An update of evaluation of intravenous sedation on diagnostic spinal injection procedures.

BACKGROUND Intravenous (IV) sedation analgesia is often employed in patients with chronic spinal pain undergoing diagnostic spinal injection procedures. The drugs used for intravenous sedation analgesia produce varying degrees of sedation, amnesia, anxiolysis, muscle relaxation, and analgesia. The very nature of these pharmacologic effects in altering the patient's level of consciousness, awareness, or response to a particular diagnostic stimulus invokes a sense of uncertainty about the results or response obtained from the diagnostic procedure. There is an ongoing controversy regarding the validity of controlled diagnostic blocks due to variability in sensitivity, specificity, and accuracy. Moreover, there is no consensus with regards to the use of sedation analgesic measures prior to controlled diagnostic blocks and their influence on the accuracy and validity of a diagnosis. OBJECTIVE To assess and update the clinically significant effects sedation analgesia procedures have on the diagnostic accuracy and validity of interventional spinal techniques. METHODS A comprehensive literature search using PubMed, EMBASE, and Cochrane Library review databases up to September 2012 was performed. The search included systematic and narrative review articles, prospective and retrospective studies, as well as cross-referencing of bibliographies from notable primary and review articles and abstracts from scientific meetings and peer-reviewed non-indexed journals. The search emphasized the effects of sedation analgesia on diagnostic spinal interventions. CONCLUSION Based on a review of the available evidence, it appears that the administration of mild to moderate sedation does not confound the results or diagnostic validity of spinal injection procedures. Specifically, immediate pain relief after cervical and lumbar facet joint controlled nerve blocks is not enhanced by IV sedation with midazolam or fentanyl. This is especially true if stringent outcome criteria are employed, such as at least 75% pain relief combined with an increase in range of motion for pain limited movements.