title: Spinal fusion for chronic low back pain: systematic review on the accuracy of tests for patient selection.
abstract: BACKGROUND
  Spinal fusion is a common but controversial treatment for chronic low back pain (LBP) with outcomes similar to those of programmed conservative care. To improve the results of fusion, tests for patient selection are used in clinical practice.
  
  
  OBJECTIVE
  To determine the prognostic accuracy of tests for patient selection that are currently used in clinical practice to identify those patients with chronic LBP who will benefit from spinal fusion.
  
  
  METHODS
  Systematic review of the literature.
  
  
  METHODS
  Studies that compared the results of magnetic resonance imaging (MRI), provocative discography, facet joint blocks, orthosis immobilization, and temporary external fixation with the clinical outcome of patients who underwent spinal fusion for chronic LBP.
  
  
  METHODS
  To determine the prognostic accuracy of tests to predict the clinical outcome of spinal fusion in terms of sensitivity, specificity, and likelihood ratios (LRs).
  
  
  METHODS
  Data sources PubMed (1966 to November 2010), EMBASE (1974 to November 2010), and reference lists were searched without restriction by language or publication status. Two reviewers independently selected studies for inclusion, extracted data for analysis, and assessed the risk of bias with the Quality Assessment of Diagnostic Accuracy Studies checklist, modified for prognostic studies. Discrepancies were resolved by consensus.
  
  
  RESULTS
  Ten studies met the eligibility criteria. Immobilization by an orthosis (median [range] positive LR, 1.10 [0.94-1.13] and negative LR, 0.92 [0.39-1.12]), provocative discography (median [range] positive LR, 1.18 [0.70-1.71] and negative LR, 0.74 [0.24-1.40]), and temporary external fixation (median [range] positive LR, 1.22 [1.02-1.74] and negative LR, 0.58 [0.15-0.94]) failed to show clinically useful prognostic accuracy. Statistical pooling was not feasible because of different test protocols, variability in outcome assessment, and heterogeneous patient populations. No studies reporting on facet joint blocks or MRI could satisfy the inclusion criteria. Obscure patient selection, high risk of verification bias, and outcome assessment with poorly validated instruments precluded strong conclusions for all tests.
  
  
  CONCLUSIONS
  No subset of patients with chronic LBP could be identified for whom spinal fusion is a predictable and effective treatment. Best evidence does not support the use of current tests for patient selection in clinical practice.
authors.affiliation: Department of Orthopaedics, Research School CAPHRI, Maastricht University Medical Center, P. Debyelaan 25, PO Box 5800, 6202 AZ Maastricht, The Netherlands. p.willems@mumc.nl
authors.forename: Paul C
authors.initials: PC
authors.lastname: Willems
authors.forename: J Bart
authors.initials: JB
authors.lastname: Staal
authors.forename: Geert H I M
authors.initials: GH
authors.lastname: Walenkamp
authors.forename: Rob A
authors.initials: RA
authors.lastname: de Bie
mesh_terms: D059350:Chronic Pain / Q000175:diagnosis / Q000601:surgery*; D006801:Humans; D017116:Low Back Pain / Q000175:diagnosis / Q000601:surgery*; D018579:Patient Selection; D012680:Sensitivity and Specificity; D013123:Spinal Fusion / Q000379:methods*; D016896:Treatment Outcome