What is a Peripheral Nerve?
Your body’s nervous system is made up of your brain, spinal cord, and peripheral nerves. The peripheral nerves are the nerves that extend beyond your brain and spinal cord to your organs and extremities—all the way to your fingertips and toes. Peripheral, by definition, means “on the edge” or “outer part” of something.
How does peripheral nerve stimulation work?
Peripheral nerve stimulation (PNS) targets the nerve(s) that transmit pain signals to your brain. This treatment involves a small surgical procedure that places a tiny electrical device (a wire-like electrode) next to a peripheral nerve. The electrode delivers rapid electrical pulses that are felt like mild tingling. Peripheral nerve simulators work much like spinal cord simulators, except that the mild electrical currents are sent directly to the peripheral nerves outside of the spinal cord.
These impulses change the way your brain perceives pain. The electrical pulses interrupt or change the pain signals sent from the nerve to the brain.
PNS was invented in the mid-1960s, even before the commonly used spinal cord stimulation. Starting in 2012, a number of therapeutic devices that stimulate peripheral nerves or that provide peripheral nerve field stimulation received regulatory approval in a number of regions around the world for the treatment of neuropathic pain and, in some geographic areas, for the treatment of migraine headaches and overactive bladder.
The devices and their protocols differ, but each has three basic components:
- A battery or power source
- A thin wire connected to electrodes that deliver the pulses to the peripheral nerve
- A remote control-type device that allows the patient to adjust the pulse settings.
In appropriate candidates, PNS is covered by Medicare and the majority of private insurance companies.
What types of pain does peripheral nerve stimulation treat?
PNS can treat pain from head to toe, as shown in the picture above, including these conditions:
- Complex regional pain syndrome (CRPS, RSD)
- Peripheral neuropathy
- Foot, ankle, knee, and shoulder pain, especially following surgeries or if surgery is not an option
- Headache disorders, including occipital neuralgia
- Ilioinguinal neuralgia (pain in the lower abdomen and upper thigh)
- Intercostal neuralgia (pain in the chest wall and upper trunk)
- Lateral femoral cutaneous neuropathy (pain in the outer thigh)
- Pain following hernia surgery surgery
- Painful nerve injuries
- Post-amputation (stump) pain or phantom limb pain
- Postherpetic neuralgia (burning pain caused by shingles)
- Post-thoracotomy syndrome (pain persists along a thoracotomy incision)
- Trigeminal neuralgia (pain in the face)
What is the procedure like?
During the testing period (trial), the electrode is connected to an external device, and if the trial is successful, a small generator is implanted into the patient’s body. Similar to heart pacemakers, electricity is delivered from the generator to the nerve or nerves using one or several electrodes.
The patient is able to control stimulation by turning the device on and off and adjusting stimulation parameters as needed. If the test is successful, as determined by the physician and the patient at the conclusion of the testing period, which usually runs for 1 week, the patient can receive an implant.
The implantation is conducted as an outpatient procedure that takes about 1 hour.
Because the implant is so small, it can be implanted nearly painlessly. You will be sedated during the procedure. The clinician will use a local anesthetic on your skin and make a small incision or use a small needle to insert the device wire under your skin near the targeted nerve.
What happens after the PNS device is implanted?
You will receive thorough instructions about operating the device. You may receive special instructions about going through airport security or having an MRI.
The PNS devices are patient-friendly since you don’t have to wear the external parts of the device all the time, just when you are hurting. Patients can remove external parts to bathe, shower, and swim.
Complications are rare with PNS and are usually limited to superficial skin infection. With new devices, the implant stays in place, and “lead migration,” in which the lead wires move, is rare. Device programming appointments may be needed a few times a year.
A patient can live with a PNS implant forever, but importantly, the device can be removed if it doesn’t relieve their pain. Patients like the idea that this treatment can be reversible, unlike major surgery.
Overall, PNS can be a good fit for patients who want to get off pain medications or avoid surgery.
