Comparing Lateral Branch Capture Capabilities of Bipolar, Monopolar Sacroiliac Joint Radiofrequency Ablation Techniques

The current monopolar sacroiliac joint radiofrequency ablation techniques may not be capable of capturing all lateral branches, contributing to a less than optimal clinical outcomes.

According to an anatomic comparison recently published in Pain Medicine, bipolar sacroiliac joint (SIJ) radiofrequency ablation (RFA) techniques might better capture sacral lateral branches (LBs) than monopolar techniques.

The cadaveric fluoroscopy study compared the percentage of LBs captured when lesions were created in 40 cadaveric SIJs using 4 bipolar and 3 monopolar RFA techniques. In total, 17 versions were tested.

The research revealed that both the mean LB and 100% capture rates were greater for the bipolar (93.4%-99.7% and 62.5%-97.5%, respectively) than for the monopolar techniques (49.6%-99.1% and 2.5%-92.5%). In addition, the percentage of LBs that would be captured was statistically significantly greater for each of the bipolar versions than for all versions of the conventional monopolar technique (P <0.0005).

There were also no statistically significant differences among the bipolar techniques (P =1.00). For the bipolar versions, 1.5% to 29.2% of LBs would not be captured at S1 and 0% at S2 through S4 vs 0% to 29.2% at S1 through S4 for the cooled monopolar techniques vs 36.9% to 100% at S1 through S4 for the conventional monopolar technique.

Based on their findings, the researchers concluded that if lesions were created, “the RFA needle placement locations of the bipolar techniques evaluated may be capable of capturing all LBs, but those of the current monopolar techniques evaluated may not.”

Limitations of the current study include mapping all 17 versions of 7 current SIJ RFA techniques. Technical factors and the tissue environment present during SIJ RFA might affect lesion morphology in clinical practice.

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The researchers noted, “If the lesion size assumptions made in the current study are not valid, then the results of the current study would be different.” Thus, further research is required “to compare the lesion morphology generated in vivo in humans by various SIJ RFA techniques.”

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Roberts SL, Stout A, Loh EY, Swain N, Dreyfuss P, Agur AM. Anatomical comparison of radiofrequency ablation techniques for sacroiliac joint pain [published online February 5, 2018]. Pain Med. doi 10.1093/pm/pnx329