Thermal Conductance Through the Skull Base From Endoscopic Surgery Cauterization Instruments: Cadaver and Goat Model

Abstract

Objective Cauterization prevents hemorrhage and optimizes the surgical field during endoscopic sinus surgery but may cause injury to nearby structures. The objective of this study is to examine thermal conductance from cauterization equipment across the skull base. Study Design Cadaver and animal model. Setting Surgical skills laboratory of an academic tertiary medical institution. Methods A pilot study was conducted with a deidentified cadaver head and expanded to a goat head animal model. Endoscopic dissection was performed to expose the lamina papyracea, ethmoid roof, sphenoid roof, and frontal sinus. Cautery was applied to the frontal sinus of goat heads, and temperatures were measured via thermocouple sensors placed along the intracranial skull base. Surgical instruments studied included monopolar, bipolar, and endoscopic bipolar devices at various power settings. Results Temperature increase, as averaged across all cautery powers and measurement positions, was highest for the monopolar cautery (17.55 °C) when compared with the bipolar and endoscopic bipolar devices (<2 °C for bipolar, Endo-Pen, Stammberger, and Wormald; P < .001). Monopolar cautery reached 30.86 °C at high power when averaged over all positions ( P < .001) as compared with <3 °C for the other instruments. Temperatures rose as power of cautery was increased from low to medium and high. Temperatures decreased as the distance of the thermocouple sensor probe from the cautery origin increased. Conclusion Thermal conductance across the skull base varies depending on equipment and power of cautery, with monopolar resulting in the largest temperature increase. Choice and implementation of cauterization instruments have implications on inadvertent transmission of thermal energy during endoscopic sinus surgery.