Quantification and Comparison of Droplet Formation During Endoscopic and Microscopic Ear Surgery: A Cadaveric Model

Abstract

Objectives The COVID-19 pandemic and the disproportional spread of the disease among otorhinolaryngologists raised concerns regarding the safety of health care staff. Therefore, a quantitative risk assessment for otologic surgery would be desirable. This study aims to quantitatively compare the risk of perioperative droplet formation between microscopic and endoscopic approaches. Study Design Experimental research. Setting Temporal bone laboratory. Methods The middle ear of whole head specimens was injected with fluorescein (0.2 mg/10 mL) before endoscopic and microscopic epitympanectomy and mastoidectomy. Fluorescent droplet deposition on the surgical table was recorded under ultraviolet light, quantified, and compared among the interventions. Drilling time, droplet proportion, fluorescein intensity, and droplet size were assessed for every procedure. Results A total of 12 procedures were performed: 4 endoscopic epitympanectomies, 4 microscopic epitympanectomies, and 4 mastoidectomies. The mean (SD) proportion of fluorescein droplets was 0.14‰ (0.10‰) for endoscopic epitympanectomy and 0.64‰ (0.31‰) for microscopic epitympanectomy. During mastoidectomy, the deposition of droplets was 8.77‰ (6.71‰). Statistical comparison based on a mixed effects model revealed a significant increase (0.50‰) in droplet deposition during microscopic epitympanectomy as compared with endoscopic epitympanectomy (95% CI, 0.16‰ to 0.84‰). Conclusions There is considerable droplet generation during otologic surgery, and this represents a risk for the spread of airborne infectious diseases. The endoscopic technique offers the lowest risk of droplet formation as compared with microscopic approaches, with a significant 4.5-fold reduction of droplets between endoscopic and microscopic epitympanectomy and a 62-fold reduction between endoscopic epitympanectomy and cortical mastoidectomy.

Otitis Media Practice During the COVID-19 Pandemic

“…COVID-19 emergence required otologists to adopt a changed mindset for otologic office procedures and ear surgery. Otologic surgery, including drilling of the mastoid, is known to cause a substantial dispersion of small and large aerosols (Anschuetz et al, 2021;Chari et al, 2021;Hajiyev and Vilela, 2021;Merven and Loock, 2021;Sharma et al, 2021) and droplets (Sharma et al, 2020;Mohan et al, 2021;Sharma et al, 2021), and is a cause of concern regarding contamination in the operating room (OR). To prevent unnecessary risk of infection, otologic procedures were categorized as urgent versus elective, according to different authors and otolaryngological societies (Kozin et al, 2020;Leboulanger et al, 2020;Pattisapu et al, 2020;Saadi et al, 2020), suggesting that urgent operations should be performed, while all other operations should be postponed, depending on the pathology and the patient's preference.…”

COVID-19 and otologic surgery

“…20 A cadaveric study comparing droplet spread during endoscopic drill atticotomy, microscopic drill atticotomy, and cortical mastoidectomy demonstrated a significant 4.5-fold reduction in droplet generation between endoscopic and microscopic atticotomy and a 62-fold reduction between endoscopic atticotomy and cortical mastoidectomy. 22 No literature currently exists regarding the usage of drape barrier systems when using powered instruments in endoscopic ear surgery, however the basic ideas of adapting a containment system should theoretically apply.…”

Endoskopische Ohrchirurgie in Deutschland

“…Die geringe Häufigkeit des Bohrereinsatzes in nur einem Drittel der EES-Kliniken war daher zu erwarten. Trotzdem bietet die EES-Technik aber gerade angesichts der derzeitigen SARS-CoV-2-Pandemie gegenüber dem mikroskopischen Vorgehen deutliche Vorteile mit einer geringeren Tröpfchenbildung im Op.-Feld [ 2 ]. Die Entwicklung eines geeigneten Systems mit Spülung und Absaugung wäre daher auch aus diesem Grund sinnvoll.…”