Certain Factors May Reduce ESS-Induced Smell Improvement in CRSwNP

Endoscopic sinus surgery (ESS) was associated with an improvement in self-reported olfactory function among patients with chronic rhinosinusitis with nasal polyps (CRSwNP), although some risk factors may adversely affect sense of smell recovery. Results were published today in Frontiers in Surgery.

Cited by researchers as a predominant dysfunction present in CRSwNP, prior research shows diminished olfactory function has improved with ESS, especially in patients who did not achieve a clinically meaningful recovery after appropriate medical therapy. However, the improvement rate varies greatly: from 25% to 100%.

“Because olfactory examinations such as Sniffin sticks only represent patients’ olfactory level at the time the test is performed, an overall subjective judgment of olfaction by patients over time is also needed to reflect dynamic changes in olfaction as they impact patients’ quality of life,” said the study authors. “Identifying risk factors of olfactory dysfunction and postoperative olfactory recovery are essential for guiding physicians and patients regarding outcomes that can be achieved by ESS.”

Researchers conducted a prospective analysis of 56 patients with CRSwNP aged 24 to 63 years who failed medical treatment and completed functional ESS at the Department of Otolaryngology, Qilu Hospital, Shandong University, in China.

Participants reported their self-evaluated olfactory dysfunction score preoperatively and 1, 3, and 12 months after ESS. Preoperative clinical characteristics, CT scan (Lund–Mackay CT score [LMS]), and sinonasal endoscopy examination results (Lund-Kennedy [LK] endoscopy score) were collected prior to surgery.

Factors that predicted olfactory loss and affected the improvement of olfaction after ESS were also evaluated, including age, sex, duration of olfactory dysfunction, blood eosinophil counts, asthma, allergic rhinitis, prior surgery, LMS, LK endoscopy score, and peripheral distribution of CT opacification.

Of the study cohort, 8.9% (n = 5) presented with normosmia, 23.2% (n = 13) had mild impairment, 23.2% (n = 13) had moderate impairment, and 44.7% (n = 25) had complete anosmia. Olfactory improvement was observed 1 month after ESS.

Overall, 73.2% (n = 41) of patients experienced sustained recovery of subjective olfaction, in which the self-evaluated olfactory dysfunction score significantly improved from 2.04 to 0.64 (P < .001) after 12 months. Thirteen (23.2%) patients reported no change, and 2 (3.6%) patients suffered from deterioration.

In evaluating potential predictors of olfactory dysfunction, LMS (r = 0.593; P < .001) and LK endoscopy scores (r = 0.265; P < .05) were found to correlate with the preoperative olfactory dysfunction score. Multivariate logistic regression analysis also revealed that longer duration of olfactory dysfunction, blood eosinophilia, lower LMS, and peripheral distribution of CT opacification were risk factors that adversely affected the recovery of olfactory function (P < .05).

Speaking on limitations of the analysis, the researchers said that the subjective olfactory dysfunction ratings used were not validated by other studies. “Future studies on finding a standard subjective olfactory rating system may be needed,” they said.

Reference

Ye P, He S, Tang S, et al. Improvement of subjective olfactory dysfunction in chronic rhinosinusitis with nasal polyps after endoscopic sinus surgery. Front Surg. Published online June 15, 2022. doi:10.3389/fsurg.2022.870682