Impact of intradural abnormalities on symptoms and clinical outcomes in Chiari malformation

This study aims to investigate the impact of intradural abnormalities on symptoms and clinical outcomes in Chiari malformation.

A retrospective study was conducted on 189 patients with Chiari malformation who underwent posterior fossa decompression with duraplasty or tonsillectomy. Intradural abnormalities were categorized as arachnoid abnormalities, foramen of Magendie (FoM) obstruction, and tonsillar abnormalities. Clinical outcomes were assessed using the symptoms improvements, Chicago Chiari Outcome Scale (CCOS), complications and re-operation.

A total of 189 patients with Chiari malformation were included in the study. 79.4 % of the patients were female, with a mean age of 45.0 ± 10.7 years (range: 16-62 years). Common intradural abnormalities included arachnoid adhesions (68.3 %), obstruction of the foramen of Magendie (FoM) (50.3 %), and tonsillar hypertrophy (38.6 %). Obstruction of FoM was more frequently observed in patients with Valsalva provoked headaches (53.7 % vs. 12.8 %, p < 0.001), syringomyelia (93.7 % vs. 67.0 %, p < 0.001). CCOS scores (12.5 ± 2.3 vs. 13.3 ± 2.0, p = 0.027) and improved (53.7 % vs. 78.7 %, p = 0.001) were lower in the obstruction group. Tonsillar abnormalities were associated with higher incidence of Valsalva provoked headaches (61.6 % vs. 15.5 %, p < 0.001) and gait instability (43.8 % vs. 6.0 %, p < 0.001).

Intradural abnormalities, particularly obstruction of FoM and tonsillar abnormalities, are correlated with symptoms and clinical outcomes in Chiari malformation.