Induration of the cricoid cartilage complicates prosthetic laryngoplasty in a horse.

The research article presents a case study where difficulties were encountered during a laryngoplasty operation on a horse due to the hardening of the cricoid cartilage. The researchers suggest that radiographic examinations before surgery could help identify potential issues related to this condition, which is often associated with aging.

Needle Penetration and Suture Placement Complications

• An 11-year-old American Paint gelding horse, with grade IV left laryngeal hemiplegia, was subjected to a prosthetic laryngoplasty. The procedure was performed for teaching purposes and was not intended to extend the horse’s life.
• The operation met with difficulties due to the hardening of the cricoid cartilage in the larynx, making it difficult for the needle to penetrate. This resulted in the needle breaking and a new needle had to be used.

Post-Mortem Analysis

• Upon palpating the larynx post-mortem, it was found that the cricoid cartilage had hardened.
• A radiographic examination was subsequently conducted, revealing diffuse radiopaque speckling, indicating the presence of hard substances within the cartilage.
• However, histologic examination did not find accumulations of calcium salts, which are typically associated with hardening or mineralization. Instead, it was found that there was a significant loss of proteoglycans within the cricoid cartilage.

Findings and Conclusions

• Laryngeal mineralization, or the hardening of the larynx, was identified as a common occurrence in both horses and humans with advancing age.
• The researchers found that the loss of proteoglycan and the subsequent stiffening of the cricoid cartilage contributed to the intraoperative complications documented in this case.
• To mitigate such complications, the researchers recommend conducting radiographic examinations of the larynx prior to performing a prosthetic laryngoplasty.
• They warn, however, that interpretations of such examinations should be undertaken with caution, as increased radiodensity may either suggest mineralization, or simply represent changes due to a variation in proteoglycan concentration, monomer size or charge.