Objective: Rheumatoid arthritis (RA) is an inflammatory disease that affects the craniovertebral junction (CVJ). Patients may suffer from atlantoaxial instability (AAI) and basilar invagination (BI) with variable presentations ranging from pain to quadriparesis. Managing these patients is often challenging due to their chronic use of steroids, methotrexate, and biologics; which impedes bone and wound healing. We report our experience with the surgical management of these patients undergoing fusions at the CVJ.
Materials and methods: We conducted a retrospective study identifying all patients with the diagnosis of RA who underwent spinal fusions at our institution over the past 11 years. A total of 205 patients were identified amongst which 18 patients (8.8%) who underwent 20 fusions involving the CVJ. Demographic, clinical, and radiographic data were analyzed.
Results: Five patients had AAI and 13 patients had BI. Two patients with C1-2 fusions underwent reoperation: One for pseudoarthrosis and one for BI. The average preoperative Nurick was 1.4 and improved to 0.5 postoperatively (P < 0.001). After conducting analyses stratified by dichotomous preoperative variables, the presence of steroids, methotrexate, biologics, and prednisone dosage less than 7.5 mg did not affect outcomes. Prednisone dosages ≥7.5 mg had significantly smaller improvements in Nurick score compared to patients not on steroids or on prednisone dosages <7.5 mg (0.40 vs 1.36, P = 0.042). Similarly, patients on biologics had significantly smaller improvements in Nurick score compared to patients not on biologics (0.27 vs 1.16, P = 0.038).
Conclusion: Fusions at the CVJ in patients with RA on daily prednisone dosages of less than 7.5 mg and/or methotrexate can be performed safely with good outcomes, fusion rates, and acceptable complication profiles. Daily prednisone dosages of more than 7.5 mg or biologics may impact clinical outcomes.
Keywords: Biologics; craniovertebral junction; methotrexate; rheumatoid arthritis; steroids.