Advances in Clinical Outcomes of Endoscopic Lumbar Sympathectomy: Analysis of 494 Consecutive Patients at a Single Institution

<b>Background/Objectives</b>: Endoscopic lumbar sympathectomy (ELS) is the definitive treatment for primary plantar hyperhidrosis (PPLH). This study analyzed the mid-term clinical outcomes and technical factors related to ELS. <b>Methods</b>: Retrospective reviews of patients who had ELS for PPLH between July 2019 and May 2023 were analyzed. The study period was categorized into three eras based on the timing when laser Doppler flowmetry (LDF) and PMR (psoas muscle relaxation) were applied; period A represented the initial surgical approach, period B included LDF, and period C included LDF and PMR during surgery. The impacts of these techniques on operative and short-term outcomes were assessed. Additionally, risk factor analysis was performed to find relevant factors related to the reappearance of plantar sweating in long-term follow up. As most patients underwent endoscopic thoracic sympathectomy (ETS) as well, risk assessment for compensatory hyperhidrosis was also investigated. <b>Results</b>: A total of 474 patients were included, and the numbers of patients by periods were as follows: <i>n =</i> 28 in period A, <i>n =</i> 198 in period B, and <i>n =</i> 248 in period C. Operating times were significantly different, with proportional decreases seen with the introduction of LDF and PMR (<i>p <</i> 0.001). In the long-term, reappearance of plantar sweating was noted in 21 patients (4.4%). Risk factors for the reappearance of plantar sweating included an age over 35 years [odds ratio {OR} (95% confidence interval {CI}) 4.57 (1.56-13.40), <i>p =</i> 0.006] and a history of lumbar sympathetic ganglion block (LSGB) prior to ELS [OR (95% CI), 269 (29.30-2460), <i>p <</i> 0.001]. Of 474 patients, 390 (82.3%) patients underwent both ETS and ELS. Risk factors for compensatory hyperhidrosis were age >25 years [OR (95% CI) 0.60 (0.40-0.90), <i>p =</i> 0.014] and concomitant ETS [OR (95% CI) 5.63 (1.88-16.90), <i>p =</i> 0.002]. Compensatory hyperhidrosis among patients who only had ELS was less observed (4/24, 16.7%). <b>Conclusions</b>: ELS is highly effective in treating plantar hyperhidrosis, and LDF and PMR improved perioperative outcomes. Age over 35 and a prior history of LSGB were found to be related to worse long-term outcomes of ELS. Our findings suggest that ELS with additional LDF and PMR could improve outcomes for patients with PPLH.