78. The current incidence of adjacent segment pathology following cervical disc arthroplasty (CDA) or anterior cervical discectomy and fusion (ACDF): a systematic review and meta-analysis of randomized clinical trials

Abstract

BACKGROUND CONTEXT The introduction of CDA has provided a biomechanically sound alternative to ACDF, helping to preserve motion and potentially reduce adjacent segment pathology. To date, studies have shown conflicting results on the true impact of ACDF and CDA on adjacent levels. PURPOSE To assess rates of radiographic adjacent segment degeneration (ASDeg) and symptomatic adjacent segment disease (ASDis), as well as reoperation rates due to adjacent segment pathology in patients who have undergone anterior cervical discectomy and fusion (ACDF) vs cervical disc arthroplasty (CDA). STUDY DESIGN/SETTING Meta-analysis of randomized controlled trials (RCTs). PATIENT SAMPLE A total of 18 studies were included in the final analysis, comprising 4,082 total patients with 1,854 patients who underwent ACDF and 2,454 who underwent CDA. OUTCOME MEASURES The pooled outcomes of interest included: adjacent segment degeneration, adjacent segment disease and reoperation for adjacent segment pathology. Adjacent segment degeneration was defined as changes on plain radiographs or magnetic resonance imaging (MRI) at segments adjacent to a previously operated level. Adjacent segment disease or symptomatic adjacent segment pathology was defined by persistent neck pain and new-onset radiculopathy/myelopathy. Symptomatic adjacent segment pathology requiring additional surgical intervention was categorized as reoperation due to adjacent segment pathology. METHODS A comprehensive search of RCTs was performed in PubMed from 2012 to 2019. Relevant studies included were assessed for quality using the Cochrane Beck Review Group guidelines. Rates of ASDeg, ASDis, and reoperation due to adjacent segment pathology were extracted and included in the final analysis. RESULTS Overall, ACDFs compared to CDAs had higher rates of radiographic adjacent segment degeneration (45.26% vs 31.91%), symptomatic ASDis (16.21% vs 10.96%), and reoperation (8.53% vs 5.26%, respectively; all p CONCLUSIONS Currently, CDA has lower rates of adjacent segment degeneration, disease, and reoperation rates compared to ACDF in those with at least 2 years follow-up. CDA may be a viable alternative to ACDF; however, further long-term studies are warranted to ensure consistency and establish longevity of our findings. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.