Form of spinal cord stimulation avoids disruptive side effects
By Elizabeth Crown
Ask anyone with chronic back or leg pain to describe its impact, and you’ll learn that the pain interferes with every aspect of life — work, relationships, everyday tasks — and that its toll is devastating.
Chronic back pain and leg pain, defined as pain lasting longer than three months, are leading causes of doctor visits in the United States, according to the National Institutes of Health. According to the NIH, there are 70 possible causes of chronic back pain, which range from minor causes such as musculoskeletal strain to more serious conditions including degenerative disc disease, disc herniation, lumbar spondylosis and spinal stenosis. These forms of chronic pain cost our society billions of dollars in lost productivity, health care expenses and disability compensation.
Persistent back and leg pain, like some other forms of chronic pain, often are resistant to traditional therapies, including surgery and low-frequency spinal cord stimulation, known as SCS. An SCS system delivers electrical pulses (typically 40 to 60 hertz) via electrodes implanted in the spine, causing paresthesia, a tingling or buzzing sensation, to mask a patient’s perception of pain.
Conventional SCS has drawbacks: Patients must be awakened during the implantation procedure to report the location of paresthesia relative to the area of pain. Many patients also dislike the tingling, which may prevent sleep and interfere with everyday functions like driving.
“There is a substantial clinical need for improved treatment for chronic pain,” says Adam C. Young, MD, assistant professor of anesthesiology and pain medicine at Rush University Medical Center.
Young and Sandeep D. Amin, MD, assistant professor of anesthesiology and medical director of the University Pain Center at Rush Oak Park Hospital, were among the first interventional pain specialists in the Chicago area to treat patients with an advanced SCS therapy called Nevro Senza. They began using the system in research trials in April of 2015 and more broadly when the U.S. Food and Drug Administration approved it the following month. Rush currently is one of about a half dozen sites in the greater Chicago area offering Senza, compared to more than 100 providing traditional SCS treatment.
Increasing the frequency of relief
The Senza SCS system delivers high-frequency electrical pulses to the spinal cord at a rate of up to 10,000 hertz per second via small electrodes that are placed near the spinal cord and connected to a compact, battery-powered generator implanted under the skin. The Senza system uses a rechargeable battery.
The patented Senza therapy also differs from traditional SCS, in that it provides back and leg pain relief without paresthesia, thus eliminating the need to awaken patients during the implantation.
Besides liberating the patient from persistent tingling or buzzing, Senza does not cause the jolts and shocks traditional SCS patients may experience during positional changes, such as standing up, sitting down or bending over. This feature allows the system to limit sleep disturbances. In addition, unlike traditional SCS, using the Senza system does not restrict patients from driving a motor vehicle.
A recent clinical study in the journal Anesthesiology showed that in addition to reducing chronic back and leg pain, Senza enabled many patients to reduce their intake of pain medications — which often are misused and can lead to heroin addiction — and experience improved quality of life.
“The number of deaths due to prescription opioids has escalated significantly over the past decade and surpassed the number of deaths caused by illegal drugs, such as heroin,” Young observes. “Spinal cord stimulation offers nonpharmacologic pain relief to patients suffering with chronic pain. For patients on opioids, it offers a realistic way to achieve pain relief and wean opioids.”
Because the system doesn’t cause paresthesia, it enables chronic pain patients to keep the high-frequency stimulation therapy on during the night and while driving, which conventional stimulation does not allow. “This important feature allows patients to achieve a functional status that is close to baseline,” Amin says.
Young used Senza to treat a patient who suffered from both back and leg pain that did not respond to surgery, epidural injections, medications or physical therapy. The patient left the outpatient surgery center a few hours after the implantation procedure and followed up with Young regularly over the following week.
“His pain improved by 90 percent over that time. One of the more interesting things is that his pain relief improved day by day,” he says. “I am delighted to have access to cutting-edge technology to treat the patients who can benefit most from it.”