Olfactory function after functional endoscopic sinus surgery for chronic sinusitis.

One hundred and fifteen patients suffering from chronic sinusitis were observed to analyse the prevalence of olfactory dysfunction and the influence of FESS. Pre-operative questionnaires were supplemented by examination of olfactory thresholds and discrimination. Pre-operatively, 58% of the collective were aware or complained of any olfactory deficit. However, the olfactory tests demonstrated that of the collective 52% were hyposmic and 31% anosmic. Eight per cent of the hyposmic patients presented with an isolated reduction of their ability to discriminate odours. Post-operative improvements were found in 70%. Normosmia was post-operatively achieved in 25% of the hyposmic patients, but only in 5% of the anosmic patients. Olfaction changed to the worse in 8% after FESS. Therefore, the prevalence of olfactory dysfunction in chronic sinusitis is pre-operatively higher, and the rate of improvement is lower than generally assumed. The extent of sinus disease as measured by the degree of intranasal polyposis correlates with olfactory dysfunction. Resections of the middle turbinate may have a negative effect on olfaction, due to damage to the olfactory fila or alteration of the normal aerodynamic pattern within the olfactory cleft. However, this hypothesis is based on a few observations and needs to be verified by further investigations.