Efficacy of the nasal airflow-inducing maneuver in the olfactory rehabilitation of laryngectomy patients: A systematic review and meta-analysis

Introduction: This is the first systematic review and meta-analysis to investigate the effectiveness of the nasal airflow-inducing maneuver (NAIM) in olfactory rehabilitation for total laryngectomy (TL) patients.

Methods: We conducted a systematic literature search following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The inclusion criteria required that patients must have undergone a TL with subsequent NAIM training for at least 2 weeks and olfactory evaluation. The impact of NAIM on olfactory outcomes compared to that at baseline was measured. Olfactory measures included the Sniffin' Sticks Test, Smell Disk Test, Scandinavian Odor Identification Test, and Quick Odor Detection Test. The primary outcome measures were the proportion of patients with normosmia at baseline and after intervention.

Results: Seven studies from 2000 to 2023 comprising a total of 290 TL patients met the inclusion criteria. The meta-analysis revealed that prior to intervention, the pooled proportion of patients with normosmia was 0.16 (95% confidence interval [CI]: 0.09‒0.27, p = 0.01). After intervention, the same proportion increased to 0.55 (95% CI: 0.45‒0.68, p = 0.001). Among the included patients, 88.3% were initially anosmic or hyposmic, which was reduced to 48.9% after NAIM practice, with 51.1% achieving normosmia. The percent improvement was not found to be significantly associated with the timing of intervention post-TL (p = 0.18).

Conclusions: NAIM increased the proportion of patients who achieved normosmia in TL patients. NAIM stands out as a safe, easily teachable maneuver with promising results. Further efforts are warranted to provide specific recommendations and guidelines for the use of NAIM in clinical practice.