Relationship between different cervical curvature and spinal cord posterior movement after laminectomy with lateral mass screw fixation and its influence on the operative effect

Objective To investigate the relationship between cervical curvature (CC) and spinal drift distance after laminectomy with lateral mass screw fixation and the influence on the operative effect. Methods From October 2016 to December 2017, a total of 85 patients with cervical spondylotic myelopathy (CSM) underwent laminectomy with lateral mass screw fixation in handan central hospital, and 78 patients were followed up completely.After the operation, according to the Harrison method, they were divided into 2 groups(Group A (43 cases, 0°≤CC≤16.5°); Group B (35 cases, CC>16.5°)). The spinal drift distance, nerve recovery, axial symptoms and C5 palsy in the groups were recorded and analyzed. Results The CC was 8.5°±3.8° in group A and 19.6°±3.0° in group B (t=14.071, P=0.000). The laminectomy width in group A was (22.1±1.7) mm, in group B was (21.8±1.5) mm, the difference between the two groups was not statistically significant (P>0.05). The distance of spinal cord backward movement was (1.7±0.4) mm in group A and (3.2±0.7) mm in group B. There was significant difference between the two groups (t=11.879, P 0.05). Conclusion The greater the curvature of cervical spine is, the more fully the spinal cord moves backward.The loss of curvature of cervical spine is related to the occurrence of axial symptoms.The curvature of cervical spine is not related to the recovery of nerve function and the occurrence of C5 nerve paralysis. Key words: Lateral mass screw fixation; Cervical spondylotic myelopathy; C5 palsy; Axial symptoms