Background: This study aims to examine the efficacy of clipping in thoracic sympathectomy based on electrophysiological evaluation and to investigate whether nerve conduction can be formed by collateral nerve extensions as a result of the clipping procedure to different levels of sympathetic nerve.

Methods: Newly sacrificed six sheep hemithoraces were studied between August 2016 and October 2016. Thoracic sympathectomy was performed by clipping at T2, T3, T4, and T5 sympathetic chain levels and their branches. Electrophysiological studies were performed with an electromyography device and the filter range was 1 Hz with 20 ?V/D amplification. Signals were processed digitally; bipolar subdermal needle electrodes were used as stimulation and recording electrodes (Ø 0.75 mm); and the ground electrode was placed in the intercostal muscle where the thoracic sympathectomy procedure would be performed.

Results: Electrophysiological evaluations showed that clips placed on the main sympathetic chain branches and sympathetic nerve trunk prevented collateral impulse conduction and stimulated potentials were not recorded. However, sympathetic conduction continued at the same intensity after removal of the clips.

Conclusion: Clipping of different regions of the sympathetic nerve provides electrophysiological blockage of the sympathetic nerve, and conduction continues after removal of the clips. However, the shortand long-term postoperative electrophysiological results after removal of the clips over the sympathetic nerve is still a question mark.

Keywords : Clipping, electrophysiology, thoracic sympathectomy