Original Research Article
The Effect of Sedation on the Accuracy and Treatment Outcomes for Diagnostic Injections: A Randomized, Controlled, Crossover Study
- Conflicts of Interest: The authors declare they have no conflicts of interest.
- Funding Source: Funded in part by the Centers for Rehabilitation and Sciences Research, Uniformed Services University of the Health Sciences, Bethesda, MD.
- The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Department of the Army or the Department of Defense.
- ClinicalTrials.gov Identifier: NCT01472835.
Background and Objective
Diagnostic injections are used to diagnose myriad pain conditions, but are characterized by a high false-positive rate. One potential cause of inaccurate diagnostic blocks is the use of sedation. We sought to determine the effect of sedation on the validity of diagnostic injections.
Randomized, crossover study in which 73 patients were allocated to receive a diagnostic sacroiliac joint or sympathetic nerve block performed either with or without sedation using midazolam and fentanyl. Those who obtained equivocal relief, good relief lasting less than 3 months, or who were otherwise deemed good candidates for a repeat injection, received a subsequent crossover injection within 3 months (N = 46).
Setting and Patients
A tertiary care teaching hospital and a military treatment facility.
In the primary crossover analysis, blocks performed with sedation resulted in a larger mean reduction in pain diary score than those done without sedation (1.2 [2.6]; P = 0.006), less procedure-related pain (difference in means 2.3 [2.5]; P < 0.0001), and a higher proportion of patients who obtained > 50% pain relief on their pain diaries (70% vs. 54%; P = 0.039). The increased pain reduction was not accompanied by increased satisfaction (sedation mean 3.9 [1.1] vs. 3.7 [1.3]; P = 0.26). Similar findings were observed for the parallel group (N = 73) and omnibus (all sedation vs. no sedation blocks, N = 110) analyses. No differences in outcomes were noted between the use and non-use of sedation at 1-month.
The use of sedation during diagnostic injections may increase the rate of false-positive blocks and lead to misdiagnoses and unnecessary procedures, but has no effect on satisfaction or outcomes at 1-month.