Olfaction in nasal polyp patients after Reboot surgery: an endotype-based prospective study

PURPOSE: To report biomarkers present in the olfactory mucosa in chronic rhinosinusitis with nasal polyps (CRSwNP) in comparison with nasal polyps and to nasal mucosal tissues from control patients. To evaluate the kinetics of smell over 6 months in patients who underwent Reboot surgery. METHODS: Cohort study from May 2021 to May 2022. We collected samples of olfactory mucosa and nasal polyps from 16 CRSwNP patients and inferior turbinate samples from 20 control subjects. The study was not randomized for surgical and/or medical treatment. Samples were analyzed by Luminex and Unicap 100 to measure biomarkers of inflammation (IL1-β, IL4, IL5, IL6, IL17, CCL3, CCL4, G-CSF, SE-IgE, total IgE and ECP). 12 of the CRSwNP patients underwent Extended Sniffin’tests at timepoints 1–4 days pre-surgery, and 1, 3 and 6 months after Reboot surgery. RESULTS: Type-2 markers were significantly elevated in OM and polyp tissue in CRSwNP (n = 16) vs. controls (n = 20), P < 0.05. TDI scores improved already 1 month (P < 0.05) after surgery and remained stable for 6 months. Type-2 inflammation in nasal polyps was associated with decreased sense of smell and taste before surgery, but improved after surgery (P = 0.048). Type-3 inflammation was present in the olfactory mucosa and was associated with a better sense of smell before surgery, but a smaller improvement of smell afterward. CONCLUSIONS: Type-2 inflammation is present in the olfactory mucosa in CRSwNP patients and is associated with smell loss. Reboot surgery, aiming to completely remove inflamed sinus mucosa, significantly improves the smell in this group of patients. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00405-022-07813-w.