Dorsal Root Ganglion (DRG) Stimulation
What Is DRG stimulation?
DRG or dorsal root ganglion is also known as posterior root ganglion is a bundle of sensory nerve cell bodies within the epidural space. The dorsal root ganglion carries sensory neural signals from the peripheral nervous system to the central nervous system, which includes the spinal cord It is an easily accessible structure in the spine that plays a key role in the development and management of chronic neuropathic pain
Injury or irritation of the dorsal root ganglion can lead to intractable symptoms of neuropathic pain that may or may not respond to typical treatments. This can lead to additional complications in the form of impairment in functioning for the individual spinal cord stimulation.
Applying stimulation to the DRG allows treating specific areas of the body with pain hence targeting specific focal area. Easy accessibility of DRG makes it a perfect target for treating chronic neuropathic pain that is not treated with traditional spinal cord stimulation, such as the hand, chest, abdomen, foot, knee or groin pains.
What is the mechanism of DRG stimulation?
Dorsal root ganglion stimulation works by blocking the transmission of pain. As every sensation passes through dorsal root ganglion, the signal of pain to the spinal cord and brain is interrupted. Stimulating the nerve bundles with low-intensity electrical impulses is also believed to reduce pain by replacing the sensation with a pleasant tingling sensation, known as paresthesia.
What is a DRG stimulation system made up of?
The system consists of three components:
Electrodes: These are a straight insulated wire with a curve on the tip to fit around the DRG. There are four electrical contacts near the tip to deliver the electrical pulses. The wire is passed into the spine through a large hollow needle. Up to four wires can be connected to one IPG so up to four DRGs can be stimulated, each with its own wire.
An implantable pulse generator (IPG): It is a small box that contains a battery and circuitry to produce the stimulus current:. If the electrode is being put in the lower back (e.g. for leg pain) the IPG is usually implanted under the skin of the abdomen (tummy). If the electrode is being put in the spine in the neck (e.g. for arm pain) the IPG may be implanted under the skin below the collar bone.
Programmer: It is a handheld device that is given to the patient to adjust the stimulator to control pain.
Risks associated with DRG stimulation
As with every surgical procedure, there are risks involved with dorsal root ganglion neuromodulation. Though very little is known about the consequences of injecting pain relieving medication within the dorsal root ganglion or the spinal cord, neuromodulation of the neural tissue within this area is believed to be safe and completely reversible. The procedure itself for implanting the device is regarded as safe and conducted in such a way as to avoid inflammation or additional pain to the individual. In fact, many may return to normal activities of daily function within several days.
Risks associated with the condition are considered to be mild in nature and generally include minor bleeding at the site of the injections, infection, neural injury, and local anesthetic systemic toxicity. Individuals may also have a reaction to the medication used during the procedure.
How is a DRG stimulator inserted?
The procedure is carried under local anesthesia. When the skin has been numbed, a needle is passed into the space near the DRG and the electrical lead is fed through it and guided into place using Xrays.
Since the patient is awake, the effect of stimulation can be tested via the lead straight away. If the patient feels the tingling sensation, the procedure is completed by making a small incision around 3 cm nearby to allow placement of an implantable pulse generator under the skin and connecting the lead to it. If the test stimulation doesn’t give a definitive effect on the patient’s pain, a temporary extension wire is attached to the lead which is then brought out through the skin so that it can be tested for a few days using an external stimulator, before deciding whether the system is working well enough to complete.
How DRG stimulation Works?
DRG Stimulation is a more advanced and refined version of traditional spinal cord stimulation. Instead of positioning the leads over the posterior aspect of the spinal cord, smaller and more precise leads are placed over the dorsal root ganglion itself. Specifically, it is placed on the ganglia residing in the lumbar and sacral regions of the spine. This allows for greater and more targeted control of pain in the lower limbs.
-Largest study to date concerning lower limb pain associated with CRPS (ACCURATE Study), patients reported that the DRG Stimulator gave them significantly greater pain relief than SCS
-No changes in paresthesia intensity (pins and needles sensation) when changing body position as compared to SCS
-A more precise and targeted area of administration i.e. no feeling of electrical stimulation outside their area of pain
Indications for getting a DRG stimulator:
Dorsal root ganglion is now being preferred over spinal cord stimulation. Patients trialed with DRG stimulation have a greatly improved chance of success with much better pain relief.
In addition to CRPS, DRG stimulation can also treat:
- Discogenic pain due to degenerative disc disease
- Post-herpetic neuralgia
- Phantom limb pain
- Groin pain after a hernia repair (post-herniorrhaphy neuralgia)
- Lumbar radiculopathy
- Foot pain
- Neuropathic pain due to peripheral neuropathy
- Neuropathic chest wall pain
- Lumbar stenosis
- Chronic postsurgical pain
Reviews from our patient that got DRG stimulator
Dorsal root ganglion stimulation is a procedure for providing relief from symptoms of chronic pain resulting from a neural injury. This interventional approach is regarded as a relatively safe and effective procedure, with a low risk for side effects. The dorsal root ganglion is considered an ideal target for delivering pain relief because of a more targeted approach. Also dorsal root ganglion requires less neuronal stimulation to alter pain hence the devices for this treatment can work for a long time.
Another benefit of dorsal root ganglion stimulation is that the dorsal root ganglion lacks the protective capsular membrane that is found on other peripheral nerve fascicles. It has a permeable connective tissue, making it an ideal target for the application of neuromodulation.
The Food & Drug Administration (FDA) just granted approval to DRG Stimulation for use within the U.S. as of February 2016 for the treatment of CRPS. Currently, the only device capable of DRG Stimulation is called the Axium which is available. Our site in Fort Lauderdale is the first site in Florida to implant the DRG stimulator.