title: A novel scoring system for assessing Chiari malformation type I treatment outcomes.
abstract: BACKGROUND
  Outcome assessment for the management of Chiari malformation type 1 is difficult because of the lack of a reliable and specific surgical outcome assessment scale. Such a scale could reliably correlate postoperative outcomes with preoperative symptoms.
  
  
  OBJECTIVE
  We developed a novel scoring system and applied it retrospectively to 146 patients treated at our institution in order to create and verify a simple and quantifiable assessment of Chiari outcomes.
  
  
  METHODS
  The Chicago Chiari Outcome Scale (CCOS) uses 4 postoperative outcome categories (pain, nonpain symptoms, functionality, and complications) graded 1 to 4 for a total possible score of 16. As a comparison with current Chiari outcome methodology, each patient was also placed into a gestalt outcome group of "improved," "unchanged," or "worse" (I/U/W). Patients were stratified by CCOS scores and by I/U/W group.
  
  
  RESULTS
  Stratifying patients by total CCOS scores showed that patients who achieved CCOS scores between 13 and 16 were predominantly in the I/U/W improved group (n = 101, 69%); scores between 9 and 12 were predominantly I/U/W unchanged (n = 39, 27%), and scores between 4 and 8 were I/U/W worse (n = 6, 4%). Symptom subscore results provided insight into the specifics of the overall outcome in addition to the more quantitative nature of the 16-point scale.
  
  
  CONCLUSIONS
  We describe a CCOS that assigns higher scores to patients judged improved by gestalt I/U/W ratings and lower scores to those who were unchanged or worse while defining outcome in 4 specific subcategories. As such, this CCOS should allow for a more unified and quantifiable outcome assessment after Chiari surgery.
authors.affiliation: Section of Neurosurgery and Pritzker School of Medicine, The University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Aliaga
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Hekman
authors.forename: Reza
authors.initials: R
authors.lastname: Yassari
authors.forename: David
authors.initials: D
authors.lastname: Straus
authors.forename: Gaurav
authors.initials: G
authors.lastname: Luther
authors.forename: Judy
authors.initials: J
authors.lastname: Chen
authors.forename: Ajay
authors.initials: A
authors.lastname: Sampat
authors.forename: David
authors.initials: D
authors.lastname: Frim
mesh_terms: D000293:Adolescent; D000328:Adult; D001139:Arnold-Chiari Malformation / Q000175:diagnosis* / Q000601:surgery*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011183:Postoperative Complications / Q000175:diagnosis*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012720:Severity of Illness Index; D016896:Treatment Outcome; D055815:Young Adult