Efficacy of Foramen Magnum Decompression upon the CSF Dynamics of Chiari Type I associated Syringomyelia

Abstract

The pressure dissociation between the ICP and spinal canal pressure caused by the disturbance in CSF flow at the level of foramen magnum region is believed to be responsible for the development and expansion of the syringomyelic cavity that is associated with Chiari type I malfbmation ． The pulpose of this article is to record observations conceming thc changes of CSF hydrodynamics in the spin 皿 canal be負 )re and after surgery for負 ) ramen magnum decompression ( FMD ) ， and to cvaluate the effect of FMD on syringornyelia from the hydrodynamic point of vi． ew ． Thirteen syringo 皿 yelia patients with the mean age of 42， 5 ， who underwent FMD wi ． th dural plasty in our institute from l994 to 1997 ， agreed to be measured for the pressure volume index ( PVI ) and CSF outflow resistance ( Ro ) by the bo】 us lumbar intrathecal i 皿 jection method that was previously descibed by Marmarou in terms of the various neck positions ． PVI in neutral ， extened and flexed position were improved by 74，