A Five-Year Comparative Effectiveness Analysis of Anterior Cervical Discectomy and Fusion Versus Cervical Total Disc Replacement.

Anterior cervical discectomy and fusion (ACDF) continue to be regarded as the benchmark surgical intervention for single-level cervical disc disease, particularly in patients presenting with radiculopathy, myelopathy, or combined myeloradiculopathy . The technique involves an anterolateral cervical approach for disc excision and interbody fusion, enabling effective neural decompression, restoration of cervical lordosis, maintenance of disc height, and provision of immediate segmental stability . Despite its proven clinical success, the obligatory segmental immobilization inherent to ACDF leads to altered cervical biomechanics and increased mechanical loading across adjacent motion segments .This predisposes patients to adjacent segment pathology, which encompasses adjacent segment degeneration (ASDeg)-radiological deterioration without clinical symptoms-and adjacent segment disease (ASDis), defined by symptomatic deterioration requiring clinical or surgical intervention.

Longitudinal clinical series have demonstrated that symptomatic ASDis develops at an estimated rate of nearly 2.9% per year, with approximately 25.6% (96/374) of patients expected to manifest new disease at an adjacent level within a decade following fusion. Radiographic degeneration is even more prevalent, with reported rates as high as 92% (266/288) on extended follow-up . Cervical total disc replacement (TDR) has emerged as a biomechanically advantageous, motion-preserving alternative that seeks to mitigate the drawbacks associated with fusion. By maintaining near-physiological segmental kinematics, TDR reduces compensatory hypermobility and stress transfer to adjacent segments while preserving motion at the operated level . Biomechanical investigations confirm that arthroplasty maintains segmental mobility and decreases adjacent-level motion compared with fusion. Clinical studies similarly report that TDR provides outcomes comparable to or better than ACDF in terms of pain relief, neurological improvement, functional recovery, and patient satisfaction, with lower secondary surgery rates (10/164 [6.1%] vs 24/189 [12.7%]) . Meta-analyses consistently demonstrate lower pooled rates of ASDeg following TDR (7-17%) relative to ACDF (25-33%), although differences in symptomatic ASDis and reoperation rates remain variable-likely attributable to heterogeneity in study design, follow-up duration, patient selection, and implant characteristics.