If oral medications and other strategies have not sufficiently relieved neuropathic pain, and surgery has been ruled out, implantable pain management systems may be an option.
Three therapies—spinal cord stimulation, peripheral nerve stimulation, and pain pumps—reduce pain without extensive surgery. Each therapy is provided on a trial basis first. After the trial period, the person decides whether to use the therapy over the long term.
Implantable pain management does not work for everyone, but when it is successful, people experience significant advances in daily functioning.
Spinal Cord Stimulation and Peripheral Nerve Stimulation to Ease Pain
Spinal cord stimulation therapy and peripheral nerve field stimulation are related types of electrical stimulation that treat chronic pain. Mild electrical pulses are directed to disrupt pain messages to the brain, reducing the feeling of pain.
To begin spinal cord stimulation, thin insulated wires called leads are equipped with electrical contacts and inserted into the space surrounding the spinal cord. In peripheral nerve field therapy, the leads are placed just under the skin. In both types of stimulation, a small implanted generator sends the electrical pulses and is attached by a wire to the leads. (During the trial period, an exterior generator is used.)
The patient is awakened during implantation surgery to provide feedback on where the pulses should be directed to relieve pain. Some patients have both spinal cord stimulation and peripheral nerve field therapy at the same time.
Stimulation therapy does not eliminate all the pain, but pain is reduced by at least half for the majority of patients, leading to a major improvement in daily activities.1
Disadvantages and Risks
Device-related problems are fairly common, and there is a small risk of infection. Serious complications, such as a hemorrhage or neurological damage—including paralysis—are rare.
The other drawback is that spinal cord stimulation does not relieve pain for everyone who uses it. About 50% to 60% of people using a low-frequency system and 80% or more of those using a newer high-frequency system achieve major relief.2,3
Intrathecal Pain Pump
Medication is delivered directly to the spinal cord when an intrathecal pain pump is implanted. Sending medication to the pain receptors near the spine interrupts pain signals to the brain, easing the perception of pain.
To begin the procedure, the person is placed under local or general anesthesia. A thin tube, or catheter, is inserted into the fluid-filled area around the spinal cord known as the intrathecal space. A small pump is implanted in the front of the body, usually in the abdomen, and the pump and catheter are attached.
Medication is injected into a reservoir in the pump by the doctor, then sent by the pump through the catheter. Morphine (brand names MS Contin, Kadian, and others) is one medication often administered with a pain pump. The doctor fills the reservoir with medication during implantation, and then refills it about once a month through an injection in the doctor’s office. Pumps can be programmed to suit individual preferences on timing of the prescribed medication. The option for round-the-clock medication is a major advantage of the pain pump.
More than one medication can be added to the pump, if needed. This could include an opioid (also called a narcotic) another pain medication, or a local anesthetic to treat neuropathic pain. The opioids morphine, ziconotide, and baclofen are approved by the U.S. Food and Drug Administration for continuous delivery, but other medications are also used.
By targeting delivery of the medication, a much lower dose can be used, reducing side effects. While pain pumps cannot eliminate pain entirely, they may offer significant pain relief that leads to improved day-to-day functioning. Many people are able to reduce their reliance on other medications when they use a pain pump.
As with spinal cord stimulation and peripheral nerve field therapy, the individual undergoes a trial period before using the therapy long term. The pain pump can be removed at any time.
Disadvantages and RisksReactions to medications are the most common complication with pain pumps, followed by problems with the catheter used. Less common risks include, but are not limited to, infections, spinal damage, development of a granuloma—an inflammation of tissue—at the end of the catheter, and death.
Implantable pain relief can be considered for those in severe pain who have not had success with medications and other treatments.