Randomized Controlled Trials Comparing Cervical Disc Arthroplasty (CDA) and Anterior Cervical Discectomy and Fusion (ACDF) in Degenerative Spine Diseases: A Systematic Review and Meta-analysis

Introduction: Anterior Cervical Discectomy and Fusion (ACDF) is an established treatment for cervical degenerative disc disease. However, ACDF can cause loss of cervical spine range of motion and potentially accelerate adjacent segment degeneration. Cervical Disc Arthroplasty (CDA) seeks to preserve the native motion of the cervical spine, which theoretically can reduce the incidence of adjacent-level degeneration. Literature regarding the relative efficacy of ACDF versus CDA remains inconsistent. Our study aims to investigate the difference in outcomes between ACDF and CDA and identify factors contributing to the heterogeneity in the literature.

Methods: We systematically searched Ovid, Embase, Scopus, Cochrane, and Clinicaltrials.gov through September 2023, and included RCTs comparing ACDF and CDA for degenerative disc disease. Studies were extracted by two authors and verified by a third. Random or fixed-effect meta-analysis were used based on heterogeneity. Our primary outcome was the difference in clinical outcomes between the two groups. Our secondary outcomes were the differences in radiological outcomes, surgical characteristics, complication rate, and length of stay.

Results: Out of 584 articles, 35 studies derived from 25 RCTs were included. A total of 4530 patients were involved (2081 ACDF and 2449 CDA). 2063 were males (45%) and mean age was 45 years. In terms of our primary outcomes, CDA showed superior neurological and overall success. For our secondary outcomes, CDA demonstrated significantly lower chance of adjacent-level disease, higher chance of heterotopic ossification, and higher range of motion at the operated level. Additionally, CDA had lower reoperation, and dysphagia rates, but significantly longer operative time than ACDF. The inclusion of myelopathic patients and variations in follow-up between groups contributed to the observed effect heterogeneity among studies.

Conclusion : Our study found that CDA showed superiority in achieving overall and neurological success, with a lower incidence of dysphagia, adjacent-level degeneration, and reoperation rates, but longer operative time.