Safety and efficacy of new integrated bipolar and ultrasonic scissors compared to conventional laparoscopic 5-mm sealing and cutting instruments

Abstract

Background: Hemostasis is a central issue in laparoscopic surgery. Ultrasonic scissors and bipolar clamps are commonly used, with known advantages with each technique.

Methods: The prototype of new surgical scissors, delivering ultrasonically generated frictional heat energy and bipolar heat energy simultaneously (THUNDERBEAT(®) [TB]), was compared to ultrasonic scissors (Harmonic ACE(®) [HA]) and an advanced bipolar device (LigaSure(®) [LS]) using a pig model. As safety parameters, temperature profiles after single activation and after a defined cut were determined. As efficacy parameters, seal failures and the maximum burst pressure (BP) were measured after in vivo sealing of vessels of various types and diameters (categories 2-4 and 5-7 mm). Moreover, the vertical width of the tissue seal was measured on serial histological slices of selected arteries. The cutting speed was measured during division of isolated arteries and during dissection of a defined length of compound tissue (10 cm of mesentery). Burst-pressure measurement and histological analysis were performed by investigators blinded to the used sealing device.

Results: Using the TB, the burst pressure in larger arteries was significantly higher (734 ± 64 mmHg) than that of the HA (453 ± 50 mmHg). No differences in the rate of seal failures were observed. The cutting speed of the TB was significantly higher than that of all other devices. Safety evaluation revealed temperatures below 100 °C in the bipolar device. The maximum temperature of the HA and the TB was significantly higher. No relevant differences were observed between the HA and the TB.

Conclusions: The ultrasonic and bipolar technique of the TB has the potential to surpass the dissection speed of ultrasonic devices with the sealing efficacy of bipolar clamps. However, heat production that is comparable to conventional ultrasonic scissors should be minded for clinical use.

Fig. 1

Detailed view of the jaws of the different devices used in the present experiments

Fig. 2

Cross section of the jaws of the TB illustrating its mode of operation. Bipolar energy is delivered laterally (red arrows) and ultrasonic energy centrally (blue arrows), leading to additional sealing and simultaneous division of the tissue

Fig. 3

Burst pressure measured after in vivo sealing and division of arteries (p values significant by post-hoc comparison are indicated)

Fig. 4

A–C Exemplary slides of arterial seals (hematoxylin and eosin stain) showing the seal width and the typical aspect of gas vapor formation, predominantly in the ultrasonic devices (HA and TB). D Histological length of the arterial seal (p values significant by post-hoc comparison are indicated)

Fig. 5

Time needed for division of arteries in both vessel categories (p values significant by post-hoc comparison are indicated)

Fig. 6

Time needed for sealing and cutting of a standardized length of 10 cm of small bowel mesentery (p values significant by post-hoc comparison are indicated)

Fig. 7

A Exemplary thermal camera views of the three instruments at the time of maximum heat production (upper row). The color scale encoding the respective temperature (in °C) is depicted on the right-hand side of the figure. B Exemplary temperature curves measured with the thermocamera during and after single activation of the devices. C Temperature curves of the thermosensor after repeated activation during fast dissection of 10 cm of small bowel mesentery