Background: Preoperative inflammation of the olfactory cleft may cause not only the obstruction of this area, but also damage of the olfactory neuroepithelium, resulting in anosmia. Therefore, the evaluation of the affected olfactory cleft by computed tomography (CT) might help predict postoperative olfaction.
Methods: Fifty-two patients who underwent functional endoscopic sinus surgery for chronic rhinosinusitis (CRS) with nasal polyps were examined preoperatively and at 6 months after surgery. OMU CT was obtained preoperatively and olfactory function tests such as the butanol threshold test, the cross-cultural smell identification test, and questionnaires were performed at the initial preoperative visit and at 6 months after surgery. The correlation between the status of the olfactory cleft on CT and the postoperative olfactory results were investigated.
Results: The findings of olfactory cleft opacification and the CT scores had a negative correlation with preoperative olfactory results (p < 0.05). The olfactory cleft opacification showed a stronger correlation with the preoperative olfactory results than the CT score. The total olfactory cleft opacification score and anterior olfactory cleft opacification score (AOCS) were more significantly correlated with the postoperative olfactory results than the other parameters (p < 0.05). Among the CT findings, the AOCS was a significant prognostic factor of olfactory results after surgery; these findings were significant on multiple regression analysis (p < 0.05). The postoperative olfactory scores and the improvement of olfactory scores after surgery were increased more in the mild AOCS group than in the moderate and severe AOCS groups (p < 0.05). Recovery and normosmia rates were much better in the mild AOCS group in this study (p < 0.05).
Conclusion: Preoperative CT findings, especially the anterior portion of the olfactory cleft, had a statistically significant association with the postoperative olfactory results in patients with CRS with nasal polyps.