184 Effect of Cervical Deformity Correction on Spinal Cord Volume and Stenosis

Abstract

Abstract INTRODUCTION There persists a debate on whether simple isolation of points of stenosis is sufficient or whether certain deformities must also be mitigated to restore neurologic concerns in patients with spinal deformity. Despite indications that cervical kyphosis has a significant effect on spinal cord volume, there remains no studies examining pre- and post-operative effect of deformity corrections on spinal cord volume and number of stenotic levels. METHODS Cervical deformity patients with pre-operative and 1-year MRI’s available were assessed for spinal canal volume at each interspace and at each body from C2-C7/T1. Stenotic vertebral levels were measured using Pavlov's method from C2-T1. Changes in spinal cord volume and number of stenotic levels from baseline to 1-year according to decompression technique used (laminectomy, foraminotomy, discectomy, or corpectomy) and type of pre-operative cervical deformity were measured using t-tests, and improvement in radiographic alignment and myelopathy scores using bivariate correlation tests. RESULTS >14 patients were evaluated. 11 received an osteotomy, 8 a decompression procedure, 6 received a posterior-only approach while the remaining received anterior-then-posterior approach. Patients presented with an average canal volume of 272.4 mm2 and 4.6 stenotic levels. At 1-year, average canal volume was 343.8 (29% increase), and average stenotic levels was 2.9. Patients with deformity apices in the cervical spine had less baseline canal volume (cervical apex: 231.6 mm2 vs. lower apex: 303.6 mm2, P = 0.022) as well as more stenotic levels cervical apex: 6.0 vs. lower apex: 3.4, P = 0.049). There was no significant relationship between decompressive techniques and volume (with decompression: ? +75mm2, w/o: ? +64mm2, P = 0.591). CONCLUSION This analysis shows a 29% increase in canal volume and correction of stenosis in cervical deformity patients. Realignment resulted in an increase in canal volume irrespective of decompression procedure. This preliminary analysis highlights a need for further investigation of spinal cord changes in deformity cases.