Background: For single-level cervical degenerative disorders, an anterior cervical discectomy (ACD) is often performed with interposition of an intervertebral spacer. Most surgeons prefer a cage or arthroplasty, although superiority in comparison with other types of spacers, or leaving out a spacer, still has never been proven. Polymethylmethacrylate (PMMA) is a cost-friendly spacer with reported clinical outcome similar to other spacers. Therefore, the aim of this study was to assess long-term clinical outcome of ACD with PMMA as a spacer compared with ACD with a cage or without a spacer.
Methods: A retrospective cohort study among patients with cervical degenerative disorders requiring a single-level ACD was performed in two hospitals in the Netherlands. Subgroups were made for PMMA, cage and no spacer. The primary outcome measure was the Neck Disability Index, secondary outcome measures were complication and reoperation rates, quality of life, workability and the need of additional treatments (e.g. physiotherapy, selective nerve root block, spinal cord stimulation). A 1:1 propensity score matching was performed that adjusted for age, gender, body mass index, comorbidities, duration and type of symptoms, and level of surgery.
Results: A total of 241 patients were included in the study, with a median follow-up of 9.4 years. Propensity score matching revealed no statistically significant differences in all clinical outcome parameters between all subgroups. Complications, reoperations and the need for additional treatments were similarly distributed as well. A sensitivity analysis in which multiple PMMA patients were implemented (1: many matching) demonstrated equal results.
Conclusions: No differences in long-term clinical outcome were demonstrated between ACD with PMMA compared to ACD with cage, or without any intervertebral spacer. Complication and reoperation rates were equal among the matched cohorts. In conclusion, PMMA is an effective, safe and cost-friendly alternative with equal long-term clinical outcome compared to other surgical techniques for cervical degenerative disorders.