Hyposmia following laryngectomy: experimental model

Area of Science:

• Otolaryngology
• Neuroscience
• Pathology

Background:

• Hyposmia is a common observation after laryngectomy.
• The exact causes of post-laryngectomy hyposmia remain debated.
• Previous hypotheses focused on altered airflow, but neurological factors were less explored.

Purpose of the Study:

• To investigate the pathological changes in olfactory mucosa following laryngectomy.
• To elucidate the contributing factors to hyposmia after larynx removal.
• To explore the role of airway changes versus potential neurological pathways.

Main Methods:

• An animal model using 18 dogs was developed.
• Dogs were divided into three groups: control, tracheostomy, and tracheostomy with laryngeal denervation (simulating laryngectomy).
• Olfactory mucosa biopsies were analyzed 4-6 months post-surgery.

Main Results:

• Dogs undergoing tracheostomy showed cystic degeneration of secretory glands in olfactory mucosa.
• Dogs with tracheostomy and laryngeal denervation exhibited olfactory mucosa involution with connective tissue replacement and olfactory nerve fiber ballooning.
• Both surgical groups displayed significant olfactory mucosa changes compared to controls.

Conclusions:

• Post-laryngectomy hyposmia is linked to both altered nasal airflow and denervation.
• Findings suggest a neurological connection involving the vagus nerve and olfactory cortex contributes to olfactory dysfunction.
• The study provides evidence for a neurogenic component in hyposmia following laryngectomy.