2026 Proffered Presentations
S278: A DOUBLE-BLIND, RANDOMIZED, PLACEBO-CONTROLLED TRIAL OF OLFACTORY TRAINING FOLLOWING PARASELLAR ENDOSCOPIC SKULL BASE SURGERY
Michael Z Cheng, MD1; Evelyn Chang1; Joon Soo Kim1; Sahar Assi, MD1; Rachel Stemme1; Wassim Najjar, MD1; Varun Vohra, MD1; Debraj Mukherjee, MD, MPH2; Nicholas R Rowan, MD1; 1Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins Medicine; 2Department of Neurosurgery, Johns Hopkins Medicine
Introduction: Endoscopic endonasal skull base surgery (EESBS) has transformed the management of parasellar lesions, improving postoperative outcomes and reducing surgical morbidity. Nonetheless, patients commonly report sinonasal complaints such as olfactory dysfunction, even when olfactory-sparing techniques are used. Given the neuroplasticity of the olfactory system and growing interest in olfactory training (OT), we conducted a randomized, double-blind, placebo-controlled trial to evaluate the efficacy of OT in promoting recovery of olfaction and sinonasal quality of life (QoL) following EESBS.
Methods: Patients undergoing EESBS for benign sellar and parasellar pathology were randomized 1:1 to receive an active olfactory training kit (four scented essential oil sticks) or a placebo kit (unscented sticks), distributed at the first postoperative visit. Olfactory function and QoL were assessed preoperatively and at three postoperative visits through 3 months. Assessments included visual analog scales (VAS) for subjective olfaction and taste; Sniffin’ Sticks for olfactory threshold, discrimination, and identification; and QoL instruments including the Skull Base Inventory (SBI), Anterior Skull Base Nasal Inventory-12 (ASK-12), and Olfactory Dysfunction and Odor Rating (ODOR) scale. Pre- to postoperative changes were compared for the entire group using the Wilcoxon signed-rank test, and differences between the placebo and active groups were evaluated at each time point using the Mann-Whitney U test.
Results: Twenty eight of 41 enrolled patients completed all study visits and were included in the analysis (14 per group). The placebo group was younger (41.4 ± 12.8 vs. 53.0 ± 16.0 years, p=0.04) and had a higher proportion of females (92.9% vs. 35.7%, p<0.01), with no significant differences in race or tobacco/alcohol use. Across the cohort, psychophysical olfactory function declined at the first postoperative visit but returned to baseline by 3 months. Sinonasal QoL, measured by ASK-12 and ODOR, showed a similar transient decline with recovery to baseline. Skull base–related QoL (SBI) improved significantly at 3 months compared with preoperative status (+7.2 ± 11.3, p<0.01), representing a clinically meaningful and statistically significant improvement. In contrast, subjective olfaction on VAS was significantly worse at 3 months relative to baseline (−7.2 ± 20.9, p=0.02), highlighting a discordance between patient perception and objective psychophysical testing. Meanwhile, subjective taste on VAS returned to baseline. No significant differences were observed between the active and placebo groups in olfactory or QoL outcomes at any postoperative time point.
Conclusion: In this randomized, placebo-controlled trial, OT with scented versus unscented sticks was not associated with differences in recovery of olfaction or sinonasal quality of life after EESBS. The lack of effect may reflect limited power, nonspecific benefits of sniffing, or minimal impact of OT when the olfactory mucosa is preserved. By 3 months postoperatively, overall QoL improved, yet patients continued to report subjective olfactory dysfunction despite normalized psychophysical testing, an important consideration for patient counseling. These findings highlight a dissociation between objective and subjective recovery and support the need to compare OT with the current standard of care, which involves no intervention.