Retronasal olfaction in chronic rhinosinusitis

Objective: The goals of this study were to assess retronasal olfaction in patients with chronic rhinosinusitis (CRS) and describe clinical factors that influence retronasal olfaction. This study sought to investigate the influence of retronasal olfaction on patient-perceived outcomes and examine the relationship between retronasal and orthonasal olfaction. Methods: Retronasal olfactory function was tested using odorized powders in the oral cavity, whereas Sniffin' Sticks test (Burghart Instruments, Wedel, Germany) were used to assess orthonasal function prospectively in 69 adult CRS patients. Endoscopic evaluation of the olfactory cleft was scored using the Olfactory Cleft Endoscopy Scale (OCES). Several quality-of-life (QOL) instruments relating to sinonasal, olfactory, and chemosensory functions were used to assess the interactions between patient-reported outcome measures and retronasal olfaction. Results: There was strong correlation between retronasal and total orthonasal olfaction scores (r = 0.77, P < 0.001) as well as retronasal scores with orthonasal subscores. Retronasal scores were worse in patients with nasal polyposis (P = 0.002), asthma (P = 0.04), and aspirin-exacerbated respiratory disease (AERD) (P = 0.02), whereas OCES was the only independent predictor of retronasal olfaction (r = −0.42, P < 0.001). Significant correlation existed between retronasal olfaction and olfactory-specific QOL and chemosensory smell scores. Conclusion: Few studies have examined retronasal olfaction in CRS patients. In this cohort, CRS patients demonstrated deficits in retronasal olfaction, with worse scores in patients with nasal polyposis, asthma, and AERD. Retronasal olfaction scores correlate with degree of inflammation of the olfactory cleft. Retronasal olfaction correlated strongly with orthonasal olfaction and patient-reported smell and taste metrics, although orthonasal olfaction may have a stronger correlation with these metrics. Level of Evidence: NA. Laryngoscope, 2437–2442, 2018.