Analysis of Cervical Sagittal Balance in Treating Cervical Spondylotic Myelopathy: 1-Level Anterior Cervical Corpectomy and Fusion Versus 2-Level Anterior Cervical Discectomy and Fusion

BACKGROUND Anterior cervical corpectomy and fusion (ACCF), together with anterior cervical discectomy and fusion (ACDF) are both effective clinical treatments for cervical spondylotic myelopathy (CSM). Cervical sagittal balance is critical to preserving normal alignment, and is also associated with clinical outcomes. MATERIAL AND METHODS We retrospectively reviewed patients who had suffered from CSM and had undergone 1-level ACCF or 2-level ACDF surgery between December 2016 and November 2017. Forty-eight patients were identified: 25 in the ACDF group and 23 in the ACCF group. All patients received follow-up for more than 12 months. The demographic data, radiographic parameters, and clinical efficacy were compared between and within groups, both pre- and postoperatively. RESULTS Both groups acquired good clinical efficacy; both Japanese Orthopedic Association (JOA) scores and Neck Disability Index (NDI) scores improved significantly. At the final follow-up visit, patients in the ACCF and ACDF groups did not differ significantly in C2-C7 Sagittal Vertebral Axis (cSVA), T1 Pelvic Angle (TPA), Neck Tilt (NT), Thoracic Inlet Angle (TIA), JOA, or NDI scores. However, the ACDF group had a significantly larger Cobb angle and T1 Slope (T1S) than the ACCF group. The postoperative Cobb angle increased significantly only in the ACDF group, while postoperative T1S significantly increased in both ACCF and ACDF groups. CONCLUSIONS Anterior cervical surgery may change the sagittal balance in terms of T1S or Cobb angle. No significant difference was found between ACCF and ACDF in clinical outcomes or representative global sagittal parameters. ACDF achieved more lordosis improvement than ACCF, with higher T1S. Surgeons need to pay extra attention to cervical sagittal balance, rather than focusing solely on decompression.