title: Impact of clinical trials on neurosurgical practice: an assessment of case volume.
abstract: OBJECTIVE
  To evaluate the effect of important trials on the practice of neurosurgery.
  
  
  METHODS
  We hypothesized that evidence from trials addressing the management of intracranial aneurysms (International Subarachnoid Aneurysm Trial [ISAT]) and nontraumatic intracerebral hemorrhages (Surgical Trial in Intracerebral Hemorrhage [STICH]) and vertebral augmentation for osteoporotic vertebral body fractures had a significant impact on the frequency of the corresponding neurosurgical procedures. A Medicare administrative database was queried for corresponding Common Procedural Terminology codes and units billed per calendar year. The effects of ISAT and STICH were evaluated using a generalized linear model. The effect of the vertebral augmentation study was evaluated using a t test.
  
  
  RESULTS
  After publication of ISAT in 2002, the rate of increase in proportion of cerebral aneurysms that were treated with embolization (Common Procedural Terminology code 61624) per year increased from 3.9% to 5.5% (P = 0.01). After publication of STICH in 2005, the number of craniotomies performed for intracerebral hematoma decreased from 2341 in 2002 to 1646 in 2011 (P = 0.03). After 2 publications in 2009, performance of vertebral augmentation decreased from a high of 99,961 in 2009 per year to 77,108 in 2013 (P = 0.002).
  
  
  CONCLUSIONS
  Randomized clinical trials remain the gold standard in the medical community to demonstrate efficacy, but their true impact relies on rapid and extensive assimilation into everyday medical practice. However, the described methodology establishes a temporal relationship only and does not prove causation. Nonetheless, trends in procedural volume suggest that the results of these select randomized clinical trials had a significant effect on neurosurgical practice affecting Medicare patients within an interval of a few years.
authors: Department of Neurosurgery, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA. Electronic address: ssimon@hmc.psu.edu.
authors: Scott D
authors: SD
authors: Simon
authors: Center for Quantitative Sciences, Vanderbilt University, Nashville, Tennessee, USA.
authors: Tatsuki
authors: T
authors: Koyama
authors: Department of Neurological Surgery, Columbia University, New York, New York, USA.
authors: Brad E
authors: BE
authors: Zacharia
authors: Department of Neurosurgery, Geisinger Health System, Danville, Pennsylvania, USA.
authors: Clemens M
authors: CM
authors: Schirmer
authors: Department of Neurosurgery, Vanderbilt University, Nashville, Tennessee, USA.
authors: Joseph S
authors: JS
authors: Cheng
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003399:Craniotomy / Q000706:statistics & numerical data; D016208:Databases, Factual; D004621:Embolization, Therapeutic / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000453:epidemiology / Q000601:surgery; D020300:Intracranial Hemorrhages / Q000453:epidemiology / Q000601:surgery; D008297:Male; D006278:Medicare; D009493:Neurosurgery / Q000706:statistics & numerical data*; D010024:Osteoporosis / Q000150:complications / Q000453:epidemiology; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D016032:Randomized Controlled Trials as Topic / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D016103:Spinal Fractures / Q000453:epidemiology / Q000209:etiology / Q000601:surgery; D014481:United States / Q000453:epidemiology
keywords: Aneurysm; Cerebellar hematoma; Neurosurgery; Randomized trial; Vertebral augmentation