Reducing the risks of endoscopic sinonasal surgery in the Covid-19 era.

Objectives: Many routine sinonasal procedures utilising powered instruments are regarded as aerosol-generating. This study aimed to assess how different instrument settings affect detectable droplet spread and patterns of aerosolised droplet spread during simulated sinonasal surgery in order to identify mitigation strategies.

Design: Simulation series using three-dimensional (3-D) printed sinonasal model. Fluorescein droplet spread was assessed following microdebriding and drilling of fluorescein-soaked grapes and bones, respectively.

Setting: University dry lab.

Participants: 3-D printed sinonasal model.

Main Outcome Measures: Patterns of aerosolised droplet spread.

Results And Conclusion: There were no observed fluorescein droplets or splatter in the measured surgical field after microdebridement of nasal polyps at aspecific irrigation rate and suction pressure. Activation of the microdebrider in the presence of excess fluid in the nasal cavity (reduced or blocked suction pressure, excessive irrigation fluid or bleeding) resulted in detectable droplet spread. Drilling with either coarse diamond or cutting burs resulted in detectable droplets and greater spread was observed when drilling within the anterior nasal cavity. High-speed drilling is a high-risk AGP but the addition of suction using a third hand technique reduces detectable droplet spread outside the nasal cavity. Using the instrument outside the nasal cavity inadvertently, or when unblocking, produces greater droplet spread and requires more caution.