Changes in the sympathetic skin response after thoracoscopic sympathectomy in patients with primary palmar hyperhidrosis

Objective To investigate whether thoracic sympathectomy induced any change in the pattern of abnormalities or in the waveform of the sudomotor skin response (SSR) in patients with primary palmar hyperhidrosis (PPH). Methods We recorded the SSR to median nerve electrical stimuli before and after bilateral thoracoscopic sympathectomy in 27 patients with PPH. We analyzed the changes in amplitude, type of waveform and pattern of abnormality. Results All patients reported symptomatic improvement. The amplitude of the SSR decreased significantly in patients examined within 1 year after surgery, but was not different in patients examined after 1 year. The number of abnormally enhanced responses reduced after surgery, but there was no significant change in the number of patients with enhanced excitability recovery or with double-peak responses to single stimuli. There was a significant increase in the number of SSRs with a predominantly negative waveform after surgery. Conclusions The persistence of SSR abnormalities after surgery suggests that the central nervous system dysfunction is not modified by sympathectomy. The change of the waveform to predominantly negative type after surgery could be the consequence of the decrease in the production of sweating. Significance Our results show the effects of sympathectomy on the SSR and on its abnormal patterns in patients with PPH.