Intraoperative neurophysiological monitoring during microvascular decompression for trigeminal neuralgia

Trigeminal neuralgia (TN) is a severe neuropathic disorder marked by sudden, shock-like episodes of facial pain caused by pathological irritation of the trigeminal nerve. Microvascular decompression (MVD) remains the only intervention that directly alleviates the neurovascular conflict underlying classical TN. Because the procedure is performed near cranial nerves VII and VIII as well as the brainstem, intraoperative neurophysiological monitoring (IONM) has become an essential component for minimizing surgical morbidity. Among existing modalities, brainstem auditory evoked potentials serve as the most dependable technique for protecting auditory pathway function. Additional methods—such as trigeminal somatosensory evoked potentials and free-running/triggered electromyography—provide complementary information that enables early detection of nerve stress or impending injury. This review synthesizes current physiologic concepts, monitoring strategies, and clinical evidence supporting the application of IONM during MVD for TN.