Anterior cervical discectomy and fusion with stand-alone anchored cages versus posterior laminectomy and fusion for four-level cervical spondylotic myelopathy: a retrospective study with 2-year follow-up

BACKGROUND: The optimal treatment for multi-level cervical spondylotic myelopathy (CSM) remains controversial. Posterior approach is most commonly used, but complicated with insufficient decompression and postoperative axial neck pain. The anterior approach is effective in neural decompression with less surgical trauma. However, the profile of the plate or the possible construct failure may cause dysphagia after surgery. Recently, anterior cervical discectomy and fusion (ACDF) with self-anchored cage is reported to have a superior result over ACDF with anterior plates and screws in three-level CSM. The purpose of the study is to compare the clinical and radiological outcomes of ACDF using stand-alone anchored cages to that of laminectomy with fusion (LF) for treating four-level CSM. METHODS: Twenty-six patients underwent four-level ACDF (Group A) and 32 patients with four-level LF (Group B) were retrospectively reviewed and followed-up for 24 months. Clinical efficacy was evaluated by comparing pre- and post-operative Japanese Orthopedic Association (JOA) and Neck Disability Index (NDI) scores. Operative time, blood loss, fusion, lordosis change and complications were evaluated. RESULTS: There was significantly less blood loss in Group A (163.4 ± 72.1 ml) than Group B (241.0 ± 112.3 ml) (P < 0.05). Both groups demonstrated significant improvements in JOA and NDI scores after surgery with similar operative time. Improvements in cervical lordosis and fused segment lordosis were more pronounced in Group A (11.3 ± 5.9°, 9.7 ± 5.3°) than Group B (5.8 ± 4.6°, 5.5 ± 4.5°) (P < 0.05). Loss of lordosis in the cervical spine and fused segment was more prominent in Group A (11.7 ± 2.2°, 6.7 ± 3.2°) than Group B (7.5 ± 3.8°, 3.7 ± 3.4°) (P < 0.05) at the final follow-up. Complication rate in Group A and Group B was 57.69 and 18.75%, respectively. CONCLUSIONS: ACDF using a stand-alone anchored cage showed similar clinical results to LF for the treatment of four-level CSM, with better lordosis correction and less blood loss. However, ACDF was associated with more loss of lordosis after surgery and more non-unions.