Peripheral nerve stimulators

Peripheral nerves are the nerves outside the spine and brain, running to your back muscles, shoulders, arms, legs and head. When one keeps sending pain signals, gentle electrical pulses near that nerve can change the signal so less pain reaches the brain. This is peripheral nerve stimulation (PNS).

Unlike a spinal cord stimulator, which works at the spinal cord, PNS works right at the nerve that serves the painful area. It is usually used for pain in one region, such as one shoulder, one knee or one side of the lower back.

On ultrasound, the nerve looks like a small honeycomb-shaped oval, and the needle appears as a bright line approaching it. On X-ray, the thin lead shows up as a fine white coil.

PNS can be tried when medicines, physical therapy or injections have not helped enough, and it is appealing to people who want to avoid more medicines or surgery. It is also an option for people who are not candidates for a spinal cord stimulator.

Other options include nerve blocks, genicular nerve ablation for knee pain and epidural steroid injections for pain from the spine.

1. 1
   Mapping the target

   You lie in a comfortable position. The doctor uses ultrasound or X-ray to find the nerve that serves the painful area, then cleans and numbs the skin.

2. 2
   Testing

   A thin needle is guided near the nerve. A mild test current is turned on, and you tell the doctor when you feel a comfortable tingling or muscle pulsing over your painful area.

3. 3
   Placing the lead

   The lead is released through the needle, and the needle is removed. The lead's tiny coil anchors it in the tissue. Sometimes a second lead is placed.

4. 4
   Connecting the device

   The lead exits the skin and is covered with a clear bandage. A small stimulator is clipped or stuck onto the skin nearby, programmed, and you are shown how to use it.

The procedure usually takes 30 to 60 minutes, and you go home shortly afterward. Implanted systems may need a small incision and take a little longer.

1. First few days
   Mild soreness where the lead enters the skin. Start using the stimulator as instructed, often for several hours a day or around the clock.
2. Weeks 1 to 8
   Keep the bandage clean and dry. Sponge bathe, or cover the site carefully for a quick shower if you are told you can. No baths, hot tubs or swimming. Change batteries or charge the device as shown, and keep a pain log.
3. Around day 60
   Clinic visit to remove the lead. The bandage is lifted and the lead is gently pulled out in seconds. A small bandage covers the spot.
4. Months after
   Follow-up to see whether relief has lasted. If pain returns after a treatment that worked, repeating it or an implanted system may be discussed.

In published studies of the 60-day system, many people with chronic back, shoulder or post-amputation pain had at least 50% less pain during treatment, and a good number still had meaningful relief months after the lead was removed. Results vary, and not everyone responds.

I like peripheral nerve stimulation for people whose pain lives in one clear area and who would rather not add another medicine. I use ultrasound to see the nerve directly, and during placement I ask you where you feel the tingling so we can match it to your pain. I tell patients that the temporary system is a real treatment, not just a test, and that the goal is relief that outlasts the wire.

Fabio Komlos, MD, interventional radiologist · About Dr. Fabio Komlos