The ratio of C2–C7 Cobb angle to T1 slope is an effective parameter for the selection of posterior surgical approach for patients with multisegmental cervical spondylotic myelopathy

To our knowledge, laminectomy with fusion (LCF) and laminoplasty alone (LP) are both effective posterior surgical approaches for decompression of cervical spondylotic myelopathy (CSM). However, which one is suitable for patients has no standard answer. This study estimated whether the ratio of C2–C7 Cobb angle to T1 slope (CL/T1S) could be an indication of posterior surgical approach. We retrospectively reviewed 128 patients with at least 6 months of follow-up who underwent LCF or LP. Radiological measurements, including C2–C7 Cobb angle, decompressed Cobb angle, T1 slope, cervical sagittal vertical axis, and curvature index (CI), and clinical outcomes, including Japanese Orthopedic Association score and visual analogue scale were evaluated. ROC curve analysis was used to identify discriminative power of CL/T1S ratio to predict kyphotic deformity and severe lordosis loss. The t-test and Mann–Whitney U-test were used to evaluate the difference between LCF and LP. Kruskal–Wallis H – test and ANOVA were used to evaluate the difference among different ratio CL/T1S groups. The cervical lordosis decreased after LCF or LP (p