Excised larynx evaluation of wedge-shaped adjustable balloon implant for minimally invasive type I thyroplasty.

Abstract

OBJECTIVES/HYPOTHESIS: To describe the method of inserting a wedge-shaped adjustable balloon implant (wABI) via a minithyrotomy for medialization thyroplasty and evaluate its effect on a range of phonatory parameters using the excised larynx bench apparatus. STUDY DESIGN: Repeated measures with each larynx serving as its own control. METHODS: A prototype wABI was deployed in six excised canine larynges of various sizes through a minithyrotomy and then filled with saline. Mucosal wave, aerodynamic, and acoustic parameters were measured for three conditions: normal, vocal fold paralysis, and paralysis with the wABI. RESULTS: Phonation threshold pressure (P&#x2009;<&#x2009;.001), flow (P&#x2009;<&#x2009;.001), and power (P&#x2009;=&#x2009;.002) were significantly lower for wABI compared to paralysis trials; values did not differ significantly from normal trials. Percent jitter (P&#x2009;=&#x2009;.002) and percent shimmer (P&#x2009;=&#x2009;.007) were also significantly decreased compared to the paralysis condition, and values were not significantly different compared to normal. The mucosal wave was preserved after insertion of the wABI. CONCLUSIONS: Effective vocal fold medialization with preservation of the mucosal wave was observed with the wABI in this preliminary excised larynx experiment. The wABI offers the potential for a minimally invasive insertion in addition to postoperative adjustability. Further studies in living animals and humans are warranted to evaluate clinical utility. LEVEL OF EVIDENCE: NA.