Hyperhidrosis is a disorder characterized by excessive sweating that occurs in up to 1% of the population. The excessive sweating can occur in the hands (palmar hyperhidrosis), in the armpits (axillary hyperhidrosis), or in the feet (plantar hyperhidrosis). Although nobody understands the exact cause of this excessive sweating in specific individuals, it is known that the sweating is controlled by the sympathetic nervous system.
The human body possesses two different sets of nerves: the somatic nervous system and the autonomic system. The somatic nervous system is the system of voluntary nerves that give us sensation (pain, heat, and touch) as well as the control of our muscles that allow us to move the different portions of our body at will. The autonomic nervous system, on the other hand, is the involuntary nervous system. Many of our bodily functions occur without conscious control such as the rate at which we breathe, the beating of our heart, and the production of sweat, which is important for regulating body temperature. The autonomic nervous system is made up of two components: the sympathetic and the parasympathetic systems. It is the sympathetic nervous system that controls the sweating throughout our bodies.
Although there is ongoing research investigating this abnormality, it is not known what specific defect occurs that results in excessive sweating. Whether it is the over activity of the sympathetic nervous chain or the sweat glands themselves is uncertain.
Patients with hyperhidrosis have excessive sweating that hampers their activities of daily living. It is sometimes brought on by stress, emotion, or exercise, but can also occur spontaneously. Patients with palmar hyperhidrosis have wet, moist hands that sometimes interfere with grasping objects. Most patients with palmar hyperhidrosis also consider it a difficult social problem since every time they shake hands, they leave the other person's palm very moist, a sensation most people find unpleasant. Those who suffer from axillary hyperhidrosis sweat profusely from their underarms causing them to stain their clothes shortly after they dress. Once again, this proves to be very unsightly and a social disadvantage. Plantar hyperhidrosis is the excessive sweating of the feet and leads to moist socks and shoes as well as increased foot odor.
The initial treatment for hyperhidrosis is usually medical and does not involve surgery. There are ointments and salves available (i.e., Drysol) that are astringents that tend to dry up the sweat glands. Another treatment is iontopheresis. This consists of a treatment of electrical stimulation, usually in the hands. Patients place their hands in a bath through which an electrical current is passed. This treatment tends to "stun" the sweat glands and can decrease the secretion of sweat for periods of 6 hours to one week. One of the most recent treatments proposed is the injection of botulinum toxin (Botox) into the area of excessive sweating. This is a toxin that affects nerve endings and decreases the transmission of the nerve impulses to the sweat glands thus resulting in decreased sweating. It generally requires several injections in the palms or underarms and it remains effective from one to six months. Repeated injections are nearly always required to maintain an adequate level of dryness.
In addition to the above treatments, many medicines have been utilized with varying success. These include both sedatives (in those patients with stress-induced hyperhidrosis) and medications that affect the nervous system. A family practitioner or internist often begins the initial treatment for hyperhidrosis. Cases not responding to simple treatment regimens are often then referred to a specialist such as a dermatologist or neurologist. In general, surgery is contemplated only when the less invasive medical treatments have failed to provide adequate treatment.
The surgical treatment of hyperhidrosis involves destroying or removing a specific portion of the main sympathetic nerve. As noted above, the sympathetic nerves are part of a separate and parallel nervous system. Their anatomic location is separate from the somatic (voluntary) nerves that control sensation and motor function. The sympathetic nerve "chain" is formed by a plexus of nerves located next to the ribs in the chest. The spine is made up of vertebra, which are blocks of bone stacked one on top of another like building blocks. The branches that form this sympathetic "chain" come from between these building blocks and end in a bundle of cells called a ganglion. There is a ganglion at each vertebral level of the spine and all these ganglions are attached one to another longitudinally to form the "sympathetic chain." A sympathetic nerve branch then comes off each of these ganglions and travels out to enervate blood vessels and sweat glands in the body. The surgical therapy for hyperhidrosis entails removing or destroying the specific ganglion that cause sweating in the arm and the axillae. There are a variety of ways of dealing with the sympathetic ganglions including removing them, cauterizing them, cutting the branches, and clipping them. Different surgeons have been trained in different techniques and all appear to be effective in a high percentage of cases. No specific technique has proven definitively to be superior to the others.
In order to treat palmar (hand) hyperhidrosis, the T2 ganglion is removed or destroyed. Many surgeons will also remove the third ganglion to maximize the chance of completely preventing sweating of the hands. In order to treat the armpit, the second and third ganglia are removed or destroyed. Similarly, some surgeons will also destroy the fourth ganglion to once again maximize complete relief from armpit sweating.
In the past, this often required a moderate to large sized incision in the chest which required cutting muscles and separating ribs to expose the sympathetic chain. However, recent advances in technology have produced less invasive methods, such as the so-called endoscopic thoracic sympathectomy (ETS), also known as thoracoscopic sympathectomy. This entails general anesthesia for the patient. Once asleep, two or three small (5-10 mm) incisions are made below the armpit. Through these holes, a telescope is passed which is attached to a miniature video camera. Thus, the sympathetic chain can be identified. Through the remaining one or two incisions, instruments are placed to allow the surgeon to remove or destroy the specific ganglions as dictated by the patient's symptoms. To perform this operation, the patient's lung must be collapsed to allow adequate space for the surgeon to maneuver. Following completion of the operation, the lung is re-expanded and the incisions are closed. Occasionally a small tube is left inside the chest to allow evacuation of air, however, this is usually removed within hours of the surgery. After one side is completed, the surgeon then turns his/her attention to the opposite side and an identical procedure is performed.
Typically, the patient remains in the hospital for a period of 12-24 hours following surgery. There is post-operative pain following surgery and most patients will require some oral pain medication for a period of 7-10 days following surgery.
There are certain risks that are common to all forms of surgery. These include allergic reaction to anesthetic agents or drugs, or infection at the site of operation. Because the telescope and instruments are passed between the ribs, it is possible to damage the artery, vein or nerve which run beneath each rib. This could potentially lead to bleeding or inflammation of the nerve with chronic irritation or pain. Finally, although the majority of these operations are performed on young adults, occasionally older patients will undergo the procedure. These patients are subject to the risks of cardiac problems (heart attack, abnormal rhythm), stroke, pneumonia, blood clots, and urinary tract infections. The incidence of any of the above potential complications is very low (1% or less) but such problems can arise with any form of surgery, and patients must be aware of all the risks no matter how small.
There are some potential side effects of the surgery. The most common of these is compensatory sweating which occurs in up to 50-60% of patients. One must remember that sweating is one form of regulating the body's heat. If the operation prevents sweating in the upper chest, back and arms, it is possible that patients will notice a greater amount of sweating elsewhere in their body in order to compensate for the lack of sweating in the upper extremities. This is called "compensatory sweating" and can occur on the face, abdomen, back, buttocks, thighs, or feet. While this appears to be merely a nuisance for most patients, occasionally (5-10% of the time) it can be severe and interfere with the patient's lifestyle.
A second potential side effect is gustatory sweating. Patients who develop this problem note increased sweating when they are eating. This occurs in approximately 5-10% of patients but is rarely severe.
Finally, there is a small but real incidence of Horner's syndrome (1%). This occurs when the highest sympathetic ganglion (the first ganglion or "stellate" ganglion) is damaged during the operation. When this occurs, the patient notes three findings on the side of the face where the stellate ganglion was injured. These include a slight droop in the eyelid, a small or narrow pupil, and the lack of sweating on that side of the face. This syndrome is sometimes reversible over a period of weeks to months, but may also prove to be permanent. Although the incidence of this is quite low (1%), it is a potential complication of which all patients should be aware. Overall, with the exception of compensatory sweating, the incidence of complications or side effects remains gratifyingly low.
The probability of success varies with the anatomic location of the excessive sweating. ETS will cure approximately 95-98% of excessive hand (palmar) hyperhidrosis and approximately 75-80% of armpit (axillary) hyperhidrosis. Approximately 25% of patients with hyperhidrosis of the feet (plantar) will note some improvement, however, the operation is not designed to treat this disorder and should not be used primarily if this is the only complaint.
Although ETS is overall a safe and highly effective method of treatment for the hyperhidrosis syndrome, it must be realized that it remains a surgical procedure with the inherent risks described above. As with most disorders, non-invasive medical forms of therapy should be tried prior to surgery. It is only when these prove to be unsuccessful or impractical for long-term use that a surgical procedure should be contemplated. Once the decision to pursue surgery is made, patients would best be served looking for a board certified thoracic surgeon experienced in performing video-assisted thoracic surgery (VATS) otherwise known as thoracoscopy.
