The Impact of Multilevel Anterior Cervical Discectomy and Fusion on Cervical Sagittal Alignment: A Comparative Study of Single-, Two-, and Three-Level Procedures

Objectives: Cervical degenerative disc disease (CDD) significantly compromises patients’ quality of life through the induction of radiculopathy and myelopathy. This study endeavored to compare the clinical and radiological outcomes of anterior cervical discectomy and fusion (ACDF) in patients presenting with single-, two-, and three-level CDD. Methods: A retrospective analysis was conducted on 94 patients who underwent ACDF between December 2018 and December 2023. Patients were categorized into single-level (n = 36), two-level (n = 40), and three-level (n = 18) CDD groups. Preoperative and postoperative radiological (X-ray, MRI) and clinical (Japanese Orthopedic Association [JOA], Visual Analog Scale [VAS]) data were rigorously analyzed. Results: Statistically significant improvements in postoperative JOA and VAS scores were observed across all cohorts. Notably, the three-level CDD group exhibited a significantly lower JOA improvement rate compared to the single-level group (p = 0.040). All groups demonstrated a marked increase in cervical lordosis and disc height postoperatively (p < 0.05). Patients undergoing three-level ACDF presented with lower JOA scores than those undergoing single- or two-level procedures. Logistic regression analysis identified that the preservation of the disc height significantly correlated with a higher likelihood of achieving a greater JOA improvement. Conclusions: ACDF is established as a safe and efficacious surgical intervention for patients with single-, two-, and three-level CDD. The implementation of hybrid prostheses appears to be instrumental in maintaining lordosis in multilevel ACDF. Three-level ACDF is associated with diminished JOA improvement rates compared to single-level ACDF. Further longitudinal, multicenter investigations are warranted to validate these findings.