Quantification of biomaterial dispersion during otologic procedures and role of barrier drapes in Covid 2019 era - a laboratory model.

BACKGROUND: Aerosol generation during temporal bone surgery caries the risk of viral transmission. Steps to mitigate this problem are of particular importance during the coronavirus disease 2019 pandemic. OBJECTIVE: To quantify the effect of barrier draping on particulate material dispersion during temporal bone surgery. METHODS: The study involved a cadaveric model in a simulated operating theatre environment. Particle density and particle count for particles sized 1-10 µ were measured in a simulated operating theatre environment while drilling on a cadaveric temporal bone. The effect of barrier draping to decrease dispersion was recorded and analysed. RESULTS: Barrier draping decreased counts of particles smaller than 5 µ by a factor of 80 in the operating theatre environment. Both particle density and particle count showed a statistically significant reduction with barrier draping (p = 0.027). CONCLUSION: Simple barrier drapes were effective in decreasing particle density and particle count in the operating theatre model and can prevent infection in operating theatre personnel.

'POLIDON' Approach-A Novel Solution for the ENT & Skull Base Surgeons in COVID-19 era.

Health care providers (HCP) of ENT and Skull base surgery are highly vulnerable and mostly infected by novel coronavirus as they have to examine and perform procedures directly in oral cavity, oropharynx, nose, nasopharynx, where coronavirus remains in plenty. ENT & Skull base surgeons need to do several aerosol generating procedures (AGP). Most of the endoscopic and microscopic ENT & skull base surgery are AGP; like-mastoid surgery, sinus surgery, surgery of pituitary, tympanomastoid paraganglioma, temporal bone malignancy, tracheostomy etc. All of we know, COVID negative by RT-PCR test is not always COVID negative. In COVID-19 pandemic-routine, even cancer surgeries are avoided or postponed for the sake of safety of HCPs. Moreover, in case of surgical emergency there's no way to refuse a patient for not having a report of COVID test. We thought about neutralizing or destroying the novel coronavirus from it's route of entry zone, as well as preventing aerosol to be transmitted in the air of OT. We designed a novel approach, i.e. 'POLIDON' (POLIDON = Polythene + Povidone Iodine), which can be the solution for these patients as well as surgeons or HCPs of above mentioned specialties. Use of Povidone Iodine as mouthwash and nasal spray or irrigation for both patient and HCPs prior to surgery is proposed. Then, use of simple polythene as barrier drape of patient or operative area for prevention of spread of aerosol in OT during surgery is the other component. With the POLIDON' approach-all these ENT & skull base surgeries can be done with more safety and confidence.

Aerosol Dispersion During Mastoidectomy and Custom Mitigation Strategies for Otologic Surgery in the COVID-19 Era.

OBJECTIVE: To investigate small-particle aerosolization from mastoidectomy relevant to potential viral transmission and to test source-control mitigation strategies. STUDY DESIGN: Cadaveric simulation. SETTING: Surgical simulation laboratory. METHODS: An optical particle size spectrometer was used to quantify 1- to 10-µm aerosols 30 cm from mastoid cortex drilling. Two barrier drapes were evaluated: OtoTent1, a drape sheet affixed to the microscope; OtoTent2, a custom-structured drape that enclosed the surgical field with specialized ports. RESULTS: Mastoid drilling without a barrier drape, with or without an aerosol-scavenging second suction, generated large amounts of 1- to 10-µm particulate. Drilling under OtoTent1 generated a high density of particles when compared with baseline environmental levels (P < .001, U = 107). By contrast, when drilling was conducted under OtoTent2, mean particle density remained at baseline. Adding a second suction inside OtoTent1 or OtoTent2 kept particle density at baseline levels. Significant aerosols were released upon removal of OtoTent1 or OtoTent2 despite a 60-second pause before drape removal after drilling (P < .001, U = 0, n = 10, 12; P < .001, U = 2, n = 12, 12, respectively). However, particle density did not increase above baseline when a second suction and a pause before removal were both employed. CONCLUSIONS: Mastoidectomy without a barrier, even when a second suction was added, generated substantial 1- to 10-µm aerosols. During drilling, large amounts of aerosols above baseline levels were detected with OtoTent1 but not OtoTent2. For both drapes, a second suction was an effective mitigation strategy during drilling. Last, the combination of a second suction and a pause before removal prevented aerosol escape during the removal of either drape.

Demonstration and Mitigation of Aerosol and Particle Dispersion During Mastoidectomy Relevant to the COVID-19 Era.

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.