ETS: Risks
Complications
- Horner's Syndrome
Caused by injury to the stellate ganglion (T1) or portions of the sympathetic trunk above this ganglion. Such an event is either due to a miscalculation of the level (too high interruption with direct lesion of the stellate ganglion) or, even if the level has been chosen correctly, due to uncontrolled dispersion of heat energy along the nerve when using electrocautery in coagulation mode. Normally, this is only an issue during surgery for facial hyperhidrosis or blushing; in patients with palmar hyperhidrosis it may occur only if the operation involves the ganglion Th2 (obsolete).
Three symptoms characterize this syndrome: drooping eyelid, narrow pupil (miosis) and a receded eyeball. A unilateral Horner's syndrome is more evident and cosmetically disturbing because of the asymmetry than a bilateral. If there is only an impaired function caused by swelling of the stellate ganglion due to mechanical or thermal irritation, without the ganglion having suffered permanent damage, the syndrome usually appears after a delay of some hours and disappears again in the course of days or weeks. In case of permanent damage, corrective surgery (lifting of the eyelid - blepharoplasty) is required.
- Pneumothorax
We have to distinguish:
- a) Residual gas (CO2) remaining in the pleural space: this does not require any measure because it will be absorbed by the pleura within a few hours, unless there is a large quantity left.
- b) Air in the pleural cavity resulting from a leak on the surface of the lung. Although it is a relatively rare event (about 0.2-0.3% of the operated patients), this is still the most common among all complications. As a rule, the pneumothorax can easily been treated with suction drainage (Bülau) for a few hours up to a couple of days.
- Hemorrhage
Even more rarely, hemorrhage occurs during surgery or in the aftermath (<1%). Major bleeding is an absolute rarity, mostly discrete bleeding occurs from small vessels, readily controllable endoscopically; the use of electrocautery can, however, represent a risk if heat coagulation is used indiscriminately, as this may damage other structures.
- Infection
Infections are exceedingly rare in the chest. Most surgeons who deal with this kind of surgery have never seen postoperative infections, not even after thousands of ETS-operations.
- Insufficient effect
Unsatisfactory result is uncommon, if the patient has undergone surgery for palmar or facial hyperhidrosis, because the outcome of a correctly performed procedure is very reliable. The cause of unilateral or bilateral failure is most often an error in choosing the level of interruption on the sympathetic chain (too low). In rare cases, the reason for the weak effect has to be ascribed to an individual variation in the path of the nervous signals, diverting to higher ganglia. In patients with facial blushing this is slightly more common.
Side effects
- Reactive (Compensatory) Sweating - CS
 |
Massive reactive sweating
front-side of trunk
(Minor's Iodine-Starch-Test) |
This is the most common side effect and is experienced, with widely varying intensity, by most individuals who have undergone sympathetic surgery. Published reports cite an occurrence from only a few percent up to >90%, depending on how this type of sweating is defined. When asking the patient "do you experience any increased sweating in other areas of the body", most of them will reply that their sweating has increased. At the question "do you suffer from significant compensatory sweating", the incidence will be significantly lower.
Reactive sweating occurs mainly on the trunk (from the upper chest to the abdomen - especially over the lower part of the sternum - or on the back), less often on the legs.
Approximately 10% of the patients hardly notice any increase in perspiration after the procedure.
The other extreme is a small group of patients suffering from severe compensatory hyperhidrosis (CHH), a condition that may interfere massively with quality of life. Patients had been operated for craniofacial hyperhidrosis are overrepresented in this group, because they often have a genetic predisposition for oversensitivity to heat. Among patients operated for palmar hyperhidrosis, massive compensatory hyperhidrosis has been observed particularly in individuals who had undergone interruption of the sympathetic chain at or above the ganglion T2 (most of them operated in the 80's and 90's).
The majority reacts with light to moderate reactive sweating, which is mostly not perceived as particularly troublesome. It occurs usually at higher ambient temperatures or during physical exercise, in the warm season more pronounced than in winter. For this category of patients the reactive sweating is significantly less stressful than the condition for which they were operated, although there may be situations where it may appear with annoying intensity.
Regarding the severity of compensatory sweating and the satisfaction rate there are significant differences in the single patient groups:
- a) Palmar hyperhidrosis: these patients have the lowest degree of troublesome compensatory sweating and on the highest level of satisfaction (98%). This applies primarily to those in which an ETS on the T3 ganglion was performed. An interruption at or above T2 results in significantly more sweating.
- b) Facial Blushing: in this group, compensatory sweating usually turns out less intense, as these individuals usually do not present a concomitant dysfunction in sweat regulation. Clip removal rate is around 1%.
- c) Craniofacial hyperhidrosis: patients with this disorder often seem to be affected by a "malfunctioning thermostat". The block of the sympathetic chain will prevent the outgoing nervous signals to reach the head, but it will not reduce the amount of signals at the source. Therefore they will try to find an alternative path. Only psychologically induced signals (stress provoked by facial sweating) may be markedly diminished. The high incidence of compensatory sweating in this group accounts also for a relatively large number of patients requesting removal of the clips (12.5% = 1/8).
A main factor determining the incidence of major side effects is represented by the surgeon's in-depth knowledge of the anatomy of the sympathetic chain and the awareness that utmost technical accuracy has to be employed when interrupting it. The growing number of patients with disabling consequences of ETS reveals that approximate technique is still prevailing. A detailed analysis of the issue can be found here.
Treatment of compensatory hyperhidrosis is difficult. Treatment usually requires a combination of non-surgical measures to obtain an acceptable result. Drugs (anticholinergics), antiperspirants and botulinum toxin (the latter in selected areas of the body where sweating is particularly intense) may improve the overall situation. Additional surgical interventions on the sympathetic nervous system (e.g. T4-T10 sympathectomy) have shown variable results. Clip removal, however, where applicable, should be undertaken as soon as possible to give the nerve a chance to recover at least part of its function.
In many cases, however, compensatory sweating shows spontaneous improvement over time, provided that collateral injury to adjacent ganglia has been avoided, particularly partial damage.
- Gustatory sweating
A phenomenon of sweating in the face triggered by consumption of food, especially spicy food, experienced by about 20% of the patients. It may vary from minimal moisture to, rarely, real sweat attacks. This perspiration seems paradoxical because in contrast to the otherwise lowered or abolished perspiration after surgery for palmar or facial hyperhidrosis. Only in a few cases, gustatory sweating may become a problem and require treatment. The cause is unknown.
- Depressant effect on the cardiocirculatory system
Surgery involving the T2 ganglion or above may result in a lower heart rate at rest and lower blood pressure. Also under physical strain, the upper limit of the heart rate tends to become somewhat lower (10-20 beats/minute). In many cases, this appears to be an advantage, particularly to patients with erythrophobia who experience frequent episodes of tachycardia when blushing which intensifies the stress.
Furthermore, the operation may have favorable effects in patients with tachyarrhythmias or high blood pressure. On the other hand, people with very low baseline blood pressure may experience orthostatic hypotension (fall in blood pressure when moving to the upright position). Again, a limited sympathectomy / blockade causes less side effects on the cardio-circulatory system than an operation extended to several levels/ganglia. Severe bradycardia (very slow heart rate) is an exceedingly rare (<0.1%), but very serious complication and may, in extreme cases, even require the implantation of a pacemaker. It has so far been only observed in patients in whom several segments of the sympathetic trunk were interrupted. For the same reason sympathectomy should be limited to the minimum steps necessary to achieve the desired effect.
In T3 surgery (palmar hyperhidrosis), side effects on the circulatory system are marginal or unmeasurable.
Recurrence
Patients operated for hyperhidrosis can expect a very low risk of relapse (<2%), and also a partial reappearance of increased sweating hardly ever reaches the level of the original hyperhidrotic state. Months after surgery, many patients may notice a gradual return of a slight to moderate degree of perspiration/moisture. This trend is welcome as it allows for a better grip in the hands and the compensatory sweating tends to decrease parallely. Extending surgery on the sympathetic chain to several levels may reduce the (small) risk of relapse, but this will usually create more intense side effects and should therefore be avoided. The aim should be to achieve an acceptable compromise between desired effect and negative side effects.
The risk of relapse is lowest for facial sweating (<1%), around 2-3% for palmar sweating and significantly higher for facial blushing (> 10%, some authors report up to 25%).
In the event of a severe recurrence of palmar sweating after previous intervention on the T2 ganglion, a reoperation targeting the T3 ganglion is almost always successful, with very limited increase in compensatory sweating. If recurrences affect a patient after previous T3 surgery, a T2-operation could be considered (risk for significant increase of compensatory sweating).
Much more difficult is the treatment of recurring facial blushing. In the first place, pharmacological treatment should be tested, since drugs may show better effect after surgery than without blockade of the sympathetic nervous system.
Limitation of complications and side effects: technical aspects
Experience over the last 25 years has shown that the side effects in some cases can reach extreme levels, without this being predictable in an individual case, since the central autonomic nervous system reacts very individually to an interruption of the sympathetic chain.
Overenthusiastically radical or not sufficiently atraumatic surgical technique seems to increase the number of those who regret the surgery because of the very problematic sequelae. This has even led to the formation of interest groups by affected patients with the aim to warn other patients from sympathetic surgery and its consequences.
Non only newbies, but also insiders are confused over the incredible array of surgical methods that run under the common denomination "ETS" and the fact that there is no real standard on how to perform ETS for different dysfunctions of the sympathetic nervous system. Attempts to define a standard approach have resulted in highly questionable guidelines. To get a deeper look into this chaos, you may read "Controversial issues on ETS".
There is no doubt that the surgical technique plays a most important role for the prevention of significant complications and side effects. The following factors are important:
- Level:
The decisive factor for the risk of side effects is primarily the level of the sympathetic trunk, where the interruption is performed. Basically, the interruption should not be executed at an unnecessarily high level. This is especially true for palmar hyperhidrosis, where the involvement of the ganglion T2 is associated with a statistically significantly higher risk for serious side effects, without increasing the desired effect significantly.
It also makes little sense to set the interruption at too low a level with the purpose to diminish the side effects, since experience shows that the therapeutic effect can not be reliably achieved.
- Method of interruption(cold cut, cutting current, heat coagulation, blended current, "clamping"):
- Division
To sever the nerve, electrocautery with pure cutting current should be used. This will seal the cut surface of the nerve, reducing the risk of neuroma formation (not uncommon with "cold cut", e.g. division with scissors). The depth effect (heat effect) of cutting current is minimal, since the tissue in contact with the electrode evaporates immediately. The resulting vapor increases the electrical resistance (tissue impedance) within in fractions of a second which interrupts the current flow. A nerve division can also be technically performed with high intensity coagulating current, but due to the heat extending deep into the tissue this can lead to extensive thermal damage to the nerve and to surrounding tissues and should therefore be avoided.
- Heat Coagulation
With coagulating current or blended current the heat is transferred to the tissue more slowly and with high penetration. Therefore, there is a significant risk for damage to the nerve over a difficult to control distance, which may lead to Horner's syndrome in procedures at the level of 2 Rib. Moreover, there is risk to produce thermal collateral damage to surrounding tissues, in particular to the intercostal nerve which may cause weeklong neuralgic pain and paresthesia/hypoesthesia in the chest wall or upper arm. Therefore, heat coagulation should be avoided where ever possible!
- Neurocompression ("Clamping")
Alternatively, the nerve can be compressed, using titanium clips, and thus rendered incapable of transmitting nervous signals. In case of facial hyperhidrosis and facial blushing, this method of interrupting the nervous function is becoming the dominant one. In case of severe complications (Horner's syndrome) or side effects, there is a chance to restore the function of the nerve, at least partially, by removing the clamp.
This method does not seem to have the same advantages when it comes to palmar hyperhidrosis: a single clip often leads to recurrence and a circling of the T3 ganglion with several clips does not seem to leave much chance for recovery; furthermore, clamping is technically more complex and therefore more prone to technical failure. Regarding effect and side effects, the clips have not shown to offer significant advantages. Rate of clip removal (T3) is extremely low (<1%).
- Extension:
As a principle, the aim should be to achieve the desired effect with the least possible measure. Although, as already mentioned, a radical approach (destruction of several connections or ganglia) reduces the risk of relapse, increases however the proportion of those who have to fight with severe side effects in the aftermath of surgery.
- Destruction / Lesion of Ganglia vs. Interganglionic Interruption:
Only in operations below the ganglion T2, a complete elimination of a ganglion can be considered and possibly even bring benefits. The ganglion T2 should remain intact because of the higher risk of side effects. Necessary interruptions should occur above the ganglion and, if possible, using a potentially reversible method (clamping).
- Atraumatic Surgical Technique:
Particular caution is required when using coagulation in order to avoid thermal damage to close-by structures and tissues like periosteum (bone skin), syndesmoses (fibrous joint capsules) and especially intercostal nerves. Weeklong neuralgic pain in the chest, back and arm are not uncommon after indiscriminate use of coagulation. The formation of adhesions between the pleura and lung are also favored by excessive tissue trauma.
The relatively low recurrence rate as opposed to the potentially deleterious side effects should definitely induce surgeons to prefer surgical methods that limit side effects, rather than striving after radicality to "guarantee" "eternal" and total dryness.
