Ex vivo investigation of the effect of the transverse arytenoid ligament on abduction of the arytenoid cartilage when performing equine laryngoplasty.

The research article discusses how severing the transverse arytenoid ligament (TAL) may increase the abduction, or movement, of the arytenoid cartilage during laryngoplasty surgery in horses.

Objective and Methodology:

The study focuses on the role of the TAL in the movement of the arytenoid cartilage during a modified laryngoplasty surgery. The researchers used 13 equine larynges (throat organs), applying different levels of force on the arytenoid cartilage.

• The force was steadily increased on the left arytenoid cartilage, going up in 3 Newton (N) increments from 0 to 24 N.
• Digital images of the larynx’s front were taken to ascertain the variation in the left arytenoid angle depending on the different force inputs.
• Both the left and right arytenoid cartilages were tested, and the entire process was repeated after the TAL was dissected.

Alongside this, the TAL from seven other horses’ larynges were separately examined using histology to understand its makeup and structure.

Findings:

Key insights from the study are as follows:

• Increasing the force applied on the left arytenoid cartilage resulted in a progressive increase in its angle (p < 0.001), implying more movement.
• When the same force increase was applied to the right arytenoid cartilage, the angle of the left arytenoid reduced (p < 0.001).
• Following the dissection of the TAL, the average angle of the left arytenoid saw a slight increase. This outcome suggests a higher degree of movement achievable with a given force, once the TAL is cut.
• The microscoping examination of the TAL revealed that it wasn’t a distinct ligament but a confluence of the left and right arytenoideus transversus muscles.

Implications:

The findings indicate that the TAL plays a notable role in the movement of the arytenoid cartilage during laryngoplasty procedures. TAL transection, or its surgical removal, could potentially facilitate greater movement of the cartilage, enhancing surgery outcomes. However, the study recommends that the effectiveness and safety of TAL transection should be evaluated on loaded larynges and in horses surgically affected with recurrent laryngeal neuropathy.