The relationship between preoperative cervical alignment and postoperative spinal cord drift after decompressive laminectomy and arthrodesis for cervical spondylotic myelopathy

Abstract

Background Cervical spondylotic myelopathy represents a debilitating disorder, often resulting in significant neurological impairment over time. Cervical laminectomy has enjoyed a successful track record in the surgical management of these patients. Little is understood regarding the significance of postdecompressive migration of the spinal cord in relation to patient outcome. Methods Preoperative and postoperative cervical spine MRIs of 28 patients who underwent cervical laminectomy and fusion for the treatment of CSM were reviewed. Radiographic parameters including preoperative cervical alignment, LDI, space available at the level cepahlad/caudad to the decompression, percent spinal cord expansion at the radiographically most compressed level, and spinal cord drift to the midpoint of the spinal cord were measured and subsequently analyzed for statistical correlation. The recovery rate based on the mJOA score was calculated for each patient and analyzed for correlation with spinal cord drift. Results The Cobb angle C2-7, cervical spinal angle, and CCI represented tightly correlated measures of cervical alignment. The preoperative cervical alignment did not statistically correlate with postoperative spinal cord drift. No statistical correlation was revealed between postdecompressive spinal cord drift and recovery rate. Conclusions Preoperative cervical alignment does not statistically correlate with postoperative spinal cord drift in patients undergoing multisegmental decompressive laminectomy and fusion for CSM. The observation of significant posterior shifting of the spinal cord in the context of straight or kyphotic preoperative alignment suggests that posterior decompression and arthrodesis represent a viable option in the surgical management of patients with CSM with nonlordotic preoperative alignment.