Direct Visualization of Laryngeal Mucociliary Clearance in Adults

Abstract

Objectives: Mucociliary clearance is a protective mechanism of the respiratory tract that facilitates the removal of foreign particles and microorganisms. There is a paucity of data on the mucociliary clearance in the adult larynx. Our study aims to visualize and describe the mucociliary clearance of the adult larynx in healthy subjects. Methodology: Subjects were identified from a volunteer database. Exclusion criteria included laryngeal disease, previous laryngeal surgery, recent upper respiratory infection, and current smoking. A high-definition videolaryngoscope was used to visualize the larynx. The larynx was topicalised with local anesthetic. Methylene blue was placed on both false vocal cords and at the petiole of the epiglottis. Dye clearance was recorded and analyzed. Results: In total, 10 participants participated, 7 men and 3 women, with a mean age of 42 ± 15.7 years (range: 25-71). The average reflux symptom index score was 1.4. Clearance of the dye from the false vocal cords followed a uniform lateral flow, up onto the aryepiglottic folds. The dye from the petiole had minimal vertical movement. Swallowing cleared dye from the aryepiglottic folds. The average time for dye clearance to the aryepiglottic fold was 2.21 ± 1.14 minutes. Conclusions: This is the first study visualizing the mucociliary clearance of the larynx. Ciliary directionality was consistent in the participants studied, with dye moving superolateral from the false cords to the aryepiglottic fold. Swallowing was an effective mechanism for clearance from the endolarynx, when the dye had reached the aryepiglottic fold. Future research can study potential alterations in laryngeal mucociliary clearance in chronic disease states.

Methods for the assessment of human airway ciliary function

“…Thick mucus in cystic fibrosis can prevent normal ciliary waveform [9]. Airway MCC in vivo has been studied with clearance time for dye [10], saccharin and/ or charcoal [11,12] or radioactive isotopes [13]. Recently, in vivo MCC has been advanced through optical coherence tomography [14,15].…”