Hyperhidrosis

What is hyperhidrosis?
What is the sympathetic nervous system?
What causes the sympathetic system to malfunction?
What are the symptoms of hyperhidrosis?
What is the treatment for hyperhidrosis?
What surgery is performed to treat hyperhidrosis?
How is this surgery performed?
What are the risks of surgery?
What are the chances of success?
What can I expect after surgery?
What questions should I ask my surgeon?
Summary

WHAT IS HYPERHIDROSIS?
Hyperhidrosis is a disorder characterized by excessive sweating. Although sweating is a normal bodily function that helps regulate body temperature in hot weather and during exercise, patients with hyperdidrosis often sweat excessively even in mild weather and at rest.

Focal Hyperhidrosis is characterized by excessive sweating that is not generalized but located in specific body regions. The excessive sweating can occur in the hands (palmar hyperhidrosis), the armpits (axillary hyperhidrosis), the face (cranio-facial hyperhidrosis) or the feet (plantar hyperhidrosis). Focal Hyperhidrosis occurs in up to 3% of the population. While there may be a genetic component involved in the susceptibility to this disorder, nobody understands the exact cause. We do however know that sweating is controlled by the sympathetic nervous system.

WHAT IS 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 itself 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.

The main structure of the sympathetic nervous system is a linear complex of nerves called the sympathetic chain. There are actually two sympathetic chains, one located to the right of the spine and one to the left of the spine. The chains are each actually a long string of nerves which begin in the neck and travels down into the chest and into the abdomen. These sympathetic chains run parallel to the spine and lay about 1 inch away from the vertebrae (the spinal bones). Each chain is about 1-2 mm thick but is easily visible to the naked eye.

WHAT CAUSES THE SYMPATHETIC SYSTEM TO MALFUNCTION?
Although there is ongoing research investigating this abnormality, it is not known what specific defect occurs that results in excessive sweating. The cause of hyperhidrosis appears to be an abnormal and hyperactive central nervous system response to emotional stress but it can also occur spontaneously or intermittently. The sweat glands themselves appear to be normal.

WHAT ARE THE SYMPTOMS OF HYPERHIDROSIS?
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. Frequently the patient with palmar hyperhidrosis will have cool or cold hands that are sweating. 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. Indeed severe hyperhidrosis has been shown to significantly impair the affected person’s quality of life by a number of scientifically validated measurements.

Those who suffer from axillary (armpit) 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 embarrassment. Some individuals may need to wear multiple layers of clothing and change garments frequently.

Plantar hyperhidrosis is the excessive sweating of the feet and leads to moist socks and shoes as well as increased foot odor.

Craniofacial hyperhidrosis is excessive sweating of the forehead and face, often associated with facial blushing, the combination of which causes social embarrassment and difficulties with make-up.

WHAT IS THE TREATMENT FOR HYPERHIDROSIS?
The initial treatment for hyperhidrosis is usually medical and does not involve surgery. There are astringent (drying) ointments and salves that tend to dry up the sweat glands. The most common are aluminum-based compounds available as over the counter anti-perspirants or prescription strength such as Drysol. The lotion is usually applied at night while the hands are driest and washed off in the morning. Skin irritation is the most common side effect.

Another treatment is iontophoresis. This consists of a treatment of electrical stimulation, usually in the hands. Patients place their hands in a bath through which an electrical current (usually direct 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. Treatments usually last 30 to 40 minutes and can be performed at home with a commercially available battery powered device. Treatments can be performed daily or less often depending upon effectiveness. It may take a couple of weeks to determine if the technique has any benefit. Skin irritation and discomfort are the most likely side effects to be reported. Some dermatologists will perform this technique in their office possibly with a more elaborate alternating current machine and additional agents in the water bath to try to improve success.

One of the more recently introduced treatments 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 multiple (20-40) injections in the superficial skin of 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. Patients with palmar hyperhidrosis treated in this fashion are sometimes challenged with pain upon injection and fine muscle weakness.

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 should be contemplated only if the less invasive medical treatments have failed to provide adequate treatment.

WHAT SURGERY IS PERFORMED TO TREAT HYPERHIDROSIS?
The surgical treatment of hyperhidrosis involves destroying or removing a specific portion of the main nerve of the sympathetic nervous system, the structure known as the sympathetic chain. 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 not actually a single nerve but is rather a plexus of nerves which joins together in a single structure which runs vertically along he ribs and is located about an inch away from the spine. 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 innervate blood vessels and sweat glands in the body.

The surgical therapy for hyperhidrosis entails interrupting the transmission of nerve impulses at a specific site along along the sympathetic chain. The appropriate site of surgical interruption depends upon the patient’s symptom complex (highest for the face, lowest for the armpits and in between for the hands). There are a variety of ways of interrupting the transmission of signals through the sympathetic chain. The chain can be simply cut and divided, a short portion of the chain can be removed, clips can be applied to crush the chain or a portion of it can be destroyed by electrical cauterization. Although each of these techniques has its own theoretical advantages, no specific technique has proven to be definitively superior to the others. Different surgeons have been trained in various techniques and all appear to be effective in a high percentage of cases. Although in the early days of this surgery entire portions of the chain were sometimes removed, it is now recognized that removal of a large section of the chain is not necessary for success and may indeed cause increased side effects.

HOW IS THIS SURGERY PERFORMED?
Although in the past this surgery was performed through large open incisions, sympathetic surgery is now routinely performed by minimally invasive methods, such as the so-called ETS, which stands for endoscopic thoracic sympathectomy (also known as thoracoscopic sympathectomy or sympathicotomy). The patient is placed under general anesthesia and, once asleep, one or more (up to three) small (3-10 mm) incisions are made below the armpit. A telescope is then attached to a miniature video camera and the “videoscope” is passed into the chest cavity through one of these incisions. With this videoscope, the sympathetic chain can be visualized after first gently moving the lung out of the way. Through the remaining one or two incisions, instruments are placed to allow the surgeon to interrupt the chain at the specific level dictated by the patient's symptoms. Following completion of the operation, the lung is returned to its natural position and the incisions are closed. Occasionally a small tube is left inside the chest to allow evacuation of air, however, this is usually removed quickly, 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.
In order to reduce confusion and standardize, The Society of Thoracic Surgeons has recommended that a “rib-based” nomenclature be used when describing the performance of the operation.

In order to treat palmar (hand) hyperhidrosis, recent randomized controlled trials have demonstrated that Surgery performed at the R3, R4 levels (third and fourth ribs)- essentially interrupting the third ganglia or R4,R5 (fourth and fifth ribs)- fourth ganglia; provides excellent control of palmar sweat with on balance improved patient satisfaction and overall quality of life than surgery at higher levels of the chain.

The recent body of literature suggests that the highest success rates occur when interruption is
performed at the top of R3 or the top of R4 for palmar-only hyperhidrosis. R4 may offer a lower
incidence of compensatory hyperhidrosis but moister hands. For palmar and axillary, palmar, axillary and
pedal and for axillary-only hyperhidrosis interruptions at R4 and R5 are recommended. The top of R3 is
best for craniofacial hyperhidrosis.

Typically, the patient remains in the hospital for a period several hours following surgery but will usually go home the same day. There is some post-operative pain following surgery and most patients will require some oral pain medication for a period of seven to 10 days following surgery.

WHAT ARE THE RISKS OF SURGERY?
There are certain risks that are common to all forms of surgery. These include allergic reaction to anesthetic agents or drugs (1% incidence or less), infection at the site of operation (1%) and bleeding (1%).
There are however some potential side effects specific to the surgery. The most common of these is compensatory sweating which occurs to some extent in the large majority of patients. One must remember that sweating is an important method for regulating body heat. The operation for palmar hyperhidrosis not only prevents sweating in the hands but also in the arms, upper chest and back as well. In order to compensate for the lack of sweating in the upper extremities, most patients will notice a greater amount of sweating elsewhere in their body. This is called "compensatory sweating" and can occur on the face, abdomen, back, buttocks, thighs, or feet. Upon careful questioning, almost all patients will notice some increased sweating especially during exercise or warmer times of the year. This phenomenon of increased bodily sweating is a necessary tradeoff to achieve relief of excessive hand and/or armpit sweating and it is a bargain with which the vast majority of patients are extremely satisfied. For most, the compensatory sweating is merely a nuisance. However, no medical treatment or operation is perfect in all cases, and ETS is no exception. There is a small minority of patients (2-5%) for whom the compensatory sweating is so severe that it interferes with the patient’s lifestyle as much or more that the original hyperdidrosis disorder. Although it is felt that the incidence of this compensatory sweating can be minimized by limiting the extent of interruption of the sympathetic chain, there is still the chance for this debilitating side effect and nobody can predict in whom this rare complication will occur.

A slight reduction in heart rate can occur as a result of this operation. While for the great majority of patients this is of no consequence, patients who have an abnormally low heart rate or problem with their heart’s electrical conduction system should be cautioned about a further reduction in heart rate. Patients that are highly competitive athletes that may require compensatory increase in heart rate or vascular tone with exercise should be told that their exercise capacity could theoretically be reduced and be encouraged to drink large quantities of electrolyte containing fluids during sports.

Another potential side effect is gustatory sweating. Patients who develop this problem note increased sweating when they are eating. This occurs in approximately 1% 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. Other less common complications include pneumothorax requiring chest tube drainage (1%), pleural effusion (1%), acute bleeding or delayed hemothorax (1%), chylothorax, and persistent intercostals neuralgia (<1%).

WHAT ARE THE CHANCES OF SUCCESS?
The probability of success varies with the anatomic location of the excessive sweating. ETS will effectively treat approximately 95-98% of excessive hand (palmar) hyperhidrosis and approximately 75-85% of armpit (axillary) hyperhidrosis. Patients with palmar and axillary sweat combined also have excellent satisfaction similar to that of patients with palmar only sweating. In general patients with palmar or palmar and axillary combined are the most satisfied with 98 % of treated patients likely to recommend the surgery to a friend or relative. While not likely, there is a small chance that symptoms could recur after surgery, requiring further treatment. Interestingly, a fraction of patients with hyperhidrosis of the feet (plantar) will note some improvement in that area even though the operation is not designed to treat this disorder and should not be used primarily if this is the only complaint.

WHAT CAN I EXPECT AFTER THE SURGERY?
The excessive sweating of focal hyperhidrosis is controlled immediately after the surgery. The patient will notice warmer, drier hands right away. It sometimes takes a little time for some patients to ”un-learn” the many avoidance techniques they have used to try to hide or cope with the condition. There will be some pain or discomfort at the incision sites but his is usually well controlled with a pain pill. Similar to other surgeries or stresses, a patient may feel a little more fatigued for a week or two after surgery. It is wise to avoid scheduling the procedure at a time when a patient needs to be operating at peak efficiency such as exams for students or important work or social events.

WHAT QUESTIONS SHOULD I ASK THE SURGEON?
- What technique do you use to perform the surgery?
- Will I be staying in the hospital overnight?
- Will I have a drain after surgery?
- What is the experience of the surgical team?
- What follow-up is planned?

SUMMARY
Although ETS is overall a safe and highly effective method of treatment for focal hyperhidrosis, it is important to realize 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 with a demonstrated interest in the field.

|||