The influence of different corrective procedures on cerebellar tonsillar position in patients with adult idiopathic scoliosis

English Keywords:Adult idiopathic scoliosis  Cerebellar tonsil  Surgical management  Magnetic resonance imaging

English Abstract:

  【Abstract】 Objectives: To investigate the impact of different posterior surgical correction procedures on the alteration of cerebellar tonsil position in patients with adult idiopathic scoliosis(ADIS), and to analyze the correlation between tonsillar displacement and the degree of spinal deformity correction. Methods: A retrospective analysis was conducted on 40 ADIS patients who underwent surgical treatment in the Department of Orthopedics at the Second Affiliated Hospital of Kunming Medical University between September 2018 and September 2025. Patients were stratified into two cohorts according to the surgical procedure: the posterior vertebral column resection(PVCR) group(n=10) and the posterior spinal fusion(PSF) group(n=30). Radiographic parameters, including the Cobb angle(CA), thoracic kyphosis(TK), lumbar lordosis(LL), coronal balance distance(CBD), and sagittal vertical axis(SVA), were measured on standing full-length spine radiographs. The position of the cerebellar tonsils was measured on midsagittal cervical magnetic resonance imaging(MRI). An independent samples t-test was employed to compare intergroup differences in cerebellar tonsil positional changes and spinal parameters. Paired-samples t-tests were utilized to assess intragroup differences in tonsil position pre- and post-operatively. Pearson correlation analysis was performed to evaluate the relationship between the degree of cerebellar tonsillar displacement and the magnitude of spinal deformity correction. Correlation heatmaps were generated using GraphPad Prism 8.0 software. Results: The PVCR group exhibited significantly longer operative time, greater intraoperative blood loss, and larger CA and TK compared with the PSF group(P<0.05). Postoperative cerebellar tonsil positions in both the PVCR and PSF groups demonstrated significant cephalad migration compared to preoperative levels(P<0.05), with the PVCR group exhibited a more pronounced degree of displacement. Pearson correlation analysis revealed a moderate positive correlation between the degree of cerebellar tonsillar displacement and △CA and △TK(r=0.371, P=0.018; r=0.448, P=0.004). Conclusions: ADIS patients exhibit a tendency toward cephalad migration of the cerebellar tonsils following surgical correction. Patients undergoing PVCR procedures demonstrate a more significant degree of displacement. The extent of tonsillar displacement appears to be moderately positively correlated with the degree of correction of coronal scoliosis and sagittal kyphosis.