The present report concerns a series of patients with syringomyelia in which a characteristic myelographic appearance was demonstrated; in the supine Trendelenburg position, contrast medium failed to flow into the cisterna magna but instead flowed forward into the prepontine cistern. In all 6 of our cases which were operated upon this appearance was found to be due to dense arachnoiditis of the posterior fossa and upper cervical cord binding down the cerebellar tonsils and occluding the foramen of Magendie. A similar appearance was noted in 1 other patient in whom operation was thought not to be indicated. Only 1 patient had a previous history of meningitis, thought to be tuberculous; in the remainder no cause for the arachnoiditis was found. Two developed acute obstructive hydrocephalus at some stage of their illness. Also reported are the autopsy findings on a further patient who developed syringomyelia following proven tuberculous meningitis. These demonstrated dilatation of the central canal of the spinal cord which communicated both with the fourth ventricle and with extensive syringomyelic cavities, which were partly ependymal-lined. It is concluded that the findings support the hydrodynamic theory of syringomyelia suggested by Gardner (1965), and that arachnoiditis of the foramen magnum region must be considered together with Chiari anomalies and tumours of this area in the pathogenesis of this syndrome. These patients, unlike those with Chiari anomalies, are not significantly improved by surgical decompression at the foramen magnum and it is for the latter group of cases that this operation should be reserved. Perhaps in the adhesive cases ventricular drainage will prove to be the best form of treatment.
ASJC Scopus subject areas
- Clinical Neurology