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 <.001), flow (P <.001), and power (P =.002) were significantly lower for wABI compared to paralysis trials; values did not differ significantly from normal trials. Percent jitter (P =.002) and percent shimmer (P =.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.

Pre- and intraoperative acoustic and functional assessment of the novel APrevent® VOIS implant during routine medialization thyroplasty

“…In 2011, Hoffman et al introduced a concept of an adjustable balloon implant (ABI) for MT, demonstrating adequate and effective medialization with significant improvements in aerodynamic and acoustic parameters in an excised canine laryngeal model [12,13].…”

Excised larynx evaluation of subthyroid cartilage approach to medialization thyroplasty

“…If a higher sample size were used, it is possible that additional differences between certain experimental conditions could become apparent. Furthermore, although the excised model has been used in the past to study treatments for VFP, it cannot account for all clinical issues and human responses to thyroplasty. The excised canine larynx model only demonstrates one point in time, and thus cannot predict long‐term stability of the implant or perfectly translate to humans.…”

Development of Excised Larynx

“…56 Hoffman et al evaluated an adjustable balloon implant using an excised canine larynx, and found a much less invasive method of type I thyroplasty. 57 In a subsequent study, an excised canine larynx was used to evaluate type IIIB thyroplasty combined with bilateral type I thyroplasty for lowering pitch while maintaining the tension of the vocal folds. 58 Thompson et al modified the approach of medialization thyroplasty by performing medialization thyroplasty via the subthyroid cartilage approach on an excised canine larynx, showing that it is possible to improve acoustic and aerodynamic parameters without requiring to make a window on thyroid cartilage.…”