Spinal cord monitoring in patients with spinal deformity and neural axis abnormalities: A comparison with adolescent idiopathic scoliosis patients

STUDY DESIGN. A retrospective review of spinal cord monitoring (SCM) results of patients with neural axis abnormalities (NAA) as compared with a control group of adolescent idiopathic scoliosis (AIS) patients. OBJECTIVE. To analyze SCM on a group of patients who had a NAA undergoing spinal deformity surgery. SUMMARY OF BACKGROUND DATA. To our knowledge, only 1 report in the literature has analyzed the accuracy and reliability of SCM in patients with NAA. METHODS. Over a 10-year period, 41 patients with NAA had SCM while undergoing surgery for spinal deformity. These patients were retrospectively compared with a group of 136 AIS patients. RESULTS. The average ages were similar (14.4 vs. 14.6 years), but there were more males (48.8% vs. 19.1%) and greater preoperative curve magnitude in the NAA group (65.9° vs. 59.8°) (P < 0.05). Good baseline values were achieved less often in the NAA group for somatosensory-evoked potentials (SSEP) (85.4% vs. 98.5%) and motor-evoked potentials (MEP) (82.6% vs. 100%) (P < 0.05). Significant deviations from baseline values were seen more often in the NAA group for SSEP (8.6% vs. 1.5%) and MEP (5.3% vs. 2.5%). There were no false negatives in either group. CONCLUSIONS. SCM in patients who have NAA can be more difficult to obtain than in AIS but results in few false positives and does not miss neurologic injury.