Atraumatic atlantoaxial subluxation in pediatric enthesitis-related juvenile idiopathic arthritis: illustrative case.

backgroundJuvenile idiopathic arthritis (JIA) is the most common pediatric rheumatological disease, yet cervical spine involvement remains an underrecognized but potentially devastating manifestation. Atlantoaxial subluxation (AAS) arises from inflammatory changes causing ligamentous laxity and instability. OBSERVATIONS: A 13-year-old female presented with progressive neck pain. Imaging revealed a 10-mm atlantodental interval on CT, along with hyperintensity and stretching of the transverse atlantal ligament on MRI. She underwent a posterior C1-2 open reduction and fusion. Subsequent rheumatological workup confirmed enthesitis-related JIA, based on polyarticular arthritis, HLA-B27 positivity, and elevated inflammatory markers. To contextualize this case, the authors performed a systematic review and meta-analysis of JIA-related AAS across 21 studies. The pooled incidence of AAS was 14%, with a mean age at JIA onset of 8.47 years and a female predominance of 62%. Enthesitis-related arthritis emerged as the most frequently reported subtype, and 94.4% of patients with AAS improved posttreatment. LESSONS: This case and supporting literature underscore the importance of early detection and multidisciplinary management of AAS in pediatric patients with JIA. Timely neurosurgical stabilization, combined with optimized immunosuppressive therapy, can prevent neurological compromise. Future research should focus on standardized diagnostic thresholds and outcome measures to guide best practices. https://thejns.org/doi/10.3171/CASE25121.