title: Complication-Effectiveness Analysis for Unruptured Intracranial Aneurysm Surgery: A Prospective Cohort Study.
abstract: BACKGROUND
  The aim of intervention for unruptured intracranial aneurysms (UIAs) is safe, effective treatment.
  
  
  OBJECTIVE
  To analyze a prospective database for variables influencing the risk of surgery to produce a risk model adjusting this risk for effectively treated aneurysms.
  
  
  METHODS
  First, we identified variables to create a model from multiple logistic regression for complications of surgery leading to a 12-month modified Rankin Scale score >1. Second, we established the long-term cumulative incidence of freedom from retreatment or rupture (treated aneurysm) from Kaplan-Meier analysis. Third, we combined these analyses to establish a model of risk of surgery per effective treatment.
  
  
  RESULTS
  One thousand twelve patients with 1440 UIA underwent 1080 craniotomies. We found that 10.1% (95% confidence interval [CI], 8.4-12.0) of craniotomies resulted in a complication leading to a modified Rankin Scale score >1 at 12 months. Logistic regression found age (odds ratio, 1.04; 95% CI, 1.02-1.06), size (odds ratio, 1.12; 95% CI, 1.09-1.15), and posterior circulation location (odds ratio, 2.95; 95% CI, 1.82-4.78) to be significant. Cumulative 10-year risk of retreatment or rupture was 3.0% (95% CI, 1.3-7.0). The complication-effectiveness model was derived by dividing the complication risk by the 10-year cumulative freedom from retreatment or rupture proportion. Risk per effective treatment ranged from 1% for a 5-mm anterior circulation UIA in a 20-year-old patient to 70% for a giant posterior circulation UIA in a 70-year-old patient.
  
  
  CONCLUSIONS
  Complication-effectiveness analyses increase the information available with regard to outcome for the management of UIAs.
authors.affiliation: Departments of *Clinical Medicine and‡Statistics, Macquarie University, New South Wales, Australia.
authors.forename: Michael Kerin
authors.initials: MK
authors.lastname: Morgan
authors.forename: Markus
authors.initials: M
authors.lastname: Wiedmann
authors.forename: Nazih N
authors.initials: NN
authors.lastname: Assaad
authors.forename: Gillian Z
authors.initials: GZ
authors.lastname: Heller
mesh_terms: D000368:Aged; D017542:Aneurysm, Ruptured / Q000453:epidemiology; D002560:Cerebrovascular Circulation; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications / Q000601:surgery*; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000009:adverse effects / Q000379:methods*; D020769:Posterior Cerebral Artery; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012086:Reoperation / Q000706:statistics & numerical data; D018570:Risk Assessment; D012307:Risk Factors; D016896:Treatment Outcome