Short-term outcomes of olfaction in patients with eosinophilic chronic rhinosinusitis after endoscopic sinus surgery and an assessment of prognostic factors

Background Olfactory dysfunction is one of the common symptoms of eosinophilic chronic rhinosinusitis (ECRS), for which endoscopic sinus surgery (ESS) is the standard treatment. Although the success rates of ESS for restoring olfaction in CRS have been reported, those for ECRS, as defined by new Japanese diagnostic criteria, remain unclear and the parameters affecting improvement rates have not yet been identified. Methods Eighty-four patients with ECRS who underwent full-house ESS were retrospectively investigated. Olfactory function was examined using T&T recognition thresholds before and 3 months after surgery. Results The total positive improvement rate in olfaction was 76.2% (64 of 84) and the mean T&T recognition threshold decreased significantly from 5.2 +/- 1.1 to 3.0 +/- 1.8 after surgery (p < 0.001). Some factors, including negative intravenous olfaction test, presence of olfactory cleft (OC) lesions, a history of sinus surgery, age >= 45 years, and being male, were more frequent in the olfaction refractory group. Furthermore, improvement of the T&T recognition threshold was significantly lower for factors of negative intravenous olfaction testing, the presence of OC lesions, and being male. Age and the proportion of blood eosinophils correlated with improvement. Conclusion Herein we examined prognostic factors for olfactory outcomes in ECRS treated with ESS. The intravenous olfaction test, presence of OC lesions, sex differences, and age (the cut-off value was 45 years) were identified as independent prognostic factors for olfactory outcomes 3 months after surgery.