Spinal cord stimulation gives significant improvement in pain relief for chronic pain sufferers

6 Oct 2006

An international multicentre study presented at the annual meeting of the European Federation of the International Association for the Study of Pain (IASP) Chapters (EFIC) shows that neurostimulation in combination with conventional medical management is significantly more effective than conventional medical management alone for patients suffering from persistent leg and back pain despite anatomically successful spine surgery.

Initial results of the trial, known as the PROCESS study (for prospective, randomized, controlled, multicentre study to evaluate the effectiveness and cost-effectiveness of spinal cord stimulation), were presented by principal investigator Dr Kumar. The new data — the first to be released from the PROCESS study — indicate that for a group of patients with chronic back and leg pain, spinal chord stimulation (SCS) plus conventional medical management (CMM) provides a significantly greater improvement in pain relief, quality of life, functional capacity, and treatment satisfaction than CMM alone after six months of treatment.

"Patients with severe and persistent pain after anatomically successful spine surgery represent one of the most difficult treatment problems in clinical practice, the real-world setting of our trial," said Dr Krishna Kumar chairman of the neurosurgery department at the University of Saskatchewan's Regina General Hospital in Canada. "Our findings show that spinal cord stimulation 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, restore their quality of life and functional capacity as well."

Professor Per Hansson, world renowned pain physician and researcher from the Karolinska Institute in Stockholm Sweden said, "Today, many physicians are unaware of the possible benefits of Neurostimulation in patients for whom pharmacological management has not adequately controlled their pain. The results of this study challenge the present status quo of endless poly-pharmacy with minor if any pain relief and considerable cognitive and other side effects when promising alternatives exist".

EFIC President Professor Serdar Erdine, chairman of the pain department at Istanbul Medical University, commented, "EFIC has a long standing commitment to supporting and presenting clinical research at our congresses. We are happy that these results were presented at the European Forum of the IASP chapters".

More than 500,000 patients undergo spine surgery for chronic pain each year in Europe alone, and in the majority of cases the surgery successfully relieves the pain. According to published reports, however, some patients continue to experience disabling pain after recovering from surgery. These patients are sometimes diagnosed with failed back surgery syndrome (FBSS).

In the PROCESS study, 48 percent of the SCS patients experienced a 50 percent or greater improvement in leg pain as assessed by a visual analog scale (VAS) — the study's primary endpoint — compared with 9 percent of the CMM-only patients (p=0.0001).

The PROCESS study, the largest of its kind undertaken to date, enrolled 100 patients from 12 academic medical centres in Australia, Belgium, Canada, Israel, Italy, Spain, Switzerland, and the United Kingdom who were randomly assigned to receive CMM with or without SCS for a period of 24 months. Its primary endpoint was a reduction in leg pain of 50 percent or greater on a 100-point VAS. Secondary endpoints included health-related quality of life as assessed by two standard questionnaires; functional capacity as assessed by a standard disability index; and patient satisfaction. All endpoints were evaluated at six months.

To qualify for study enrollment, which ended in June 2005, patients were required to have chronic neuropathic pain — predominantly in one or both legs, with a leg pain VAS score of 50 or greater — following at least one spine surgery. At baseline (the beginning of the study), patients had an average leg pain VAS score of 75, and an average of 4.7 years had elapsed since their last spine surgery. Fourteen (29%) of the 48 patients who received a stimulator had a complication that required additional surgery.

Funded by Medtronic, Inc. (NYSE: MDT) (Medtronic Europe Sarl), the study was designed and supervised by an independent steering committee. All SCS patients in the study received Medtronic Synergy (r) neurostimulation systems.

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