Development , validation , and incorporation of a small number of disease-specific patient-based instruments will improve the quality of research and care of CM-I patients
OBJECT Chiari malformation Type I ( CM-I ) is a common and often debilitating neurological disease .
Efforts to improve treatment of CM-I are impeded by inconsistent and limited methods of evaluating clinical outcomes .
Pathophysiology of persistent syringomyelia after decompressive craniocervical surgery. Clinical article.
OBJECT Craniocervical decompression for Chiari malformation Type I ( CM-I ) and syringomyelia has been reported to fail in 10%-40 % of patients . The present prospect i ve clinical study was design ed to test the hypothesis that in cases in which syringomyelia persists after surgery , craniocervical decompression relieves neither the physiological block at the foramen magnum nor the mechanism of syringomyelia progression . METHODS The authors prospect ively evaluated and treated 16 patients with CM-I who had persistent syringomyelia despite previous craniocervical decompression .  Testing before surgery included the following : 1 ) clinical examination ; 2 ) evaluation of the anatomy using T1-weighted MR imaging ; 3 ) assessment of the syrinx and CSF velocity and flow using cine phase-contrast MR imaging ; and 4 ) appraisal of the lumbar and cervical subarachnoid pressures at rest , during a Valsalva maneuver , during jugular compression , and following the removal of CSF ( CSF compliance measurement ) . During surgery , ultrasonography was performed to observe the motion of the cerebellar tonsils and syrinx walls ; pressure measurements were obtained from the intracranial and lumbar intrathecal spaces . The surgical procedure involved enlarging the previous craniectomy and performing an expansile duraplasty with autologous pericranium . Three to 6 months after surgery , clinical examination , MR imaging , and CSF pressure recordings were repeated . Clinical examination and MR imaging studies were then repeated annually . RESULTS Before reexploration , patients had a decreased size of the CSF pathways and a partial blockage in CSF transmission at the foramen magnum . Cervical subarachnoid pressure and pulse pressure were abnormally elevated . During surgery , ultrasonographic imaging demonstrated active pulsation of the cerebellar tonsils , with the tonsils descending during cardiac systole and concomitant narrowing of the upper pole of the syrinx . Three months after reoperation , patency of the CSF pathways was restored and pressure transmission was improved . The flow of syrinx fluid and the diameter of the syrinx decreased after surgery in 15 of 16 patients . CONCLUSIONS Persistent blockage of the CSF pathways at the foramen magnum result ed in increased pulsation of the cerebellar tonsils , which acted on a partially enclosed cervical subarachnoid space to create elevated cervical CSF pressure waves , which in turn affected the external surface of the spinal cord to force CSF into the spinal cord through the Virchow-Robin spaces and to propel the syrinx fluid caudally , leading to syrinx progression . A surgical procedure that reestablished the CSF pathways at the foramen magnum reversed this pathophysiological mechanism and resolved syringomyelia . Elucidating the pathophysiology of persistent syringomyelia has implication s for its primary and secondary treatment
Development , validation , and incorporation of a small number of disease-specific patient-based instruments will improve the quality of research and care of CM-I patients
OBJECT Chiari malformation Type I ( CM-I ) is a common and often debilitating neurological disease .
Efforts to improve treatment of CM-I are impeded by inconsistent and limited methods of evaluating clinical outcomes .