Transoral Robotic Surgery (TORS) vs. Transoral Laser Microsurgery (TLM): histopathological comparison of the cutting characteristics

Introduction:

In this study we compare the cutting characteristics of a CO₂ laser (Lumenis AcuPulse) with the effect of a monopolar cautery (Intuitive Surgical Permanent Cautery Spatula at ERBE VIO dV) of the surgical robot Da Vinci Xi (Intuitive Surgical) on the model of the pig's tongue.

Methods:

Sections each approx. 10 mm long were made with different laser powers (SuperPulse) and different electrosurgical settings (Auto Cut and Forced Coag). The tissue was formalin-fixed and paraffin-embedded. Histological preparations with a thickness of 2 µm were prepared and stained in hematoxylin-eosin (HE). Digital evaluation was performed with an Olympus BX53 microscope and QuPath (Open Source) software. The maximum width and depth of the lesions as well as the maximum diameter of the coagulation damage in the tissue were measured.

Results:

As expected, both an increase in the cutting effect and an expansion of the coagulation zones were observed with an increase in the energy applied, irrespective of the technique used. With the CO₂ laser we could determine the largest absolute cutting depth as well as the smallest cutting width and coagulation width in relation to the cutting depth. Using the monopolar instrument, however, wider sections and larger coagulation zones were observed. In forced coagulation mode, these can reach a multiple of the expansion observed with the laser.

Conclusion:

Due to the more favorable ratio of the cutting depth to the extent of the coagulation damage in the CO₂ laser, this enables a better histological assessment of the surgical margins and therefore appears to be particularly advantageous for small tissue samples.

Publication History

Publication Date:
23 April 2019 (online)