Discussion
Simulated tonsil surgery using Coblation technology results in detectable splatter around the surgical field and on the surgeon. The most common area in the surgical field to be contaminated were the quadrants anterior and posterior to the oral cavity. There was reduced frequency of splatter in both lateral quadrants (Figure 3). This is due to the position of the surgeon’s hand within the surgical field which corroborates with the finding of splatter on both hands (Figure 4). Splatter was detected on the face visor but interestingly, was also found on the mask and around the eyes which were areas under the visor. The results of this study, and in the light of the current pandemic, emphasises the importance of appropriate PPE and strict donning and doffing practice.
We were unable to undertake the splatter assessments during real-life surgery due to the suspension of elective surgery throughout the spring and summer of 2020. We believe that our experiments on a life-like model simulated real surgery and provided a consistent and repeatable platform to undertake the experimental observations. The strawberries were saturated in fluorescein dye which was also added to the saline irrigation bag (Figure 1b,c) to facilitate detection of droplet splatter. While excepting that fresh strawberries were not a substitute for tonsils, it is frequently used to simulate tonsils at instructional courses. We decided not to use porcine or bovine soft tissue due to the health and safety issues of utilising the operating theatre suite in our institution.
It was an arbitrary decision to activate the Coblation wand for 5 minutes during each experiment. Appreciating that different surgical styles and practices exist, we felt that 5 minutes was an average duration required to complete a unilateral tonsillectomy and that the duration mimicked our clinical practice.
This is the first study to assess for droplet splatter contamination around the surgical field and on the surgeon after Coblation tonsillectomy. Previous studies, undertaken during actual surgery, have focused on either the monopolar or bipolar diathermy which clearly demonstrated splatter contamination on the surgeon’s face1,2,3. The latter diathermy resulted in greater splatter. These studies were published following concerns that transconjunctival exposure was a potential route of transmission for hepatitis viruses and the human immunodeficiency virus in health care workers. The consensus from these studies was for surgeons to wear goggles during tonsil surgery in order to mitigate the risk of transconjunctival contamination.
A recent study on monopolar tonsillectomy demonstrated greater spread of the surgical plume at higher energy settings11O’Brien DC, Lee EG, Soo JC, Friend S, Callaham S, Carr MM. Surgical Team Exposure to Cautery Smoke and Its Mitigation during Tonsillectomy. Otolaryngol Head Neck Surg. 2020 Sep;163(3):508-516.. The authors concluded that the addition of a suction catheter held by a surgical assistant reduced the detectable spread of the surgical plume. We did not alter the settings on the Coblation power console but elected to use the default settings which are recommended by the manufacturer and reflects our clinical practice. Furthermore, our experiments did not consider the introduction of an additional suction as we wanted to demonstrate the splatter patterns from Coblation tonsillectomy which is routinely undertaken without an assistant bearing in mind that the wand has a built-in suction port.
The results of our study demonstrate that a face visor is insufficient to prevent splatter on the surgeon’s face. It must be assumed that if splatter droplets could be detected in our study, that there will be smaller droplets deposited on the surfaces which were undetectable or remain aerosolised. This study confirms that Coblation tonsil surgery is an AGP. Given that coronaviruses are approximately 0.125μm in size and are frequently carried in respiratory droplets, it is possible that surgical techniques regarded as aerosol generating may risk airborne transmission of SARS-CoV-2 during surgery. The small particle size of the virus and the extent airborne aerosols may travel has highlighted the need for specific PPE to protect against inhaled transmission.
This study cannot determine if N97 surgical masks and goggles are sufficient protection from the risk of viral transmission. Air-purifying respirators systems and hoods may seem to be the obvious choice, but it should be remembered that extended use of these PPE is uncomfortable and restricts communication between staff in the operating suite22Verbeek JH, Rajamaki B, Ijaz S, Sauni R, Toomey E, Blackwood B, Tikka C, Ruotsalainen JH, Kilinc Balci FS. Personal protective equipment for preventing highly infectious diseases due to exposure to contaminated body fluids in healthcare staff. Cochrane Database Syst Rev. 2020 May 15;5:CD011621.Succinct key points:The Covid-19 pandemic has highlighted tonsillectomy as an aerosol generating procedure (AGP). This is the first study to assess for droplet splatter contamination around the surgical field and on the surgeon during Coblation tonsillectomy. Droplets were detected in all four quadrants of the surgical fields with the greatest in the upper (nearest to surgeon) and lower quadrants. Splatter droplets were most frequently occurring on the hands of the surgeon followed by the forearm, and less frequently on the visor, neck, and chest. 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.Legend to tables and figuresFigure 1. Experimental setup: (a) Head model with Boyle–Davis and Draffin rods in-situ. (b) Fluorescein-soaked strawberries used to mimic tonsils. (c) Fluorecein infused into saline irrigation bag and tubing connected to Coblation pump. (d) Close-up of simulated tonsil surgery using the Coblation Procise wand. Note the hole in the black sheet covering the model but providing access to the oropharynx.Figure 2 . a) Quadrants of surgical field b)Anatomical subsites of surgeon (Right and left hands, forearms and arms, chest, neck and face) including face shieldFigure 3 . Frequency of detected droplet spread around the surgical field by individual (a and b) and average (c); 0 = white, 1-2 = yellow, 3-4 = orange and 5 = red.Figure 4 . Heatmap of anatomical areas of each surgeon (a and b) including face shield.. The need for better protection must be balanced between user comfort, ability to communicate effectively more complicated donning or doffing procedures, and ultimately compliance to PPE recommendations.