Healthcare Industry News: deep brain stimulation
News Release - November 8, 2006
Deep Brain Stimulation Benefits Primary Dystonia Sufferers Says Study Published in New England Journal of MedicineTreatment with Medtronic Therapy Significantly Reduced Severity of Symptoms and Degree of Disability in Patients with Disabling Movement Disorder
MINNEAPOLIS--(HSMN NewsFeed)--According to research published in the Nov. 9, 2006, issue of The New England Journal of Medicine, deep brain stimulation - a therapy pioneered by Medtronic, Inc. (NYSE:MDT ) - can provide significant and sustainable benefits to people with disabling forms of dystonia, a neurological movement disorder that forces parts of the body into abnormal, sometimes painful, movements or postures.
Also known as deep brain stimulation (DBS), the treatment uses a second-generation Medtronic implantable neurostimulation system - consisting of a device akin to a cardiac pacemaker connected with extensions to two thin insulated wires called leads that are inserted into the brain (one for each side). The system sends a steady stream of electrical pulses to precisely targeted areas of the brain involved in motor control.
The 40 patients who took part in this randomized, double-blind, sham-controlled clinical trial - the first of its kind involving deep brain stimulation for dystonia - "had marked disability owing to primary generalized or segmental dystonia, despite optimal pharmacologic treatment, with a disease duration of at least five years." All patients received a deep brain stimulation implant with the electrodes positioned in the globus pallidus pars interna (GPi), or the internal pallidum - part of the brain's movement center.
Study participants were randomly assigned to one of two groups: Half the patients began receiving stimulation after the system was surgically implanted, the other half received no stimulation for three months before their devices were turned on. Neither the patients nor the independent dystonia experts who evaluated them knew who was receiving deep brain stimulation for the first three months of the study.
"This study fulfills the stringent criteria of Class I evidence and, hence, the results will have implications on future dystonia treatment guidelines worldwide," explained the study's two principal investigators - Prof. Reiner Benecke and Dr. Jens Volkmann from the neurology departments of the University of Rostock and the University of Kiel, respectively, in Germany - in a joint statement. "Neurostimulation (DBS) should be implemented much earlier in the course of generalized or segmental dystonia as there are no alternatives in this population."
Three months after randomization, patients in the neurostimulation group experienced a 39.3 percent improvement in the movement score of the Burke-Fahn-Marsden Dystonia Rating Scale, compared to a 4.9 improvement in the sham-stimulation group. Similarly, neurostimulation patients recorded a 37.5 percent reduction in the scale's disability scores, compared to an 8.3 percent reduction among sham-stimulation patients. After six months of treatment with deep brain stimulation, patients from the sham-stimulation group realized a 36.8 percent improvement in the motor score, and the average improvement in the motor score among all study patients reached 46 percent.
The authors reported that "a total of 22 adverse events occurred in 19 patients, including four infections at the stimulator site and 1 lead dislodgment. The most frequent nonserious adverse event was dysarthria" (slurred speech). According to the report, no study patients experienced intracranial hemorrhage during surgery, which is a risk with DBS.
"This study provides more evidence of the safety and potential benefit of deep brain stimulation as a treatment for patients with debilitating forms of primary dystonia involving multiple parts of the body," said Dr. Michele Tagliati, associate professor of neurology and division chief of movement disorders at Mount Sinai School of Medicine in New York. "Its randomized, controlled, and blinded design, which accounts for the placebo effect, makes the results all the more compelling."
According to the Dystonia Medical Research Foundation, approximately 300,000 people in North America suffer from some form of dystonia, which ranges from writer's cramp to spasmodic torticollis. Dystonia is characterized by involuntary muscle contractions, which force certain parts of the body into abnormal, sometimes painful, movements or postures. It can affect any part of the body - including the arms and legs, trunk, neck, eyelids, face, or vocal cords - and is classified in three ways: age of onset, distribution of symptoms, and underlying cause. Severe dystonia can significantly impair quality of life by making basic activities of daily life, such as bathing, dressing, walking, eating, and sleeping, difficult or painful to perform. Besides deep brain stimulation, other treatment options for dystonia include oral medications, botulinum toxin injections, and ablative surgery. These therapies may be used alone or in combination. Only a physician can diagnose dystonia and help determine which course of treatment may be appropriate.
The study involved patients with primary generalized or segmental dystonia. "Primary" refers to the presence of dystonia in the absence of any other underlying disorder. "Generalized" means the symptoms involve several body areas on both sides of the body, whereas "segmental" indicates that two or more adjacent body areas are involved.
deep brain stimulation therapy from Medtronic is approved in the U.S. by the Food and Drug Administration (FDA) for unilateral or bilateral stimulation of the GPi or subthalamic nucleus (STN) to aid in the management of chronic, intractable (drug refractory) primary dystonia, including generalized and/or segmental dystonia, hemidystonia, and cervical dystonia (torticollis) in patients seven years of age and older. The approval is provided under a humanitarian device exemption (HDE), a designation granted to implantable therapies for which safety but not efficacy has been proven. The device has also received CE Mark in Europe for this indication.
"This study meets the rigorous standard of design and execution for Class I clinical evidence," said Dr. Richard E. Kuntz, M.D., senior vice president of Medtronic, and president of the company's Neurological business. "The investigators should be commended for completing an excellent piece of research that adds significantly to the scholarship of deep brain stimulation."
Published under the title "Pallidal Deep-Brain Stimulation in Primary Generalized or Segmental Dystonia," the study (by Kupsch et al.) was supported by a research grant from Medtronic and was conducted independently at 10 academic medical centers in Germany, Norway, and Austria.
Medtronic, Inc. (www.medtronic.com), headquartered in Minneapolis, is the global leader in medical technology - alleviating pain, restoring health, and extending life for millions of people around the world.
Any forward-looking statements are subject to risks and uncertainties such as those described in Medtronic's Annual Report on Form 10-K for the year ended April 28, 2006. Actual results may differ materially from anticipated results.
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