Dynamic anterior cervical plating for multi-level spondylosis: Does it help?

Abstract

Study design: Randomized controlled trial.Objective: To compare fusion rates, time to fusion, complication rates and subsidence between 1) a static, 2) a dynamic angulation, and 3) a dynamic translation plate in anterior cervical discectomy and fusion for symptomatic degenerative cervical disease.Methods: Thirty-six patients with two level, symptomatic cervical degenerative changes requiring surgery were randomized in a blinded fashion to receive a statically locked plate, Cervical Spine Locking Plate (CSLP) (Synthes, Paoli, PN, USA), an Atlantis Vision® Anterior Cervical Plate System (Medtronic, Memphis, TN, USA) which allows angular dynamization, or a Premier® Anterior Cervical Plate System (Medtronic) which allows translational dynamization. Structured data collection and measurement protocols were used. Intervertebral composite allograft cages were used in all groups. Identical external immobilization and antiinflammatory medication protocols were followed. X-rays were obtained at preset time points postoperatively. Assessment of the primary outcomes was blinded. Rate of and time to fusion, graft/instrumentation complications, subsidence, and reoperation for adjacent level disease were measured. Paired t-test and three-way Analysis of Variance test (ANOVA) were used to assess statistical differences between groups.Results: The three groups were similar demographically. Fusion rates in the CSLP, Atlantis and Premier plate groups were 100%, 91%, and 92% respectively. Mean time to fusion was 6.1, 8.3 and 6.3 months respectively but differences were not statistically significant. Mean subsidence in the groups was 1.9, 1.6, and 2.6 mm respectively. Subsidence was found even for the static (CSLP) plate, but no statistically significant differences were found.Conclusions: We found no clinical advantage of dynamic plates over static plates with regards to fusion rates, time to fusion, subsidence, complications, or adjacent-level surgery. Static plating allows for subsidence at similar levels to dynamic plating.Methods evaluation and class of evidence (CoE)Methodological principle:Study design: RCT• Cohort Case control Case seriesConcealed allocation (RCT)Intent to treat (RCT)•Blinded/independent evaluation of primary outcome•Complete follow-up of ≥85%*•Adequate sample sizeControl for confounding†•Evidence class:II*Reliable data are data such as mortality or reoperation.†Authors must provide a description of robust baseline characteristics, and control for those that are unequally distributed between treatment groups.The definiton of the different classes of evidence is available on page 83.