Positive and negative predictors for good outcome after decompressive surgery for Chiari malformation type 1 as scored on the Chicago Chiari Outcome Scale.
OBJECTIVE
Posterior fossa decompression (PFD) is commonly applied as treatment for Chiari malformation type 1 (CM1), an entity which is associated with a variety of presenting symptoms but little data correlating symptoms to surgical outcome. We applied the Chicago Chiari Outcome  Scale (CCOS), a novel 16-point tool for evaluating outcome, to a consecutive series of CM1 patients to identify specific factors or symptoms that predispose to a better or worse surgical outcome.


METHODS
A series of 167 CM1 patients who underwent initial PFD at our institution (consisting  of suboccipital craniectomy, C1 laminectomy, subarachnoid exploration, and expansile autologous pericranial duraplasty) were reviewed. Pre-operative signs, symptoms, and characteristics were recorded, and odds ratios were calculated to identify significant pre-operative factors corresponding  to a better or worse outcome on the CCOS.


RESULTS
Sensory deficits and peripheral neuropathy correlated with a lower score on the CCOS. Younger age at the time of surgery and, strikingly, presence of syringomyelia both correlated with a higher CCOS score.


CONCLUSIONS
Our  results identify specific presenting factors that correlated with a better or worse outcome after CM1 decompression. These data also demonstrate that CCOS scoring allows for a rigorous comparison of outcome in different patient populations and between variable operative techniques. Application  of CCOS scoring to a larger patient population undergoing a variety of operative CM1 treatments should allow for better-informed decisions regarding patient selection and treatment options for CM1.
Section of Neurosurgery and the Pritzker School of Medicine, The University of Chicago, USA.
Katherine E
KE
Hekman
Leonardo
L
Aliaga
David
D
Straus
Aman
A
Luther
Judy
J
Chen
Ajay
A
Sampat
David
D
Frim
D000293:Adolescent; D001139:Arnold-Chiari Malformation / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery*; D019299:Decompression, Surgical / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012720:Severity of Illness Index; D016896:Treatment Outcome; D055815:Young Adult