Optimization of sympathectomy to treat palmar hyperhidrosis: the systematic review and meta-analysis of studies published during the past decade

Single-center experience of thoracoscopic sympathectomy for palmar hyperhidrosis with long-term postoperative questionnaire survey

OBJECTIVES

Thoracoscopic sympathectomy is an effective treatment for palmar hyperhidrosis. However, compensatory hyperhidrosis occurs frequently as a postoperative complication of the procedure. The goal of this study was to elucidate the clinical significance of thoracoscopic sympathectomy using our surgical procedure.

METHODS

Consecutive 151 patients who underwent thoracoscopic sympathectomy for palmar hyperhidrosis were studied. In addition, to investigate patients' satisfaction and long-term quality of life, 111 patients were asked to complete a mailing questionnaire survey, and 84 responded (response rate of 75.7%).

RESULTS

All of the 151 patients reported a reduction in palmar sweating during the immediate postoperative period. None of the patients had pneumothorax, hemothorax, Horner's syndrome, or worsening of bradycardia. Based on the questionnaire, the surgical success rate was 98.8%. None of the patients had a recurrence of palmar hyperhidrosis during the long-term postoperative period. However, compensatory hyperhidrosis was reported in 82 patients (97.6%). In total, 94.0% of patients had high levels of postoperative satisfaction.

CONCLUSIONS

Thoracoscopic sympathectomy is an effective surgical treatment for palmar hyperhidrosis. By contrast, the careful preoperative explanation of compensatory hyperhidrosis is considered to be very important.

Fifteen Years' Experience of Thoracoscopic Sympathetic Chain Interruption for Palmar Hyperhidrosis in Children and Adolescents: Evaluation of Different Techniques

Background: Thoracoscopic sympathetic chain interruption is a definitive and effective therapy for severe primary palmar hyperhidrosis (PPH). Well-known methods include sympathectomy, sympathotomy, and clipping, but the occurrence of compensatory sweating offsets these methods. This study aims to report our experience with thoracoscopic sympathetic chain interruption in a large group of patients of age <18 years with PPH, focusing on surgical outcomes, complication rates, and patient satisfaction. Patients and Methods: This retrospective study included patients who underwent thoracoscopic sympathectomy, sympathotomy, or clipping for severe PPH between April 2008 and March 2023 at the Pediatric Surgery Department, Al-Azhar University Hospitals. Demographic and clinical data, operative steps, postoperative outcomes, complications, and patient satisfaction were reviewed from the patients' medical records. Results: During the 15-year study period, 420 children with PPH underwent bilateral thoracoscopic sympathetic chain interruption by either sympathectomy, sympathotomy, or clipping, with a sex ratio of 60% being females. The mean ages were 12 ± 3.48, 13 ± 2.45, and 13 ± 2.45 years, respectively. Sympathectomy was performed in 190 patients (45.2%), sympathotomy in 170 patients (40.5%), and clipping in 60 patients (14.3%). All patients had completed follow-up, with mean periods of ∼43 ± 5 months, 45 ± 3 months, and 42 ± 6 months, respectively. Complete palmar dryness was achieved in 405 patients (overall 96.4%) (97.8% after sympathectomy, 97.05% after sympathotomy, and 90% after clipping), whereas 2.1%, 2.9%, and 10% of patients experienced symptom recurrence, respectively, denoting significant statistical differences. Overall, 94 patients (22.4%) experienced compensatory sweating. Eventually, 409 patients (97.4%) were satisfied with the outcome, whereas 11 patients (2.6%) reported dissatisfaction, yet no significant differences found. Conclusion: The presented three modalities of thoracoscopic sympathetic chain interruption for PPH in children and adolescents are safe and effective, with overall very high postoperative satisfaction, despite a relatively high rate of compensatory sweating in sympathectomy group. Other major complications in this age population were scanty.

Evaluation of quality of life (QOL) of young patients with primary hyperhidrosis (PH) before and after endoscopic thoracic sympathectomy (ETS)

BACKGROUND

Primary hyperhidrosis (PH) affects young patients and may cause emotional distress and a negative quality of life (QOL).

OBJECTIVE

We sought to evaluate the QOL of children and adolescents with PH treated by endoscopic thoracic sympathectomy.

METHODS

A study of 220 patients was performed, based on submitted QOL questionnaires from their first consultation. Patients were evaluated within 1 week and 24 months after surgery.

RESULTS

Before endoscopic thoracic sympathectomy, the QOL in relation to PH was declared very poor by 141 patients, and poor by the remaining 79 (P = .552). Postoperative cure was reported in 100% of palmar and axillary PH cases, and in 91.7% of facial PH. After 24 months, the QOL was described as much better by 212 patients, a little better by 6 patients, and 2 patients reported no change.

LIMITATIONS

Convenience sampling was used and patients were taken from private practice only, raising the possibility of bias in gathering the data.

CONCLUSION

Onset of PH symptoms was mainly before the age of 10 years and substantially affected daily activities. Endoscopic thoracic sympathectomy cured PH and promoted significant improvement in the QOL of these young patients.

Quality of life after thoracic sympathectomy for palmar hyperhidrosis: a meta-analysis

OBJECTIVE

Palmar hyperhidrosis affects 0.6-10% of the general population, having an important impact in patients' quality of life. The definitive treatment for palmar hyperhidrosis is thoracic sympathectomy. The purpose of this study is to evaluate the quality of life after thoracic sympathectomy for palmar hyperhidrosis.

METHODS

The interest studies were searched in six comprehensive databases. The quality of the studies was assessed using the risk of bias tool recommended by the Cochrane system evaluation manual. Meta-analysis was performed with RevMan version 5.3. The outcome of interest was quality of life. The subgroup analysis and sensitive analysis were performed.

RESULTS

Nine trials, including 895 patients, with accessible data comparing preoperative quality of life score with postoperative quality-of-life score were used for data analysis. Compared with preoperative quality-of-life score, application of thoracic sympathectomy improved the postoperative quality of life of palmar hyperhidrosis patients (MD = 57.81, 95% CI 53.33-62.30). Subgroup analysis of the different thoracic sympathectomy segment showed that there was no significant difference in the results obtained when operated with single segment or multiple segments (single segment: MD = 61.16, 95% CI [56.10, 66.22], multiple segments: MD = 52.14, 95% CI [48.39, 55.88]).

CONCLUSION

The meta-analysis provided evidence of the improved quality of life after thoracic sympathectomy for palmar hyperhidrosis.

Interventions for hyperhidrosis in secondary care: a systematic review and value-of-information analysis

BACKGROUND

Hyperhidrosis is uncontrollable excessive sweating that occurs at rest, regardless of temperature. The symptoms of hyperhidrosis can significantly affect quality of life. The management of hyperhidrosis is uncertain and variable.

OBJECTIVE

To establish the expected value of undertaking additional research to determine the most effective interventions for the management of refractory primary hyperhidrosis in secondary care.

METHODS

A systematic review and economic model, including a value-of-information (VOI) analysis. Treatments to be prescribed by dermatologists and minor surgical treatments for hyperhidrosis of the hands, feet and axillae were reviewed; as endoscopic thoracic sympathectomy (ETS) is incontestably an end-of-line treatment, it was not reviewed further. Fifteen databases (e.g. CENTRAL, PubMed and PsycINFO), conference proceedings and trial registers were searched from inception to July 2016. Systematic review methods were followed. Pairwise meta-analyses were conducted for comparisons between botulinum toxin (BTX) injections and placebo for axillary hyperhidrosis, but otherwise, owing to evidence limitations, data were synthesised narratively. A decision-analytic model assessed the cost-effectiveness and VOI of five treatments (iontophoresis, medication, BTX, curettage, ETS) in 64 different sequences for axillary hyperhidrosis only.

RESULTS AND CONCLUSIONS

Fifty studies were included in the effectiveness review: 32 randomised controlled trials (RCTs), 17 non-RCTs and one large prospective case series. Most studies were small, rated as having a high risk of bias and poorly reported. The interventions assessed in the review were iontophoresis, BTX, anticholinergic medications, curettage and newer energy-based technologies that damage the sweat gland (e.g. laser, microwave). There is moderate-quality evidence of a large statistically significant effect of BTX on axillary hyperhidrosis symptoms, compared with placebo. There was weak but consistent evidence for iontophoresis for palmar hyperhidrosis. Evidence for other interventions was of low or very low quality. For axillary hyperhidrosis cost-effectiveness results indicated that iontophoresis, BTX, medication, curettage and ETS was the most cost-effective sequence (probability 0.8), with an incremental cost-effectiveness ratio of £9304 per quality-adjusted life-year. Uncertainty associated with study bias was not reflected in the economic results. Patients and clinicians attending an end-of-project workshop were satisfied with the sequence of treatments for axillary hyperhidrosis identified as being cost-effective. All patient advisors considered that the Hyperhidrosis Quality of Life Index was superior to other tools commonly used in hyperhidrosis research for assessing quality of life.

LIMITATIONS

The evidence for the clinical effectiveness and safety of second-line treatments for primary hyperhidrosis is limited. This meant that there was insufficient evidence to draw conclusions for most interventions assessed and the cost-effectiveness analysis was restricted to hyperhidrosis of the axilla.

FUTURE WORK

Based on anecdotal evidence and inference from evidence for the axillae, participants agreed that a trial of BTX (with anaesthesia) compared with iontophoresis for palmar hyperhidrosis would be most useful. The VOI analysis indicates that further research into the effectiveness of existing medications might be worthwhile, but it is unclear that such trials are of clinical importance. Research that established a robust estimate of the annual incidence of axillary hyperhidrosis in the UK population would reduce the uncertainty in future VOI analyses.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42015027803.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Effectiveness of bilateral clipping of the thoracic sympathetic chain for the treatment of severe palmar and/or axillary hyperhidrosis and facial flushing

INTRODUCTION

Division of the thoracic sympathetic chain is the standard treatment for severe palmar and/or axillary hyperhidrosis and facial flushing. Clipping is an alternative option which allows the block to be reverted in cases of intolerable compensatory sweating.

METHODS

This is a prospective study performed to assess: a) results of clipping of the thoracic sympathetic chain in patients with palmar and/or axillary hyperhidrosis and facial flushing; and b) to determine the improvement obtained after removal of the clip in patients with unbearable compensatory sweating. We included 299 patients (598 procedures) diagnosed with palmar hyperhidrosis (n=110), palmar and/or axillary hyperhidrosis (n=78), axillary hyperhidrosis (n=35), and facial flushing (n=76), who underwent videothoracoscopic clipping between 2007 and 2015.

RESULTS

128 men and 171 women were treated, with mean age of 28 years. A total of 290 patients (97.0%) were discharged within 24hours. The procedure was effective in 92.3% (99.1% in palmar hyperhidrosis, 96,1% in palmar and/or axillary hyperhidrosis, 74.3% in axillary hyperhidrosis, and 86.8% in facial flushing). Nine patients (3%) presented minor complications. Compensatory sweating developed in 137 patients (45.8%): moderate in 113 (37.8%), severe in 16 (5.3%) and unbearable in 8 (2.7%). The clip was removed in these 8 patients; symptoms improved in 5 (62.8%), with sustained effect on hyperhidrosis in 4 of them.

CONCLUSIONS

Clipping of the thoracic sympathetic chain is an effective and safe procedure. If incapacitating compensatory sweating develops, this technique allows the clips to be removed with reversion of symptoms in a considerable number of patients.

Anxiety after Sympathectomy in patients with primary palmar hyperhidrosis may prolong the duration of compensatory hyperhidrosis

Background

Compensatory hyperhidrosis (CH) is a frequent side effect after sympathectomy for the treatment of primary palmar hyperhidrosis. We determined the effects of demographic and clinical factors which may increase the duration of CH (DCH).

Methods

One hundred twenty-two patients who had undergone sympathectomies from 2014 to 2016 were retrospectively reviewed. Anxiety was evaluated using the State and Trait Anxiety Inventory score. Follow-up evaluations continued until CH remitted. A Cox proportional hazards model was used to determine the association between DCH and variables.

Results

DCH ranged from 5 to 27 weeks (median, 11.47 weeks). Severe CH (HR = 0.318, 95% CI, 0.136–0.741) and exacerbated anxiety 1 month post-operatively (HR = 0.816, 95% CI, 0.746–0.893) may prolong CH. A positive correlation between post-operative anxiety and DCH was common in patients with moderate or severe CH, and in cases with forearm CH.

Conclusions

Pre- and post-operative anxiety should be evaluated, and anti-anxiety treatment is offered to patients with moderate-to-severe CH to shorten the DCH.

Electronic supplementary material

The online version of this article (10.1186/s13019-018-0736-3) contains supplementary material, which is available to authorized users.

Optimal targeting of sympathetic chain levels for treatment of palmar hyperhidrosis: an updated systematic review

BACKGROUND

Palmar hyperhidrosis involves excessive sweating of the palms, with no known etiology. Endoscopic thoracic sympathectomy (ETS) is a safe and effective treatment for palmar hyperhidrosis, but compensatory hyperhidrosis is a common complication after ETS, leading to reduced patient satisfaction and postoperative quality of life. However, the appropriate level of the sympathetic chain to target with ETS to achieve maximum efficacy and reduce the risk of compensatory hyperhidrosis (CH) is controversial. In this systemic review, we investigated the appropriate level of sympathectomy for palmar hyperhidrosis.

METHODS

PRISMA guidelines were implemented to complete a systematic review. We performed a computerized systematic literature search using PubMed and EMBASE from January 1990 to July 2016. We chose the Cochrane Collaboration's tool and the methodological index for non-randomized studies tool for examining study bias.

RESULTS

A total of 4075 citations were identified, of which 91 were eligible for inclusion, including 68 observational studies and 23 comparative trials. In observational studies, sympathectomies showed similar efficacies for curing PH at different levels. However, T2-free groups (i.e., at levels T3, T4, or T3-T4 combined) could render a lower risk of Horner's syndrome (0 vs. 1.21 ± 0.49%, p = 0.036) and CH (28.75 ± 7.25 vs. 57.46 ± 3.86, p = 0.002) compared with T2 involved. In comparative trials, there were 12 studies describing the comparison between T2-free ETS and T2 involved, and 9 of 12 (75%) showed T2-free ETS could reduce the incidence of CH. Overall, lowering the level and limiting the extent of sympathectomy could reduce the incidence of complications.

CONCLUSIONS

Cumulative data from more than 13,000 patients suggest that ETS is a safe, effective, and reproducible procedure with a high degree of patient satisfaction. Currently available evidence suggests that T2-free ETS may reduce the incidence of compensatory hyperhidrosis without compromising success rates and safety.

Thoracoscopic sympathicotomy in the treatment of palmar hyperhidrosis

Background

Primary hyperhidrosis interferes with social activities and requires an effective and safe treatment. We aimed to compare the therapeutic outcomes of unilateral single-port sympathicotomy and open surgery.

Methods

Forty patients with primary palmar hyperhidrosis underwent sympathicotomy; 20 had open surgery, and 20 had video-assisted thoracic surgery. Complete resection of the T1 to T4 ganglia was performed by open surgery, and cutting and cauterization of the sympathetic chain between the T2 and T3 ganglia in the dominant hand was undertaken using video-assisted thoracic surgery. The patients were followed up at 1, 3, 6, and 12 months after surgery.

Results

The mean operative times were 39.6 ± 1.46 and 79.8 ± 1.53 min in the video-assisted thoracic surgery and open surgery group, respectively. The mean hospitalization was 2.2 ± 0.41 days after video-assisted thoracic surgery and 3.3 ± 0.47 days after open surgery. Complications included delayed hemothorax, compensatory hyperhidrosis, and wound infection. The mean blood loss during surgery and time to return to work were significantly less in the video-assisted thoracic surgery group. Excessive sweating was completely alleviated in the dominant hand in all patients, and in the opposite hand in 60% and 65% of the video-assisted thoracic surgery and open surgery group, respectively.

Conclusion

Single-port sympathicotomy between the T2 and T3 ganglia ipsilateral to the dominant hand is a safe, minimally invasive, and effective treatment for primary palmar hyperhidrosis. Alleviation of excessive sweating in the opposite hand can also be achieved in a large proportion of these patients.

Electric vs. harmonic scalpel in treatment of primary focal hyperhidrosis with thoracoscopic sympathectomy

BACKGROUND

Hyperhidrosis is defined as excessive sweating beyond the physiologic needs of a person. Palmar hyperhidrosis in the adolescent period may have an impact on school work and may cause psychological problems. Thoracoscopic sympathectomy is now used routinely to treat patients with disabling primary hyperhidrosis or facial blushing.

PATIENTS AND METHODS

From January 2008 to December of 2009 bilateral thoracoscopic sympathectomy Th2-Th4 was performed to 79 patients aged from 17 to 55, who suffered from palmar, axillar or craniofacial hyperhidrosis. For the first 39 patients (group A) thoracoscopic sympathectomy was performed using electric scalpel and for the next 40 patients (group B) thoracoscopic sympathectomy was performed using harmonic scalpel.

RESULTS

Based on our results we did not find any significant differences between electric or harmonic scalpel usages for thoracoscopic sympathectomy. Moreover, there was no significant difference between complications and the severity of pain, with slightly higher intensity of pain with harmonic scalpel usage. Both electric and harmonic scalpel provided adequate treatment for primary hyperhidrosis, with the fact that non-disposable electric scalpel costs were less than that of the disposable harmonic scalpel.

CONCLUSIONS

Sympathectomy should be preferred for palmar hyperhidrosis treatment, as it is much technically shorter, simpler to implement, and also easier to learn. Thoracoscopic sympathectomy is safe and effective for the treatment of primary palmar hyperhidrosis in the adolescent period without any major side effects.

Thoracic sympathectomy: a review of current indications

BACKGROUND

Thoracic sympathetic ablation was introduced over a century ago. While some of the early indications have become obsolete, new ones have emerged. Sympathetic ablation is being still performed for some odd indications thus prompting the present study, which reviews the evidence base for current practice.

METHODS

The literature was reviewed using the PubMed/Medline Database, and pertinent articles regarding the indications for thoracic sympathectomy were retrieved and evaluated. Old, historical articles were also reviewed as required.

RESULTS AND CONCLUSIONS

Currently, thoracic sympathetic ablation is indicated mainly for primary hyperhidrosis, especially affecting the palm, and to a lesser degree, axilla and face, and for facial blushing. Despite modern pharmaceutical, endovascular and surgical treatments, sympathetic ablation has still a place in the treatment of very selected cases of angina, arrhythmias and cardiomyopathy. Thoracic sympathetic ablation is indicated in several painful conditions: the early stages of complex regional pain syndrome, erythromelalgia, and some pancreatic and other painful abdominal pathologies. Although ischaemia was historically the major indication for sympathetic ablation, its use has declined to a few selected cases of thromboangiitis obliterans (Buerger's disease), microemboli, primary Raynaud's phenomenon and Raynaud's phenomenon secondary to collagen diseases, paraneoplastic syndrome, frostbite and vibration syndrome. Thoracic sympathetic ablation for hypertension is obsolete, and direct endovascular renal sympathectomy still requires adequate clinical trials. There are rare publications of sympathetic ablation for primary phobias, but there is no scientific basis to support sympathetic surgery for any psychiatric indication.

Sympathotomy for palmar hyperhidrosis: the cutting versus clamping methods

PURPOSE

Endoscopic thoracic sympathectomy/sympathotomy for the treatment of palmar hyperhidrosis is generally performed by either cutting or clamping the sympathetic chain. However, it remains unclear as to which of these methods is more effective and has fewer side effects. This study was conducted to compare the effects of sympathotomy by cutting or clamping at T3 on two outcomes--postoperative palmar sweating and compensatory sweating; it also evaluated postoperative patient satisfaction.

METHODS

The participants were among 289 patients who underwent bilateral sympathotomy at T3 for palmar hyperhidrosis. These patients were sent questionnaires by mail to assess their self-reported degree of postoperative palmar sweating and compensatory sweating, as well as their level of satisfaction. Of the 92 patients who responded to the questionnaire, 54 had undergone sympathotomy by cutting (cutting group) and 38 by clamping (clamping group).

RESULTS

The degree of postoperative palmar sweating was significantly lower in the cutting group than in the clamping group. However, compensatory sweating was significantly more severe in the cutting group than in the clamping group. No significant difference was observed in the degree of patient satisfaction between the groups.

CONCLUSIONS

Sympathotomy by clamping at T3 was less effective in reducing the primary symptom of postoperative palmar sweating, but induced less compensatory sweating than did sympathotomy by cutting at T3. However, both methods were similar with regard to patient satisfaction. The degree of postoperative palmar sweating and the severity of compensatory sweating were inversely correlated with the degree of patient satisfaction.

Compensatory sweating after restricting or lowering the level of sympathectomy: a systematic review and meta-analysis

OBJECTIVE

To compare compensatory sweating after lowering or restricting the level of sympathectomy.

METHOD

A systematic review and meta-analysis were conducted of all randomized controlled trials published in English that compared compensatory sweating after lowering or restricting the level of sympathectomy. The Cochrane collaboration tool was used to assess the risk of bias, and the Mantel-Haenszel odds ratio method was used for the meta-analysis.

RESULTS

A total of 11 randomized controlled trials were included, including a total of 1079 patients. Five of the randomized controlled trials studied restricting the level of sympathectomy, and the remaining six studied lowering the level of sympathectomy.

CONCLUSIONS

The compiled randomized controlled trial results published so far in the literature do not support the claims that lowering or restricting the level of sympathetic ablation results in less compensatory sweating.

Quality of life after sympathetic surgery at the T4 ganglion for primary hyperhidrosis: clip application versus diathermic cut

INTRODUCTION

Limited procedures at the T4 ganglion show low rates of compensatory sweating (CS). The aim of the study was to compare endoscopic sympathetic block (ESB) via clip application with endothoracic sympathicotomy (ETS) via diathermy with special regard on patients' quality of life (Qol).

PATIENTS AND METHODS

Treatment success, side effects and patient satisfaction were evaluated in a prospectively gathered database of a tertiary-care referral hospital. Two disease-specific Qol questionnaires were used (Keller, Milanez de Campos).

RESULTS

406 operations were performed in 205 patients (ESB4 N = 114, ETS4 N = 91) with a median follow-up of 12 months. Both procedures improved Qol significantly (P < 0.001) and the degree of improvement was equal in both groups. Palmar and axillary HH were ameliorated after both procedures (P < 0.001). Accordingly, plantar HH decreased after ESB4 (P = 0.002), while remaining unaltered after ETS4. Nineteen patients (9.3%) reported CS and 10 patients (4.9%) judged it as "disturbing". Nine of the latter belonged to the ETS4 group compared to one ESB patient (P = 0.015). Patients developed higher rates of plantar CS after ETS4 compared to ESB4 (P = 0.006). Five patients (2.4%) from both cohorts reported persistence of axillary HH. Recurrence of axillary symptoms was found in 5 ESB4 patients. Satisfaction rates did not differ significantly.

CONCLUSION

Patients' Qol and satisfaction rates are similar in both treatment groups for upper limb HH. Outcome and recurrence rates speak in the favor of ETS4, severity of CS and potential reversibility argue for ESB4.

Turning the tide: a history and review of hyperhidrosis treatment

Hyperhidrosis is a potential cause of severe physical and psychological distress, interfering in activities of daily living. Over the past 100 years, advances have been made regarding the treatment of this debilitating condition with some success. Surgical treatment with sympathectomy was successfully performed for hyperhidrosis in the early part of the 20th century, with various modifications of the technique over the past 100 years. Topical aluminium salt antiperspirants, anticholinergic medications, iontophoresis and botulinum toxin introduced less invasive ways to manage this condition. This historical review will enable dermatologists and non-dermatologists to manage this distressing condition.

Long-term outcomes associated to video-assisted thoracic sympathotomy for palmar-axillar subtype of the hyperhidrosis

OBJECTIVE

Surgery for both palmar and axillar hyperhidrosis usually includes the interruption of the sympathetic chain in multiple levels. This study aimed to determine the long-term outcomes associated to video-assisted thoracic sympathotomy (VATS) of T2, T3 and T4 ganglia for these cases.

METHODS

Analysis of the outcomes obtained from 36 patients regarding the rate of resolution of the symptoms and the compensatory sweating (CS). All subjects were followed-up for 36 months.

RESULTS

Good outcomes were observed in 98.6% for palmar and 60% for axillary hyperhidrosis (p=0.0423), respectively. Of the subjects, 86% reported some postoperative episode of CS, however only 45% (p=0.0031) still noticed it at the end of the follow-up period.

CONCLUSIONS

VATS is effective for the excessive palmar sweating, whereas it is fully efficient for only two thirds of the cases sustaining associated axillar hyperhidrosis. CS is expected as a rule following the proposed operative protocol, however it is usually self-limited.

Compensatory hyperhidrosis following thoracic sympathectomy: a biophysical rationale

A side-effect of endoscopic thoracic sympathectomy (ETS) is compensatory hyperhidrosis (CH), characterized by excessive sweating from skin areas with intact sudomotor function. The physiological mechanism of CH is unknown, but may represent an augmented local sweat rate from skin areas with uninterrupted sympathetic innervation based on evaporative heat balance requirements. For a given combination of activity and climate, the same absolute amount of evaporation (if any) is needed to balance the rate of metabolic heat production both pre- and post-ETS. However, the rate of local sweating per unit of skin surface area with intact sudomotor activity must be greater post-ETS as evaporation must be derived from a smaller skin surface area. Under conditions with high evaporative requirements, greater degradations in sweating efficiency associated with an increased dripping of sweat should also occur post-ETS, further pronouncing the sweat rate required for heat balance. In conclusion, in addition to the potential role of psychological stimuli for increased sudomotor activity, the existence of CH post-ETS can be described by the interplay between fundamental thermoregulatory physiology and altered heat balance biophysics and does not require a postoperative alteration in physiological control.