New Neurosurgical Procedure May Help Treat Obesity

New Neurosurgical Procedure May Help Treat Obesity

Hypothalamic Gamma Knife irradiation is a novel approach to the treatment for obesity and may be key to producing sustained weight loss. David A. Vincent, MD, a neurosurgical resident at the University of Virginia, will be presenting the results of an experimental study examining the efficacy of Gamma Knife irradiation to control obesity at the 49th Annual Meeting of the Congress of Neurological Surgeons, October 30 - November 4, 1999 in Boston, Massachusetts.

In the experiment, 36 Zucker rats were randomized into treatment and non-treatment groups. The treatment group received two doses of 40Gy radiation to the hypothalamus. The rats were then observed and weekly weights were obtained for 34 weeks. During this time, the animals were allowed unlimited access to food and water.

Beginning at week nine, and continuing throughout the study, the treated animals experienced a significant reduction in weight.

"The results of the trial are far greater than we expected," said Dr. Vincent. "None of the rats exhibited adverse effects or became emaciated. Rather, the treatment rats assumed a new and lower set body weight, thereby suggesting that the function of the weight-associated hypothalamic nuclei was modulated and probably not destroyed."

Since the 1940s, scientists have known that an area of the brain, known as the hypothalamus, plays a key role in regulating food intake and body weight. In these classic experiments with rats, lesions in one part of the hypothalamus resulted in obese rats, whereas lesions in another part of the hypothalamus blocked the urge to eat and even caused death by starvation. However, the lack of understanding of the hypothalamic centers that control the complex mechanisms inhibited further research progress.

"This study may shed some light on the various hypothalamic centers that control body weight and regulate hunger," said Dr. Vincent. "By examining the effect of Gamma Knife irradiation on the hypothalamus, we could begin to unravel the mystery of how to control complex mechanisms of feeding and body weight."

The Gamma Knife is a non-invasive neurosurgical tool designed to minimize the effects of radiation by sending multiple radiation beams to converge on one target point. The helmet-like device is worn by the patient and has 201 round holes in it, which aim a single, high dose of Gamma Knife radiation at the targeted tissue. The treatment is done in a single sitting and results in increased biological efficacy with decreased hospital stay and side effects.

"A great deal of work has yet to be done," said Dr. Vincent, "but the fact that the treatment rats lose weight and stabilize at a new, lower set weight is exciting. It is my hope that future trials will continue to be effective and shed more light on the field of obesity research."

One in three, or 58 million American adults ages 20-74 are overweight. Of those, more than 67 percent are clinically obese. Doctors and scientists generally agree that men with more than 25 percent body fat and women with more than 30 percent body fat are obese. These individuals are at greater risk for developing a host of diseases, including diabetes, heart disease, stroke, and some forms of cancer.

Founded in 1951, the Congress of Neurological Surgeons (CNS) is a scientific and educational association with approximately 4,800 members worldwide. The CNS is dedicated to advancing the specialty of neurological surgery in order to provide the highest quality of neurosurgical care to the public. Neurological surgery is the medical specialty concerned with the diagnosis and treatment of patients with injury to, or diseases of, the brain, spine and peripheral nerves.

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Media Representatives: To view the online press room, visit http://www.neurosurgery.org/pubpages/news/cn99mediakit.html. If you would like to cover the meeting or interview a neurosurgeon - either on-site or via telephone - please contact Deia Lofendo at (847) 518-2519 or call the Annual Meeting press room at the meeting beginning Sunday, October 31, at (617) 954-2595.

To view a special presentation on Gamma Knife Radiosurgery, visit http://www.neurosurgery.org/pubpages/whatis/radiosurgery.html.