Table 1 Clinical features in 19 patients

Demographics

 Mean age, years(range)

41.8 ± 12.1(20–66)

 Sex(M/F)

6:13

Clinical symptoms, n (%)

 Sensory disturbance

15 (78.9%)

 Motor dysfunction

10(52.6%)

 Neck pain

5 (26.3%)

 Ataxia

8 (42.11%)

Radiologic features, n (%)

 Occipitalization of C1

8 (42.1%)

 Chiari malformation

100 (100%)

 Syringomyelia

13 (68.4%)