Syringomyelia-Chiari complex: magnetic resonance imaging and clinical evaluation of surgical treatment.

Thirty patients with syringomyelia-Chiari complex who underwent posterior fossa decompression or syringosubarachnoid shunting were studied clinically and by magnetic resonance (MR) imaging to assess the changes in the syrinx and in their clinical picture after surgery. When symptoms of posterior fossa compression were present, posterior fossa decompression was performed; however, when symptoms of posterior fossa compression were absent, the choice of posterior fossa decompression or syringosubarachnoid shunting depended, respectively, on whether the syrinx was narrow or wide on MR imaging. At least 1 year after surgery, subjective improvement or arrest of disease was recorded in 73% of the patients. The present study suggests that: 1) the symptoms attributed to spinal cord damage have no significant relationship to the size of the syrinx on MR images; 2) the surgical techniques employed in this series (posterior fossa decompression or syringosubarachnoid shunt) were equally useful in inducing syrinx collapse; and 3) when posterior fossa decompression is performed, plugging of the obex is not necessary for syrinx collapse.