The pharyngeal plexus-mediated glottic closure response and associated neural connections of the plexus.

IMPORTANCE

There continues to be a paucity of data regarding the pharyngeal plexus (PP) and its interconnectivity with the laryngeal nerves and function.

OBJECTIVE

To identify the specific neural pathways involved in the glottic closure reflex (GCR)-like pathway of the PP and other pathways to the thyroarytenoid (TA) muscle in the porcine model.

DESIGN, SETTING, AND ANIMAL SUBJECTS: Animal experimental study from September 2013 to June 2014 conducted in a tertiary academic medical center on male Yorkshire pigs.

INTERVENTIONS: Contraction of the TA was detected with electromyography (EMG) during electrical stimulation of the PP in 7 porcine necks. Subsequently, the external branch of the superior laryngeal nerve (eSLN), communicating nerve of Galen (NG), and the recurrent laryngeal nerve (RLN) were sequentially transected to help elucidate the path of neural conduction.

MAIN OUTCOMES AND MEASURES: Confirmation of TA muscle contraction by EMG.

RESULTS

Stimulation of the PP evoked a response from the TA muscle in 6 of 7 subject animals. In 3 of 7 subjects, a long latency response (mean, 14.62 milliseconds) was identified, which was eliminated only after transection of the RLN. In 3 of 7 subjects, a short latency response (mean 3.05 milliseconds) was identified, which disappeared in 1 subject each by eSLN, RLN, and NG transection.

CONCLUSIONS AND RELEVANCE: We identified the specific neural pathway involved in the PP's GCR-like pathway. We also noted a variable direct pattern of innervation to the TA.