The evaluation of surgical therapy for syringomyelia by means of magnetic resonance imaging

Magnetic resonance imaging (MRI) was performed to evaluate surgical therapy in 18 patients with syringomyelia. Fourteen patients had a Chiari I-syringomyelia complex, ten of whom underwent Gardner's operation - suboccipital craniectomy, upper cervical laminectomy, arachnoid dissection around the foramen Magendie, dural plasty, and plugging of the obex. Postoperative MRI studies revealed a collapse of the syringomyelic cavity in the 10 patients; and an enlargement of the cisterna magna, with an upward displacement of the cerebellar tonsiles, an increase in the size of the anterior-posterior diameter of the medulla, and a widering of the lower part of the fourth ventricle in 9 patients. These MR findings were comparable with clinical improvement and the cessation of neurologic deterioration in patients with syringomyelia. Using cine MR images, the flow of cerebral spinal fluid (CSF) was analyzed in 6 patients. The turbulent flow of CSF in the cisterna magna was not detected before surgery. There was an active flow inside the syrinx in all the preoperative patients, but it was much less active in the patients who had undergone Gardner's operation, although they had a residual syrinx inside the spinal cord. This suggested that the pulsatile flow inside the syrinx might be transmitted from the fourth ventricle through the patent central canal. (Namekawa, K)