Peripheral Nerve Stimulation

Peripheral nerve stimulation is a minimally invasive treatment for chronic pain caused by peripheral nerve damage.

The peripheral nerves connect your brain and spinal cord with the rest of the body. Pain arises from the signals produced by a nerve when it is stimulated by tissue damage or when the nerve itself is damaged (neuropathic pain).

Peripheral nerve stimulation involves stimulation of the affected nerves using electrical impulses generated by a small electrical device (a wire-like electrode) implanted in your body. This interrupts the transmission of pain signals so that, instead of pain, you experience a mild tingling.

Anatomy

The nervous system consists of the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS comprises the brain and spinal cord, while the PNS is made up of nerves that carry information to and from the brain to the rest of the body. There are three types of nerves that are included in the PNS: Autonomic nerves that control blood pressure, bladder functions and sweat levels; motor nerves that control the muscles; and sensory nerves that transfer sensations like cold, heat or pain to the brain.

Indications

Your physician may recommend peripheral nerve stimulation when pain becomes chronic, and medications and therapy are not helping in easing the pain. Peripheral nerve stimulation can be used to treat a number of painful conditions, such as:

• Peripheral neuropathy
• Complex regional pain syndrome (CRPS)
• Trigeminal neuralgia (pain in the face)
• Intercostal neuralgia (pain in the chest wall and upper trunk)
• Ilioinguinal neuralgia (pain in the lower abdomen and upper thigh)
• Occipital neuralgia (a rare type of chronic headache disorder)
• Low back pain
• Neck pain
• Nerve injuries
• Migraine and other headache syndromes
• Post-amputation pain syndrome
• Diabetic peripheral neuropathy

Preparation

In general, preparation for peripheral nerve stimulation may involve the following:

• Your doctor will perform a neuropsychological examination and provide you with some pain charts to get a better understanding of your pain and to plan the procedure. The charts include a pain diary which should be filled out over a week.
• You should inform your doctor if you are or might be pregnant, have had any previous health conditions, are taking any blood-thinning medications such as aspirin, or are allergic to any medications or anesthesia.
• Do not stop taking your regular medications until instructed by your doctor.
• Arrange for someone to drive you home after the procedure.

Surgical procedure

The procedure for peripheral nerve stimulation is performed in 2 steps that include the following:

Step 1  (Electrode Implantation)

This first step is a trial period to determine if the therapy is effective in treating your chronic pain prior to implanting the device permanently. It involves placement of a stimulating electrode in close proximity to peripheral nerves in order to control pain.

• You will be instructed to lie down on the procedure table and anesthesia will be injected to numb the site of insertion.
• A small incision will be made.
• Through the incision, one or two electrodes (wires) are inserted and fixed along the targeted nerves.
• The electrode wires are connected to an external stimulator which you can control to produce the impulses.
• Following insertion of the electrodes, you will be kept under observation in the recovery room and can return home the same day.
• The trial lasts for about a week, and if you have significant pain relief and are happy with the results, the second step is performed. The trial also helps your doctor determine the right amount of stimulation for ideal pain relief.

Step 2  (Battery Insertion)

This step will be performed a few days or weeks after a successful trial.

• During this procedure, anesthesia will be administered, and the temporary external wires will be removed.
• Wires running under the skin are attached from the electrodes to a battery-operated internal stimulator implanted under your skin and programmed to deliver the determined level of stimulation. The internal stimulator is usually placed in the upper buttock, chest wall, or under the arm.

Post-Procedure care

After the peripheral nerve stimulation procedure, you will be kept under observation for a few hours and discharged when you are deemed stable. On discharge, you will receive post-care instructions, and will be informed about certain restrictions such as avoiding metal detectors at airports. Avoid strenuous activity for at least 6 weeks. You may do gentle exercise such as walking every day. Your incision site should be kept dry and should heal within 2 weeks, at which time you will have a follow-up appointment.

Risks and Complications

As with any procedure, there may be certain risks and complications associated with the peripheral nerve stimulation procedure, which include:

• Nerve damage
• Pain
• Scar tissue formation
• Infection
• Bleeding
• Muscle cramps
• Malfunctioning of the stimulator or damage to the leads (electrical connection)

Summary

Peripheral nerve stimulation, frequently referred to as PNS, is a commonly employed approach to treat chronic pain. It is an extremely safe procedure that is performed under local anesthesia on an outpatient basis. PNS has been noted to be effective in up to 70% of the individuals selected for treatment.