The surgical cutting edge: An experimental and computational investigation

Casey, Vincent
“Surgical smoke” is an airborne by-product of electrosurgery comprised of vapour and suspended particles. Although concerns exist that exposure to this smoke may be harmful, there is a poor understanding of the smoke in terms of particle size, morphology, composition, and biological viability. In particular, it is not known how the biological tissue source and cutting method influence the smoke. Other surgical instruments also generate airborne by-products and aerosols, such as ultrasonic and high-speed cutting devices, but the particulate created during each type of procedure has not been investigated. Therefore, the first study of this thesis sought to understand the airborne by-products produced during tissue cutting using energy-based surgical devices. The objective of this study was to develop a collection method for airborne by-product from surgical cutting to enable comprehensive analyses of the particulate burden, composition, and biological viability. A novel custom-built device was designed based on the principles of electrostatic precipitation, which was able to capture and enable analysis of surgical smoke particulate. A second experimental approach was developed, using impingement filtration, which facilitated laser diffraction-based particle sizing and biological activity assessment. The electrostatic precipitation device and impingement filtration system were applied to collect and characterise aerosolized/airborne by-products generated by electrosurgery, ultrasonic and high-speed cutting of bone and liver tissue. The study detected particles outside the size ranges previously reported in literature for surgical smoke and aerosolised surgical cutting by-products. Furthermore, this study reported for the first time that electrosurgical smoke and, even more so, aerosolised particulate from ultrasonic cutting of soft tissue (liver) contains metabolically active cells. Moreover, it was reported that that bone saws and ultrasonic cutting do not liberate viable cells from bone. The second study of this thesis sought to analyse the efficiency of the electrostatic precipitation collection device using computational methods. Electrostatic precipitation is a complex process that is difficult to analyse empirically without specialised equipment and it can be expensive to build numerous prototypes to assess device design. Computational modelling is a technique used to simulate and study complex systems, which may otherwise be difficult or expensive to investigate experimentally. Although several aspects of the design of an electrostatic precipitator are known to influence particle collection, a comprehensive study of the influence of specific parameters for collection of particles from surgical smoke has not been investigated. Therefore, the primary objective of this study was to investigate how fluid flow, electrostatic field, space charge density and particle trajectory influence particle collection from surgical smoke. The second objective is to investigate the application of the electrostatic precipitator (presented in Chapter 3) under various operating conditions to ultimately provide an advanced insight into the operating parameters that influence the performance/efficiency of the device in terms of particle collection. The computational analysis provides an insight into operating parameters that positively influence efficiency, such as smaller plate spacing, more wires, increased voltage and reduced velocity and reveals that the electrostatic device efficiently collects particles. Together, these studies provide an enhanced understanding of airborne particulate by-product that is generated when using energy-based surgical devices. The information elucidated from this body of work can inform future surgical procedures and it is proposed that smoke evacuation should be used while cutting using energy-based surgical devices.
NUI Galway
Publisher DOI
Attribution-NonCommercial-NoDerivs 3.0 Ireland