Dorsal root ganglion stimulation is a minimally invasive option to treat intensive pain from causalgia or complex regional pain syndrome. It provides targeted pain relief to lower extremity areas, including the pelvis, groin, hip, knee, ankle, and foot. This specialized, non-opioid technology works by disrupting pain signals that travel between the dorsal root ganglia and the brain.
What is dorsal root ganglion stimulation?
Dorsal root ganglion (DRG) stimulation is a neurostimulation technology that targets and relieves pain at the source. This therapy is similar to traditional spinal cord stimulation (SCS), which has been used safely for decades.
However, spinal cord stimulation doesn’t always work for people with causalgia or complex regional pain syndrome (CRPS). DRG stimulation uses different stimulation targets than SCS. It has proven more effective for pain relief in the lower extremities.
Dorsal root ganglion stimulation uses a small generator device similar to a pacemaker. During an outpatient procedure, a doctor implants under the skin near the buttocks. It delivers mild electrical stimulation through thin, insulated electrical leads to dorsal root ganglia along the spinal column. The stimulation modifies or blocks nerve activity to minimize the sensation of pain reaching the brain.
A dorsal root ganglion stimulator implant lets you directly control its stimulation activity using a small external remote.
What is a dorsal root ganglion?
Each of us has clusters of nerve cells along our spinal column called dorsal root ganglion. Each ganglion acts as a gatekeeper. It transmits sensory information from the peripheral nervous system to the central nervous system.
Research has helped identify which groups of dorsal root ganglia nerve cells control pain signals from specific body areas. Some areas where we can map ganglia include the pelvis, groin, hip, knee, ankle, and foot. This is where some people experience intense causalgia or CRPS pain.
Medical Term Breakdown
The term “ganglia” refers to multiple ganglion structures.
How does a dorsal root ganglion stimulator work?
A dorsal root ganglion (DRG) stimulator system includes a small, implanted pulse generator called a neurostimulator. Stimulation is targeted with small wires, called leads, attached to the DRG stimulator.
During an outpatient procedure, a doctor positions the leads next to the dorsal root ganglia. These dorsal root ganglia map to specific chronic pain locations in the lower body.
The neurostimulator, when activated, delivers tiny electrical pulses through the leads to the dorsal root ganglion. These impulses mask the feeling of pain traveling to the brain.
A patient can control their neurostimulator with an external remote. The remote can turn the device on or off and increase or decrease the stimulation level. It can also activate different custom programs for a specific patient to handle pain.
The DRG neurostimulator does not eliminate what is causing a patient’s pain. But it does change how a patient’s brain perceives the pain.
What does dorsal root ganglion stimulation feel like?
With spinal cord stimulation systems, some users feel light tingling, called paresthesia, when using the device.
However, dorsal root ganglion systems have the advantage of lower required stimulation levels – and precise targeting. This helps DRG system patients avoid, or experience minimized paresthesia. Clinical studies have shown that many users feel nothing and experience pain relief without any tingling.
When did the FDA first authorize dorsal root ganglion stimulation?
Dorsal root ganglion stimulation has been used since February 2016, when the U.S. Food and Drug Administration approved it. The FDA specifically approved it for lower extremity complex regional pain syndrome, types I and II.
Only one manufacturer in the world currently offers this stimulation system.
Who is a good candidate for dorsal root ganglion stimulation?
A good candidate will have neuropathic pain associated with chronic regional pain syndrome (CRPS).
A good candidate will:
- Have had chronic pain from CRPS that has lasted six months or more.
- Have tried conservative treatments for CRPS for at least six months without improvement in their condition.
Individuals who have one of the following conditions are good candidates:
- Neuropathic pain after surgical procedures (causalgia or CRPS II):
- Groin pain after hernia repair.
- Chronic pain after total knee and hip replacements.
- Chronic pain after foot and ankle surgery.
- Pelvic pain after surgery or trauma.
- Phantom pain after lower extremity amputations.
- Causalgia (or CRPS II) pain from a traumatic hip, knee, ankle, or foot injury.
- CRPS I (or reflex sympathetic dystrophy (RSD)) of the lower extremities.
What are the advantages of a dorsal root ganglion stimulator vs. a spinal cord stimulator?
Spinal cord stimulation remains a highly effective therapy to target chronic, severe pain that other medical options cannot manage. However, causalgia or complex regional pain syndrome presents unique treatment challenges that dorsal root ganglion stimulation can better handle.
There are four key advantages of targeting the dorsal root ganglion with neurostimulation for pain relief:
- Specific Body Area Targeting. Dorsal root ganglion stimulation can focus pain relief on a very specific targeted body area. This helps to limit the extraneous tingling sensation throughout the body, known as paresthesia, that spinal cord stimulator users often experience.
- Lower Energy Use. A very thin layer of spinal fluid sits between the leads delivering the stimulation and the dorsal root ganglion cells. Because this layer is so thin, DRG stimulation only requires 1/10th of SCS’s energy requirements. As a result, the DRG stimulator’s batteries last much longer.
- Marginal Likelihood of Lead Migration. Leads are less likely to move because a dorsal root ganglion sits in a tiny space. A clinical study completed in 2016 reported a less than 1 percent migration rate. By comparison, traditional spinal cord stimulation reported a 14 percent migration rate.
- Minimal Body Position Effects. Whether standing, sitting, walking, or lying down, an individual receives the same pain relief and stimulation. In contrast, stimulation for spinal cord stimulation patients varies depending on body position.
Neurostimulation Medical Devices
Dorsal root ganglion (DRG) stimulators are part of a larger class of neurostimulation devices. Additional classses of neurostimulators include spinal cord stimulators (SCS) and peripheral nerve stimulators (PNS).
What are the two stages of the dorsal root ganglion stimulator implant procedure?
After your pain management doctor determines you are a candidate for DRG stimulation therapy, the procedure has two stages.
The first is a trial stage, which is temporary. It helps confirm your experience in how well a DRG neurostimulation system may work for you. This provides first-hand experience with a dorsal root ganglion stimulator before committing to an implanted system.
The second is the surgical implant procedure. You and your doctor will review how well the trial went for you. You’ll then proceed to this next step if you both determine that a permanent DRG neurostimulator is appropriate for you.
How is a dorsal root ganglion stimulation trial procedure performed?
You will normally have a dorsal root ganglion stimulation trial procedure at an outpatient surgery center.
- Temporary Leads Placed. A doctor will place temporary leads near your dorsal root ganglia using a small insertion device. They will numb the area around the insertion using a local anesthetic. The leads are small, flexible, insulated wires.
- Leads Located. The doctor will then apply test stimulation. They will ask you how it feels to determine the best lead locations.
- External Neurostimulator Connected. After the placement of the leads, your doctor will attach them to a temporary neurostimulator outside your body. This device will provide stimulation therapy during the trial.
- Neurostimulator Programmed. Your medical team will configure your trial stimulation device in the recovery room to achieve optimal performance.
How long does a dorsal root ganglion stimulation trial last?
A dorsal root ganglion stimulator trial period can last 5 to 7 days.
- During the trial, you can use an external remote control to relieve pain.
- When you return home, you will have a chance to try things that were difficult to do because of your pain.
- Your doctor will provide instructions on limits for physical activity to prevent the trial leads from dislodging.
- When you shower or bath, you must keep the trial system dry because it isn’t waterproof.
- The benefits of a screening trial may be immediate, or they may take a few days.
After the trial period, a medical professional will remove the trial stimulator leads in a simple office procedure. There then is a waiting period before stage 2.
How is the permanent dorsal root ganglion stimulation surgery performed?
Following a successful trial, you and your doctor will decide if a permanent implant is a good option.
If you decide to proceed, the permanent implant procedure will be similar to a trial procedure. It will normally be performed at an outpatient surgery center or hospital under conscious sedation.
During the surgery, your doctor will place permanent leads in the epidural space near your dorsal root ganglia. They will permanently implant a neurostimulator under the skin in the upper buttock region.
What are the risks associated with a dorsal root ganglion stimulator?
All surgeries have risks, even minimally invasive surgeries.
During the trial, complications can occur, including bleeding into the epidural space, infection, and other side effects. You should not undergo a trial if you have an active infection on the day of the procedure.
Risks for permanent dorsal root stimulator surgery include:
- Experiencing pain at the implant site.
- A loss of the therapy’s effectiveness.
Patients considering a dorsal root ganglion stimulator should discuss all risks with their doctor. Not everyone responds to dorsal root ganglion stimulation similarly, and individual experiences may vary.
What are the benefits of dorsal root ganglion stimulation?
Dorsal root ganglion stimulation therapy can provide CRPS I or II sufferers with long-term pain relief in the lower extremities. It is not a replacement for spinal cord stimulation but is an appropriate alternative in the right clinical situations.
DRG stimulation has a history of success in treating pain in lower extremity areas. It can provide targeted relief in the pelvis, groin, hips, knees, ankles, and feet.
Patients using DRG stimulation also have minimal or no paresthesia due to the proximity of leads to nerve cells.
What happens immediately after a permanent DRG stimulator is implanted?
After the permanent implementation surgery, it may take several weeks to recover. During that time, your doctor will advise you to avoid certain activities. These may include movements that involve lifting, bending, and twisting. The dorsal root ganglion stimulator has specific guidelines that you should discuss with your doctor.
After the procedure, your stimulator will be set up for your specific needs. Your doctor and medical team will also guide you on safely using your stimulator in your daily life.
You can control your dorsal root ganglion stimulator with an external remote. You can turn on or off stimulation, increase or decrease intensity levels, and switch between different programs to alleviate pain.
When should you call your doctor after the procedure?
In general, you should contact your doctor if:
- You have pain around the implant that lasts longer than two weeks.
- You notice significant redness around your wound areas. In this case, your doctor must check for infection or, in rare cases, a reaction to the implant.
- You plan to make major lifestyle changes due to having better control over your pain.
- You notice that the stimulator stops working. In this case, you should turn the device off before contacting your doctor.
Can you drive or operate heavy machinery if you have a dorsal root ganglion stimulator?
It’s important not to operate automobiles, motorized vehicles, or any heavy machinery with a neurostimulator turned on. It would be best if you switched it off in these situations. Sudden stimulation activity can potentially distract you from the safe operation of the vehicle or equipment.
Can you use advanced diagnostic imaging with a dorsal root ganglion stimulator?
You may get X-rays or a CT scan with a dorsal root ganglion stimulator if powered off. Before undergoing an imaging scan, it is important to inform your doctor, nurse, or technician about your dorsal root ganglion stimulator. You should follow any instructions that they provide you.
However, you must be careful about magnetic resonance imaging (MRI) scans. DRG patients should consult their pain management doctor and device manufacturer before considering an MRI scan. Patients must be cautious about opening themselves to the potential for injury or damage to the device.
Can a dorsal root ganglion stimulator be removed?
Your doctor can safely remove your DRG stimulator surgically. The most common reason for removal is inadequate pain relief. This decision may come after years of living with the device.
Some issues may occur over time, requiring additional surgical procedures to correct. Although unlikely, the leads may move from where your doctor originally positioned them. This can reduce the effectiveness of the device in controlling pain.
A lead or the implanted neurostimulator may break. This could be the result of a fall or other trauma. Or in rare cases, there could be a malfunction with the device.
You should discuss your options with your pain specialist to surgically address these situations.