Intraoperative Neurophysiological Monitoring: Its Role in Spinal Deformity Surgery

As surgical techniques have become more complex and minimally invasive surgeries have advanced, the risk of spinal cord and nerve root damage during spine and spinal cord surgery including spinal deformity surgery has increased. This has established intraoperative neurophysiological monitoring (IONM) as a crucial tool for mitigating these risks. The current gold standard for IONM is somatosensory evoked potential (SEP) for sensory pathway monitoring and transcranial stimulation motor evoked potential (Tc-MEP) for motor pathway monitoring, but other modalities are also used. For monitoring sensory pathways, spinal cord stimulation spinal cord evoked potentials (Sp-SCEP) and SEP are employed. For motor pathways, transcranial stimulation spinal cord evoked potential (Tc-SCEP/D-wave) and Tc-MEP are used. Additionally, spontaneous electromyography (sEMG) and triggered electromyography (triggered EMG) are utilized for nerve root monitoring. To prevent postoperative neurological complications, it is essential to have a thorough understanding of each modality’s characteristics and to implement a multimodal monitoring approach, appropriately combining multiple modalities based on the specific clinical condition.