In an earlier article we considered Dorsal Root Ganglion (DRG) Stimulation and how it was gaining momentum as an alternative to Spinal Cord Stimulation (SCS) in the long term management of chronic pain.
What is Dorsal Root Ganglion Stimulation?
The Dorsal Root Ganglion is a branch nerve of the spinal cord and, just like a traffic light, it can regulate pain signals before they enter the spinal cord and travel to the brain.
In the more traditional SCS, leads are placed in the epidural space behind the spinal cord, further from the nerves. Conversely, the DRG is very accessible and this means that when implanting a DRG Stimulator, smaller leads can be placed much closer to the target nerves allowing the system to better focus the stimulation on the areas where pain is felt. This includes areas where traditional SCS has struggled, such as the lower leg and foot.
In one clinical trial in the US which mostly involved people suffering CRPS, it was found that at one year following implantation of a DRG Stimulator, 74% of participants reported greater than 50% pain relief. One third reported pain relief of 80% or more.
Side effects of SCS
A major side-effect of SCS is paresthesia, which often manifests as tingling, burning, or prickling sensations, particularly when changing body position. Whilst some newer models of SCS are able to deliver pain relief without paresthesia, those receiving DRG Stimulators are less likely to experience this effect in any event.
The reason why paresthesia is prevalent following SCS comes down to the combined effects of gravity and the highly conductive properties of cerebrospinal fluid. However, because the cerebrospinal fluid near the DRG is relatively thin, the incidence of paresthesia is substantially less.
In addition to greater pain relief and less paresthesia, studies have shown that patients receiving DRG Stimulators reported both less discomfort and improved mood scores at 12 months post-implantation than those receiving SCS.
So, are DRG Stimulators the way forward?
Whilst early results have been promising, DRG Stimulation remains a relatively novel technique and consequently there is currently only limited data regarding its long term efficacy and possible long term side effects. Indeed, whilst it has been available in other countries for a little longer, in the huge US market the FDA only approved the technique in early 2016.
Manufacturers and the medical profession are cautiously suggesting that if pain relief is achieved by DRG Stimulation, this is likely to persist for ‘some years’. Beyond that, they just don’t know.
As to whether DRG Stimulation is currently an option for you may simply come down to where you are receiving treatment. In the UK a number centres are now offering DRG Stimulation, including the Walton Centre in Liverpool and Oxford University Hospitals. It is also increasingly available privately, for example, at the Harley Street Clinic.
Ultimately, given the significantly greater volume of data available, as well as more widespread familiarity with the technique, it is unlikely that DRG Stimulation will surpass SCS any time soon. However, as DRG Stimulation becomes more widely available, patient choice, albeit guided by those treating them, is likely to be the determining factor in the DRG versus SCS debate.
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