Background: There is ongoing controversy regarding the validity of controlled diagnostic blocks due to variability in sensitivity, specificity, and accuracy. Consequently, identification of false-positive rates, false-negative rates, and placebo responses is crucial. The reasons described for false-positive responses to diagnostic anesthetic blocks are many; however, sedation and psychological factors have been implied as causes. Further, there is no consensus with regards to sedation prior to controlled diagnostic blocks and their influence on the accuracy and validity of a diagnosis.
Study design: A systematic review of the literature evaluating the influence of sedation on diagnostic spinal interventional techniques.
Objectives: To systematically assess the quality of clinical studies evaluating the diagnostic accuracy of controlled diagnostic blocks in the diagnosis of chronic spinal pain.
Methods: A comprehensive evaluation of the literature relating to sedation in diagnostic interventional techniques was performed. The methodologic quality assessment of the studies was carried out by utilizing Agency for Healthcare Research and Quality (AHRQ) methodologic quality criteria with scores of 50 or higher included in the assessment of the level of evidence. Level of evidence was based on the U.S. Preventive Services Task Force (USPSTF) criteria for the assessment of accuracy of diagnostic studies.
Limitations: All 3 of the studies were produced by one group of authors. Thus paucity of the literature on the subject of facet joint pain and the lack of literature on the subjects of discogenic pain and sacroiliac joint pain are major limitations.
Results: Three studies were identified which met inclusion and methodologic assessment quality criteria. Sedation can be a confounding factor in a small population of patients specifically if fentanyl is employed and non-stringent criteria are followed. Based on the 3 randomized double-blind trials with stringent criteria utilizing 80% pain relief and the ability to perform prior painful movements without any significant pain following the diagnostic injection in evaluation of facet joint pain, the indicated evidence is Level II-1.
Conclusion: This systematic review provides no significant evidence of the influence of sedation either with midazolam or fentanyl in the evaluation of cervical and lumbar facet joint pain with controlled cervical and lumbar facet joint nerve blocks with an indicated evidence of Level II-1, with application of stringent criteria of at least 80% pain relief and the ability to perform previously painful movements after the diagnostic blocks.