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Otol Neurotol ; 42(4): 614-622, 2021 04 01.
Article in English | MEDLINE | ID: covidwho-1313901


HYPOTHESIS: Aerosols are generated during mastoidectomy and mitigation strategies may effectively reduce aerosol spread. BACKGROUND: An objective understanding of aerosol generation and the effectiveness of mitigation strategies can inform interventions to reduce aerosol risk from mastoidectomy and other open surgeries involving drilling. METHODS: Cadaveric and fluorescent three-dimensional printed temporal bone models were drilled under variable conditions and mitigation methods. Aerosol production was measured with a cascade impactor set to detect particle sizes under 14.1 µm. Field contamination was determined with examination under UV light. RESULTS: Drilling of cadaveric bones and three-dimensional models resulted in strongly positive aerosol production, measuring positive in all eight impactor stages for the cadaver trials. This occurred regardless of using coarse or cutting burs, irrigation, a handheld suction, or an additional parked suction. The only mitigation factor that led to a completely negative aerosol result in all eight stages was placing an additional microscope drape to surround the field. Bone dust was scattered in all directions from the drill, including on the microscope, the surgeon, and visually suspended in the air for all but the drape trial. CONCLUSIONS: Aerosols are generated with drilling the mastoid. Using an additional microscope drape to cover the surgical field was an effective mitigation strategy to prevent fine aerosol dispersion while drilling.

COVID-19/prevention & control , Mastoidectomy/adverse effects , Aerosols , COVID-19/transmission , Cadaver , Humans , Mastoidectomy/instrumentation , Mastoidectomy/methods , SARS-CoV-2
Otol Neurotol ; 42(4): 606-613, 2021 04 01.
Article in English | MEDLINE | ID: covidwho-913295


BACKGROUND: During the Covid-19 pandemic, otolaryngologists are at risk due to aerosol-generating procedures such as mastoidectomy and need enhanced personal protective equipment (PPE). Eye protection can interfere with the use of a microscope due to a reduction in the field of vision. We aimed to study the effect of PPE on the microsurgical field. METHODS: Five surgeons measured the visual field using digital calipers at different power settings. They were done with no PPE, a surgical mask, FFP3 mask (N99), and with the addition of small goggles, large vistamax goggles, vistamax plus a face shield, and only a face shield. The measurements were repeated with rings of 5 mm increments. We also measured the "eye relief" of the microscope which is the ideal distance for maximum field of view. RESULTS: There was no major reduction of the field with the surgical or FFP3 mask. But even simple goggles reduced the field up to 31.6% and there were progressive reductions of up to 75.7% with large goggles, 76.8% when a face shield was added, and 61.9% when only face shield was used. The distance rings more than 5 mm also affected the field of view.The eye relief of our eyepiece was found to be 15 mm. CONCLUSION: The current PPE eye protection is not compatible with the use of a microscope. There is scope for research into better eye protection. Mitigation strategies including barrier drapes and alternative techniques such as endoscopic surgery or use of exoscopes should also be considered.

COVID-19/prevention & control , Microsurgery , Otolaryngologists , Personal Protective Equipment/adverse effects , Visual Fields , COVID-19/transmission , Humans , Mastoidectomy/adverse effects , Microsurgery/instrumentation , Microsurgery/methods , SARS-CoV-2
Otol Neurotol ; 41(9): 1230-1239, 2020 10.
Article in English | MEDLINE | ID: covidwho-197201


BACKGROUND: COVID-19 has become a global pandemic with a dramatic impact on healthcare systems. Concern for viral transmission necessitates the investigation of otologic procedures that use high-speed drilling instruments, including mastoidectomy, which we hypothesized to be an aerosol-generating procedure. METHODS: Mastoidectomy with a high-speed drill was simulated using fresh-frozen cadaveric heads with fluorescein solution injected into the mastoid air cells. Specimens were drilled for 1-minute durations in test conditions with and without a microscope. A barrier drape was fashioned from a commercially available drape (the OtoTent). Dispersed particulate matter was quantified in segments of an octagonal test grid measuring 60 cm in radius. RESULTS: Drilling without a microscope dispersed fluorescent particles 360 degrees, with the areas of highest density in quadrants near the surgeon and close to the surgical site. Using a microscope or varying irrigation rates did not significantly reduce particle density or percent surface area with particulate. Using the OtoTent significantly reduced particle density and percent surface area with particulate across the segments of the test grid beyond 30 cm (which marked the boundary of the OtoTent) compared with the microscope only and no microscope test conditions (Kruskall-Wallis test, p = 0.0066). CONCLUSIONS: Mastoidectomy with a high-speed drill is an aerosol-generating procedure, a designation that connotes the potential high risk of viral transmission and need for higher levels of personal protective equipment. A simple barrier drape significantly reduced particulate dispersion in this study and could be an effective mitigation strategy in addition to appropriate personal protective equipment.

Aerosols , Coronavirus Infections/prevention & control , Mastoid/surgery , Mastoidectomy/adverse effects , Occupational Exposure/prevention & control , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Betacoronavirus , COVID-19 , Cadaver , Fluorescein , Humans , Microscopy , Occupational Health , Operating Rooms , Personal Protective Equipment , SARS-CoV-2 , Surgeons , Temporal Bone/surgery