This is a prospective clinical study that includes all patients with Primary Focal Hyperhidrosis, who will be operated on with Bilateral Thoracoscopic Sympathectomy.

Bilateral thoracoscopic sympathectomy will be performed with general anesthesia, using single lung ventilation and monopolar cautery for transection of the sympathetic chain.

Persons with PFH who underwent the BTS were classified into three groups, depending the level of transaction of sympathetic chain:

1. transection at the level from the second to the forth thoracic sympathetic ganglion (T2- T4);
2. transection at the level from the third to the forth thoracic sympathetic ganglion (T3-T4)
3. transection at the level from the second to the third thoracic sympathetic ganglion (T2-T3)..

Participants will be assessed using the HDSS and gravimetric sweat testing. A reduction of ≥ 2 points in HDSS score or a ≥ 50% reduction in sweat production will be considered a successful outcome. Data will be aggregated as the proportion of participants achieving these reductions.

The DLQI will be administered preoperatively and at 3 months postoperatively to evaluate changes in quality of life. The DLQI is a 10-item questionnaire where higher scores indicate greater impairment. The primary endpoint will be the mean reduction in DLQI score from baseline to 3 months, with a reduction of ≥ 5 points considered clinically significant