From the Research Dept.
New Study to Examine the Efficacy of Burst Neurostimulation
By Ted Swing, Ph.D.
One of the frontiers in the treatment of chronic pain is neurostimulation (also called neuromodulation). Neurostimulation involves devices that deliver electrical pulses to alter nerve responses. When used in the brain, this can be used to prevent epileptic seizures or treat Parkinsonâ€™s disease. The most common applications of neurostimulation involve the treatment of central or peripheral nerves in order to produce pain relief. The electrical pulses sent by a neurostimulator trigger sensations in nearby nerves that are often felt as a mild tingling or buzzing sensation. This sensation replaces some or all of the pain that would have otherwise been perceived in that nerve.
Spinal Cord Stimulators
The first type of neuromodulation device, developed in 1968, is called a spinal cord stimulator (SCS). Spinal cord stimulators are devices implanted under the skin along the spine. The device consists of a battery and pulse generator, along with electrodes running along the spinal nerves. These electrodes are positioned to stimulate the specific nerves for the area or areas where that patient has pain. These devices have proven effective for many patients and are widely used today for chronic pain that is not adequately relieved by other treatments.
Potentially Unpleasant Stimulation
One of the challenges with spinal cord stimulators is that the intensity of the stimulation felt by the patient can vary, for example by time of day, type of activity or by body position. A particular level of stimulation may provide effective relief when the patient is standing, but then become too intense when they sit down. This intense stimulation could be unpleasant. Alternatively, if the neurostimulator were set to a level that is effective in one body position, it may become insufficient to cover their pain in a new position. Though the stimulation delivered by the device can be adjusted by the patient to prevent periods of unpleasant or insufficient stimulation, it would be preferable if relief could be produced consistently without potential discomfort. Further, for a small percentage of patients, the feeling of neurostimulation in general is considered unpleasant.
One possible solution to these challenges is the use of burst stimulation. Rather than delivering constant pulses of electrical stimulation, burst stimulation would involve very brief pulses of stimulation (for example, a series of five electrical pulses in a row, each lasting 1/1000 of a second). These bursts would be repeated many times each second. Previous research shows that such pulses are too short to felt by the patient, but are capable of producing pain relief. One of the leaders in neurostimulation devices, St. Jude Medical, has begun a study comparing burst stimulation to standard stimulation. This study will determine if the pain relief produced by burst stimulation is as good as or better than standard stimulation.
St. Jude SUNBURST Study
The St. Jude SUNBURST study will include patients with moderate to severe pain in the trunk or limbs that is not adequately relieved by medications or other treatments. These patients must be appropriate candidates for implantation of a neurostimulation device and meet other criteria, including not being pregnant, having cancer, or being immunocompromised. Patients who qualify will have a trial spinal cord stimulator implanted for several days. This will show whether or not neurostimulation is effective in relieving the patientâ€™s pain. If it is, then a permanent spinal cord stimulator will be implanted. Patients are then randomly assigned to receive either standard stimulation throughout the study or periods of standard and burst stimulation. The study will then involve at least four follow up visits over the next 24 weeks and then an additional visit every six months until the study is completed. Arizona Pain will be taking part in this study. If you are interested in learning more about this study, you can speak with your pain management providers or contact me directly at TedS@arizonapain.com.
Ted Swing has more than nine years of research experience and four years of teaching experience in psychology, has published in top psychology and medical journals, and has presented his research at major conferences. He received his Ph.D. in Social Psychology from Iowa State University and has been the Research Director at Arizona Pain since May 2012.