Surgical treatment of type I Chiari malformation with syringomyelia in adults.

The surgical treatment of six adult patients with Type I Chiari malformation associated with syringomyelia is reported. Two patients presented with acute respiratory insufficiency, which is common in Type II and rare in the Type I anomaly. One patient initially appeared with unilateral vocal cord palsy that was followed by wasting and fasciculation of the tongue and limb muscles. Two patients had a typical central cord syndrome and the last patient had hemiparesis and gait disturbance. The first patient was diagnosed clinically. Two patients were studied by computed tomographic metrizamide myelogram (CTMM). The last three patients were diagnosed by magnetic resonance imaging (MRI) scan. All patients were operated on with a modified 'Gardner procedure'. Symptoms related to cervico-medullary compression improved satisfactorily. Signs of central cord syndrome, however, remained stationary event though the follow-up MRI examinations revealed good resolution of the syringomyelia. One patient died within one week of surgery. MRI makes the diagnosis of this anomaly much easier and is the ideal tool for follow-up study. Clinicians should include this malformation in the differential diagnosis when considering cases of syringomyelia.