Mechanical evaluation of a modified prosthetic laryngoplasty using a toggle technique for the equine arytenoid cartilage

Recurrent laryngeal neuropathy is a frequent cause of poor performance and upper airway noise in horses. This disorder results in varied degrees of upper airway obstruction due to neurogenic atrophy of the cricoarytenoideus dorsalis muscle secondary to degeneration of the recurrent laryngeal nerve. The treatment of choice in horses with recurrent laryngeal neuropathy is the prosthetic laryngoplasty, which utilizes a suture prosthesis to replace the function of the cricoarytenoideus dorsalis and abduct the arytenoid cartilage. The most frequent complication associated with the prosthetic laryngoplasty is gradual loss of arytenoid abduction in the post-operative period. This gradual loss is typically attributed to cyclic fatigue of the muscular process of the arytenoid and partial suture pull-through from the cartilage. A modified laryngoplasty technique was developed to add strength and stability to the prosthesis with the purpose of reducing cyclic fatigue. This modified technique utilizes a titanium suture toggle passed through the muscular process and base of the arytenoid to distribute loading over a larger area of cartilage. The objectives of this study were to compare the biomechanical properties of the standard technique to the modified laryngoplasty technique in both monotonic and cyclic loading. Larynges from 41 horses were collected following euthanasia and used for mechanical testing. Laryngoplasty constructs were performed using a standard technique on one side and a modified technique on the other. For monotonic loading, the laryngoplasty constructs were prepared and suture ends attached to a load-frame, then distracted at 100 mm/minute until failure. Mean load at failure and failure modes were compared between techniques. For cyclic loading the arytenoid cartilages were maximally abducted and constructs were circumferentially loaded for 10,000 cycles. Loss of arytenoid abduction was evaluated every 500 cycles using both a subjective grading scale and objective change in rima glottidis cross sectional area. In monotonic loading, the modified laryngoplasty constructs failed at a higher load (191N ± 29N) than the standard laryngoplasty constructs (91N ± 44N, P<0.001). None of the modified constructs failed by suture pull-through from the muscular process of the arytenoid cartilage, whereas most of the standard laryngoplasty constructs failed by suture pulling through the muscular process of arytenoid cartilage. In cyclic testing, 11/20 (55%) of standard laryngoplasty constructs reached surgical failure, considered a Dixon grade 3, while 0/20 (0%) of modified laryngoplasty constructs failed. The modified laryngoplasty constructs lost less rima glottidis cross sectional area compared to the standard laryngoplasty constructs (P<0.001) in circumferential loading. Overall, the modified laryngoplasty technique proved superior to the standard laryngoplasty in both monotonic and cyclic loading.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

VMS-Veterinary Clinical Medcne

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2017

Author dc:creator

• Secor, Erica Jane

Contributors dc:contributor

• Gutierrez-Nibeyro, Santiago
• Horn, Gavin P.
• McCoy, Annette M
• Mitchell, Mark A.

• Equine
• Recurrent laryngeal neuropathy
• Laryngoplasty

Statement dc:rights

• Copyright 2017 Erica Secor

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/98325

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/98325