A prospective controled randomized multicenter study to evaluate severity of compensatory sweating after one-stage bilateral thoracic sympathectomy versus unilateral thoracic sympathectomy in the dominant side

This prospective randomized multicenter study demonstrates that while one-stage bilateral thoracic sympathectomy offers superior symptom control and quality-of-life improvements for primary palmar hyperhidrosis compared to unilateral surgery, it carries a significantly higher risk of severe compensatory sweating, supporting a staged approach where unilateral surgery may suffice for some patients.

The Gist

The Big Picture: The "Sweaty Hand" Problem

Imagine your hands are like two sponges that are constantly dripping water, even when you aren't hot or exercising. This is Palmar Hyperhidrosis. It's not just a nuisance; it ruins your ability to hold a pen, shake hands, or use a touchscreen without leaving a wet fingerprint. It can make people feel embarrassed and avoid social situations.

For years, the standard "cure" has been a surgery called Sympathectomy. Think of the nerves that control your sweat glands as electrical wires running up your spine. The surgery cuts these wires (specifically at the T4 level) to stop the signal from reaching your hands.

The Dilemma: The "Over-Correction" Side Effect

Here's the catch: When you cut the wires to stop the hands from sweating, your body gets confused. It thinks, "Hey, I can't sweat from my hands anymore, so I need to dump all that heat somewhere else!"

This leads to Compensatory Sweating (CS). Instead of wet hands, you might get a soaking wet back, chest, or stomach. For many patients, this new problem is almost as bad as the old one.

The Study's Question: One Cut or Two?

The researchers wanted to know: Is it better to cut the wires on both sides at once (Bilateral), or just on the dominant hand first (Unilateral) and see what happens?

They treated this like a cooking experiment. They had 163 people with sweaty hands and split them into two groups:

1. The "All-in" Group (Bilateral): They cut the nerves on both sides immediately.
2. The "Test Drive" Group (Unilateral): They cut the nerves on the dominant side only. If the patient was still unhappy with the other hand later, they could come back for a second surgery (a "Two-Stage" approach).

The Results: The Good, The Bad, and The "Maybe"

1. How well did it stop the sweating?

• The "All-in" Group: Both hands became dry almost instantly. It was like turning off two faucets at the same time.
• The "Test Drive" Group: The dominant hand became dry, just like the other group. But the other hand? It stayed wet for most people.
  • The Silver Lining: About 1 in 7 people in the "Test Drive" group found that their non-operated hand got better on its own without a second surgery. It's like the body's thermostat recalibrated itself slightly.

2. The "Side Effect" (Compensatory Sweating)

This is where the groups differed the most.

• The "All-in" Group: Because they cut both sides of the nervous system, their bodies had to work harder to cool down. 40% of them developed severe compensatory sweating (soaking wet backs/torsos).
• The "Test Drive" Group: Because they only cut one side, their bodies had a "safety valve" on the other side. Only 21% developed severe sweating.
  • Analogy: Imagine a dam holding back water. If you break the dam in two places at once (Bilateral), the flood is massive. If you break it in one place (Unilateral), the flood is smaller, and the other side of the river can still handle some of the flow.

3. Quality of Life

• The "All-in" Group: They felt the best overall. Their hands were dry, and their confidence skyrocketed. They were willing to trade the risk of a wet back for dry hands.
• The "Test Drive" Group: They felt much better than before surgery, but not quite as good as the "All-in" group because they still had one wet hand.

The "Two-Stage" Strategy: The Best of Both Worlds?

The study looked at the people in the "Test Drive" group who decided to go back for the second surgery later.

• The Result: When they finally got the second surgery, their second hand became dry, and their quality of life jumped up to match the "All-in" group.
• The Safety Net: Crucially, when they did the second surgery later, they did not get the severe sweating side effects as often as the people who did both at once. It seems the body handles the shock better if you do it in two steps.

The Bottom Line: What Should You Do?

Think of this like buying a car:

• Bilateral Surgery (One-Stage): You buy the fully loaded, top-tier model immediately. It has all the features (dry hands), but it's expensive (high risk of severe side effects).
• Unilateral Surgery (Staged): You buy the base model first. It works great on the driver's side. If you realize you need the passenger side fixed later, you can upgrade. The best part? You might find the base model is enough for you, saving you the cost of the upgrade. And if you do upgrade later, it's a smoother ride with fewer side effects.

The Takeaway:
If you want the absolute best result immediately and are willing to risk a wet back, go Bilateral.
If you want to be cautious, minimize the risk of severe side effects, and are okay with a "wait and see" approach, go Unilateral. You can always fix the other hand later, and you might even find you don't need to.

The doctors concluded that there is no single "perfect" answer. It depends on what the patient values more: immediate perfection or a safer, step-by-step approach.

Technical Summary

1. Problem Statement

Primary palmar hyperhidrosis (PH) is a debilitating condition affecting approximately 2.8% of the population, causing significant psychosocial distress and functional impairment. While Video-Assisted Thoracic Sympathectomy (VATS) is the gold standard surgical treatment, it is frequently associated with Compensatory Sweating (CS)—excessive sweating in previously unaffected body regions (e.g., trunk, back, abdomen). CS is the most common adverse event, occurring in up to 90% of patients, and severe cases can lead to patient dissatisfaction comparable to preoperative symptoms.

The clinical dilemma lies in balancing symptom control against the risk of CS. While one-stage bilateral sympathectomy (BTS) offers complete bilateral control, it carries a higher risk of severe CS. Unilateral sympathectomy (UniS) on the dominant side is hypothesized to reduce CS risk while potentially providing some contralateral benefit, but robust comparative data, particularly from diverse populations, has been lacking.

2. Methodology

• Study Design: A prospective, randomized, controlled, multicenter clinical trial conducted across 11 centers in Brazil.
• Participants: 163 adult patients (age ≥18, BMI ≤28) diagnosed with primary palmar hyperhidrosis.
• Randomization: Patients were randomized 1:1 into two groups:
  1. BTS Group (n=83): One-stage bilateral thoracic sympathectomy (T4 ganglion resection).
  2. UniS Group (n=80): Unilateral sympathectomy on the dominant side only.
• Staged Protocol: Patients in the UniS group who remained dissatisfied after 6 months could elect to undergo contralateral surgery, forming a third cohort: Two-Stage Bilateral (2stS).
• Intervention: General anesthesia with thermoablation of the sympathetic chain at the T4 level (between the 4th and 5th ribs).
• Outcome Measures:
  • Sweating Severity: Assessed using the Hyperhidrosis Disease Severity Scale (HDSS) across 18 anatomical sites. CS was defined as new sweating in areas with preoperative HDSS=1, graded as mild (HDSS=2) or severe (HDSS=3 or 4).
  • Quality of Life (QoL): Measured using two validated instruments: HidroQOL (18 questions) and the Horn Questionnaire (10 questions).
  • Follow-up: Assessments at baseline, 2 months, and 6 months. The 2stS group had additional assessments at 8 and 12 months post-second surgery.
• Statistical Analysis: Mixed models, ANCOVA, and non-parametric tests were used to compare groups, adjusting for baseline values.

3. Key Contributions

• First Large-Scale Pragmatic Trial in Brazil: This is the first prospective, randomized, multicenter study in a Brazilian population comparing these strategies, offering high external validity due to the country's climatic and ethnic diversity.
• Refined CS Definition: The study utilized a rigorous, site-specific definition of CS based on the transition from HDSS=1 to higher scores, allowing for precise grading of severity rather than binary presence/absence.
• Evaluation of the "Staged" Strategy: It provides empirical data on the efficacy of a "wait-and-see" approach (UniS followed by contralateral surgery only if necessary), a strategy often debated but rarely quantified in randomized trials.
• Dual-QoL Instrumentation: The use of both HidroQOL and Horn questionnaires provided a comprehensive view of the psychosocial and functional impacts of the different surgical strategies.

4. Key Results

A. Symptom Control (HDSS)

• Dominant Hand: Both BTS and UniS provided excellent and comparable control of the operated hand. At 6 months, ~91% of patients in both groups achieved HDSS 1–2 in the treated hand.
• Contralateral Hand (UniS): In the UniS group, the untreated hand remained severe (HDSS 3–4) in 86% of patients at 6 months. However, **14% of UniS patients** showed spontaneous improvement in the untreated hand without a second surgery.
• Bilateral Control: BTS resulted in immediate and sustained HDSS 1–2 in both hands for >90% of patients.

B. Compensatory Sweating (CS)

• Incidence of Absence: The proportion of patients with no CS was similar between groups (~25%).
• Severity: Severe CS was significantly more frequent in the BTS group (40.4%) compared to the UniS group (21.0%, p=0.0344).
• Mild CS: The UniS group had a higher rate of mild CS (53.2%) compared to BTS (34.1%).
• 2stS Group: Among the 16 UniS patients who opted for contralateral surgery, CS incidence was 56.2%, but the vast majority was mild; only one patient developed intense CS.

C. Quality of Life (QoL)

• BTS Superiority: The BTS group demonstrated significantly greater and more sustained reductions in Horn and HidroQOL scores (indicating better QoL) compared to UniS at both 2 and 6 months (p < 0.001).
• 2stS Trajectory: Patients in the 2stS group showed progressive QoL improvement. After the second surgery, their scores dropped significantly, eventually matching the QoL gains seen in the primary BTS group, with a median Horn score reduction of >24 points.

5. Significance and Conclusion

This study establishes that while one-stage bilateral sympathectomy (BTS) offers the most complete symptom control and the highest QoL improvement, it comes at the cost of a significantly higher risk of severe compensatory sweating.

Unilateral sympathectomy (UniS) is a viable alternative that:

1. Provides excellent control of the dominant hand.
2. Reduces the risk of severe CS by nearly half compared to BTS.
3. Offers a "staged" pathway where ~14% of patients achieve bilateral relief without a second surgery, and those who do require a second procedure (2stS) achieve outcomes comparable to primary BTS with a lower risk of severe CS.

Clinical Implication: The authors advocate for a shared decision-making model. Clinicians should present patients with the trade-off: immediate, maximal bilateral relief with higher CS risk (BTS) versus a staged approach that minimizes severe CS risk, allows for a subset of patients to avoid a second surgery, and achieves comparable long-term outcomes for those who proceed to completion. This strategy is particularly relevant in tropical climates where CS severity may be exacerbated.