Induration of the Cricoid Cartilage Complicates Prosthetic Laryngoplasty in a Horse

Objective— To report intraoperative complications during needle penetration and suture placement through the cricoid cartilage during a prosthetic laryngoplasty procedure.
Study Design— Case report.
Methods— An 11-year-old American Paint gelding with grade IV left laryngeal hemiplegia underwent a terminal prosthetic laryngoplasty for teaching purposes. Passage of the needle through the cricoid cartilage was difficult and resulted in needle breakage before eventual success using a new needle. The larynx was examined postmortem.
Results— Palpation of the larynx revealed hardening of the cricoid cartilage. Radiographic examination indicated the presence of diffuse radiopaque speckling. Histologic examination did not find accumulations of calcium salts, rather it revealed a loss of proteoglycans within the cricoid cartilage.
Conclusions— Laryngeal mineralization occurs in the horse and human with advancing age. The loss of proteoglycan and subsequent stiffening of the cricoid cartilage likely resulted in the intraoperative complications noted in this report.
Clinical Relevance— Radiographic examination of the larynx before performing a prosthetic laryngoplasty may reveal the presence of areas of increased radiodensity. The interpretation of this is to be made with caution as it may represent mineralization, or hardening due to the changes in proteoglycan concentration, monomer size or charge.