Subjective Smell Improvement After Endoscopic Sinus Surgery

Subjective — but not objective — olfactory improvements in patients who underwent endoscopic sinus surgery for chronic rhinosinusitis with nasal polyps were maintained up to 6 months after surgery, according to results of a new study. 

The literature regarding olfactory improvement after endoscopic sinus surgery in these patients is conflicting, ranging from 25% to 100%, often because of the lack of objective testing, said senior author John Lee, MD, associate professor in the department of otolaryngology-head and neck surgery at the University of Toronto, Canada.

Patients with chronic rhinosinusitis with nasal polyps are initially treated with standard therapies such as intranasal corticosteroids to reduce inflammation. When patients fail these therapies, endoscopic sinus surgery is ʹʹstill the mainstay of treatment,ʹʹ Lee told Medscape Medical News. 

With more treatment options becoming available, it is important to be able to provide real-world data regarding the effectiveness of endoscopic sinus surgery ʹʹfor improving olfaction in our patients so that they are properly informed of potential outcomes of treatment,ʹʹ he added. 

In particular, interest in the use of FDA-approved biologics for patients has increased in recent years, and one of the main purported benefits is the ability to improve the patient’s sense of smell, Lee explained. 

Results of the study were presented by study coauthor Elysia M. Grose, MD, also of the University of Toronto, at a late-breaker presentation at the American Academy of Otolaryngology-Head and Neck Surgery 2024 Annual Meeting.

The researchers reviewed data from 41 adult patients with chronic rhinosinusitis with nasal polyps who underwent endoscopic surgery at a single center from July 2022 to May 2024. The mean age of the participants was 47.8 years, and 41% were female. Almost half (47%) had a history of previous sinus surgery, and 26% had aspirin-exacerbated respiratory disease. Olfactory improvement was assessed using the Sino-nasal Outcome Test (SNOT-22) and the Sniffinʹ Sticks odor identification test before surgery and again at 1, 3, and 6 months after surgery. 

Prior to surgery, the average Sniffinʹ Sticks score was 5.7 odors identified out of 16, and the average SNOT-22 score was 4.2 (on a scale of 0-5, with 5 being the worst symptoms). 

Overall, the mean SNOT-22 smell scores decreased by 2.2, 2.4, and 2.3 points at 1, 3, and 6 months, respectively (P < .001). Significant mean improvements also appeared on examination of the smell element of the SNOT-22 score only, Lee told Medscape. 

Sniffin’ Sticks identification scores improved by 2.5, 2.7, and 1.1 points at 1, 3, and 6 months, respectively. However, these improvements were statistically significant at 1 and 3 months (P < .001) but not at 6 months (P >.05).

ʹʹOverall, we were surprised to see that subjectively, patients do in fact typically report significant improvements in their sense of smell following surgery and this is sustained up to 6 months post-surgery,ʹʹ said Lee. 

This is important for patient counseling prior to surgery, and ʹʹis in contrast to what some physicians or patients may believe regarding the potential impact of surgery on smell,ʹʹ he said. 

The shorter duration of improvement based on objective measures highlights the need for ongoing long-term follow-up and treatment of these patients, he added. 

ʹʹFurthermore, we need to investigate how the use of objective testing may allow surgeons to intervene earlier with additional therapies when olfactory dysfunction is detected,ʹʹ Lee told Medscape.

Olfactory Dysfunction Is ʹCommon Complaintʹ

ʹʹOlfactory dysfunction, or difficulty smelling odors, is a common complaint among patients with chronic rhinosinusitis with nasal polyps. However, it is unclear what the likelihood of olfactory improvement will be after endoscopic sinus surgery,ʹʹ said 

Said Kevin Hur, MD, an otolaryngologist with Keck Medicine of USC, in an interview. 

ʹʹPrevious studies have reported that nasal polyp patients are more likely to have improvement in olfaction after sinus surgery compared to chronic rhinosinusitis patients without nasal polyps; however, I was surprised to see that the objective improvement regressed at 6 months, which I have not seen reported before,ʹʹ Hur noted.

ʹʹThe results of this study are important in helping surgeons counsel patients on the possible outcomes from surgery,ʹʹ said Hur. 

ʹʹBased on the results of this study, surgeons can tell patients with nasal polyps that, on average, patients report improvement in their ability to smell after sinus surgery at 1, 3, and 6 months after surgery, but that improvement may start to decrease at 6 months based on objective tests,ʹʹ he said.

Hur agreed with the researchers that more studies are needed to follow nasal polyp patients after surgery for a year or multiple years to determine longer-lasting olfactory improvement. ʹʹAlso, more in-depth analysis is needed to identify which factors are associated with a higher or lower likelihood of olfaction improvement after surgery,ʹʹ he said. 

The study received no outside funding. The researchers had no financial conflicts to disclose. Hur had no financial conflicts to disclose.