Definition for Sympathectomy
From Biology Forums Dictionary
Sympathectomy is a surgical procedure that destroys nerves in the sympathetic nervous system. The procedure is performed to increase blood flow and decrease long-term pain in certain diseases that cause narrowed blood vessels. It can also be used to decrease excessive sweating. This surgical procedure cuts or destroys the sympathetic ganglia, which are collections of nerve cell bodies in clusters along the thoracic or lumbar spinal cord.
Purpose
The autonomic nervous system controls such involuntary body functions as breathing, sweating, and blood pressure. It is subdivided into two components, the sympathetic and the parasympathetic nervous systems.
The sympathetic nervous system speeds the heart rate, narrows (constricts) blood vessels, and raises blood pressure. Blood pressure is controlled by means of nerve cells that run through sheaths around the arteries. The sympathetic nervous system can be described as the "fight or flight" system because it allows humans to respond to danger by fighting off an attacker or running away. When danger threatens, the sympathetic nervous system increases heart and respiratory rates and blood flow to muscles, and decreases blood flow to such other areas as skin, digestive tract, and limb veins. The net effect is an increase in blood pressure.
Sympathectomy is performed to relieve intermittent constricting of blood vessels (ischemia) when the fingers, toes, ears, or nose are exposed to cold (Raynaud's phenomenon). In Raynaud's phenomenon, the affected extremities turn white, then blue, and red as the blood supply is cut off. The color changes are accompanied by numbness, tingling, burning, and pain. Normal color and feeling are restored when heat is applied. The condition sometimes occurs without direct cause but is more often caused by an underlying medical condition, such as rheumatoid arthritis. Sympathectomy is usually less effective when Raynaud's syndrome is caused by an underlying medical condition. Narrowed blood vessels in the legs that cause painful cramping (claudication) are also treated with sympathectomy.
Sympathectomy may be helpful in treating reflex sympathetic dystrophy (RSD), a condition that sometimes develops after injury. In RSD, the affected limb is painful (causalgia) and swollen. The color, temperature, and texture of the skin changes. These symptoms are related to prolonged and excessive sympathetic nervous system activity.
Sympathectomy is also effective in treating excessive sweating (hyperhidrosis) of the palms, armpits, or face.