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.