Surgical treatment outcome on a national cohort of 176 patients with cervical manifestation of rheumatoid arthritis

PURPOSE: Rheumatoid arthritis (RA) affecting the cervical spine results in instability and deformity that can be divided into the subtypes C1–C2 horizontal (atlantoaxial instability), C0–C2 vertical (basilar invagination), subaxial, and combined instabilities. The aim of this study was to compare the surgical treatments and outcomes of RA-related deformity and instability in a population-based setting. PATIENTS AND METHODS: All patients with RA in the national Swespine register from January 1, 2006, to March 20, 2019, were assessed. Baseline characteristics, surgical treatments, European Myelopathy Scale (EMS), Neck Disability Index, the Visual Analog Scale for neck and arm pain as well as pre- and postoperative imaging were analyzed. The follow-up time points were at 1-, 2-, and 5 years after surgery. RESULTS: A total of 176 patients were included. There were 62 (35%) patients with C1–C2 horizontal instability, 48 (27%) with C0–C2 vertical instability, 19 (11%) patients with subaxial instability, 43 (24%) patients with combined instability, and 4 patients without instability served as controls. The EMS improved in the C1–C2 horizontal instability group after fusion surgery (Δ =2.6 p) but remained within baseline confidence intervals in the other groups. All patients regardless of instability improved in pain. The subaxial instability had the highest risk of death within 5 years after surgery (11/19, 58%). The most dangerous complications due to implant failure were seen in patients instrumented with laminar hooks. CONCLUSION: The neurological outcome after fusion surgery is poor and the death rate is high in patients with cervical RA-related instability and deformity.