Results from a two-level multicentre US Food and Drug Administration (FDA) investigational device exemption (IDE) study have shown superior outcomes with the Simplify cervical disc (NuVasive) compared to anterior cervical discectomy and fusion (ACDF) in appropriately selected patients with two-level cervical spondylosis.
The purpose of the study, the findings of which were published by Domagoj Coric (Carolina Neurosurgery & Spine Associates, SpineFirst, Charlotte, USA) et al, in the Journal of Neurosurgery: Spine, was to evaluate the safety and efficacy of the PEEK-on-ceramic cervical total disc replacement (cTDR) device for the treatment of two-level cervical disc disease with radiculopathy and/or myelopathy.
The study was a prospective, non-randomised, historically controlled FDA investigational device exemption trial evaluating the Simplify cervical artificial disc for use at two levels. The ACDF control group was derived from a propensity score–matched cohort of patients who participated in an earlier cervical arthroplasty prospective, randomised trial in which similar indications were used. The follow-up duration was 24 months. The primary outcome was a four-point composite success classification. Other validated clinical and radiographic assessments were also evaluated.
The investigational group (n=182) was compared with patients who underwent ACDF (n=170) in a historical control group using propensity score analysis. The overall composite success rate was statistically significantly greater in the cTDR group compared with the ACDF group (86.7% vs. 77.1%; p<0.05).
The mean Neck Disability Index scores improved significantly in both groups, with cTDR significantly lower at some follow-up points. At the 24-month follow-up, a minimum 15-point improvement in Neck Disability Index scores was achieved in 92.9% of the cTDR group and 83.5% of the ACDF group (p>0.05).
In both groups, neck and arm pain scores improved significantly (p<0.05) by six weeks and improvement was maintained throughout follow-up. Segmental range of motion was maintained at both treated segments in the cTDR group.
MRI performed in the cTDR group at 24 months postoperatively found minimal changes in facet joint degeneration and the rate of subsequent surgical intervention was 2.2% in the cTDR group and 8.8% in the ACDF group.
“I am excited to see the outstanding clinical and radiographic results of the Simplify disc’s two-level IDE added to the growing body of Level I evidence supporting the safety and efficacy of cervical arthroplasty,” said Coric.
Kyle Malone, vice president of scientific affairs at NuVasive, added: “This peer-reviewed publication adds to the growing body of clinical evidence in support of the Simplify disc. The Simplify disc continues to demonstrate superiority in comparison to alternative techniques. As the most effective technology in the cTDR procedure segment, we are excited for the differentiated technology to help more patients around the globe.”