extent of the consequent primary effects and side effects. When performed endoscopically as is usually the case, the surgeon penetrates the chest cavity making multiple incisions about the diameter of a straw between ribs. This allows the surgeon to insert the video camera (endoscope) in one hole and a surgical instrument in another. The operation is accomplished by dissecting the nerve tissue of the main sympathetic chain. Another technique, the clamping method, also referred to as 'endoscopic sympathetic blockade' (ESB) employs titanium clamps around the nerve tissue, and was developed as an alternative to older methods in an unsuccessful attempt to make the procedure reversible. Technical reversal of the clamping procedure must be performed within a short time after clamping (estimated at a few days or weeks at most), and a recovery, evidence indicates, will not be complete. Physical, mental and emotional effects Sympathectomy works by disabling part of the autonomic nervous system (and thereby disrupting its signals from the brain), through surgical intervention, in the expectation of removing or alleviating the designated problem. Many non-ETS doctors have found this practice questionable chiefly because its purpose is to destroy functionally disordered, yet anatomically typical nerves. Exact results of ETS are impossible to predict, because of considerable anatomic variation in nerve function from one patient to the next, and also because of variations in surgical technique. The autonomic nervous system is not anatomically exact and connections might exist which are unpredictably affected when the nerves are disabled. This problem was demonstrated by a significant number of patients who underwent sympathectomy at the same level for hand sweating, but who then presented a reduction or elimination of feet sweating, in contrast to others who were not affected in this way. No reliable operation exists for foot sweating except lumbar sympathectomy, at the opposite end of the sympathetic chain. Thoracic sympathectomy will change many bodily functions, including sweating, vascular responses, heart rate, heart stroke volume, thyroid, baroreflex, lung volume, pupil dilation, skin temperature and other aspects of the autonomic nervous system, like the essential fight-or-flight response. It reduces the physiological responses to strong emotions, such as fear and laughter, diminishes the body's physical reaction to both pain and pleasure, and inhibits cutaneous sensations such as goose bumps. A large study of psychiatric patients treated with this surgery showed significant reductions in fear, alertness and arousal. Arousal is essential to consciousness, in regulating attention