Does olfactory function improve after endoscopic sinus surgery?

Abstract

To examine the impact of endoscopic sinus surgery (ESS) on olfactory impairment in patients with chronic rhinosinusitis (CRS) over intermediate and long-term follow-up. We hypothesized that patients with mild olfactory dysfunction (hyposmia) would benefit from ESS, whereas patients with severe olfactory dysfunction (anosmia) would not. Prospective, multi-institutional cohort study. A total of 111 patients presenting for ESS for treatment of CRS were examined preoperatively, and at 6 and 12 months postoperatively. Demographic, comorbidity, and Smell Identification Test (SIT) data were collected at each time point. Univariate and multivariate analyses were performed. The prevalence of gender-adjusted olfactory dysfunction prior to surgery was 67.5 percent. Surprisingly, hyposmic patients did not significantly improve after surgery. In contrast, patients with anosmia significantly improved after ESS (baseline, 6-month SIT scores: 9.7 +/- 2.0, 21.3 +/- 11.2; P = 0.001). Improvement was sustained at 12-month follow-up (21.7 +/- 10.7; 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). Contrary to our hypotheses, patients with severe olfactory dysfunction significantly improved after ESS and sustained improvement over time, whereas patients with mild olfactory dysfunction did not.