Impact of residual ethmoid cells on postoperative course after endoscopic sinus surgery for chronic rhinosinusitis

Endoscopic sinus surgery (ESS) is a worldwide standard surgical procedure for chronic rhinosinusitis (CRS). Residual ethmoid cells (RECs), which result from failure to completely remove them, have been thought to be a cause of recurrence of CRS. Our objective was to investigate the relationship between the REC score and post ESS recurrence of CRS.

From January 2002 through December 2003, a total of 138 consecutive CRS patients (86 men and 52 women; mean age: 44 years) underwent ESS at the Department of Otorhinolaryngology, Ota General Hospital. CT was performed at 6 or more months post ESS for all patients. The left and right ethmoid sinuses were each divided into superior-anterior, inferior-anterior and posterior parts. The extent of RECs in each part was assessed using a 3-grade scoring system. The outcome of CRS was classified into a satisfactory outcome group and a poor outcome group based on the improvement rate determined from the pre ESS and post ESS CT image findings. The two groups were then compared for the age, gender, presence/absence of nasal polyps, presence/absence of allergic rhinitis, presence/absence of asthma, the peripheral eosinophil count (%) and the total REC score. In addition, the individual correlations between the above variables and the poor outcome group were analyzed by logistic regression analysis.

The total REC score was 0 in only 35 (25.4%) of the total patients. The most common total REC scores were 1-6 in 85 (61.6%) patients. The superior-anterior part had the largest number of patients with an REC score of 1 or more. The satisfactory outcome group comprised 97 patients (70.3%), while the poor outcome group comprised 41 patients (29.7%). Comparison of these two groups found that the peripheral eosinophil count, the prevalence rate of asthma and the total REC score were each significantly higher in the poor outcome group than in the satisfactory outcome group. Logistic regression analysis identified a peripheral eosinophil count of ≥9.5%, the presence of asthma and a total REC score of ≥4 as factors that correlated significantly with a poor outcome.

The findings of this study indicate that RECs are involved in the recurrence of CRS following ESS. It can be thought that how to achieve full opening of the superior-anterior part of the ethmoid sinus, which includes the frontal recess, will be an issue in the future.