Laryngeal sensation recovery by reinnervation in rabbits

To assess the possibilities of restoring laryngeal sensation in an animal model by way of the internal branch of the superior laryngeal nerve (ibSLN) bilateral section and anastomosis to itself or to transposition nerves (i.e., lingual, glossopharyngeal, and great auricular nerves).

Prospective study using New Zealand rabbits.

Six groups of rabbits were operated on and evaluated: healthy controls (n = 6); section without reinnervation (denervated group, n = 7); section and reinnervation with ibSLN (SLN-SLN group, n = 9); and section and anastomosis with the lingual nerve (lingual group, n = 7), the glossopharyngeal nerve (glossopharyngeal group, n = 6), and the great auricular nerve (GA group, n = 7). After 9 months, recovery of a laryngeal closure reflex was assessed by stimulation of the epiglottis and nerve anastomosis.

Laryngeal sensation was restored in 14.3% in the denervated group, 66.6% in the SLN-SLN group, 71.4% in the lingual group, 100% in the GA group (P < .001), 50% in glossopharyngeal group. Some anastomoses were severed. When anastomosis was intact, a laryngeal closure reflex was observed in 91.7% of the rabbits of the SLN-SLN group (P < .001), 80% in the lingual group (P < .001), 100% in the GA group (P < .05) and 100% of the glossopharyngeal group.

Rehabilitation of supraglottic laryngeal sensation is feasible by way of anastomosis of the ibSLN to itself, but also to the lingual, glossopharyngeal, and great auricular nerves. These results suggest that this type of procedure may be useful in humans to prevent aspiration and subsequent pneumonia as related to lesions of the laryngeal reflex pathway. It could also be considered one stage toward the functional rehabilitation of a transplanted larynx.