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

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.

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.

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 (χ² = 9.96, p = 0.041).

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.