Research on thermal damage of recurrent laryngeal nerve by the high frequency electric knife / 中华内分泌外科杂志

ABSTRACT

Objective To investigate the heat effects of the high-frequency electric knife on the recurrent laryngeal nerve ( RLN) in pigs and the safety margin in which electric knife can be used .Methods Totally 12 pigs for experiment were randomly divided into 3 groups by the distance between the head of the electric knife and the nerve(2 mm, 1 mm, 0 mm).The application time of the electric knife touching RLN was set to be 3 s and the application energy of the electric knife was 90 W.The data of electromyogram were measured by means of nerve detector before and after operation .Statistical analysis was made based on those data .The nerve tissues were taken to make paraffin sections so that the histological change can be observed and compared before and after damage.Results The data from electromyogram by nerve detector indicated that the difference of the amplitude of group 2(1 mm)and group 3(0 mm)had statistical significance(P<0.05)within group.There were significant difference of the amplitude between the 3 groups.Histological study showed that the tissues of group 3(0 mm)had obvious injury .Conclusions In thyroid surgery , the safety range of high frequency electrical knife used around RLN isthe distance from electrical knife head to nerve should be no less than 2 mm.