Peripheral nerve stimulation (PNS) is a medical therapy that delivers mild electrical impulses to specific peripheral nerves to alleviate chronic pain. This non-pharmacological solution aims to reduce pain perception and improve quality of life when other treatments have not been successful.
What Peripheral Nerve Stimulation Is
Peripheral nerve stimulation is a neuromodulation technique that targets nerves located outside the brain and spinal cord. This distinguishes PNS from spinal cord stimulation (SCS), where leads are placed near the spinal cord. In PNS, stimulating leads are positioned directly over or near the specific peripheral nerve causing pain.
PNS is a minimally invasive procedure. It involves placing a small electrical device, similar to a pacemaker, near the affected nerve. This method allows for precise pain control in localized areas by focusing on individual nerves.
How Peripheral Nerve Stimulation Works
Peripheral nerve stimulation delivers small electrical impulses directly to targeted peripheral nerves. These impulses interact with nerve fibers, effectively “masking” or “modulating” pain signals before they reach the brain, reducing pain perception.
Many patients experience these electrical impulses as a mild, comfortable tingling sensation, known as paresthesia, which replaces the painful feeling. Some modern PNS systems can even provide therapy without any noticeable sensation. This electrical stimulation is thought to activate large-diameter nerve fibers, which then interfere with the central processing of pain signals in the spinal cord, aligning with the “gate control theory” of pain.
Conditions Addressed by PNS
Peripheral nerve stimulation treats various chronic pain conditions, especially those involving nerve damage or localized neuropathic pain. It is considered when conservative treatments like medication, physical therapy, or injections have not provided sufficient relief. PNS is effective for pain localized to a specific nerve distribution or a focal area involving a few nerves.
Conditions commonly addressed by PNS include neuropathic pain, often described as burning, shooting, or tingling sensations. Examples include diabetic neuropathy, post-surgical pain, and pain from nerve trauma or injury. Complex Regional Pain Syndrome (CRPS), which can affect a limb, is another condition where PNS shows promising results. PNS is also used for occipital neuralgia, which causes severe headaches, and other chronic headaches.
The PNS Procedure and Device
A peripheral nerve stimulation system comprises two main components: a thin, wire-like lead containing electrodes and a compact pulse generator. The electrodes are surgically placed near the specific peripheral nerve, while the pulse generator delivers electrical impulses. Depending on the device, the pulse generator may be external and worn outside the body, or implanted under the skin, similar to a pacemaker.
The treatment process involves a two-stage approach. The first stage is a temporary trial period, lasting several days to about a week, where temporary leads are placed to assess the therapy’s effectiveness. During this trial, the patient controls the stimulation with an external device. If the trial provides significant pain relief, a permanent PNS system is then implanted in a minimally invasive outpatient procedure.
Candidacy for PNS
Individuals considered for peripheral nerve stimulation experience chronic, localized neuropathic pain that has not responded to other non-surgical interventions. These conservative treatments include medications, physical therapy, and nerve blocks. A thorough evaluation by a pain specialist is important to determine if PNS is an appropriate option.
Candidates have pain in a peripheral extremity where other treatments, such as fully implanted spinal cord stimulators, are not suitable or have been ineffective. Factors considered include the pain’s specific origin, like nerve injury or post-surgical pain, and whether it can be traced to a particular nerve distribution. Psychological readiness and commitment to the treatment process are also important for patient selection.