Accuracy of precision diagnostic blocks in the diagnosis of chronic spinal pain of facet or zygapophysial joint origin.

CONTEXT Facet or zygapophysial joint blocks are used extensively in the evaluation of chronic spinal pain. However, there is a continuing debate about the value and validity of facet joint blocks in the diagnosis of chronic spinal pain. The value of diagnostic facet joint injections may have been overlooked in the medical literature. OBJECTIVES To determine the accuracy of facet joint blocks in the diagnosis of chronic spinal pain of facet joint origin and also determine the rationale, principles, false-positive rate, and diagnostic utility of facet joint blocks as well as prevalence of facet joint pain. METHODS Relevant literature was identified through searches of MEDLINE, EMBASE (Jan 1966- Mar 2003), manual searches of bibliographies of known primary and review articles, and abstracts from scientific meetings. Studies were selected if they were either placebo-controlled or comparative local anesthetic blocks and met 3 of the 5 criteria established by the Agency for Healthcare Research and Quality. Information extracted from each study included the details about the study, type, design, patient eligibility criteria, and statistical analysis. Studies were excluded from analysis if they were simply a review or descriptive or involved only a single-block. RESULTS The data showed that there was conclusive evidence demonstrating that facet joints have a nerve supply and are capable of causing pain with provocation in normal volunteers that reproduces typical pain attribution clinically to facet joints. The studies demonstrated a prevalence of facet joint pain in chronic spinal pain patients of 15% to 45% in lumbar spine, up to 48% in thoracic spine, and 54% to 67% in the cervical spine. Single diagnostic blocks showed a false-positive rate of 27% to 63%. CONCLUSION The diagnostic accuracy of controlled local anesthetic facet joint blocks is high in the diagnosis of chronic spinal pain.