Ex vivo biomechanical stability of 5 cricoid-suture constructs for equine laryngoplasty.

This research conducted an ex vivo study on equine (horse) larynges to explore how biomechanically stable five different suture constructs are while performing laryngoplasty – a surgical procedure to fix a dysfunctional larynx. Their findings suggest that applying a metallic button (MB) construct in the cricoid cartilage could potentially reduce loss of abduction and increase pullout forces, pointing towards enhanced post-op stability. However, further in vivo tests are required to confirm these results.

Research Methods

• The study was conducted on seventy-five larynges from equine cadavers (dead horses).
• Each larynx was installed with one of five distinct suture constructs. This process intrinsically differs based on the pattern and type of suture used.
• In the first two constructs, a standard laryngoplasty procedure was followed where the suture is threaded through the cricoid once, including its caudal edge. Different sutures were used in each construct — one used Ethibond, and the other used Fibertape.
• In the third construct, Fibertape was looped through the cricoid twice — a different method known as the Double Loop (DL).
• The fourth and fifth constructs are distinct from the others in that they do not include the caudal edge of the cricoid; they only loop through the main body of the cricoid in a U shape. One of these constructs was further supplemented with a Metallic Button (MB) while the other only featured the U-shaped loop (U).

Testing and Comparison

• These constructs were then subjected to cyclic loading and a single cycle to failure test to survey their biomechanical stability.
• Different parameters like the left-to-right arytenoid angle quotient reduction (an indicator of loss of abduction), suture migration, and load at failure were compared across the constructs.

Results

• In terms of reducing the left-to-right arytenoid angle quotient (LRQ), the MB and U constructs performed better than the Ethibond Standard (ES) constructs.
• During cyclic loading, suture migration – a potential source of instability – was lesser in MB, U, and DL in comparison to ES constructs.
• However, the load at failure was lower for Fibertape Standard (FS) and U than ES constructs. (Load at failure determines the maximum load or stress before the subject fails.)

Conclusions and Limitations

• According to the analysis, an MB construct when applied to the cricoid cartilage could reduce the loss of abduction (a specific movement which the surgery aims to restore) and increase pullout forces, suggesting a better performance than some of the other tested constructs.
• The results, however, are based solely on ex vivo studies and testing on live animals (in vivo) is required to verify and further explore these results.