A novel endoscopically placed stent to relieve glottic obstruction from bilateral vocal fold paralysis

Congenital bilateral vocal fold paralysis (BVP) is a rare but serious condition often requiring a tracheostomy to temporize the airway. In cases of idiopathic BVP, studies suggest waiting twelve months prior to laryngeal surgery because of a high rate of spontaneous recovery. Therefore a less invasive and reversible intervention would be optimal. A prospective study in a piglet model was undertaken to evaluate the efficacy of a novel spring-loaded stenting device designed to maintain laryngeal patency in an in vivo animal model of BVP.

Eight Yorkshire piglets had BVP induced by surgical division of the recurrent laryngeal nerves. Stents were endoscopically deployed between the arytenoid vocal processes. Animals were recovered and monitored for stridor, dietary intake, and weight gain. Animals were sacrificed after five days. Airway resistance using a calibrated manometer was measured at four time-points: baseline, BVP induction, stent insertion, and pre-sacrifice.

Six of eight animals survived greater than five days with an average weight gain of 1.9kg (p=0.003). Relative inspiratory resistance increased from baseline after inducing BVP (1.00 vs. 1.468, p=0.0315) and decreased to baseline levels with stent insertion (1.468 vs. 1.092, p=0.0238). Expiratory resistance was not significantly influenced by stage of measurement (p=0.236). Of the two animals not surviving the protocol, one had an unrelated anesthesia complication and the other a malpositioned stent.

The novel stent was successful in relieving the inspiratory resistance associated with BVP, without compromising swallowing and daily function. This may hold promise in temporarily securing the pediatric airway in the setting of BVP.