Topical Therapies to Prevent Aerosolization of Respiratory Viral Particles during Endonasal Skull Base Surgery: A Practical Review

Abstract

Background: The potential reservoir of severe acute respiratory syndrome coronavirus (SARS-CoV-2) in the nasopharynxand upper airway of infected or asymptomatic patients undergoing endonasal procedures amid the ongoing coronavirusdisease 2019 (COVID-19) pandemic may put skull base surgeons and their teams at high risk of exposure to aerosolizedviral particles during endonasal procedures. Strategies to mitigate the risk of potential aerosol-generating procedures(AGPs) have been promoted at a feverish pace, and significant effort has been made to optimize guidelines limitingaerosolization. This review summarizes the use of topical therapies as a perioperative infection control strategy, detailingefficacy, safety, and delivery options. Methods: A PubMed/MEDLINE and Scopus database review of articles was conducted querying topical therapies, includingpovidone-iodine (PVP-I), chlorhexidine, saline, surfactants, alcohols, and interferon activity against coronaviruses, andsafety for peri-operative use. Results: Few clinical studies specifically investigate the in vivo viricidal activity of topical agents against SARS-CoV-2 in theperioperative setting. Of topical agents with viricidal potential, PVP-I is supported by the most robust investigations-invitro studies have shown that PVP-I solutions as low as 0.5% can completely inactivate SARS-CoV-2 with 15 seconds ofcontact time, and solutions as low as 0.23% may neutralize SARS-CoV-2 homologues. Regarding safety, PVP-Iconcentrations of 2.5% and greater are associated with ciliotoxicity effects on human respiratory epithelial cells, but can betolerated up to 5% when administered intraorally, and up to 1% as a sinus irrigation formulation. As for other agents,preliminary studies show that chlorhexidine mouthwash may transiently decrease the SARS-CoV-2 virus load below thedetectable limit in saliva for 2 to 4 hours, but in isolation it is less effective than PVP-I in vitro studies. Furthermore,chlorhexidine and other antiseptics including ethanol have a worse safety profile than PVP-I, including increasedflammability and ototoxicity. Studies also show that hypertonic saline nasal irrigation and gargling leads to decreasedduration of illness, transmission, and viral shedding among patients with the common cold, including coronaviruses, andwas well tolerated barring some reports of nasal irritation, epistaxis, and headache. Conclusions: Several topical therapies, including PVP-I and hypertonic saline, may be at least temporarily effective atinactivating SARS-CoV-2 in the perioperative setting. However, these interventions are not without potential risks, includingciliotoxicity, which adversely impacts the mucociliary clearance of pathogens, and the efficacy of these agents is limited byavailable clinical data. However, thoughtful, evidence-based approaches should be considered as a sustainable option toreduce the risk of respiratory viral particle aerosolization in AGPs, such as endonasal skull base surgery.