title: Dynamic compared to rigid fixation in lumbar spine: a systematic review.
abstract: OBJECTIVE
  The objective of this review is to reveal the quality of published data and the effect size of DPFs compared to rigid fixation in lumbar spine.
  
  
  BACKGROUND
  since 2002, several dynamic pedicle fixation (DPF) systems have been developed with the aim to stabilize the spine without the undesirable effects of rigid lumbar spine fixation. Nearly ten years later, there are several studies on these dynamic systems.
  
  
  METHODS
  A systematic review was done in MEDLINE/PubMED, Embase, Cochrane Central Register of Randomized Trials and Google Scholar to assess the quality of published literature and the available studied outcomes in randomized controlled trials of DPF.
  
  
  RESULTS
  Only three papers described randomized trials studying DPF. One of them focused on protection of adjacent level disease provided by DPF.
  
  
  CONCLUSIONS
  It was not possible to reveal any evidence for benefits using DPF compared to rigid fixation in surgery for lumbar spine.
authors.affiliation: IAMSPE, São Paulo, SP, Brazil.
authors.forename: Ricardo Vieira
authors.initials: RV
authors.lastname: Botelho
authors.affiliation: Medicine School, City University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Rafael
authors.initials: R
authors.lastname: Bastianello
authors.affiliation: Medicine School, City University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Luciana DiniGianini de
authors.initials: LD
authors.lastname: Albuquerque
authors.affiliation: University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Wanderley Marques
authors.initials: WM
authors.lastname: Bernardo
mesh_terms: D006801:Humans; D016268:Internal Fixators; D008159:Lumbar Vertebrae / Q000293:injuries* / Q000601:surgery*; D011643:Publishing; D011785:Quality Assurance, Health Care; D016032:Randomized Controlled Trials as Topic; D016103:Spinal Fractures / Q000601:surgery*; D013123:Spinal Fusion / Q000295:instrumentation*; D053831:Surgical Fixation Devices; D016896:Treatment Outcome