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Thoracoscopic Sympathectomy for Hyperhidrosis
Axillary and palmar hyperhidroses are relatively common disorders that together affect approximately 0.5% to 1% of the population, with possibly higher percentages in those of Asian descent. Hyperhidrosis is an idiopathic overactivation of sweat glands that results in secretion of sweat in excess of that needed for typical autonomically controlled thermoregulation. It is often overlooked or untreated and can cause significant distress that may lead to a negative impact on social and professional quality of life. Simple tasks such as handshaking, writing, and handling daily objects can become daunting problems. Hyperhidrosis can become so severe that sweat can drip off a person’s fingertips and can even require multiple changes of clothing daily. Individuals with untreated hyperhidrosis have an increased risk for cutaneous skin infection if the abnormal physiology is not adequately corrected; the overall odds ratio for infection of untreated hyperhidrosis is 3.2, for dermatophyte fungus is 9.8, and for bacteria is 2.6. Hyperhidrosis is also associated with a higher risk of psychiatric disorders such as anxiety and depression. Despite the significant impact of hyperhidrosis on the quality of life of individuals suffering from the condition, a large proportion them do not seek medical attention because they believe that it is not a medical condition or that no effective interventions exist.
The diagnosis criteria for hyperhidrosis stratify its severity into four classes, according to the Hyperhidrosis Disease Severity Scale: never noticeable, tolerable but interferes, barely tolerable and frequently interferes, and intolerable and always interferes. Additional criteria include duration in the previous 6 months, bilateral with symmetry, onset before 25 years of age, family history, and asymptomatic during sleep.
Treatment options include topical therapy with metal salts, anticholinergic agents, botulinum toxin therapy, iontophoresis, and surgical disruption of the upper thoracic sympathetic chain. After initial diagnosis, medical treatments should be pursued until deemed failed because of either persistence of symptoms despite adequate intensive therapy or intolerance to medical treatment. Only after all medical options are exhausted should surgical intervention be considered. Surgery consists of sectioning the second, third, and fourth ganglia of the sympathetic chain in the chest.
History
Although the earliest surveys of the sympathetic nervous system were conducted by du Petit in 1727, the first report of surgical sympathectomy was at the level of the neck for treatment of epilepsy by Alexander in 1889. , Since then, sympathectomy has been used for numerous clinical presentations, with limited success. For example, sympathectomy has been indicated in treatment of angina, Raynaud phenomenon, exophthalmic goiter, glaucoma, various pain conditions, and spastic paralysis of lower extremities.
Bernard and Horner independently published a series of reports in the latter half of the 19th century describing sectioning of the sympathetic chain and associated clinical effects. , Since the 1920s, when Kotzareff described anhidrosis with sectioning of the sympathetic chain, sympathectomy has been commonly used for hyperhidrosis. The adaptation of endoscopic surgery was introduced in the 1940s, when Hughes described an endoscopic approach for thoracic sympathectomy.
Although endoscopic sympathectomy is the current standard surgical treatment for hyperhidrosis, a variety of other interventions have been attempted in the past. Weaver describes a series of patients treated for axillary hyperhidrosis through excision of skin and glandular tissue in the axillae. Other practitioners attempted less radical approaches, including the utilization of cryotherapy to damage the eccrine glands to achieve reduction in symptoms. Percutaneous sympathetic blocks under imaging guidance have also been used for hyperhidrosis treatment.
Anatomy and Physiology
The eccrine glands function to release serous fluid to the skin to promote cooling by evaporation and are primarily innervated by autonomic, acetylcholinergic, sympathetic neurons. Eccrine glands are distributed throughout the skin surfaces, numbering between 2 million and 4 million per person, with the highest concentrations in the axilla, palms of the hands, and soles of the feet.
The sweat response is under hypothalamic thermoregulatory control via the preoptic sweat area of the hypothalamus. Autonomic output to the eccrine glands arises both from input responding to thermoregulation and from emotional state. Therefore heightened emotions trigger a sweat response, such as sweaty palms with anxiety or nervousness.
Sympathetic pathways for eccrine sweat control originate in the preoptic sweat nucleus of the hypothalamus and travel through the nucleus raphe pallidus. In the spinal column, sympathetic fibers travel in the intermediolateral column in Rexed lamina VII. Sympathetic fibers pass out the ventral root and enter and synapse in the paravertebral sympathetic chain ganglia. Postganglionic fibers travel in peripheral nerves or arteries to their target organs, including the eccrine glands. Traditionally, the second and third sympathetic ganglia are thought to innervate sweat glands in the palms while the third and fourth ganglia innervate the axilla. Importantly, approximately 10% of the population carries the nerve of Kuntz, an additional aberrant division of the sympathetic chain arising from T1, T2, or T3. If present, the nerve of Kuntz must be sectioned to ensure that sympathectomy will be effective.
Abnormalities in the pathways associated with eccrine gland function are thought to be the root cause of hyperhidrosis, and a strong hereditary component exists for the disease. One study estimated that an allele associated with palmar hyperhidrosis may be present in up to 5% of the population, with hyperhidrosis occurring in approximately a quarter of individuals who inherit two copies of this gene. Subsequent studies have located specific genetic loci for hyperhidrosis, although other candidate genes have also been found suggesting a more complex genetic picture.
Patient Selection
Careful patient selection is critical for success. Prior to consideration for surgery, patients should have completed a range of appropriate medical therapies unsuccessfully. The mainstay of medical therapy includes over-the-counter antiperspirants and topical 20% AlCl compounds; however, chronic use of such antiperspirants can be limited by skin irritation. Medications that block α-adrenergic receptors such as phenoxybenzamine may also help symptoms. Often, these medications are poorly tolerated, as frequent side effects include hypotension and sexual dysfunction. Another, more invasive option consists of a series of topical injections of botulinum toxin A (Botox). For palmar hyperhidrosis, an average of 26 Botox injections were required for determination of success or failure. Typically, even successfully treated patients need repeated injections after several months. A more recently used medical therapy for hyperhidrosis is oxybutynin—an antimuscarinic agent more commonly prescribed for urologic conditions such as incontinence. Similar to other medical therapies, oxybutynin can lead to a variety of side effects including dry mouth and constipation, and the drug is not recommended for use during pregnancy.
Iontophoresis treatments should also be tried prior to consideration of surgical treatment. Iontophoresis involves electrical stimulation, often with tap water, and can be conducted at home; however, it requires a significant daily time commitment. Another novel treatment modality involves microwave-based stimulation of eccrine glands, thereby reducing sweat production. Although this technology has been shown to be fairly safe and efficacious, significant complications with use have been reported, and its use is limited to cases of axillary hyperhidrosis. Lastly, in selected patients, imaging with computed tomography or magnetic resonance can be useful in excluding alternative pathologies, including infection, metabolic disorders, and neoplastic processes. If hyperhidrosis remains debilitating despite these interventions, surgery should be considered.
Surgical Treatment
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