Cadaveric Simulation of Endoscopic Endonasal Procedures: Analysis of Droplet Splatter Patterns During the COVID‐19 Pandemic

Abstract

<jats:sec><jats:title>Objective</jats:title><jats:p> The primary mode of viral transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is thought to occur through the spread of respiratory droplets. The objective of this study was to investigate droplet and splatter patterns resulting from common endoscopic endonasal procedures. </jats:p></jats:sec><jats:sec><jats:title>Study Design</jats:title><jats:p> Cadaver simulation series. </jats:p></jats:sec><jats:sec><jats:title>Setting</jats:title><jats:p> Dedicated surgical laboratory. </jats:p></jats:sec><jats:sec><jats:title>Subjects and Methods</jats:title><jats:p> After instilling cadaver head specimens (n = 2) with fluorescein solution, endoscopic endonasal procedures were systematically performed to evaluate the quantity, size, and distance of droplets and splatter following each experimental condition. </jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p> There were no observable fluorescein droplets or splatter noted in the measured surgical field in any direction after nasal endoscopy, septoplasty with microdebrider-assisted turbinoplasty, cold-steel functional endoscopic sinus surgery (FESS), and all experimental conditions using an ultrasonic aspirator. Limited droplet spread was noted with microdebrider FESS (2 droplets, &lt;1 mm in size, within 10 cm), drilling of the sphenoid rostrum with a diamond burr (8, &lt;1 mm, 12 cm), and drilling of the frontal beak with a cutting burr (5, &lt;1 mm, 9 cm); however, the use of concurrent suction while drilling resulted in no droplets or splatter. The control condition of external activation of the drill resulted in gross contamination (11, 2 cm, 13 cm). </jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p> Our results indicate that there is very little droplet generation from routine rhinologic procedures. The droplet generation from drilling was mitigated with the use of concurrent suction. Extreme caution should be used to avoid activating powered instrumentation outside of the nasal cavity, which was found to cause droplet contamination. </jats:p></jats:sec>

Minimising aerosol spread during endoscopic sinus and skull base surgery. Experimental model evaluation of the efficacy of the microscope drape method

“…The control condition of external activation of the drill resulted in gross contamination. 14 These results, however reassuring, are restricted by the detectable particle size limit; the study did not formally assess the generation and potential shedding of smaller, non-visible air particles. Workman et al 13 also used an experimental cadaveric model to demonstrate the aerosol spread during various surgical procedures.…”

“…Little research is available on the risk of specific otolaryngological procedures, and conflicting information persists among regulatory bodies as to the degree of protection required for AGPs. [14][15][16] Moreover, recent reports support the capacity of coronavirus to act as an 'opportunistic' airborne pathogen during favourable conditions such as AGPs. [17][18][19] It has been proposed that measuring the level of aerosolised viral particles in rooms where AGPs are being performed on patients with Covid-19 could provide indirect evidence of the degree to which these procedures put healthcare workers at risk of aerosolised transmission, and whether exposure concentration affects risk of infection and severity of disease.…”

“…5 Recent simulation models of FESS and anterior skull base surgery using cadaveric models, fluorescein and digital cameras experimentally demonstrated aerosol formation and the spread of microdroplets as small as 20 μm (method-related limit of detection), further supporting the risk of viral transmission intraoperatively via aerosol or microdroplets. 13,14 In this context, measures to reduce the risk to operating theatre staff have been proposed by surgical societies, such as avoidance of powered instruments and diathermy, negative pressure rooms, and use of powered air-purifying respirators. Rokade et al 23 introduced the use of a microscope drape technique as an additional barrier to 'isolate' the operating field and minimise aerosol spread in the operating theatre environment.…”

In vitro comparison of surgical techniques in times of the SARS-CoV-2 pandemic: electrocautery generates more droplets and aerosol than laser surgery or drilling

“…To eliminate inter-and intraobserver variability, measurements were performed fully automatic with different computerbased algorithms described below. The method of particle measurement via counting have been widely used to assess aerosol creation [11][12][13]. Turbidity measurements are more commonly used in larger scale pollution measurements but were adapted to show aerosol generation in another way [14].…”

“…Up today, only few studies have examined the aerosol generation and distribution during specific ENT medical interventions. A previously described model used fluorescein dye for detection of particle distribution in mastoidectomy and sinus surgery [11][12][13]. However, this method was mainly used to detect the spread of droplets and to a lesser extent the formation of aerosols, which are particularly relevant in the context of the COVID-19 pandemic.…”