Spinal Cord Stimulation Provides Long-Term Relief in Failed-Back-Surgery Syndrome

Stephanie Doyle

February 15, 2008

February 15, 2008 (Kissimmee, FL) — Results of a randomized trial suggest that implanting a device that delivers electric impulses to the spine may offer long-term relief to patients with failed–back-surgery syndrome (FBSS).

Patients with FBSS continue to experience persistent or recurrent pain, disability, and reduced quality of life despite anatomically successful lumbosacral spine surgery, the authors, led by Richard B. North, MD, from LifeBridge Brain & Spine Institute, in Baltimore, Maryland, note.

In this trial, compared with conventional treatment alone, the addition of spinal cord stimulation improved pain relief, health-related quality of life, and functionality in predominantly neuropathic back-surgery patients at 6 months. In a subset of patients treated longer term, study results suggest that spinal cord stimulation can maintain significant pain relief over 24 months.

The findings, from the multicenter PROCESS trial, were presented here at the American Academy of Pain Medicine 24th Annual Meeting.

"This is the most gratifying procedure I perform," Dr. North told Medscape Neurology & Neurosurgery. He feels the future of spinal cord stimulation will be even more promising as the implantable devices continue to improve, becoming, for example, more compact.

Additional Stimulation

The multicenter PROCESS study evaluated the clinical effectiveness of the addition of spinal cord stimulation to conventional medical management in patients with FBSS.

The study included 100 patients with persistent neuropathic pain predominantly in the legs — some in the lower back — despite successful lumbosacral spine surgery, and randomized them to receive conventional medical management or conventional medical management plus spinal cord stimulation.

The primary outcome variable in this study was greater than 50% leg pain relief at 6 months. Secondary outcomes assessed were functional capacity, health-related quality of life (HRQoL), patient satisfaction, and adverse effects. (Primary-outcome results were previously published [Kumar K et al. Pain 2007;132:179-188]).

At 6 months, in an intention-to-treat (ITT) analysis, patients randomized to spinal cord stimulation had 9 times the odds of achieving the primary end point, the authors write.

Decrease of > 50% in Leg Pain Relief at 6 Months

Outcome
Odds Ratio
99% CI
Decrease of > 50% in leg pain relief
9.23
1.99 – 42.84

Compared with conventional treatment alone, spinal cord stimulation patients experienced improved functionality, improved HRQoL in 7 of 8 domains, and greater satisfaction in pain relief provided by their treatment.

At 6 months, 32 patients (73%) in the conventional-treatment group requested to switch to spinal cord stimulation — compared with 5 patients (10%) in the spinal cord group who crossed over to conventional management.

Current results focused on the subset of 42 patients who were randomized to spinal cord stimulation and continued with that treatment for 2 years.

For these patients, the researchers report statistically significant improvements (P < .001) at 24 months in all pain, quality-of-life, and function outcomes.

Over the 24 months, 25% of 87 patients receiving an electrode experienced a device-related complication requiring additional surgery, they note.

New Hope

Ken Follett, MD, PhD, incoming president of the American Academy of Pain Medicine, commented on the study for Medscape Neurology & Neurosurgery.

"Spinal cord stimulation has been around for better than 2 decades now, and a number of studies have been done, but this is one of the better ones for its breadth and depth," said Dr. Follett, who was not involved in the study. "Nerve injury pain can be very difficult to treat. It typically does not respond to more conventional treatment such as opioids. [Spinal cord stimulation] gives patients new hope."

Funding was provided by Medtronic. Dr. North reports no relevant financial relationships.

American Academy of Pain Medicine 24th Annual Meeting: Abstract 198.

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