Biomechanical testing of three constructs for prosthetic laryngoplasty in horses demonstrates advantages of differing metallic implants in the arytenoid cartilage.

OBJECTIVE

To compare the biomechanical stability of a novel arytenoid implant (tie-bolt, TB) with a suture anchor (SA) and standard laryngoplasty using suture alone (control) in equine larynges.

STUDY

DESIGN

Randomized ex vivo controlled experimental study.

SAMPLE POPULATION: Thirty equine cadaver larynges.

METHODS

Larynges were randomly assigned to TB, SA, or control groups (n = 10 each). The force of abduction was measured for each construct, then constructs underwent cyclic loading (5-50 N for 3000 cycles) to assess elongation, followed by load-to-failure testing to assess ultimate load, displacement, stiffness, and mode of failure.

RESULTS

The SA required less force to achieve 88% abduction (8.31 ± 2.46 N) than the TB (11.48 ± 3.6 N, p = .07) and controls (11.86 ± 2.99 N, p = .04). The TB had less construct elongation (2.62 ± 0.61 mm) than SA constructs (3.87 ± 1.25 mm, p = .01) and was stiffer (31.05 ± 3.38 N/mm) than both control (23.48 ± 2.06 N/mm, p < .0001) and SA constructs (18.53 ± 4.15 N/mm, p < .0001). The TB construct failed at higher ultimate load and displacement (367.25 ± 66.98 N and 19.11 ± 2.51 mm, respectively) than the control (238.14 ± 19.46 N and 14.23 ± 1.6 mm; p < .0001 for both) and SA constructs (196.55 ± 47.17 N and 16.23 ± 2.02 mm; p < .0001 and p = .01, respectively). The primary modes of failure were suture cut-through for control, implant pullout for SA, and arytenoid fracture for TB.

CONCLUSION

The SA required the least force for abduction. The TB was a stiffer construct that resulted in higher failure loads.

CLINICAL SIGNIFICANCE: The SA may reduce construct loading during abduction. The TB offers superior mechanical stability, potentially reducing long-term degradation from cyclic loading.