gms | German Medical Science

Introduction: DRG stimulation is an emerging therapy for targeting radicular pain syndromes, which are hard to treat by conventional spinal cord stimulation. Traditionally the implant procedure requires intensive intra-operative testing of the paresthesia coverage in an awake surgery setting. Often patients are unable to differentiate between the paresthesia produced in superficial or deep visceral layers resulting in misplacement of the lead.

Material and methods: 34 subjects with peripheral neuropathies due to nervous damage during prior surgeries were injected on different target levels with Lidocaine and /or stimulated with a RF needle in a CT-guided approach. Anesthetized and paresthesia induced regions were compared with the pain regions overlap. The best match has been chosen as the implant target level to implant a DRG-Neuromodulation lead under general anesthesia. If the pain was not covered on on a single level, multilevel approached have been done. Leads were placed in the level of optimal PRI and RF stimulation response at the T11, T12, L1 or L2. DRGs and stimulation parameters were programmed to direct paresthesia to the patients regions of pain.

Results: DRG stimulation resulted in paresthesias directly at the regions of pain and subsequently pain relief in all areas of pain for all subjects. The positive predicted value of the Lidocaine injection compared to the paresthesia coverage leading to pain reduction was 95.2%. The positive predicted value of the Lidocaine injection compared to the paresthesia coverage leading to pain reduction was 97.1%.No complications or adverse events occurred. All patients received a fully-implantable neurostimulator. The negative predictive value of PRI was 4.8%. The negative predictive value of RF stimulation was 2.9%

Conclusion: The results of this case series suggest that periradicular injections and RF stimulation prior to lead implantation is an excellent method to verify the right implant target site and spinal level. It offers the possibility to perform the procedure under general anesthesia without the need of intra-operative testing to confirm paresthesia overlap. The neuromodulation of the dorsal root ganglion is a viable treatment for chronic neuropathic pain in difficult anatomic areas. Investigation of long-term DRG stimulation in subjects with a variety of clinical indications is ongoing.