Study Shows Medtronic Neurostimulation Therapy Improves Chronic Neuropathic Leg And Back Pain

17 Sep 2007   

Offering hope to millions of chronic pain sufferers around the world, a major study published online by the international medical journal PAIN and supported by Medtronic, Inc. (NYSE: MDT) found that people with chronic neuropathic leg and back pain benefited significantly more from neurostimulation therapy plus conventional medical management than from conventional medical management alone.

The study, known as PROCESS (for PROspective randomized Controlled trial of the Effectiveness of Spinal cord Stimulation), showed that Medtronic neurostimulation therapy plus conventional medical management provided patients with significantly greater pain relief, quality of life, functional capacity and treatment satisfaction than conventional medical management alone after six months. Importantly, 48 percent of the patients assigned to receive neurostimulation plus conventional treatments experienced a 50 percent or greater improvement in leg pain compared to 9 percent of patients assigned to receive only conventional treatments (p<0.001).

Neurostimulation therapy, developed in the 1970s by Medtronic in partnership with physicians, uses an implantable medical system to deliver electrical pulses to the epidural space in order to block pain signals traveling through the nervous system from reaching the brain.

"Patients with persistently disabling neuropathic pain in the back and legs represent one of the most difficult treatment problems in clinical practice, the real-world setting of our trial," said the study's principal investigator, Krishna Kumar, M.D., clinical professor and chairman of the neurosurgery department at the University of Saskatchewan's Regina General Hospital in Canada. "Our findings show that neurostimulation offers patients in this situation a treatment option that can relieve their pain to a significantly greater degree than conventional medical management alone - and, as a result, helps restore quality of life and functional capacity as well. Neurostimulation therapy should therefore be added to the list of conventional treatments and routinely considered for appropriate patients."

PROCESS is the largest multi-center randomized controlled trial of neurostimulation therapy ever conducted. The study design randomly assigned 100 patients from 12 academic medical centers in Australia, Belgium, Canada, Israel, Italy, Spain, Switzerland, and the United Kingdom to receive conventional medical management or Medtronic neurostimulation therapy for a period of six months and includes long-term follow-up to 24 months. Patients assigned to receive neurostimulation were allowed to receive conventional medical therapies as needed. These included oral medications, nerve blocks, steroid injections, physical and psychological therapy, and/or chiropractic care.

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 after six months. Secondary outcomes included improvement in leg and back pain, health-related quality of life, patient satisfaction with treatment, functional capacity, 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 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.

The study reports complications and adverse events after 12 months of treatment. The main complications among patients who received neurostimulation therapy included electrode migration, infection, and loss of paresthesia. Twenty-four percent of patients in this group experienced an event that required surgery to resolve. In addition, some patients in each group experienced non-device related events, including an adverse reaction to a drug or the development of a new illness, injury or condition.

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.

"Medtronic offers a range of effective chronic pain management options, from minimally invasive spine surgery to neurostimulation and intrathecal drug therapy," said Richard E. Kuntz, M.D., senior vice president of Medtronic, Inc., and president of the company's Neuromodulation business, which includes Global Pain Management. "We are committed to making ongoing investments across the company in clinical research and product development for the benefit of people with chronic pain and their physicians."

About the Neuromodulation Business at Medtronic

Medtronic developed and leads the field of neuromodulation, the targeted and regulated delivery of electrical pulses and pharmaceuticals to specific sites in the nervous system. The company's Neuromodulation business offers innovative therapies for chronic pain, movement disorders, spasticity, overactive bladder, benign prostatic hyperplasia and gastroparesis.

About Medtronic

Medtronic, Inc., headquartered in Minneapolis, is the global leader in medical technology - alleviating pain, restoring health, and extending life for millions of people around the world.

http://www.medtronic.com