Intra-operative Neurophysiological Monitoring in Patients Undergoing Posterior Spinal Correction Surgery with Pre-operative Neurological Deficit: Its Feasibility and High-risk Factors for Failed Monitoring.

Patients with pre-operative neurological deficit suffered from a higher incidence of failed IONM results. The high-risk for failed IONM waveforms included the neuromuscular and syndromic etiologies, neurological deficit caused by cervical spine, muscle strength lower than grade 4 in patients with pre-operative neurological deficit undergoing posterior spinal correction surgery.