Surgical treatment of "hindbrain related" syringomyelia: new data for pathogenesis.

52 patients with "hindbrain related" syringomyelia underwent surgical treatment. All patients underwent primary reconstructive surgery at the craniovertebral junction. Terminal ventriculostomy was performed as the secondary operation in 2 cases. The surgical treatment arrested progression of signs in 33 (63.5%), stabilized disease in 9 (17%) cases. Postoperative deterioration occurred in 8 (15%) cases. Mortality was 4% (2 patients). Percutaneous or intra-operative injection of myodil and gas into the syrinx, as well as CT, revealed the existence of communication with the 4th ventricle in 14 patients. Investigation of cerebrospinal and syrinx fluid revealed increased level of IgG, IgM or IgA in the syrinx fluid in 16 out of 22 patients. Immunohistological examination of pia mater revealed specific staining for IgG. Thus, syrinx formation may be due to synergic action of hydrodynamic and immunopathological mechanisms. Results indicate that early surgical treatment is preferable to patients with hindbrain anomalies and hydromyelia. We consider primary reconstructive operation at the posterior fossa as the preferred surgical management of "hindbrain related" syringomyelia.