Assessment of spinal cord stimulator in treatment of chronic pain

A neurosurgeon at the University of Illinois at Chicago is assessing how well an implanted electronic device that stimulates nerve fibers in the spinal cord relieves chronic pain.

The device, made by Advanced Neuromodulation Systems, is already approved by the Food and Drug Administration, but is undergoing further evaluation at several sites throughout the United States for potential marketing overseas.

"Coping with chronic pain is one of life's greatest challenges," said Dr. Konstantin Slavin, assistant professor of neurosurgery at the UIC College of Medicine.

More than 50 million Americans suffer from chronic pain, Slavin said, and many of them become partially or totally disabled. "That's why it is important to identify effective methods for treating intractable pain, and document the extent to which these treatments can improve patients' quality of life."

Functioning like a cardiac pacemaker, which uses electrical impulses to regulate the heartbeat, the Genesis(TM) Implantable Pulse Generator transmits low-level electrical impulses to the spinal cord to modify pain signals. The electrical impulses alter messages before they reach the brain, replacing the pain signals with what patients describe as a tingling sensation.

The system, which is used to treat chronic pain in the trunk or limbs, consists of a pulse generator and leads. It is implanted during a surgical procedure that can be brief and minimally invasive, depending on the type of leads emplaced.

The leads are positioned in the space above the spinal cord, called the epidural space, with electrodes at the end of the leads in contact with the specific nerve fibers extending from the spinal cord that are the source of the patient's pain.

The pulse generator is the power source, consisting of a battery and related electronics housed in a single metal container that is about the size of a silver dollar. It is placed just under the skin in a practical location determined by the physician and patient, usually on the abdomen or just below the beltline on the back.

Patients use an external device -- a remote control -- to turn the stimulator on and off. They can increase or decrease the pulse transmitted to the nerve fibers to match their current activity or pain level.

Spinal cord stimulation is not a cure, so it doesn't usually eliminate all sensations of pain, but it can lessen the intensity of the pain, Slavin said, decreasing the need for medication and allowing patients to resume more normal activities.

The device can be used around the clock, if necessary, or only as needed during the day or night.

A total of 15 patients will be involved in the study at UIC, with up to 50 patients enrolled at five sites nationwide. Before the pulse generator is implanted and again one month, three months and six months after the surgery, participants will be asked to fill out a questionnaire that reviews medical history, pain symptoms and characteristics, pain location and quality of life.

Patients interested in obtaining more information about the study may call (800) 597-5970 and ask for the research division.

http://uillinoismedcenter.org