Energy based surgical devices such as high frequency electrotome, Harmonic scalpel and LigaSure are widely used in thyroid operations. This study is to demonstrate the difference of tissue thermal damage among different surgical instruments.

12 beagle dogs were randomly divided into 3 groups, electrotome 15 W groups (group A) , three-speed Harmonic scalpel (group B) and LigaSure middle gear group (group C) . Patients of each group received energy instruments operating on their thyroid tissue which mimics traditional thyroidectomy. The temperatures of gland tissue during procedures were monitored by infrared thermal imager, and the operated thyroid tissues were histologically analyzed.

The highest temperature was (83.9±8.2) ℃ in the electrotome group, (70.7±7.5) ℃ in three-speed Harmonic scalpel group, and (56.6±5.7) ℃ in LigaSure group. The highest temperature among the three groups was statistically significant. The electrotome (15 W) caused more serious thermal damage to thyroid tissues than that caused by either the Harmonic scalpel or LigaSure (thermal damaged depth: (0.96±0.07) mm vs (0.74±0.07) mm, P<0.01; (0.96±0.07) mm vs (0.72±0.11) mm, P<0.01) . Nevertheless, the thermal damage had no significant differences between the Harmonic scalpel and LigaSure group (P=0.845) . The thermal damage caused by the 15 W electrotome was significantly larger than that in the other two groups, and the difference had statistical significance (P<0.01) .

Compared to the high frequency electrotome, Harmonic scalpel and LigaSure lead less tissue thermal damage during thyroid surgeries, owing to less heat production. In that way, Harmonic scalpel and LigaSure are superior to electrotome in terms of safety.

Energy-based surgical devices; Thermal damage; Thyroid surgery; Harmonic scalpel; LigaSure