Objective: MRI-verified neural axis abnormality (NAA) has been described in adolescent idiopathic scoliosis (AIS) and several risk factors have been associated with the presence of NAA in AIS-patients. However, the clinical significance of these findings is not clear. The purpose of the present study was to determine the prevalence of NAAs in a large consecutive cohort of AIS patients and evaluate the clinical significance of previously proposed risk factors.

Methods: We prospectively included AIS patients referred to a tertiary facility for evaluation. Full-spine MRI scans were performed on all included patients irrespective of curve magnitude or proposed treatment modality. MRI scans were prospectively analyzed by a neuroradiologist and pathologic findings were confirmed by a second independent radiologist.

Results: Of 381 patients, NAA was observed in 34 (8.9%): 32 patients had a syrinx, one patient had an arachnoid cyst and one patient had a Chiari malformation; 4 patients were referred to neurosurgical evaluation but none received any neurosurgical treatment. There was no statistically significant difference observed between the NAA and no-NAA groups in terms of sex, major curve size, thoracic kyphosis, left thoracic curve, curve convexity, curve progression or level of pain (p > 0.05).

Conclusion: In this prospective study to examine the risk factors for NAA in AIS patients, we found that previously proposed risk factors could not predict the MRI outcome. The finding of NAAs had no clinical implication and we do not support MRI scans as a routine diagnostic modality in all AIS patients.