The challenge of performing mastoidectomy using the operating microscope
with COVID-19 personal protective equipment (PPE)
Abstract
Objective: As an aerosol generating procedure (AGP), mastoidectomy in
the COVID-19 era requires healthcare workers to wear personal protective
equipment (PPE); UK guidelines recommend an FFP-3 mask and full-face
visor. The aim of this study was to examine the effect of wearing PPE on
the view achieved using the operating microscope. Methods: Using the
operating microscope, ENT surgeons were asked to view a target so that
it filled the entire operating field. The distance between the surgeon’s
eye and the microscope was recorded and subsequently measured with the
surgeon wearing a range of PPE. In each PPE condition, surgeons scored
the visibility of the target; scores were used to calculate the visible
area of the surgical field. Results: Eleven surgeons took part,
generating 51 eye-microscope and target-view scores. Distance from the
eye to the microscope inversely correlated with diameter and area
visible (Pearson correlation coefficient -0.983 and -0.894 respectively;
p<0.001). Use of PPE increased the eye-microscope distance and
reduced the surgical view. The median area visible wearing the FFP-3
mask and full-face visor was 4% (range 4 – 16%). Conclusion: PPE
consisting of an FFP-3 mask and full-face visor is incompatible with use
of the operating microscope, with less than 10% of the surgical field
visible in most cases. Solutions that allow for concurrent use of the
operating microscope and drill during mastoid surgery are urgently
required so that surgeons are adequately protected from COVID-19
transmission.