Electromyographic and histologic evolution of the recurrent laryngeal nerve from transection and XXXX to mature reinnervation.

@entity35 @entity254
OBJECTIVES: To describe the natural evolution of recurrent laryngeal nerve (RLN) reinnervation in an animal model. STUDY DESIGN: Twenty @entity35 underwent unilateral RLN transection and @entity254 . Animals were sacrificed at 4, 8, 12, 16, and 20 weeks. Prior to sacrifice, each @entity35 underwent electromyography (EMG) and visual grading of vocal fold motion. Bilateral RLNs were harvested and evaluated histologically. RESULTS: EMG revealed synkinetic reinnervation at all time periods except at 4 weeks. EMG evolution plateaued at 16 weeks. Vocal fold motion was slight in three @entity35 at 4 weeks but was otherwise absent except for one @entity35 at 12 weeks. Histologic changes of the axons and their myelin sheaths were consistent at each time period. At 16 weeks, histologic changes plateaued. CONCLUSIONS: Consistent EMG, histologic, and vocal fold motion changes occur at specific time periods during RLN reinnervation after transection and @entity254 in a @entity35 model. Reinnervation is mature at 16 weeks. Findings corroborate theories of preferential and synkinetic reinnervation after RLN transection. Use of a @entity35 model to investigate the effect of interventions on RLN reinnervation requires a minimum of 16 weeks between transection and investigation to allow for maturation of reinnervation.
