[Clinical study of late onset Chiari type I malformation]

Eight cases, 5 males and 3 females, of Chiari type 1 malformation aged from 9 to 51 years (mean 33.3 years) were analysed. The average age of the onset of symptoms was 29.6 years, between 7 and 44 years, and that from the onset of symptoms to the presentation to the hospital was 3.3 years ranged from 1 month to 16 years. Pain (87%) in the head or in the cervical region was the most common symptoms, the former was 5 cases and the latter was 2. The next common symptoms were unsteadiness and gait disturbance (50%). Weakness of one or more limbs was the complaints of 3 (38%) of the patients, and sensory impairment was 38%. Other symptoms included stiffness of the neck and shoulder, limitation of the neck movement, abnormal head posture, rectourinary incontinence and so on. In physical examination, foramen magnum compression signs (63%) and cerebellar signs (63% were most common and lower cranial nerve palsy (38%) and intracranial hypertension (25%) were included. Abnormalities of the skull and cervical spine were common on X-ray films. The were cervical fusion or occipitalization and basilar impression. On the angiograms, descended PICA was visualized in all cases. CT metrizamide myelography was performed in 2 cases and MRI was done in 1 case. They could clearly demonstrate the descended tonsils and were found to be the most reliable radiographic examination in the disease.(ABSTRACT TRUNCATED AT 250 WORDS)