A Best-Evidence Systematic Appraisal of the Diagnostic Accuracy and Utility of Facet (Zygapophysial) Joint Injections in Chronic Spinal Pain

Background: Spinal zygapophysial, or facet, joints are a source of axial spinal pain and referred pain in the extremities. Conventional clinical features and other noninvasive diagnostic modalities are unreliable in diagnosing zygapophysial joint pain. Study Design: A systematic review of the diagnostic accuracy of spinal facet joint nerve blocks. Objective: To determine the diagnostic accuracy of spinal facet joint nerve blocks in chronic spinal pain. Methods: A methodological quality assessment of included studies was performed using Quality Appraisal of Reliability Studies (QAREL). Only diagnostic accuracy studies meeting at least 50% of the designated inclusion criteria were utilized for analysis. The level of evidence was classified as Level I to V based on the grading of evidence utilizing best evidence synthesis. Data sources included relevant literature identified through searches of PubMed and other electronic searches published from 1966 through March 2015, Cochrane reviews, and manual searches of the bibliographies of known primary and review articles. Outcome Measures: Studies must have been performed utilizing controlled local anesthetic blocks. The criterion standard must have been at least 50% pain relief from baseline scores and the ability to perform previously painful movements. Results: The available evidence is Level I for lumbar facet joint nerve blocks with the inclusion of a total of 17 studies with dual diagnostic blocks, with at least 75% pain relief with an average prevalence of 16% to 41% and false-positive rates of 25% to 44%. The evidence for diagnosis of cervical facet joint pain with cervical facet joint nerve blocks is Level II based on a total of 11 controlled diagnostic accuracy studies, with significant variability among the prevalence in a heterogenous population with internal inconsistency. The prevalence rates ranged from 36% to 67% with at least 80% pain relief as the criterion standard and a false-positive rate of 27% to 63%. The level of evidence for the diagnostic accuracy of thoracic facet joint nerve blocks is Level II with 80% or higher pain relief as the criterion standard with a prevalence ranging from 34% to 48% and false-positive rates ranging from 42% to 48%. Limitations: The shortcomings of this systematic review include a paucity of literature related to the thoracic spine, continued debate on an appropriate gold standard, appropriateness of diagnostic blocks, and utility. Conclusion: The evidence is Level I for the diagnostic accuracy of lumbar facet joint nerve blocks, Level II for cervical facet joint nerve blocks, and Level II for thoracic facet joint nerve blocks in assessment of chronic spinal pain.