Radiographic studies of the ventricles in syringomyelia

Summary Radiographic investigations of 171 patients with communicating syringomyelia have been reviewed. Hydrocephalus was found in onethird of the cases and has occasionally progressed after operation on the posterior fossa, sometimes with accompanying clinical deterioration. The outlets of the fourth ventricle were usually abnormal; tonsillar descent, arachnoiditis and both together were seen. Arachnoiditis correlated strongly with a history of difficult birth. The foramen of Magendie was sometimes patent and sometimes blocked. There was no consistent level of occlusion corresponding to a persistent roof of the fourth ventricle. The cisterna magna was usually small or obliterated but some examples of large cisterns or subarachnoid pouches were found. Radiological demonstration of a communication from the fourth ventricle to the syrinx occurred in only seven patients by positive contrast material and not by air. It is suggested that a sizable communication is rare at the time when patients seek treatment.