Correlation of Tissue Eosinophil Count and Chemosensory Functions in Patients with Chronic Rhinosinusitis with Nasal Polyps After Endoscopic Sinus Surgery

Purpose: To investigate the correlation of tissue eosinophil count and chemosensory functions in patients with chronic rhinosinusitis with nasal polyps (CRSwNP) after endoscopic sinus surgery (ESS).

Methods: This was a cross-sectional study including 40 patients with a history of ESS for CRSwNP recruited consecutively. Visual analog scale score and the Lund-Kennedy endoscopic score were recorded. Biopsies of the ethmoidal sinus mucosal were performed and evaluated. Chemosensory functions were measured by Sniffin' Sticks and chemosensory event-related potentials (CSERP). The associations between chemosensory functions and tissue eosinophil count were analyzed using Spearman correlation and partial correlation after adjusting the confounding factors. Kendall's tau-b correlation was performed between sneezing score and CSERP with ethyl alcohol (EAL) stimulation.

Results: Olfactory and trigeminal nerve function was successfully evaluated using CSERP. Postoperative tissue eosinophil count was correlated with threshold (T) score (partial correlation coefficient r = - 0.460, p = 0.012) and CSERP peak latency for olfactory (N1: partial r = 0.471, p = 0.010; P2: partial r = 0.487, p = 0.007) and mixed olfactory-trigeminal (N1: partial r = - 0.516, p = 0.008; P2: partial r = - 0.590, p = 0.002). There were also correlations between T score and N1 latency with phenyl ethyl alcohol (PEA) (partial r = - 0.560, p < 0.001), between sneezing score and N1 latency with EAL (Kendall's tau-b = - 0.40, p = 0.005).

Conclusions: Postoperative tissue eosinophilia is significantly associated with postoperative olfactory disorders as assessed by Sniffin' Sticks and CSERP peak latency. Furthermore, olfaction as measured by T score correlates with olfactory ERP latency in inflammation-associated olfactory dysfunction. Trigeminal sensitivity also appears to relate to tissue eosinophilia, indicating mucosal inflammation can affect both sensory systems in the nose.