Aim: This prospective study aimed to assess treatment outcome on olfaction in patients undergoing Endoscopic Sinus Surgery (ESS) for nasal polyposis, and to evaluate the role of previous sinus surgery and the duration of olfactory deficit as prognostic factors for olfaction improvement.
Methods: In total, 116 patients with nasal polyposis who underwent ESS were studied. Olfactory testing was performed using the Sniffin' Sticks test, preoperatively and 1-, 3- and 6-month postoperatively.
Results: The values of the composite threshold discrimination identification score were significantly lower in patients with long duration of olfactory deficit and history of previous sinus surgery in all testing sessions. Adjustment for preoperative olfactory measures and all potential confounders revealed that both parameters remained strong independent predictors of normal olfactory function; a successful outcome was more frequent in patients with short duration of olfactory deficit and in patients who had not undergone previous sinus surgeries. However all patients achieved a significant stepwise increment of all indices of olfactory function over time, after ESS.
Conclusions: Duration of olfactory deficit and previous sinus surgery presented highly significant predictive value for the short-term outcome of the olfactory function after ESS. However all patients suffering from nasal polyposis will probably improve olfaction significantly in a period up to six months after surgery.