Artificial disc replacement does not result in better outcomes than fusion for cervical radiculopathy
A study published in The Spine Journal has failed to find evidence for the superiority of artificial disc replacement (Discover, DePuy Spine) compared with fusion in the treatment of cervical radiculopathy.
Concerns regarding the decreased motion associated with anterior cervical decompression and fusion (ACDF) surgery have led to a proliferation of motion-preserving implants for the cervical spine. Martin Skeppholm, Stockholm Spine Center, Löwenströmska Hospital, Upplands Väsby/Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden, and colleagues, write that several previous studies comparing artificial disc replacement and fusion have been conducted with “cautiously positive” results in favour of artificial discs. However, those studies have been as part of FDA approval processes, which Skeppholm and colleagues note are “always associated with some risk for bias”. In this study, the authors obtained a written agreement from the company to ensure that “no interference from the company would occur. The company had no influence on the study design, follow-up or analysis of data, nor any access to data or information during the follow-up time.”
The randomised controlled multicentre trial at three spine centres in Sweden included 153 patients in total. Self-assessment with the Neck Disability Index (NDI) was the study’s primary outcome variable and EQ-5D and visual analogue scale (VAS) scores were the secondary outcome variables.
Patients were randomly allocated to either the Discover artificial disc group or the fusion with iliac crest bone graft and plating group. Randomisation was blinded to both patient and caregivers up until time for implantation. Adverse events, complications, and revision surgery was registered as well as loss of follow-up.
Data was available for 137 (91%) of the included and initially treated patients. Both groups improved significantly after surgery and NDI changed from 63.1 to 39.8 in an intention–to–treat analysis.
Though both treatments were successful, “No statistically significant difference between the artificial disc and the ACDF groups could be demonstrated with NDI values of 39.1 and 40.1 respectively, nor in secondary outcome measures (EQ-5D and VAS).” Nine patients in the artificial disc group and three in the fusion group underwent secondary surgery, two patients in each group because of adjacent segment pathology. Complication rates were not statistically significant between groups.
