The loss of resistance technique may not be an adequate method for ensuring accurate needle placement in blindly performed cervical epidural injections. The use of epidurography can improve the accuracy of needle placement and medication delivery to targeted areas of pathology.

Magnetic resonance imaging does not improve outcomes in patients who are clinical candidates for ESI and has only a minor effect on decision making. Trial Registration clinicaltrials.gov Identifier: NCT00826124.

BackgroundThere has been a surge in interest in radiofrequency ablation (RFA) of the genicular nerves over the past decade, with wide variability in selection, technique and outcomes. The aim of this study is to determine factors associated with treatment outcome.MethodsWe retrospectively evaluated the effect of 23 demographic, clinical and technical variables on outcomes in 265 patients who underwent genicular nerve RFA for knee pain at 2 civilian and 1 military hospital. A primary outcome was designated as a > 30% decrease in average knee pain score lasting at least 3 months without cointerventions.ResultsThe overall rate of a positive response was 61.1% (95% CI 55.2% to 67.0%). In univariable analysis, larger electrode size (p=0.01), repeated lesions (p=0.02), having>80% pain relief during the prognostic block (p=0.02), not being on opioids (p=0.04), having no coexisting psychiatric condition (p=0.02), having a lower baseline pain score (p=0.01) and having >3 nerves targeted (p=0.02) were associated with a positive outcome. In multivariate logistic analysis, being obese (OR 3.68, 95% CI 1.66 to 8.19, p=0.001), not using opioids (OR 0.35, 95% CI 0.16 to 0.77, p=0.009), not being depressed (OR 0.29, 95% CI 0.10 to 0.82, p=0.02), use of cooled RFA (OR 3.88, 95% CI 1.63 to 9.23, p=0.002) and performing multiple lesions at each neural target (OR 15.88, 95% CI 4.24 to 59.50, p<0.001) were associated with positive outcome.ConclusionsWe identified multiple clinical and technical factors associated with treatment outcome, which should be considered when selecting patients for RFA treatment and in the design of clinical trials.

Estimates of needle depth made with MRI were consistently slightly deeper than the actual loss-of-resistance needle depth, indicating that the provider should employ caution when using MRI predictive depths. Information garnered from preprocedure MRIs can be used to improve the safety of cervical epidural steroid injection procedures.

The results of this study found a weak positive correlation between SQ pain scores and treatment results. Further research should consider whether pain perception in conjunction with other variables might prove to be a reliable predictor for ESI and other procedural outcomes.