Background: Primary hyperhidrosis (PH) is characterized by excessive and uncontrollable secretion in the eccrine sweat glands of the craniofacial region, armpits, hands, and feet. Sympathicotomy is the most effective treatment for severe PH; however, compensatory hyperhidrosis (CH) remains the most devastating postoperative complication. The purpose of the present study was to suggest a new sympathicotomy method for PH to prevent severe CH. Methods: From March 2014 to December 2018, a total of 212 patients were included in the study. R2 (53 cases) sympathicotomy for craniofacial hyperhidrosis and R3 (79 cases) or R4 (80 cases) sympathicotomy for palmar hyperhidrosis using the thoracoscopic technique were performed, respectively. Sympathicotomy was performed using two different methods (conventional 145 cases and new 67 cases). Expanded sympathicotomy was performed as the new method (67 cases), which was divided into two groups (partialand full-expanded sympathicotomy). Operative effectiveness was evaluated by a reduction in percentage of post-operative sweating compared with pre-operative sweating and groups were divided into complete and incomplete sweat reduction characteristics. Complete sweat reduction was defined as sweat reduction ≥80% compared with preoperative sweating. The degrees of CH were classified as negligible, mild bothering (tolerable), and severe bothering (intolerable). Data on preoperative subject characteristics, disease status, operative technique, and postoperative outcomes were gathered using medical records and telephone surveys. Results: According to sympathicotomy techniques, the conventional procedure (non-expanded sympathicotomy) was performed in 145 cases and the new expanded sympathicotomy procedure was performed in 67 cases (partial-expanded sympathicotomy 28 cases; full-expanded sympathicotomy 39 cases). Craniofacial hyperhidrosis was significantly more prevalent in the older group and in female patients (P<0.001 and P=0.007, respectively). Sympathicotomy was significantly more effective in palmar hyperhidrosis than craniofacial hyperhidrosis (P<0.001). CH was significantly more severe in craniofacial hyperhidrosis than palmar hyperhidrosis after sympathicotomy (P<0.001). In craniofacial hyperhidrosis, there was no significant difference in sweat reduction and CH between conventional and the expanded sympathicotomy techniques (P=0.177 and P=0.474, respectively). In palmar hyperhidrosis, there was no significant difference in sweat reduction between the conventional and the expanded sympathicotomy (P=0.178), however, degree of CH in the conventional technique was significantly more severe than in the expanded technique (P=0.001).Regarding comparison between partial-and full-expanded sympathicotomy, there was no significant difference in sweat reduction between partial-, and full-expanded sympathicotomy; however, CH was significantly more severe in partial-expanded sympathicotomy (craniofacial hyperhidrosis P=0.006; palmar hyperhidrosis P<0.001). Irrespective of hyperhidrosis types,...