Analysis of Preoperative Factors Affecting Postoperative Spinal Canal Expansion after Posterior Decompression for the Treatment of Multilevel Cervical Myelopathy / 대한척추외과학회지

ABSTRACT

STUDY DESIGN: Retrospective analysis OBJECTIVES: To evaluate preoperative factors related with spinal canal expansion after posterior decompression for the treatment of multilevel cervical myelopathy. SUMMARY OF LITERATURE REVIEW Data about preoperative factors related with spinal canal expansion after posterior cervical decompression surgery are inconsistent. MATERIALS AND METHODS: We reviewed 67 patients with cervical myelopathy who underwent posterior laminectomy or laminoplasty. Radiologically, we evaluated the C2-7 Cobb angle and range of motion using X-rays from the preoperative assessment and final follow-up. Expansion of the spinal canal at 6 weeks postoperatively was evaluated using magnetic resonance imaging and compared with the preoperative values. The preoperative factors of age, sex, number of operated levels, operation method, and radiological parameters were investigated as factors potentially related to postoperative spinal canal expansion using multivariate regression and correlation analyses. The clinical outcome was analyzed by the Neck Disability Index (NDI) and Japanese Orthopaedic Association (JOA) scores. RESULTS: The postoperative spinal canal expansion was 4.76 mm in sagittal images and 4.31 mm in axial images, with higher values observed in males and cases of severe preoperative cord compression. A lordotic preoperative Cobb angle was related to postoperative spinal canal expansion and JOA score improvement, but without statistical significance. The clinical outcomes of NDI (18.3→14.8) and JOA scores (10.81→14.6) showed improvement, but were not significantly related with any preoperative factors. CONCLUSIONS: The amount of preoperative spinal canal stenosis was associated with postoperative spinal canal expansion after posterior decompression in multilevel cervical myelopathy. The preoperative Cobb angle was not related to postoperative spinal canal expansion or clinical improvement.