Pain control devices give out

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Pain control devices give out

By Gellene, Times Staff Writer

June 5, 2006

http://www.latimes.com/features/health/la-he-

pain5jun05,1,794606.story?coll=la-headlines-health

Spinal cord stimulators are one of the few options for patients with

extreme pain that no longer responds to drugs. Implanted near the

base of the spinal cord, the devices deliver electrical impulses to

specific nerves and block pain signals from reaching the brain.

Now researchers have found that, for one little-understood condition,

the benefits of the devices diminish over time — and disappear after

three years.

Stimulators have long offered particular hope to patients with

complex regional pain syndrome, an often-agonizing nerve disorder

that can occur after surgery or an injury involving a limb. The

condition, which can leave patients disabled and unable to work,

affects about 200,000 Americans.

Treatments include a handful of drugs ranging in strength from

acetaminophen to morphine. One in eight Americans with the disorder

has received a spinal stimulator, which is often seen as a last

resort. The device and the procedure to implant it cost around

$20,000. Previous studies of stimulators showed clear benefits, but

those trials lasted no more than two years.

The report, published as a letter in the New England Journal of

Medicine's June 1 issue, provided the first long-term look at the

performance of spinal stimulators in patients with complex regional

pain syndrome.

Dutch researchers tracked 54 patients for five years. Thirty-six

patients received stimulators and physical therapy, and 18 received

physical therapy alone.

Patients' pain intensity was rated on a scale of 1 to 10. For the

first two years, patients with stimulators reported more improvement

than patients receiving only physical therapy. The difference between

the groups was statistically significant.

After three years, however, the pain-alleviating effect of the device

diminished and was no better than physical therapy, researchers found.

Patients in the stimulator group had pain intensity of 5.2 at the end

of three years, down from 6.7 at the start of the study. The physical

therapy group had pain intensity of 6.2, down from 6.9 when the

clinical trial began.

There was no statistically significant difference in improvements

seen between the groups.

Medtronic Inc., the Minneapolis-based manufacturer of the devices,

said the stimulator models used in the study were outmoded and the

method of rating pain was too subjective.

Still, Dr. J. Schwartzman of Drexel University College of

Medicine in Philadelphia said the study results mirrored his

experience. Schwartzman said he no longer offers the devices to

patients with complex regional pain syndrome. The study should

discourage other doctors from using them, he said.

But Dr. Marius A. Kemler of the Academic Medical Center in Amsterdam,

the lead author of the report, said he had not soured on spinal cord

stimulators. Despite the disappointing results, he said, most

patients in his study would opt for spinal cord stimulators if they

could do it over, because they remain one of the only treatments

available.