A Five-Year Comparative Effectiveness Analysis of Anterior Cervical Discectomy and Fusion Versus Cervical Total Disc Replacement: A Retrospective Multiparametric Evaluation of Clinical, Radiological, and Quality of Life Outcomes

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) has long served as the gold standard for treating single-level cervical disc pathology due to its reliable decompression, restoration of cervical alignment, and high fusion rates. However, fusion-induced loss of motion may alter biomechanical loading across adjacent segments, predisposing patients to adjacent segment degeneration (ASDeg) or adjacent segment disease (ASDis), thereby affecting long-term outcomes. Total disc replacement (TDR), developed as a motion-preserving alternative, aims to maintain physiological cervical kinematics and reduce adjacent segment stress. Although both procedures demonstrate favorable short- and mid-term outcomes, comparative long-term evidence remains inconsistent. This study aimed to evaluate and compare the clinical, functional, and radiological outcomes of ACDF and TDR in patients with a comparable age distribution with single-level cervical disc prolapse or stenosis, with a minimum follow-up of five years. METHOD AND MATERIALS: Out of 2258 cervical spine patients operated at our institute, a retrospective cohort analysis was conducted on 73 patients with comparable age distribution who underwent surgical intervention for single-level cervical disc disease. Of these, 37 patients (50.7%) underwent TDR, and 36 patients (49.3%) underwent ACDF. Only patients with a minimum postoperative follow-up of five years were included. Functional outcomes were assessed using the visual analog scale (VAS) for neck and arm pain, Oswestry Disability Index (ODI), modified Japanese Orthopaedic Association (mJOA), and Nurick grade. Radiographic assessment included cervical range of motion (ROM) at the index, superior, and inferior adjacent segments using standardized flexion-extension radiographs. Appropriate statistical analyses were performed to determine intergroup significance. RESULTS: The mean follow-up duration was 5.79 ± 2.96 years in the TDR cohort and 10.88 ± 2.86 years in the ACDF cohort. The improvement in VAS for neck pain, arm pain, and ODI was not significantly different between the two groups (p = 0.479). The improvement in mJOA and Nurick grade score was seen in both the TDR and ACDF groups, but was not statistically significant (p = 0.66, p = 0.218). The absolute values of change in ROM at upper and lower adjacent levels were significantly higher (p = 0.002, p < 0.001) in the ACDF group as compared to the TDR group. The mean follow-up duration was longer in the ACDF group, reflecting earlier adoption of fusion techniques during the study period. The last follow-up radiographs have shown maintenance of cervical lordosis in TDR patients. CONCLUSIONS: TDR and ACDF both resulted in reductions in neck and arm pain and significant improvement in disability outcomes. Both procedures provided comparable improvements in myelopathy-related functional scores. TDR was associated with preservation of cervical alignment and segmental motion, while achieving clinical and neurological outcomes comparable to ACDF.