Three-dimensional models of the equine larynx can be used to perform traditional measures of arytenoid abduction and permit the positioning of modeled implants to demonstrate the anatomic feasibility of placing a rigid implant across the cricoarytenoid joint.

Abstract

To develop 3D models of larynges to compare arytenoid abduction measurements between specimens and models, and to investigate the anatomic feasibility of placing an implant across the cricoarytenoid joint (CAJ) with or without arthrotomy. Cadaveric equine larynges (n = 9). Equine larynges underwent sequential CT scans in a neutral position and with 2 arytenoid treatments: bilateral arytenoid abduction (ABD) and bilateral arytenoid abduction after left cricoarytenoid joint arthrotomy (ARTH). Soft tissue, cartilage, and luminal volume 3-dimensional models were generated. Rima glottidis cross-sectional area (CSA) and left-to-right quotient (LRQ) angles were measured on laryngeal specimens and models. Arytenoid translation, articular contact area, and length of modeled implants placed across the CAJ were measured on models. Data were analyzed using paired t test or ANOVA and Tukey's post hoc test or non-parametric equivalents (P < .05). ARTH CSA was larger for laryngeal specimens than models (P = .0096). There was no difference in all other measures of CSA and LRQ angle between treatment groups or between specimens and models. There was no difference between ABD and ARTH groups for arytenoid cartilage translation, contact area, and implant length. The articular contact area was sufficient for modeled implant placement across the CAJ with a narrow range of implant lengths (17.59 mm to 23.87 mm) across larynges with or without arthrotomy. These results support further investigation of a CT-guided, minimally invasive surgical procedure. Future studies will evaluate the outcomes of the new procedure for technical precision, biomechanical stability, and post-operative success rates for horses with recurrent laryngeal neuropathy (RLN).