Hyperbaric Oxygen Therapy in Sinonasal Disease: A Narrative Review of Mechanisms, Clinical Evidence, and Multidisciplinary Perspectives on Invasive Fungal Rhinosinusitis and Post-Radiotherapy Injury

Background: Hyperbaric oxygen therapy (HBOT) is proposed as an adjunct in two sinonasal conditions of high morbidity: acute invasive fungal rhinosinusitis (AIFRS) and post-radiotherapy injury. Methods: We conducted a narrative review and reported it against SANRA; PubMed/MEDLINE was searched (1980–2026; 1414 records screened, 589 retained), with Cochrane, society guidance and reference screening. Results: No randomised trial has tested HBOT against sinonasal endpoints in either indication. In AIFRS the dedicated evidence is four uncontrolled series (n = 27, level 4); none reports how many candidates were unfit to pressurise, the largest synthesis did not identify HBOT as a survival predictor, and the only randomised experiment—murine—was negative. Mycology guidance supports it with marginal strength only (C; quality III), and hyperbaric indication lists omit it. For radiation injury, Cochrane 2023 reports low-certainty benefit in head-and-neck tissue, but HOPON found no reduction in osteoradionecrosis after dentoalveolar surgery (6.4% vs. 5.7%; OR 1.13, 95% CI 0.14–8.92), and pooled DAHANCA-21/NWHHT2009-1 data were non-significant (70% vs. 51% healing); all sinonasal use is extrapolated from the mandible. Middle-ear, not sinus, barotrauma is the commonest ENT complication. Conclusions: HBOT is mechanistically coherent and may be considered case-by-case within a multidisciplinary team, but it is not a standard of care in either indication; the algorithm offered here is unvalidated.