Preservation of C7 spinous process does not influence the long-term outcome after laminoplasty for cervical spondylotic myelopathy

Axial pain is one of the major complications after laminoplasty, and preservation of C7 spinous process during the procedure can reduce the axial pain. However, it has not been elucidated whether laminoplasty preserving the C7 spinous process can maintain neurological improvement for a long time. The purpose of our retrospective study was to investigate the long-term neurological outcome after open-door laminoplasty preserving the C7 spinous process for cervical spondylotic myelopathy (CSM). Clinical and radiological outcomes were analysed in 42 patients who underwent open-door laminoplasty preserving C7 spinous process and followed up for more than 5 years. Neurological function was evaluated by means of the Japanese Orthopaedic Association (JOA) scoring system for cervical myelopathy. Axial pain was assessed using a visual analog scale (VAS) at the last examination. Alignment and motion of the cervical spine were measured from radiographs, and magnetic resonance imaging (MRI) was used to evaluate postoperative compression at C7. The mean JOA score was 9.4 before surgery and 12.0 at the latest follow-up. The mean VAS score in 26 patients score was 9.7/100. No compression of the spinal cord was observed in any MRI at the latest follow-up. Preservation of the C7 spinous process does not influence the long-term outcome of CSM after laminoplasty. Although we did not have a comparative group, the procedure described here should be considered as the solution.