Cohort analysis of surgically managed Chiari malformation type 1: real-world data from multi-centres

The uniform and optimal management of Chiari malformation type 1 (CM1) has not yet been established. The study aimed to investigate the clinical characteristics and surgical outcomes of patients with CM1 in China. Data from 827 patients who underwent various surgical procedures for CM1 across 14 centres in China were analysed. Clinical characteristics were evaluated, and the inverse probability of treatment weights methods was applied to estimate the relationships between risk factors and functional outcomes. Syringomyelia was observed in most cases (754; 91.17%) in this cohort. A positive correlation was found between disease duration and age at diagnosis (P = 0.0002). Conversely, disease duration showed a significant negative correlation with preoperative Japanese Orthopaedic Association (JOA) score (P < 0.0001), postoperative JOA score (P < 0.0001), and Chicago Chiari Outcome Scale score. Patients who underwent posterior fossa decompression with tonsil resection/cautery (PFDRT) surgery had the highest mean postoperative JOA score (15.51 ± 1.84) compared with those in the posterior fossa decompression (PFD), posterior fossa decompression with duraplasty, and other groups (P = 0.0297). Postoperative complications were more frequent after PFDRT than after PFD (P = 0.0443). However, the reoperation rate of PFDRT was significantly lower than that for PFD (P = 0.0057). Surgeries providing adequate cerebrospinal fluid decompression yielded superior outcomes compared with simple bony decompression or cerebrospinal fluid shunting. Age at diagnosis, craniocervical malformation, disease duration, and surgical approach are key factors influencing CM1 outcomes. Chinese Clinical Trial Registry, Number: ChiCTR2400080007, Registered on January 18th, 2024.