Ethmoid‐to‐maxillary opacification ratio: a predictor of postoperative olfaction and outcomes in nasal polyposis?

Background Inflammatory profiles for patients with chronic rhinosinusitis with nasal polyposis (CRSwNP) vary between North American and Asian populations. An elevated ethmoid-to-maxillary (E/M) opacification ratio on preoperative imaging is associated with certain postoperative outcomes in Asian populations and populations that are non-type 2 dominant. In this study we explore this factor in North American/type 2-based populations. Methods Adult patients (n = 165) from a North American population with CRSwNP who underwent endoscopic sinus surgery (ESS) were prospectively enrolled into an observational, multi-institutional study. The 22-item Sino-Nasal Outcome Test (SNOT-22), Brief Smell Identification Test (BSIT), and Lund-Kennedy (LK) endoscopic scores were obtained pre- and postoperatively. Patients were stratified according to increasing E/M ratios based on Lund-Mackay (LM) scores. Results On average, significant within-subject postoperative improvement was found in all patients for SNOT-22 total and domain scores, and also BSIT results (p <= 0.019). Preoperatively, elevated E/M ratio correlated with worse BSIT scores (r= -0.343,p< 0.001). Postoperatively, elevated E/M ratio correlated with BSIT improvement (r= 0.284,p= 0.002), but did not correlate with SNOT-22 improvement or polyp recurrence. An elevated E/M ratio was associated with greater likelihood of reporting a minimal clinically important difference in BSIT scores (chi(2)= 9.96,p= 0.041). Conclusion Elevated E/M ratios were found to associated with worse baseline olfaction and an increased likelihood of achieving a clinically meaningful postoperative improvement in olfaction in this North American population with CRSwNP. Elevated E/M ratios did not predict postoperative changes in SNOT-22 measures or polyp recurrence. This suggests that prognostic factors may vary according to geography and generalized inflammatory profiles (type 2 vs non-type 2) in patients with CRS.