Comparison of Clinical Outcomes and Sagittal Alignment After Different Levels of Anterior Cervical Discectomy and Fusion in Patients With Cervical Spondylotic Myelopathy: From One-level to Three-level

Study Design. A nonrandomized and prospective study. Objective. The aim of this study was to compare clinical outcomes and sagittal alignment after one-level, two-level, and three-level anterior cervical discectomy and fusion (ACDF) in patients with cervical spondylotic myelopathy (CSM). Summary of Background Data. ACDF is a widely used surgical approach for CSM. It remains controversial regarding to whether corrected lordosis can be maintained over time after different levels ACDF. Methods. A total of 175 patients with cervical spondylotic myelopathy who underwent ACDF were enrolled in this retrospective study. The neurofunctional assessment was performed with the Japanese Orthopedic Association (JOA) score and the recovery rate of JOA score. Radiographic parameters included C2-C7 lordosis, fused segments lordosis, T1 slope, the cervical sagittal vertical axis (cSVA). Results. Patients with more fusion levels had more operative time and blood loss and higher rate of complications. All patients showed a larger cervical lordosis than that preoperatively and the restored lordosis increased with more segments involved. The restored lordosis had little change during the whole follow-up in one-level and two-level group. CL decreased from 25.65 +/- 9.31 degrees on the third postoperative day to 20.25 +/- 10.03 degrees at the final follow-up in three-level group (P = 0.001). Only T1 slope in three-level increased significantly from preoperative 26.55 +/- 9.36 degrees to 29.06 +/- 7.54 degrees on the third postoperative day (P = 0.011) and decreased to 26.89 +/- 7.22 degrees (P = 0.043) at final follow-up. The JOA score all increased significantly at the last follow-up in each group, but the recovery rate of the JOA score in each group was similar (P = 0.096). Conclusion. ACDF with different levels had similar postoperative clinical outcomes. Three-level ACDF has an apparent advantage in restoring lordosis, a poor ability to maintain lordosis, and a higher incidence of complications compared to one-level or two-level ACDF.