Does Olfaction Improve After Endoscopic Sinus Surgery?

Abstract

Objective No large, prospective, multi-institutional cohort studies have objectively examined the impact of surgery on olfaction with long-term follow-up. The aim of this study was to objectively examine the impact of endoscopic sinus surgery (ESS) on olfactory dysfunction (hyposmia) would benefit from ESS, whereas patients with severe olfactory dysfunction (anosmia) would not. Methods In this prospective, multi-institutional cohort study, 111 patients presenting for ESS for treatment of CRS were examined pre-operatively and at 6 and 12 months postoperatively. Demographic, co-morbidity and Smell Identification Test (SIT) data were collected at each time point. Univariate and multivariate analyses were performed. Results The prevalence of gender-adjusted olfactory dysfunction prior to surgery was 67.5%: 50.4% of patients were hyposmic and 17.1% were anosmic. Surprisingly, hyposmic patients did not significantly improve after surgery (baseline, 6 month, 12 month mean SIT scores: 28.8, 30.0, 29.5). In contrast, patients with anosmia significantly improved after ESS (baseline, 6 month, 12 month mean SIT scores: 9.3, 21.3, 21.7; p=0.001); furthermore, improvement was sustained at 12-month follow-up (p=0.001). Multivariate linear regression analysis showed that baseline olfactory category and nasal polyposis were significantly associated with improvement in postoperative olfactory function (p=0.035, p=0.002), whereas age, gender, and disease-severity as measured by CT and endoscopy scores were not. Conclusions Contrary to our hypothesis, patients with severe olfactory dysfunction significantly improved after ESS and sustained improvement over time, whereas patients with mild olfactory dysfunction did not.