COMBINED BIPOLAR AND V-SHAPED LESIONS FOR LUMBAR FACET RADIOFREQUENCY ABLATION: A TECHNICAL REPORT.

INTRODUCTION: Radiofrequency ablation (RFA) is a demonstrated safe and effective treatment for chronic low back pain. RFA delivers high density electrical current near lumbar medial branch nerve. The success of RFA is contingent upon creating a lesion that overlaps the sensory nerve supplying the affected facet joint(s). Both bipolar-RFA and V-shaped active tip cannulas increase lesion size in experimental models. We describe successful application of concomitant bipolar and V-shaped lesions in a single patient with chronic low back pain caused by lumbar spondylosis.

CASE PRESENTATION: An 81-year-old male with atrial fibrillation on chronic warfarin anticoagulation was previously treated with conventional monopolar lumbar facet RFA resulting in a 75% decrement in pain intensity exceeding eight months. Nine months after the procedure, his pain returned with similar pretreatment character and was unresponsive to additional physical therapy and acetaminophen. We elected to use a V-shaped cannula to maximize lesion diameter and lengthen intervals between anticoagulant abstinence to minimize the risk. Intraoperatively, a grounding-pad malfunction compelled us to convert to bipolar-RFA by placing a second adjacent V-shaped cannula, eliminating grounding-pad requirement. Bilateral bipolar medial branch RFA of L3-L4, L4-L5, L5-S1 nerves was performed between these two cannulas without further incident. The patient had sustained analgesia that lasted over twelve months resultant from treatment.

CONCLUSION: We herein describe a technique of combined bipolar-RFA utilizing proximally adjacent V-shaped cannulas. Both bipolar and V-shaped cannulas create larger lesions in experiments. While both techniques purport theoretical advantages, the clinical superiority of a combined technique warrants continued clinical investigation.