In 2018, the International Neuromodulation Society (INS) project on Consensus Conferences published “The Neuromodulation Appropriateness Consensus Committee on Best Practices for Dorsal Root Ganglion Stimulation”. This paper, published in the journal Neuromodulation, has a goal of improving safety and efficacy for those implanting dorsal root ganglion (DRG) stimulation devices. Lead author, Timothy Deer, past president of INS and chairman of the American Society of Pain and Neuroscience, now provides the top ten takeaways of the publication.
The INS has a long history of creating consensus statements and best practice recommendations based on a careful analysis of the peer reviewed literature, expert opinion, and ongoing research. These guidelines began in 2000 with the first analysis of the field of intrathecal drug delivery and evolved into recommendations for neurostimulation for the treatment of pain. In the many years of creating this practice guidance the consensus conference has evolved with increasing vigor and careful scoring of information including data analysis and scoring tables.
The creation of a new guidance is prompted by the interval need to update the field, or new therapies that are in need of guidance. In 2018 the INS sponsored a best practice evaluation of dorsal root ganglion stimulation. Several key points were presented in these findings. Ten important points are summarised here:
- The NACC (Neuromodulation Appropriateness Consensus Committee) was created to bring key opinion leaders across the globe to provide direction for the safe and effective application for neuromodulation therapies for the larger global medical community. This publication is the first time this detailed process has been applied to DRG stimulation. This project was funded by the INS and overseen by the INS consensus committee.
- Best practice guidelines where created for DRG stimulation using extensive literature review of current research, clinical experience of Neuromodulation experts, and majority consensus on key procedural and clinical applications.
- Spinal cord stimulation (SCS) is a well-established treatment modality for chronic neuropathic pain. DRG stimulation is a form of spinal stimulation in which targeted nerves are stimulated to treat various focal neuropathic pain states. Being a significant modification of the existing SCS technique, physicians incorporating this therapy have had to seek additional training and guidance to incorporate DRG stimulation safely and effectively. This publication is a way to set current best practices for this relatively new and advanced therapy.
- There is a great deal more variability in the way DRG stimulation can be performed from a procedural standpoint as compared to traditional SCS. This manuscript makes graded recommendations on the various technical aspects of the procedure in an attempt to standardise the treatment and improve efficacy and safety.
- Another significant difference between DRG stimulation and traditional SCS is the variability of stimulation targets. In traditional SCS, the operator will place one to two leads at or around the T-8 to T12 level. In DRG stimulation, the operator can use up to four leads which can theoretically be placed at any level in the spine that contains a DRG. The manuscript defined which levels are optimal for different body parts or pain syndromes to help demystify how to best utilise DRG stimulation.
- The manuscript illustrated the high of evidence available in the literature that supports the use of DRG stimulation. The ACCURATE study alone had 152 patients with Level 1 evidence supporting DRG stimulation. This US IDE study was funded by the manufacturer and overseen by the US Food and Drug Administration (FDA). When one takes into account all of the available publications on DRG stimulation, there several hundred patients with the majority of these publications being completed without industry funding. The real world experience has largely matched the original IDE pivotal study.
- The indications for which DRG stimulation has been reported in the literature varies considerably (i.e. pain after total knee arthroplasty and pelvic pain to post-surgical chest well pain and phantom limb pain). This manuscript also evaluated all of the currently available evidence and graded it in an effort to help implanting physicians improve their outcomes by knowing which indications have the most/best evidence.
- The manuscript highlighted a number of physician-initiated studies like the DRG FOCUS study that showed the “real world” efficacy of DRG stimulation and was completed without any industry funding. These physician led studies are important for evaluating how patients potentially will respond in a clinical setting.
- New publications have been important to show how effective DRG stimulation as compared to traditional SCS, and also presents statistics on safety and the overall lower incidence of adverse events like loss of efficacy and lead migration. The safety profile of DRG is statistically the same as conventional SCS but the overall efficacy in most studies are showing improved efficacy.
- The manuscript called for additional evolution in the therapy including new product development for leads, sheaths, and battery technology. The need for a DRG paddle lead to treat complex patients is highlighted with recommendations of possible therapy growth for those who currently are not appropriately treated with current technology. In addition, the authors felt new options for hybrid systems that could allow for both spinal cord and DRG stimulation could be important for future advances.
The need for continued updates in the area of implantable devices is very important. The Consensus process will continue going forward with a focus on patient safety and efficacy. Readers should continue to survey the journal Neuromodulation for upcoming peer reviewed updates in this important manuscript series.
Timothy Deer is the president and CEO of the Spine and Nerve Center of the Virginias in Charleston, USA and chairman of the American Society of Pain and Neuroscience.