Biomechanical characterisation of equine laryngeal cartilage.
Authors: Passman S N, Cheetham J, Bonassar L J, Ducharme N G, Rawlinson J J
Journal: Equine veterinary journal
Summary
# Editorial Summary: Biomechanical characterisation of equine laryngeal cartilage Upper airway obstruction remains a significant clinical problem in racehorses, yet biomechanical data on the laryngeal cartilage structures that support the airway have been lacking. Passman and colleagues mechanically tested cartilage specimens from the cricoid and arytenoid cartilages of 11 Thoroughbred and Standardbred larynges, measuring compressive stiffness (aggregate modulus) and tissue permeability at multiple anatomical sites using confined compression testing. The cricoid cartilage proved substantially stiffer than the arytenoid (2.29 MPa versus 0.42 MPa respectively), with the rostral cricoid 20% stiffer than the caudal region; importantly, cartilage stiffness increased with age at approximately 0.13 MPa per year. These findings reveal that the equine larynx derives significant structural support from the material properties of its cartilaginous framework, with biomechanical characteristics substantially different from other species. For equine practitioners, these data provide mechanical context for understanding how laryngeal function may be compromised in younger horses and inform the biomechanical principles underlying surgical interventions such as arytenoid lateralisation, particularly regarding tissue response and long-term outcomes in horses of different ages.
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Practical Takeaways
- •The relatively straight geometry and high stiffness of equine cricoid cartilage means the larynx is mechanically robust; understanding these properties helps explain why soft tissue collapse causes obstruction rather than cartilage deformation
- •Age-related increases in cartilage stiffness may influence laryngeal function and response to surgical interventions in older horses
- •These biomechanical baseline values provide reference data for assessing laryngeal disease and optimizing surgical techniques like prosthetic laryngoplasty
Key Findings
- •Equine cricoid cartilage is significantly stiffer (2.29 MPa) than arytenoid cartilage (0.42 MPa), providing structural support to the larynx
- •Cricoid cartilage stiffness increases with age at 0.13 MPa per year
- •Rostral cricoid cartilage is 20% stiffer than caudal aspects (2.51 vs 2.09 MPa)
- •Equine laryngeal cartilage has compressive modulus an order of magnitude higher than other hyaline-composed tissues