title: Recruitment in Clinical Trials: The Use of Zelen's Prerandomization in Recent Neurovascular Studies.
abstract: OBJECTIVE
  Randomized allocation of treatment options is not well accepted within the clinical community. Some methods of implementation may be received more favorably than others. Prerandomization may be an acceptable means to facilitate recruitment in some clinical trials.
  
  
  METHODS
  We first compare randomization and prerandomization using illustrative neurovascular trials. We review some problems with conventional trials, Zelen's prerandomization as an alternative method, and the ethical issues that have surrounded prerandomization since its inception in a historic trial. Conventional and Zelen's randomization are then compared with other means to provide and verify care in the context of clinical uncertainty.
  
  
  RESULTS
  The major problem with conventional randomization is that consent is requested for 2 management options, one of which the patient will not receive. The problem with prerandomization is that treatment is allocated before the patient has consented to trial participation. Prerandomization may trade recruitment difficulties for excessive crossovers. However, other ways to practice under uncertainty and verify patient outcomes, such as case series and registries, are more ethically and scientifically problematic.
  
  
  CONCLUSIONS
  Until the ethical functions of randomized allocation of selected treatment options in the care of patients are recognized by the neurovascular community, Zelen's prerandomization may help recruitment into difficult trials and contribute a means to provide best possible care in the presence of uncertainty.
authors.affiliation: Department of Radiology, Centre hospitalier de l'Université de Montréal, Montreal, Quebec, Canada. Electronic address: jean.raymond@umontreal.ca.
authors.forename: Jean
authors.initials: J
authors.lastname: Raymond
authors.affiliation: Division of Neurosurgery, Department of Surgery, University of Alberta Hospital, Mackenzie Health Sciences Centre, Edmonton, Alberta, Canada.
authors.forename: Tim E
authors.initials: TE
authors.lastname: Darsaut
authors.affiliation: Laboratoire de recherche en éthique et vieillissement, Centre de recherche, Institut Universitaire de Gériatrie de Montréal, Montreal, Quebec, Canada.
authors.forename: David J
authors.initials: DJ
authors.lastname: Roy
mesh_terms: D006801:Humans; D019635:Neurosurgical Procedures / Q000941:ethics* / Q000379:methods / Q000592:standards; D018579:Patient Selection / Q000941:ethics*; D016032:Randomized Controlled Trials as Topic / Q000941:ethics* / Q000379:methods / Q000592:standards; D014656:Vascular Surgical Procedures / Q000941:ethics* / Q000379:methods / Q000592:standards
keywords: Consent; Randomized controlled trial; Research ethics; Vascular diseases