title: Randomized trials of neurosurgical interventions: a systematic appraisal.
abstract: OBJECTIVE
  To systematically appraise the study design and quality of reporting of randomized controlled trials (RCTs) on neurosurgical procedures and to identify potential defects and biases.
  
  
  METHODS
  Randomized controlled trials with at least five patients comparing any neurosurgical procedure against another procedure, nonsurgical treatment, or no treatment were retrieved from MEDLINE, EMBASE, and the Cochrane Library. We analyzed study design, quality of reporting, and trial results.
  
  
  RESULTS
  The median sample size in the 108 eligible reports was 68 patients. Ninety-nine trials (91.7%) reported inclusion and exclusion criteria, 55 (50.9%) mentioned the randomization mode, and 87 (80.6%) adequately described withdrawals, but only 31 (28.7%) described allocation concealment, only 23 (21.3%) gave power calculations, and only 20 (18.5%) were adequately powered. Significant efficacy or trend for efficacy was claimed in 46 reports (42.6%), and no difference between the compared procedures was found in 60 trials (55.6%). Trials with a larger sample size were more likely to report withdrawals (P = 0.02) and power calculations (P = 0.006). Only 14 trials (13.6%) were double-blind, and this was less frequent in longer trials (P = 0.02). Among quality criteria, only the reporting of randomization mode improved significantly over time (P = 0.015).
  
  
  CONCLUSIONS
  Several aspects of the design and reporting of randomized controlled trials on neurosurgical procedures can be improved. Larger, adequately powered, and accurately reported trials are needed.
authors.affiliation: Department of Neurosurgery, University of Ioannina School of Medicine, Ioannina, Greece.
authors.forename: George
authors.initials: G
authors.lastname: Vranos
authors.forename: Athina
authors.initials: A
authors.lastname: Tatsioni
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Polyzoidis
authors.forename: John P A
authors.initials: JP
authors.lastname: Ioannidis
mesh_terms: D006801:Humans; D009422:Nervous System Diseases / Q000601:surgery; D019635:Neurosurgical Procedures; D017063:Outcome Assessment, Health Care; D016032:Randomized Controlled Trials as Topic / Q000639:trends; D012107:Research Design / Q000639:trends