title: Reconsidering the logic of World Federation of Neurosurgical Societies grading in patients with severe subarachnoid hemorrhage.
abstract: OBJECTIVE
  Current data show a favorable outcome in up to 50% of patients with World Federation of Neurosurgical Societies (WFNS) Grade V subarachnoid hemorrhage (SAH) and a rather poor prediction of worst cases. Thus, the usefulness of the current WFNS grading system for identifying the worst scenarios for clinical studies and for making treatment decisions is limited. One reason for this lack of differentiation is the use of "negative" or "silent" diagnostic signs as part of the WFNS Grade V definition. The authors therefore reevaluated the WFNS scale by using "positive" clinical signs and the logic of the Glasgow Coma Scale as a progressive herniation score.
  
  
  METHODS
  The authors performed a retrospective analysis of 182 patients with SAH who had poor grades on the WFNS scale. Patients were graded according to the original WFNS scale and additionally according to a modified classification, the WFNS herniation (hWFNS) scale (Grade IV, no clinical signs of herniation; Grade V, clinical signs of herniation). The prediction of poor outcome was compared between these two grading systems.
  
  
  RESULTS
  The positive predictive values of Grade V for poor outcome were 74.3% (OR 3.79, 95% CI 1.94-7.54) for WFNS Grade V and 85.7% (OR 8.27, 95% CI 3.78-19.47) for hWFNS Grade V. With respect to mortality, the positive predictive values were 68.3% (OR 3.9, 95% CI 2.01-7.69) for WFNS Grade V and 77.9% (OR 6.22, 95% CI 3.07-13.14) for hWFNS Grade V.
  
  
  CONCLUSIONS
  Limiting WFNS Grade V to the positive clinical signs of the Glasgow Coma Scale such as flexion, extension, and pupillary abnormalities instead of including "no motor response" increases the prediction of mortality and poor outcome in patients with severe SAH.
authors.affiliation: Department of Neurosurgery.
authors.forename: Christian
authors.initials: C
authors.lastname: Fung
authors.affiliation: Department of Neurosurgery.
authors.forename: Fabienne
authors.initials: F
authors.lastname: Inglin
authors.affiliation: Department of Neurosurgery.
authors.forename: Michael
authors.initials: M
authors.lastname: Murek
authors.affiliation: Department of Neurosurgery.
authors.forename: Mathias
authors.initials: M
authors.lastname: Balmer
authors.affiliation: Department of Neurosurgery.
authors.forename: Janine
authors.initials: J
authors.lastname: Abu-Isa
authors.affiliation: Department of Neurosurgery.
authors.forename: Werner J
authors.initials: WJ
authors.lastname: Z'Graggen
authors.affiliation: Institute for Diagnostic and Interventional Neuroradiology, and.
authors.forename: Christoph
authors.initials: C
authors.lastname: Ozdoba
authors.affiliation: Institute for Diagnostic and Interventional Neuroradiology, and.
authors.forename: Jan
authors.initials: J
authors.lastname: Gralla
authors.affiliation: Department of Intensive Care Medicine, Bern University Hospital (Inselspital) and University of Bern, Switzerland.
authors.forename: Stephan M
authors.initials: SM
authors.lastname: Jakob
authors.affiliation: Department of Intensive Care Medicine, Bern University Hospital (Inselspital) and University of Bern, Switzerland.
authors.forename: Jukka
authors.initials: J
authors.lastname: Takala
authors.affiliation: Department of Neurosurgery.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Beck
authors.affiliation: Department of Neurosurgery.
authors.forename: Andreas
authors.initials: A
authors.lastname: Raabe
mesh_terms: D000368:Aged; D017542:Aneurysm, Ruptured / Q000145:classification / Q000175:diagnosis; D018450:Disease Progression; D005260:Female; D015600:Glasgow Coma Scale; D006801:Humans; D008297:Male; D008875:Middle Aged; D009493:Neurosurgery / Q000592:standards*; D011237:Predictive Value of Tests; D012025:Reflex, Pupillary; D012189:Retrospective Studies; D012955:Societies, Medical; D013345:Subarachnoid Hemorrhage / Q000145:classification* / Q000175:diagnosis* / Q000401:mortality; D016896:Treatment Outcome
keywords: GCS, mGCS = Glasgow Coma Scale, motor score of the GCS; Glasgow Coma Scale; PPV = positive predictive value; SAH = subarachnoid hemorrhage; WFNS, hWFNS = World Federation of Neurosurgical Societies, WFNS herniation scale; World Federation of Neurosurgical Societies grading; mRS = modified Rankin Scale; subarachnoid hemorrhage; vascular disorders