adjunct in complex neurosurgery, where hypoperfusion can occur without any change in standard systemic monitors. This review synthesizes the physiology and limitations of cerebral oximetry alongside evidence from sitting-position posterior fossa surgery, prone spinal instrumentation, and skull-base and vascular neurosurgery, and compares it with invasive jugular bulb and brain tissue oxygen monitoring used chiefly in neurocritical care. Cerebral oximetry reliably detects intraoperative desaturation across these settings, but systematic reviews find the evidence linking desaturation-guided intervention to improved cognitive, neurologic, or survival outcomes remains of low certainty. Invasive brain tissue oxygen and jugular bulb monitoring give more direct signals and are better validated in traumatic brain injury, though their burden limits routine intraoperative use to patients already carrying such monitors. We conclude that cerebral oxygenation monitoring is best used as one input among several in complex neurosurgical anesthesia, valuable for trend detection alongside clinical judgment and other neuromonitoring modalities, pending larger outcome trials.