Syringomyelia associated with Chiari I malformation.

An 18-year-old man with progressive paraparesis, thermal hypoesthesia, sweating abnormalities, bladder dysfunction, severe orthostatic hypotension, bilateral Babinski sign, underwent a brain MRI scan that showed downward displacement of cerebellar tonsils through the foramen magnum, consistent with Chiari I malformation, compression of the brainstem-spinal cord junction, and C1-D11 syringomyelia (6.5 mm diameter at C2 level) consistent with Chiari I syndrome. Suboccipital craniectomy and duraplasty were performed. A C2 partial laminectomy and ablation of posterior arch of the atlas was performed. MRI scans 4 days and 1 month after surgery showed a dramatic syringomyelia reabsorption (2.5 and 1 mm, respectively) associated with complete clinical recovery.