Effects of Anesthetic Fluid Injectates on Lesion Sizes in Cooled Radiofrequency Ablation

Current opinion: optimize radiofrequency ablation through electrophysiological principles, modeling, and clinical recommendations

PURPOSE OF REVIEW

This article aims to empower the interventional pain physician to utilize RFA effectively by explaining the technical and electrophysiological features of monopolar, bipolar, and internally cooled RFA. Scientific data are used to provide advice on the effective, well tolerated, and rational application of these techniques. Moreover, physicians need to know how to analyze and generalize ex-vivo and in-vivo models to the clinical setting to optimize clinical outcomes.

RECENT FINDINGS

Recent studies suggest that there are many ways to enhance the technical effectiveness of interventional pain medicine RFA through adjustments in the equipment selection and settings and the local tissue conditions specific to the targeted anatomical area. These modifications could assist in improving clinical and safety outcomes.

SUMMARY

To optimize both the efficacy and safety of RFA, physicians must understand, conceptualize, interpret, and clinically translate the basic science of RFA. This knowledge is crucial for optimizing equipment selection and settings based on target location to enhance clinical outcomes and limit technical failures.

Consensus practice guidelines on interventions for lumbar facet joint pain from a multispecialty, international working group

BACKGROUND

The past two decades have witnessed a surge in the use of lumbar facet blocks and radiofrequency ablation (RFA) to treat low back pain (LBP), yet nearly all aspects of the procedures remain controversial.

METHODS

After approval by the Board of Directors of the American Society of Regional Anesthesia and Pain Medicine, letters were sent to a dozen pain societies, as well as representatives from the US Departments of Veterans Affairs and Defense. A steering committee was convened to select preliminary questions, which were revised by the full committee. Questions were assigned to 4-5 person modules, who worked with the Subcommittee Lead and Committee Chair on preliminary versions, which were sent to the full committee. We used a modified Delphi method, whereby the questions were sent to the committee en bloc and comments were returned in a non-blinded fashion to the Chair, who incorporated the comments and sent out revised versions until consensus was reached.

RESULTS

17 questions were selected for guideline development, with 100% consensus achieved by committee members on all topics. All societies except for one approved every recommendation, with one society dissenting on two questions (number of blocks and cut-off for a positive block before RFA), but approving the document. Specific questions that were addressed included the value of history and physical examination in selecting patients for blocks, the value of imaging in patient selection, whether conservative treatment should be used before injections, whether imaging is necessary for block performance, the diagnostic and prognostic value of medial branch blocks (MBB) and intra-articular (IA) injections, the effects of sedation and injectate volume on validity, whether facet blocks have therapeutic value, what the ideal cut-off value is for a prognostic block, how many blocks should be performed before RFA, how electrodes should be oriented, the evidence for larger lesions, whether stimulation should be used before RFA, ways to mitigate complications, if different standards should be applied to clinical practice and clinical trials and the evidence for repeating RFA (see table 12 for summary).

CONCLUSIONS

Lumbar medial branch RFA may provide benefit to well-selected individuals, with MBB being more predictive than IA injections. More stringent selection criteria are likely to improve denervation outcomes, but at the expense of more false-negatives. Clinical trials should be tailored based on objectives, and selection criteria for some may be more stringent than what is ideal in clinical practice.