Sagittal Alignment Outcomes in Lordotic Cervical Spine

Abstract

STUDY DESIGN: A prospective cohort study. OBJECTIVE: To compare the radiological outcomes between three-level anterior cervical discectomy and fusion (ACDF) and plate-only open-door laminoplasty (LAMP) in patients with lordotic cervical spine. SUMMARY OF BACKGROUND DATA: Both three-level ACDF and LAMP are important surgical methods for multilevel cervical spondylotic myelopathy, but the cervical sagittal alignment outcomes and the lordosis preserving abilities between the two specific approaches have not been carefully compared. METHODS: Sixty patients, all of whom had lordotic cervical spines and underwent three-level ACDF (n = 22) or LAMP (n = 38) for the treatment of multilevel cervical spondylotic myelopathy, were prospectively studied. Upright neutral cervical lateral radiographs were assessed preoperatively, at 3 days after surgery, and at the last follow-up (1.5 years). The primary radiological outcomes are C2-7 Cobb angle, and the secondary outcomes include C2-7 sagittal vertical axis , disc height, Harrison angle, and Ishihara index. The relationship between preoperative parameters and follow-up outcomes were assessed. RESULTS: Preoperative cervical sagittal alignment parameters were similar between the two groups. Patients in the ACDF group obtained larger C2-7 Cobb angles than those the LAMP group early after surgery. However, the lordosis in the ACDF group decreased significantly during follow-up, leading to similar outcomes between the two groups. The lordosis-preserving ability of ACDF is significantly poorer than that of LAMP. Secondary radiological parameters also showed similar trends. In both groups, the preoperated Ishihara index was significantly related to follow-up C2-7 Cobb angles. For patients with Ishihara index less than 20, ACDF is more likely to produce a larger C2-7 Cobb angled at the time of follow-up. CONCLUSION: In patients with lordotic cervical spine, the sagittal alignment outcomes of the two approaches were similar, and the lordosis-preserving ability was poorer in ACDF. Further research should focus on the factors related to the lordosis-preserving ability of multilevel ACDF. LEVEL OF EVIDENCE: 3.