title: Surgical treatment of Chiari malformation with and without syringomyelia: experience with 177 adult patients.
abstract: OBJECTIVE
  This study aims to show the relationship between clinical outcome in patients who underwent surgical decompression for Chiari malformation (CM) and postoperative imaging studies, with particular emphasis on the subarachnoid cisterns of the posterior fossa.
  
  
  METHODS
  One hundred seventy-seven patients with CM, including 97 with syringomyelia, underwent posterior fossa decompressive surgery. Both the dura and arachnoid were opened in 150 of these patients, and 135 underwent reduction of the cerebellar tonsils. The patients' clinical signs and symptoms were evaluated at 2 time points after surgery. Their imaging studies were analyzed specifically for the size of the retrotonsillar and subtonsillar cisterns and the syringomyelic cavities. The authors evaluated the relationship between these imaging findings and clinical parameters.
  
  
  RESULTS
  Clinical improvement correlated strongly with enlargement of the subarachnoid cisterns, and enlargement of the cisterns also correlated with reduction in size of the syrinx cavities. Symptoms related to syringomyelia responded to reduction in size of the syrinx cavities.
  
  
  CONCLUSIONS
  Surgical decompression of the posterior fossa should aim to create relatively large subarachnoid cisterns and reduce the size of the syrinx cavity. Reduction of the cerebellar tonsils by surgical means, together with duraplasty, achieves this goal and thereby improves the clinical outcome for patients with CM. An incidental observation of the study is that obesity increases the likelihood of headache in patients with CM.
authors.affiliation: Department of Neurosurgery, David Geffen School of Medicine at UCLA, Los Angeles, California 90095, USA. ubatzdorf@mednet.ucla.edu
authors.forename: Ulrich
authors.initials: U
authors.lastname: Batzdorf
authors.forename: David L
authors.initials: DL
authors.lastname: McArthur
authors.forename: John R
authors.initials: JR
authors.lastname: Bentson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001139:Arnold-Chiari Malformation / Q000150:complications / Q000473:pathology / Q000601:surgery*; D019299:Decompression, Surgical / Q000379:methods*; D004388:Dura Mater / Q000473:pathology / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D005539:Foramen Magnum / Q000473:pathology / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D011183:Postoperative Complications; D012189:Retrospective Studies; D013346:Subarachnoid Space / Q000473:pathology / Q000601:surgery; D013595:Syringomyelia / Q000150:complications / Q000473:pathology / Q000601:surgery*; D016896:Treatment Outcome; D055815:Young Adult