Procedure
Sympathectomy involves division of adrenergic, cholinergic and sensory fibers which elaborate adrenergic substances during the process of regulating visceral function. It involves dissection of the main Sympathetic trunk in the upper thoracic region of the sympathetic nervous system, thus interrupting neural messages that ordinarily would travel to many different organs, glands and muscles. It is via these nerves of the autonomic nervous system that the brain is able to make adjustments in the body in response to changing conditions in the environment, changing emotional states, level of exercise, and other factors to maintain the body's homeostasis. This normative function is disabled or impaired by sympathectomy, because the functions these physiological mechanisms perform also regulate conditions like blushing or hyperhidrosis, that the procedure is designed to eliminate.
There is much disagreement among ETS surgeons about the best surgical method, optimal location for nerve dissection, and the nature and extent of the consequent primary effects and side effects. When performed endoscopically as is usually the case, the surgeon penetrates the chest cavity, making 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. The clamping method, also referred to as endoscopic sympathetic blockade (ESB) employs titanium clamps around the nerve tissue, and was developed in an unsuccessful attempt to make the procedure reversible. However, technical reversal of the clamping procedure must be performed within a short time after clamping (a few days or weeks at most), and a recovery, evidence suggests, will not be complete.
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 problem. Many non-ETS doctors have found this practice questionable chiefly because its purpose is to destroy anatomically normal, but functionally disordered, nerves.
Exact results of ETS are impossible to predict, because of considerable anatomic variations 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 with different parts of the body. This theory has been proven by the fact that a significant number of patients who have had sympathectomy for hand sweating might notice a reduction or elimination of feet sweating, in contrast to others who do not. No reliable operation exists for foot sweating per se except lumbar sympathectomy, at the opposite end of the SNS chain.
Lumbar sympathectomy is largely of historical interest today, being reserved for cases of severe sympathetic dystrophy or selected cases of rest pain, where is it usually done by percutaneous ablation of the lumbar sympathetic chain by phenol injection under imaging guidance. Its original use as an operation for lower limb ischaemia has been superseded by direct revascularisation operations or endovascular revacularisation procedures such as angioplasty or angioplasty with stenting of occuded arteries with reasonable runoff i.e. endovascular surgery.
A large study of psychiatric patients treated with this surgery showed significant reductions in fear, alertness and arousal. (Teleranta, Pohjavaara, et al. 2003, 2004. Online link unavailable). Arousal is essential to consciousness, in regulating attention and information processing, memory and emotion.
ETS patients are being studied using the autonomic failure protocol headed by David Goldstein, M.D. Ph.D., senior investigator at the U.S National Institute of Neurological Disorders and Stroke. He has documented loss of thermoregulatory function, cardiac denervation, and loss of vasoconstriction. Recurrence of the original symptoms due to nerve regeneration or nerve sprouting can occur within the first year post surgery. Nerve sprouting, or abnormal nerve growth after damage or injury to the nerves can cause other further damage. Sprouting sympathtetic nerves can form connections with sensory nerves, and lead to pain conditions that are mediated by the SNS. Every time the system is activated, it is translated into pain. This sprouting and its action can lead to Frey's syndrome, a recognized after effect of sympathectomy, when the growing sympathetic nerves innervate salivary glands, leading to excessive sweating regardless of environmental temperature through olfactory or gustatory stimulation.
Read more about this topic: Endoscopic Thoracic Sympathectomy