MECHANICAL TESTING OF A MODIFIED EQUINE LARYNGOPLASTY

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1008556
• Project Start Date: Nov 4, 2015
• Project End Date: Sep 30, 2016
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIVERSITY OF ILLINOIS
2001 S. Lincoln Ave.
URBANA,IL 61801

Performing Department
Veterinary Research & Extension

Non Technical Summary
The traditional treatment for recurrent laryngeal neuropathy in horses is the laryngoplasty procedure. Poor surgical outcome due to partial or complete failure of the suture anchor point in the arytenoid cartilage is common. Various strategies have been developed to mitigate this complication; however, none of these modifications have been consistently effective. We have developed a modified laryngoplasty that uses a suture button to increase the pull out strength of the arytenoid cartilage and prevent failure of the suture anchor point in the cartilage. However, in vitro testing is necessary to determine superiority over the standard laryngoplasty. Mechanical data from preliminary monotonic testing of both laryngoplasties suggests the modified laryngoplasty has higher suture pull out strength than the standard laryngoplasty.

Animal Health Component

50%

Research Effort Categories

Basic

50%

Applied

50%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
311	3810	1060	100%

Knowledge Area
311 - Animal Diseases;

Subject Of Investigation
3810 - Horses, ponies, and mules;

Field Of Science
1060 - Biology (whole systems);

Keywords

equine laryngoplasty

horses

recurrent laryngeal neuropathy

Goals / Objectives
Objective 1:To determine if a modified laryngoplasty is mechanically superior to the standard laryngoplasty during testing designed to mimic sudden suture pull through from the muscular process of the arytenoid cartilage. Objective 2.To determine if the modified laryngoplasty is superior to the standard laryngoplasty in maintaining cross sectional area of the rima glottidis and stability of the arytenoid cartilage during repeated loading designed to mimic the loads applied to the laryngoplasty immediately after surgery.

Project Methods
No live animals will be used for this research, therefore no consideration is necessary from the University of Illinois Animal Care and Use Committee. The most common cause of poor surgical outcome following laryngoplasty is partial or complete failure of the suture anchor point in the arytenoid cartilage, resulting in loss of arytenoid abduction. We have developed a novel laryngoplasty technique that uses a self-locking titanium suture button to 'toggle' the suture material to the arytenoid cartilage and prevent failure of the suture anchor point in the cartilage. However, in vitro testing is necessary to determine superiority over the standard laryngoplasty technique. We will compare the mechanical characteristics of standard and modified laryngoplasties with the specific aim of demonstrating that the modified laryngoplasty technique is mechanically superior. Normal cadaver larynges will be used to perform laryngoplasties with braided polyethylene using a standard or a modified surgical technique. A servohydraulic materials testing machine will be used to test the larygoplasties in monotonic failure and cyclic loading in order to determine the superior laryngoplasty technique.

Progress 11/04/15 to 09/30/16

Outputs
Target Audience:The target audience includes (but is not limited to)the public, the veterinarycommunity, and scientists around the world that deal with equine recurrent laryngeal neuropathy. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project provided the opportunity to Drs.Santiago Gutierrez (PI) and Erica Secor (equine surgery resident and graduate student) to perform numeroussurgical laryngoplasty constructs and become familiar with the airflow chamber built for the study. The data obtained with this investigation will be included in Dr. Secor's MS thesis. In addition, theairflow chamber built and used for the studywillallow us to continue totestmultiple novel surgical techniques for horses with airway obstruction. How have the results been disseminated to communities of interest?The results from the study will be published in the American Journal of Veterinary Researchand presented at the International Annual Symposium of the American College of Veterinary Surgeons next year. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? The main objective of the study was to determine if a modifiedlaryngoplasty technique is superior to the standardlaryngoplasty technique to restore normal airway function. Therefore, the testing model was slightly changed from the originally proposed one (one cycle-to-failure and cyclictesting model). The new objective wastocompare the effects of two laryngoplasty(standard and modified) techniques(performed in cadaveric equine larynges)on translaryngeal flow, pressure, and impedance using the airflow chamber described by Cheetham(Equine Veterinary Journal 2008). The in vitro laryngeal model used canmimicthe airflow and pressures experienced by horses at maximal exertion. For both surgicaltechniques the prosthetic suture was passed through the cricoid cartilage and through either the muscular process (standard) or the muscular process and body (modified) of botharytenoid cartilages. Each larynx was positioned in a flow chamber after placement of the standard laryngoplasty and modified laryngoplasty andsubjected to cyclic airflow. Tracheal flow, translaryngeal pressure, translaryngeal impedances, right to left quotient abduction angles and internal rima glottidis cross-sectional areas were determined and compared for both techniques.Thedata obtanied had normal distributions.Internal rima glottidis cross-sectional area, right to left abduction angle quotient, tracheal airflow, translaryngeal pressure difference, and translaryngeal impedance were compared between LP techniques using a paired-t test. The right to left abduction angle quotient and internal rima glottidis cross-sectional areas were similar (P=0.460 and P= 0.266, respectively) between laryngoplasties indicating that comparable degree of left arytenoid cartilage abduction was achieved with bothtechniques.At maximal cyclic airflow (53 L/s), the surgicalconstructs had similar (P=0.307) translaryngeal pressures (standard= 15.81± 4.68 mmHg and modified=14.84 ±2.84 mmHg, respectively) and translaryngeal impedance (standard= 0.23± 0.09 mmHg/L/s and modified=0.28± 0.05 mmHg/L/s, respectively). Based on these results it appearsthat amodified laryngoplasty technique is comparable to the standard technique to improve airflow in cadaveric larynges. This information along with previous research that showed that the modifiedlaryngoplasty technique canprevent failure of the suture anchor point in the cartilage provides preliminary data that support future investiagation of the modified laryngoplasty technique in live horses.

Publications

• Type: Journal Articles Status: Published Year Published: 2016 Citation: No Publications To List