Analysis of the three United States Food and Drug Administration investigational device exemption cervical arthroplasty trials Clinical article

Object. There are now 3 randomized, multicenter, US FDA investigational device exemption, industry-sponsored studies comparing arthroplasty with anterior cervical discectomy and fusion (ACDF) for single-level cervical disease with 2 years of follow-up. These 3 studies evaluated the Prestige ST, Bryan, and ProDisc-C artificial discs. The authors analyzed the combined results of these trials. Methods. A total of 1213 patients with symptomatic, single-level cervical disc disease were randomized into 2 treatment arms in the 3 randomized trials. Six hundred twenty-one patients received an artificial cervical disc, and 592 patients were treated with ACDF. In the three trials, 94% of the arthroplasty group and 87% of the ACDF group have completed 2 years of follow-up. The authors analyzed the 2-year data from these 3 trials including previously unpublished source data. Statistical analysis was performed with fixed and random effects models. Results. The authors' analysis revealed that segmental sagittal motion was preserved with arthroplasty (preoperatively 7.26 degrees and postoperatively 8.14 degrees) at the 2-year time point. The fusion rate for ACDF at 2 years was 95%. The Neck Disability Index, 36-Item Short Form Health Survey Mental, and Physical Component Summaries, neck pain, and arm pain scores were not statistically different between the groups at the 24-month follow-up. The arthroplasty group demonstrated superior results at 24 months in neurological success (RR 0.595, I-2 = 0%, p = 0.006). The arthroplasty group had a lower rate of secondary surgeries at the 2-year time point (RR 0.44, I-2 = 0%, p = 0.004). At the 2-year time point, the reoperation rate for adjacent-level disease was lower for the arthroplasty group when the authors analyzed the combined data set using a fixed effects model (RR 0.460, I-2 = 2.9%, p = 0.030), but this finding was not significant using a random effects model. Adverse event reporting was too heterogeneous between the 3 trials to combine for analysis. Conclusions. Both anterior cervical discectomy and fusion as well as arthroplasty demonstrate excellent 2-year surgical results for the treatment of 1 -level cervical disc disease with radiculopathy. Arthroplasty is associated with a lower rate of secondary surgery and a higher rate of neurological success at 2 years. Arthroplasty may be associated with a lower rate of adjacent-level disease at 2 years, but further follow-up and analysis are needed to confirm this finding. (DOI: 10.3171/2011.6.SPINE10623)