One year into the COVID-19 pandemic: What do we know so far from studies assessing risk and mitigation of droplet aerosolisation during endonasal surgery? A systematic review.

OBJECTIVES: As we pass the anniversary of the declaration of a global pandemic by the World Health Organisation, it invites us to reflect upon the inescapable changes that coronavirus has wrought upon ENT and, in particular, rhinological practice. As it remains unclear when we will emerge from the shadow of COVID-19, a critical analysis of the evidence base on both the assessment and mitigation of risk is vital for ENT departments worldwide. This article presents a systematic review of the literature examining articles which consider either the quantification of risk or strategies to mitigate risk specifically in the setting of rhinological surgery. DESIGN: Systematic literature review. RESULTS: The literature search yielded a total of 3406 returns with 24 articles meeting eligibility criteria. A narrative synthesis stratified results into two broad themes: (1) those which made an assessment as to the aerosolisation of droplets during sinus surgery, further sub-divided into work which considered macroscopically visible droplets and that which considered smaller particles; (2) and those studies which examined the mitigation of this risk. CONCLUSION: Studies considering the aerosolisation of both droplets and smaller particles suggest endonasal surgery carries significant risk. While results both highlight a range of innovative adjunctive strategies and support suction as an important intervention to reduce aerosolisation, appropriate use of personal protective equipment (PPE) should be considered mandatory for all healthcare professionals involved in rhinological surgery. Studies have demonstrated that close adherence to PPE use is effective in preventing COVID-19 infection.

Analysis of Droplet Splatter Patterns During Coblation Tonsil Surgery in the Covid-19 Pandemic.

OBJECTIVES: To assess droplet splatter around the surgical field and surgeon during simulated Coblation tonsil surgery to better inform on mitigation strategies and evaluate choice of personal protective equipment. METHODS: This was an observational study performed using a life-size head model to simulate tonsil surgery and fluorescein-soaked strawberries to mimic tonsils. The Coblation wand was activated over the strawberries for 5 minutes. This was repeated 5 times with 2 surgeons (totalling 10 data sets). The presence of droplet around the surgical field and anatomical subsites on the surgeon was assessed in binary fashion: present or not present. The results were collated as frequency of droplet detection and illustrated as a heatmap; 0 = white, 1-2 = yellow, 3-4 = orange, and 5 = red. RESULTS: Fluorescein droplets were detected in all 4 quadrants of the surgical field. The frequency of splatter was greatest in the upper (nearest to surgeon) and lower quadrants. There were detectable splatter droplets on the surgeon; most frequently occurring on the hands followed by the forearm. Droplets were also detected on the visor, neck, and chest albeit less frequently. However, none were detected on the upper arms. CONCLUSION: Droplet splatter can be detected in the immediate surgical field as well as on the surgeon. Although wearing a face visor does not prevent splatter on the surgical mask or around the eyes, it should be considered when undertaking tonsil surgery as well as a properly fitted goggle. LEVEL OF EVIDENCE: 5.

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.

Droplet and bone dust contamination from high-speed drilling during mastoidectomy.

OBJECTIVES: The aim of this study was to examine contamination from otolaryngologic procedures involving high-speed drilling, specifically mastoid surgery, and to assess the adequacy of PPE in such procedures. DESIGN AND SETTING: Mastoid surgery was simulated in a dry laboratory using a plastic temporal bone, microscope and handheld drill with irrigation and suction. Comparisons of distance of droplet and bone dust contamination and surgeon contamination were made under differing conditions. Irrigation speed, use of microscope and drill burr size and type were compared. MAIN OUTCOME MEASURES: Measurement of the distance of field contamination while performing simulated mastoidectomy and location of surgeon contamination. RESULTS: There was a greater distance field contamination and surgeon contamination without the use of the microscope. Contamination was reduced by using a smaller drill burr and by using a diamond burr when compared to a cutting burr. The use of goggles and a face mask provided good protection for the surgeon. However, the microscope alone may provide sufficient protection to negate the need for goggles. CONCLUSIONS: While the risks of performing mastoid surgery during the coronavirus pandemic cannot be completely removed, they can be mitigated. Such factors include using the microscope for all drilling, using smaller size drill burrs and creating a safe zone around the operating table.