Guidelines in Cerebrovascular Neurosurgery Resident Session December 2000

Guideline Methodology systematic review of the literature relating to a disease or specific treatment condition categorization according to “levels of evidence” development of “grades of recommendation” generally a consensus process

Levels of evidence for rating studies of treatment or prevention LevelDescription Iat least one properly designed RCT (I+: systematic overview / meta-analysis of RCTs) IIRCT not meeting level I criteria (e.g. low power) (II+ - systematic overview / meta-analysis level II) IIInon-randomized trial / cohort study with contemporaneous controls IVbefore-after study, cohort study with noncontemporaneous controls, case-control study Vcase series (>10 pts) without controls VIcase report / case series <10 pts

Grading System for Recommendation GradeDefinition A- based on one or more level I studies B- best evidence available is at level II C- best evidence available is at level III D- best evidence available is lower than level III and includes expert opinion

Categories for Strength of Recommendation CategoryDefinition A- good evidence for use B- moderate evidence for use C- poor evidence against use D- moderate evidence against use E- good evidence against use

… Still more terms … “Standard of care”: –handful (Nimodipine, NASCET >70%, NASCIS) “Recommendations” “Options”

Guidelines “Cookbook medicine”?

How to use Guidelines assess quality of guideline construction ensure applicability to your patient If there is high-level evidence (standard of care): –follow it! OR –delineate (and document) rationale for not following it If the evidence is poor: –decide based on (evidence & experience)