Lumbar Radiofrequency Ablation Interfering With S1 Dorsal Root Ganglion Stimulation Systems: Experience From Two Cases

BACKGROUND: Dorsal root ganglion stimulation (DRG-S) has emerged as a treatment for complex regional pain syndrome (CRPS) of the lower extremities, and recent small studies are demonstrating its potential efficacy in pain syndromes that are traditionally considered nociceptive in nature, such as axial low back pain. While improvements in neuromodulation technology have been substantial over the past decade, with DRG-S systems patients occasionally require additional interventional pain treatments for treatment of pain from other sources. Radiofrequency ablation (RFA) of medial branch nerves innervating the facet joints is an accepted therapy for pain arising from the facet joints. METHODS: We describe 2 cases from the same practice where we observed similar phenomena while performing a 2-needle monopolar lumbar RFA in patients with a DRG-S system implanted with leads positioned bilaterally at the S1 DRGs. RESULTS: Initiation of RFA resulted in motor activation and discomfort in an S1 distribution in the legs in both individual cases. CONCLUSIONS: RFA can interfere with implanted DRG-S systems, resulting in overstimulation with motor recruitment. Specific anatomical considerations and device settings that may prevent interference are discussed