The report examined clinical trial data on the Medtronic Prestige ST and the Synthes ProDisc-C. The Bryan Anterior Cervical Disc was excluded from this evaluation. The criteria for the data included; pain, functional disability, neurological status, implant and surgical adverse events and secondary reconstruction.
After two years, both studies showed that CDA's were non-inferior to ACDF's based on the neck disability index score and overall outcomes. Interestingly enough, the Prestige ST trial was found to be of "poor quality" because of systemic differences between patient groups and unclear blinding of neurological assessments. The quality of the ProDisc-C was fair.
The report concludes that both trials were similar with the notable exceptions being secondary reconstructions. The Prestige SF had 9 patients in the ACDF and 3 in the CDA category, while Synthes had 1 in the ACDF group and 0 in the CDA category.
In closing, the report points out that no study has established whether adjacent disc disease (ADD) observed after fusion is a result of altered or abnormal spinal motion patterns, rather than due to normal disease progression. The authors concluded that it cannot be determined whether CDA will reduce ADD.