The Norwegian Cervical Arthroplasty Trial (NORCAT): 2-year clinical outcome after single-level cervical arthroplasty versus fusion-a prospective, single-blinded, randomized, controlled multicenter study.
This investigation by Sundseth et al presents a prospective randomized study comparing cervical anterior discectomy and fusion (using interbody cage) versus cervical disc arthroplasty in a Norwegian population. Outcomes were determined at 2 years, which is a relatively short time period. Outcome measures included the Neck Disability Index (NDI), SF36, and EuroQol-5D-3L.
Overall, this multicenter study included 136 patients with single level disease. One of the features that added to its strengths included blinding of the surgical team until after the neural decompression was performed. While the investigators received a grant from the device manufacturers, the manuscript clearly states that the study sponsor had no involvement in the design, conduct and writing/reviewing of the manuscript. Furthermore, the sponsor “had no right of refusal for the publication data.”
The few concerns for this study include the process in which patients were worked up and chosen for the study. The authors did publish a supplemental listing of the inclusion and exclusion criteria and discussed the randomization procedures, but did not clearly identify diagnostic testing requirements and clinical exam findings necessary for patient selection.
As discussed in previously published works (Aillet et al 2013), there are some potential flaws in using the NDI as the primary outcome measure as this instrument does not include ratings process that are consistent with modern day life. However, since both groups (ACDF and Arthroplasty) completed the NDI during this study, and had similar baseline characteristics, the argument against using the NDI is minimized.
The results of this investigation go against a majority of previously published studies looking at ACDF vs Disc Arthroplasty. The authors do address this in the discussion. However, conclusions draw from this investigation may be difficult to generalize to other populations based on cultural differences in pain and recovery perceptions. It is also difficult to compare the results of this investigation with previous studies due to the technique utilized for ACDF (interbody device instead of allograft). Overall, this was a very well conducted study that appears to add very credible evidence to the short term discussion of outcomes of ACDF vs Disc Arthroplasty.