Endoscopic thoracic sympathectomy (ETS) has become the treatment of choice for patients suffering from moderate-to-severe palmar hyperhidrosis [1–3]. Despite impressive patient satisfaction rates with ETS, there has been much debate on the level of sympathectomy for treatment of hyperhidrosis. Compensatory hyperhidrosis (CH) is the most common side effect of ETS and exerts a negative impact on patient’s postoperative quality of life [4, 5]. The relationship of CH to the extent and levels of sympathectomy has been the subject of intense debate among thoracic surgeons [6]. Recent expert consensus by Cerfelio et al. [7] has suggested that the most common risk factor cited in the literature for moderate-to-severe CH was T2 ganglion interruption [8–10]. However, the number of levels interrupted has been proven inconclusive as a risk factor.

While short-term results and postoperative complications have been reported extensively in the literature, long-term follow-ups analyzing the progression of the effected treatment and its side effects for 5 years and above are rare [11, 12] and difficult.

Therefore, the aim of this study is to analyze and compare the long-term results of two different levels of denervation, T2 and T2–T3 to verify the effectiveness of different ablations on symptoms of hyperhidrosis, as well as side effects and to determine patient satisfaction from our previous randomized controlled trial [13].

Materials and methods

Most studies on VATS for palmar hyperhidrosis often involve symmetrical, single-level (T2 only) or multi-level (T2–T3) sympathectomy bilaterally. In our study, we recruited patients who had undergone asymmetrical sympathectomy to reduce the confounding effect in terms of difference in patient factors. All patients were worked up preoperatively to exclude secondary causes of hyperhidrosis including hyperthyroidism, chronic infections, malignancy, and immunological disorders. Long-term follow-up was carried out between December 2012 and December 2013.

A total of 39 patients from 2003 to 2010 were enrolled for this study and were randomized to undergo unilateral T2 and T3 blockade with contralateral blockade of T2 only. The side undergoing ablation at levels T2 or T2–T3 was randomized by the “closed envelope” method similar to the one mentioned from Katara et al. [13].

Between 2012 and 2013, these patients were subjected to telephone interview using a standardized set of questions and interview script. Both patients and the observer (interviewer) were blinded to the levels of sympathectomy. The questions can be found in Table 1. Our questionnaire used the same definition of disease severity from hyperhidrosis disease severity scale [14] adapted from the International Hyperhidrosis Society, except that instead of using a point system, we used a modified 4-grade scale: (1) none, (2) mild, (3) moderate, and (4) severe. Each patient was analyzed as a whole for overall satisfaction, the presence of recurrence of palmar hyperhidrosis, and severity of compensatory sweating. Satisfaction was rated by patients on a scale of 1 (most satisfied) to 10 (least satisfied), and the scores were categorized into four main groups: very satisfied, satisfied, dissatisfied, and very dissatisfied. Recurrence was considered when a person experienced a return of palm sweating after it was confirmed to be dry after operation, while compensation was considered if a person experienced new sweating or worsening sweating in other parts of the body that was not present before the surgery. Recurrence and compensatory hyperhidrosis of five sites (lower limb, trunk, axillae, face, and groin) were also assessed using our 4-grade scale.

Table 1 Follow-up questionnaire
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To compare T2 and T2–T3, we adopted a novel approach. The level of sympathectomy on one side was matched to the ipsilateral recurrence of palmar hyperhidrosis, the site and the severity of compensatory sweating for body parts that were not found in the midline (axilla and lower limbs specifically). The outcomes of single-level versus multi-level ablation were then compared.

Patients were informed of the purpose of the study. Domain-specific review board (DSRB) approval was granted (Reference 2012/00264). All the statistics were calculated using SPSS software version 20 (SPSS Inc., Chicago, IL, USA).

Surgical procedure

The ETS procedure was performed with the patient under general anesthesia using single-lung ventilation via a double-lumen endotracheal tube as previously described by Katara et al. [13]. A needlescopic technique was utilized. The T2 and/or T3 ganglia were identified (above the corresponding rib) and ablated using monopolar diathermy until the two ablated ends were at least 1 cm apart. A positive ablation was confirmed by a rise in temperature measured on the finger probe.

Results and analysis

Patient descriptive (Table 2)

Twenty-two out of thirty-four patients (56.4 %) responded to the telephone interview, with the others lost to follow-up (Fig. 1) due to loss of contact (patients’ contact numbers were not updated, or patients left the country). The study group consisted of patients with a male-to-female ratio of 3:1 and a mean age of 36.5 years (range 14–58 years). The side for T2 or T2–T3 ablation was randomly selected with 22 (81.8 %) patients undergoing two-level ablation on the right (group A) and 4 (18.2 %) patients undergoing the procedure on the left (group B).

Table 2 Patient characteristics and operative details
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Fig. 1
figure 1

Study profile of the randomized controlled trial to compare between unilateral T2 and contralateral T2–T3 sympathectomy in single patients

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Operation details and short-term outcomes (Table 3)

Average operative time was 42 min. All patients had a rise of >0.5 °C in probe temperature over their palms after ablation. Four cases of postoperative pneumothorax and four cases of subcutaneous emphysema were reported, and all of them were treated conservatively with in-patient observation, requiring at most a day or two of prolonged hospital stay. No mortalities were recorded.

Table 3 Operative details
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Long-term overall results (Table 4)

Patients were followed up for a mean of 105 months (range 38–153 months). All patients had confirmed that their palmar hyperhidrosis had resolved immediately after the operation, with both palms equally dry. Of the 22 patients, 4 (18 %) patients suffered from mild recurrence of palmar hyperhidrosis and 20 (91 %) patients experienced some form of compensatory sweating. Of these 20 patients, trunk compensatory was the most common with 18 reported cases (82 %), followed by the lower limb (14 cases—64 %) and axilla (10 cases—45 %). Overall, 59.1 % (13) of the patients were very satisfied with the operation, 13.6 % (3) merely satisfied, 13.6 % (3) dissatisfied, and 13.6 % (3) very dissatisfied. There were no other reported complications.

Table 4 Long-term clinical outcomes of ETS
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Long-term results based on level of ablation (T2 vs T2–T3)

Ipsilateral outcomes were compared to the level of sympathectomy performed (T2 vs T2–T3). Of the four patients who suffered from recurrence of palmar hyperhidrosis, there was no absolute difference in the severity of the sweating bilaterally. There was also no absolute difference between the site (lower limb and axilla) and severity of compensatory sweating.

Overall level of satisfaction

A total of 72.8 % of the respondents (16 out of 22) were either very satisfied or satisfied with the procedure. Among the six patients who are dissatisfied with the procedure, two (33.3 %) patients had recurrence of palmar hyperhidrosis, while four (66.6 %) patients experienced some form of compensatory sweating.

Discussion

ETS is currently recognized as the best method of treatment of palmar hyperhidrosis in terms of its efficacy and safety profile [15].

In our long-term analysis, there was no relative difference in recurrence rate between the two different levels of sympathectomy as recurrence in patients occurred symmetrically and bilaterally. Both different levels of sympathectomy brought good effects in reducing palmar hyperhidrosis equally, with immediate postoperative relief in all patients and up to 81.8 % having nonrecurrence up till 5 years postoperatively. Only two patients reported to have recurrence of symptoms of which both only had mild symptoms that did not severely affect their activities of daily living. Recurrent hyperhidrosis has been widely reported as one of the potential side effect from hyperhidrosis surgery, with incidence rate varying considerably from 0 to 65 % [11, 16]. Failure of symptom resolution can be attributed to various causes such as mistaken identification of the sympathetic level, incomplete ablation, or accessory nerve pathways [6] (Kuntz fiber). Resympathectomy has been advocated and successfully performed for immediate failures and recurrence cases [17] if the surgeon acknowledges possible anatomic variations and can overcome the problems related to pleural adhesions [18].

Compensatory sweating is the most common and distressing complication for sympathectomy. It is characterized by the appearance of excessive perspiration in regions of the body where it had not been previously observed. Different studies have had controversial results in terms of this side effect, which occurs in the literature from 3 to 98 % [19, 20]. Our study describes a higher rate of CH (91 %) than reported usual rate of around 60 % [11]. This could be attributed to the hot and humid environment of Singapore, with previous reports from countries such as Taiwan [21, 22] and Middle East countries [23] that have similar climate conditions showing high rates of CH. Besides climate, if patients are already experiencing increased sweating in regions such as the trunk, groin, or upper thighs, they are at increased risk of developing CH [7] and they should be counseled before proceeding with procedure.

The overall satisfaction rate of ETS (72.7 %) in our study was much lower than that of most studies in the literature. About two-thirds of the patients who indicated that they were dissatisfied with the procedure had complained of CH. In studies with high rates of CH, a similar level of satisfaction was seen [21, 24]. Gossot et al. [11] also reported that majority of the patients who were dissatisfied with the surgery gave severe CH as the main reason. Panhofer et al. [25] also reported that the quality of life in patients who developed severe CH was worse than before surgery. Therefore, it is important to identify the risk factors for the development of CH, so that those patients with higher risk of developing severe CH can be excluded for surgery.

Another reason that could explain the lower rates of satisfaction is the nature of the study being a long-term one. Patient satisfaction is related not only to the results (resolution of palmar sweating), but also to patient tolerance to side effects. Once the initial euphoria over the improvement in their palmar sweating dissipates, the patient’s unsatisfied perception about postoperative side effects will be amplified.

Besides compensatory hyperhidrosis, excessive dryness of the hands can also influence the degree of postoperative patient satisfaction [26, 27]. In our study, almost a quarter of patients experienced some form of overdryness of the hand. Excessive dry hands are a cause for dissatisfaction as they are inconvenient in daily life activities and require frequent use of moisturizers. Liu et al. [28] have suggested a correlation between excessively dry hands and lower degree of patient satisfaction. Although we were unable to show a statistically significant correlation in our study between dry hands and level of satisfaction due to small sample size, it is important to consider this side effect when counseling patient for operation.

In addition, it is often suggested that CH progressively disappears with time [29–32]. Our experience demonstrates that CH was still present after more than 2 years and patients did not report improvement with time. Although we did not specifically ask for the onset of CH, it was well noted in the literature [33] that most CH occurred within the first 8 weeks to a year after operation. In our study, the mean follow-up of patients with CH is about 8 years, with more than 90.2 % of the patients complaining of some form of CH still persisting. Hence, it can be admitted that the common assertion that CH vanishes with time is most likely wrong. This is in accordance with many long-term studies [11, 12] that report similar high rates of CH after long periods of follow-up.

The strength of our study lies in its long follow-up time period. In our study, we captured long-term clinical outcomes such as recurrence, CH, and patient satisfaction, which may not be accurately captured at short-term follow-up. Admittedly, our nonresponse rate was significant, despite measures to contact our patients. In addition, the unique part of our study is that we look specifically at patients who underwent asymmetrical level of thoracic sympathectomy to compare the effects of extent of sympathectomy with its long-term outcomes, as most studies compared patients who received the same level of sympathectomy bilaterally. This way of comparing reduces the heterogeneity of patient factors in affecting outcome and gives us a more accurate view of whether T2 ablation is as effective as T2–T3 ablation.

Conclusion

In conclusion, endoscopic thoracic sympathectomy is the treatment of choice for patients with primary hyperhidrosis. Our study concluded that T2 ablation in VATS for palmar hyperhidrosis was as effective as T2–T3 in terms of outcome, recurrence, and compensatory sweating. CH was an important factor in patient satisfaction, and our results suggested that a warmer climate may precipitate increased rate of severe CH. Hence, patients have to be counseled on the risks of CH, especially since our results suggest that a warmer climate may result in higher rates of CH. They must also be counseled on the other risks, such as the possibility of recurrence and hand overdryness, since these factors also have an impact on patient satisfaction. Although we had a limited number of cases and need to randomize a larger study group to substantiate our results, there seemed to be no significant difference between the extent of sympathectomy and the risks of CH or recurrence noted in our study at present.