Neuromodulation includes treatments that involve stimulation or administration of medications directly to the body’s nervous system for therapeutic purposes. The target cells for stimulation include nerves in the central and peripheral nervous systems, the autonomic nervous system, and the deep cell nuclei of the brain, resulting in modulation of their activity. Neuromodulation includes several modalities, and is a cross-disciplinary approach to pain control and neurologic dysfunction. Neuromodulation can be used to treat movement disorders, spasticity, and epilepsy, as well as pain syndromes.
Devices are implanted which can either include drug delivery pumps or neural stimulators. The most common type is spinal cord stimulation, which is used for back or lower extremity pain.
Spinal Cord Stimulation
Spinal cord stimulation (SCS) involves electrical stimulation of the spinal cord to interrupt pain signals from the spinal cord to the brain, and to trade a painful sensation with a more pleasant tingling sensation. The technology has been present since the 1960s and in the past decade has become highly effective in the treatment of pain. A device consisting of electrical leads, implanted battery, and a remote programmer, delivers electrical current in therapeutic doses to the spinal cord, for relief of neuropathic pain. It can be thought of as a pacemaker for the spine, and can often lead to pain relief with less pain medication. The main advantage lies in the ability to treat pain without relying on medications, therefore limiting side effects. The other great advantage of spinal cord stimulation is in the ability to trial the system, with temporary external leads and battery, allowing for determining pain relief with permanent consequences.
It is a proven safe and effective therapeutic approach for managing chronic pain of the neck, back, arms and legs, often after spine surgery, or for other neuropathic conditions. Advances are also being made in the treatment of pelvic pain, non-cardiac chest/angina pain, and chronic abdominal pain not due to inflammatory bowel disease. Finally, studies are showing improved blood flow following spinal cord stimulation for patients with peripheral vascular disease.
Unlike most interventional therapies, spinal cord stimulators can be placed on a trial basis, allowing you to simulate with pain relief would be like in your own home for 5-7 days with the use of temporary stimulator. This is often how most patients who qualify for the procedure determine whether to undergo the permanent implantation.
Benefits of SCS may include:
- Significant and sustained reduction in back and extremity pain
- Improved ability to function and participate in activities of daily living
- Less oral pain medications
- Reversible and nondestructive, since the therapy can be turned off or surgically removed
- Ability to adjust the therapy based on pain level
- With improvements in a person’s pain, the potential ability to participate in other forms of therapy to better help manage the pain
Deep Brain and Cortical Stimulation
Another type of neuromodulator uses deep brain stimulation, delivering electrical current to the deep nuclei of the brain, to treat diseases that include Parkinson’s and other movement disorders. Deep brain stimulation is currently utilized as a cutting edge treatment for epilepsy.
Cortical stimulation is used frequently in the treatment of epilepsy, and is also used to treat various types of pain syndromes, including neuropathic pain. Peripheral nerve stimulation, also used to treat epilepsy, is now being used to treat neuropathic neck pain and regions of local pain.
Intrathecal Drug Delivery
Drug delivery devices, the second class of neuromodulator treatments, include implantable pumps, which are able to deliver pain medication to a specific target, thus allowing a lower dosage and decreased systemic side effects. Intrathecal implants are pumps, which store and deliver medication through a catheter into the intrathecal space around the spinal cord. Before implanting an intrathecal pump, a trial intrathecal injection is performed to test the efficacy of the medication, which might be an opioid like morphine, or a muscle relaxant such as baclofen.
Intractable pain from cancer and other neuropathic conditions may often only receive limited relief with standard medication therapy. This may be due to medication side effects caused by the nature of the drug or opioid, or the limitation of higher doses causing sedation, nausea, and vomiting. To provide equivalent effects on pain, roughly 300mg of morphine would need to be given for 1mg of Intrathecal morphine.
An improvement in pain with a reduction in dose can be achieved through an intrathecal drug delivery pump, which provides medication directly from a pump implanted under the skin in your abdominal area, to the spinal fluid. This medication can last on average about 2-3 months, and can be refilled easily in the pain clinic.
A pump can help lessen chronic pain caused by:
- Failed back surgery syndrome: failure of one or more surgeries to control persistent leg pain (sciatica), but not technical failure of the original procedure.
- Cancer pain: constant pain caused by tumors compressing the spinal nerves, or scarring from previous radiation therapy.
- Complex Regional Pain Syndrome a progressive disease of the nervous system in which patients feel constant chronic burning pain.
- Peripheral neuropathy
A pump can help lessen spasticity (muscle rigidity and spasms that make movement of the arms and legs difficult) caused by:
- Cerebral palsy: a nervous disorder that impairs control of body movement.
- Multiple sclerosis: a disorder of the brain and spinal cord caused by damage to the outer layer (myelin) of nerve cells.
- Stroke: damage to the brain from lack of oxygen; due to an interruption of the blood supply.
- Brain injury
- Spinal cord injury
Transcutaneous electrical nerve stimulation is a non-invasive and drug free method of pain control, using a device with electrodes attached to the skin. There is some evidence that there is a benefit to TENS in reduction of chronic musculoskeletal pain, and may be useful in diabetic neuropathy. There is evidence to support the claim that TENS modulates or suppresses pain signals is the brain.
Electrical muscle stimulation is another form of neuromodulation, which has been thoroughly researched and is widely accepted in the rehabilitation field for pain management, treatment of neuromuscular dysfunction, tissue repair, improvement of joint range mobility, blood flow, and absorption of edema.
Treatments at Weill Cornell Pain Medicine
Our neuromodulation team, which includes specialized physicians and researchers from the Pain Medicine and Neurosurgery departments, is one of the largest and busiest in New York City.
We currently perform deep brain stimulation for treatment of Parkinson’s disease, essential tremor, dystonia, and refractory complex regional pain syndrome.
We also perform spinal cord stimulation for treating patients with failed back syndrome, radicular pain syndrome, post-laminectomy pain, peripheral neuropathy and complex regional pain syndrome.
Furthermore, advance intrathecal delivery systems are implanted for relief from cancer and neuropathic pain, and in the treatment of spasticity.
Currently, several research endeavors are underway to develop future neuromodulation procedures and applications. Our experts are hopeful that neuromodulation will continue to help bring relief, hope and increased function to patients with a variety of debilitating diseases and conditions.