Olfactory impairment after total laryngectomy: A prospective cohort study

Objective Total laryngectomy, a procedure that permanently separates the upper and lower airways and requires patients to breathe through a stoma, significantly impacts olfactory function owing to the lack of nasal airflow. This prospective cohort study aimed to investigate the reduction in olfactory function following total laryngectomy and determine the association between clinical characteristics and olfactory impairment. Methods A prospective cohort study was conducted among 40 patients (aged 44–82 years) undergoing total laryngectomy at the University Medical Center Ho Chi Minh City, Vietnam, from November 2023 to April 2025. Olfactory ability was assessed before and after surgery using the Sniffin’ Sticks test, including threshold, discrimination, and identification components, which were used to calculate a total threshold, discrimination, and identification score. Additionally, clinical characteristics were analyzed for potential associations with olfactory impairment. Results Prior to surgery, objective olfactory testing revealed that 82.5% of the patients had normosmia, and 17.5% exhibited hyposmia. Following surgery, all patients experienced olfactory impairment, with 87.5% presenting with complete anosmia. There was a statistically significant decline in olfactory function after total laryngectomy ( p  < 0.001, Wilcoxon signed-rank test). Multivariable regression analysis revealed no statistically significant associations between the clinical characteristics evaluated and postoperative olfactory impairment. Conclusions Olfactory impairment is a common and significant consequence of total laryngectomy, leading to substantial reductions in patients’ quality of life. The primary causes include loss of nasal airflow and potential structural changes in the olfactory mucosal epithelium. This highlights a universal risk because our analysis did not identify any specific clinical variables that were significantly associated with olfactory impairment. These findings underscore the critical need for standardized preoperative counseling and the implementation of postoperative olfactory rehabilitation strategies for all patients undergoing total laryngectomy.