Spontaneous laryngeal reinnervation following chronic recurrent laryngeal nerve injury

• Published in: The Laryngoscope Vol. 123; no. 9; p. 2216
• Main Authors: Kupfer, Robbi A, Old, Matthew O, Oh, Sang Su, Feldman, Eva L, Hogikyan, Norman D
• Format: Journal Article
• Language: English
• Published: United States 01.09.2013
• Subjects: Animals; Chronic Disease; Disease Models, Animal; Electrodes, Implanted; Electromyography - methods; Laryngeal Muscles - innervation; Laryngoscopy - methods; Male; Nerve Regeneration - physiology; Random Allocation; Rats; Rats, Sprague-Dawley; Recurrent Laryngeal Nerve Injuries - physiopathology; Recurrent Laryngeal Nerve Injuries - surgery; Remission, Spontaneous; Sensitivity and Specificity; Vocal Cords - innervation; Laryngeal reinnervation; vocal fold paralysis; recurrent laryngeal nerve injury; superior laryngeal nerve; thyroarytenoid muscle; animal model
• ISSN: 1531-4995
• DOI: 10.1002/lary.24049

To enhance understanding of spontaneous laryngeal muscle reinnervation following severe recurrent laryngeal nerve injury by testing the hypotheses that 1) nerve fibers responsible for thyroarytenoid muscle reinnervation can originate from multiple sources and 2) superior laryngeal nerve is a source of reinnervation. Prospective, controlled, animal model. A combination of retrograde neuronal labeling techniques, immunohistochemistry, electromyography, and sequential observations of vocal fold mobility were employed in rat model of chronic recurrent laryngeal nerve injury. The current study details an initial set of experiments in sham surgical and denervated group animals and a subsequent set of experiments in a denervated group. At 3 months after recurrent laryngeal nerve resection, retrograde brainstem neuronal labeling identified cells in the characteristic superior laryngeal nerve cell body location as well as cells in a novel caudal location. Regrowth of neuron fibers across the site of previous recurrent laryngeal nerve resection was seen in 87% of examined animals in the denervated group. Electromyographic data support innervation by both the superior and recurrent laryngeal nerves following chronic recurrent laryngeal nerve injury. Following chronic recurrent laryngeal nerve injury in the rat, laryngeal innervation is demonstrated through the superior laryngeal nerve from cells both within and outside of the normal cluster of cells that supply the superior laryngeal nerve. The recurrent laryngeal nerve regenerates across a surgically created gap, but functional significance of regenerated nerve fibers is unclear.