A numerical and experimental study of light obscuration in laparoscopy
Hossein Hadi Najafabadi1,2, Meng Wai Woo3, Vinod Suresh1,4
1Department of Engineering Science, University of Auckland, Auckland, 1142, New Zealand.
Purpose:
Aerosol particles produced during laparoscopic electrosurgery (ES) obscure light and reduce visibility. This work investigates the effect of the flow rate of insufflating carbon dioxide on light obscuration.
Methods:
Monopolar ES was performed on an excised pig liver, and the light obscuration between a viewing laparoscope and surgical site was measured in an idealised computational domain and a corresponding rigid experimental model. To replicate typical surgical use, this study assumed a 60 s period of intermittent ES with no inlet flow, followed by a 60 s period of inlet flow with no ES. Particle size distributions in the aerosol were measured, and a specific light extinction coefficient was calculated for use as an input to simulations to predict light obscuration.
Results:
Experimental results showed that obscuration increased exponentially, reaching a value of 47±2.3% after 60 s of ES. After ceasing ES, obscuration did not change significantly in the following 60 s. Introduction of carbon dioxide at flow rates of 5 l/min, 10 l/min, and 15 l/min reduced obscuration to 13±1%, 5±0.5%, and 2±0.2%, respectively, 60 s after stopping ES. Decay curves were well described by an exponential fit. Simulated decay rates agreed with experiments when inlet flow was applied.
Conclusion:
It is concluded that insufflation with carbon dioxide can reduce light obscuration, and computational models are capable of capturing the dynamics of aerosol transport in laparoscopic ES. The numerical model developed in this study can be used as a predictive tool to determine how light obscuration during laparoscopy depends on factors such as insufflation flow rate and to improve surgeon visibility.
