Neurostimulation provides sustained leg pain relief and improved
quality of life
20 November 2008
New data from a study published in the journal Neurosurgery show that spinal cord stimulation (neurostimulation therapy) provides sustained, significant improvement in otherwise intractable, chronic leg pain, quality of life and functional capacity out to 24 months of therapy.
Supported by Medtronic, Inc. (NYSE: MDT), this largest randomized, controlled neurostimulation study followed patients with chronic neuropathic leg and back pain who received spinal cord stimulation therapy along with conventional medical management to compare the results to patients who received conventional medical management alone.
While the 24-month data are newly published, earlier data points from this clinical trial provided critical evidence used for the UK’s National Institute for Health and Clinical Excellence (NICE) final guidance, which recommends access to spinal cord stimulation therapy for patients in the United Kingdom. The updated NICE guidance concluded that the use of neurostimulation for chronic neuropathic pain is safe and effective, as well as cost-effective.
Spinal cord stimulation therapy uses an implantable medical device similar to a pacemaker to deliver electrical pulses to the epidural space in order to interrupt pain signals traveling through the nervous system from reaching the brain.
The newly published 24-month results from the study, known as PROCESS (for
prospective randomized controlled trial of the effectiveness of spinal cord
stimulation), showed positive results are sustained in patients who received Medtronic neurostimulation therapy plus conventional treatments at 24 months:
Of the 42 patients who were in the neurostimulation group from the start of the study and continued on at 24 months, 69% experienced a clinically significant (at least 30%) improvement in leg pain relief and 40% had a sustained 50% or greater improvement in leg pain relief based on the study pain scale.
Of all 72 patients receiving neurostimulation plus conventional medical management at the 24-month study visit, including the 30 who opted to cross over from the conventional medical management alone group, 47% achieved 50 percent or greater improvement in the leg pain relief threshold versus only 7% of those receiving conventional medical management alone.
A surgical procedure was needed to resolve adverse events in 13 of the 42 patients randomized to neurostimulation who continued to receive stimulation at 24 months. As noted in the study report, the complications were benign and reversible and included electrode migration, infection and loss of paresthesia (a tingling sensation that is felt when the electrical stimulation is being delivered).
“The PROCESS study is the largest, randomized study of spinal cord stimulation published to date that shows the long-term potential for neurostimulation therapy in treating chronic and debilitating leg pain,” said Richard North, M.D., neurosurgeon at Lifebridge Health Brain and Spine Institute and Professor of Neurosurgery, Anesthesiology and Critical Care Medicine (ret.) at Johns Hopkins in Baltimore, Maryland.
Dr. North is a senior author on the paper and a member of the Steering Committee that was responsible for managing the PROCESS study design. “Our findings out to 24 months show that the benefits of neurostimulation therapy can be sustained for a long period of time without diminishing effectiveness. These results complement those of studies finding that carefully selected patients experience leg and back pain relief with neurostimulation. This therapy offers hope for patients whose activities are limited as a result of chronic pain that is not responsive to common treatments.”
PROCESS Study Design
The PROCESS study design randomly assigned 100 patients from 12 academic medical
centres in Australia, Belgium, Canada, Israel, Italy, Spain, Switzerland, and the United Kingdom to receive conventional medical management alone or in combination with Medtronic neurostimulation therapy for a period of six months, with long-term follow-up to 24 months. Conventional medical therapies included oral medications, nerve blocks, steroid injections, physical and psychological therapy and/or chiropractic care. After six months, patients could request to cross over to the alternate treatment group.
The study’s primary end point was the proportion of patients in each group reporting an improvement of leg pain relief of at least 50 percent at six months. Secondary outcomes included improvement in back pain, health-related quality of life and functional capacity; patient treatment satisfaction, change in use of pain therapies (pharmacological and non-pharmacological); and the frequency and nature of adverse events.
All 100 patients in the study had undergone at least one previous anatomically successful spine surgery for a herniated disk but continued to experience moderate to severe pain in one or both legs, and to a lesser degree in the back, at least six months later.
About the UK’s NICE Guidance
NICE is an independent organization responsible for providing national guidance in the United Kingdom on the promotion of good health and the prevention and treatment of ill health.
All clinical evidence included in the NICE systematic review was developed with Medtronic neurostimulation systems (403 devices used). The new guidance from NICE recommends that neurostimulation should be available to all patients who continue to experience chronic neuropathic pain for at least six months despite trying conventional approaches to pain management.
Patients will also be required to have had a successful trial of the therapy before a spinal cord stimulator is implanted. NICE has not recommended spinal cord stimulation for people with ischemic pain, ruling out the treatment for people experiencing chronic pain caused by conditions such as refractory angina and critical limb ischemia, except in the context of research as part of a clinical trial.
“In the growing field of Neuromodulation, Medtronic remains uniquely committed to investing in Class I clinical evidence that is critical for patients, physicians, physician societies and healthcare payers,” said Richard E. Kuntz, M.D., senior vice president and president of the Neuromodulation business at Medtronic. “Our product development is aimed at providing durable successful therapies, as measured in these clinical studies, for the benefit of people with chronic pain and their physicians. Our leadership is focused on all aspects of neurostimulation therapy for chronic pain, including ensuring evidence is available for important guidance decisions from worldwide authorities to also offering the largest portfolio of rechargeable and non-rechargeable devices and leads to meet patient needs.”
Along with advancing clinical evidence in support of neurostimulation, Medtronic has also introduced recent innovations in technology. The latest advance is the RestoreULTRA neurostimulation system, which offers an unparalleled advance as Medtronic’s smallest and thinnest 16-electrode, rechargeable neurostimulator. It also is the only system on the market to offer a patient programmer that allows patients to customize and adjust their own stimulation up and down the spine to maximize their pain relief.
About neuropathic pain
Associated with nerve damage or nervous system disease, neuropathic pain affects up to eight percent of the population but is often under diagnosed and under treated. Of all pain types, it is among the most severe, chronic, disabling, costly and difficult to treat. Neuropathic pain most commonly affects the back and legs.
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