[Experimental studies on the therapy of epiglottis hypoplasia in horses–transendoscopic injection of collagen and polytetrafluoroethylene].

This research explores the treatment of epiglottic hypoplasia in horses via transendoscopic injection of bovine collagen and polytetrafluoroethylene. The study found that while both substances led to an increase in epiglotic thickness, implying an improvement in its stability, bovine collagen was easier to administer and caused fewer complications than polytetrafluoroethylene.

Research Methodology

• The researchers performed epiglottic augmentation through transendoscopic injection of implant materials on ten healthy horses. Bovine collagen was used in six cases and polytetrafluoroethylene (PTFE-Paste) in the remaining four.
• The aftermath of the surgery was observed endoscopically and through contrast radiography, which was used to measure the length and thickness of the epiglottis. The gathered data was subsequently correlated with information obtained from the autopsy.
• Three and two horses from each group were euthanized at three and 12 weeks post-surgery for necropsy and histologic assessment.

Findings

• Injection of bovine collagen was easier than PTFE within the transendoscopic procedure.
• Results revealed that the epiglottic length and thickness recorded on radiographs corresponded well with those obtained during the autopsy.
• An increasing organization of the implant was observed histologically after injecting both substances. This progression correlated to the increasing time-post injection.
• Following the insertion of the collagen implant, fibrous granulation tissue and inflammation mainly comprising lymphocytes and histiocytes were exhibited. In contrast, PTFE injection resulted in the formation of a foreign body granuloma and in some cases, ulcers.
• Both substances caused an increase in epiglottic thickness suggesting an improvement in its stability. However, this thickness reached its maximum level right after the injection and declined over the observed period.

Conclusion

• Although both materials resulted in an increase of the epiglottic thickness, indicating potential enhancement in its stability, bovine collagen was deemed more suitable for the transendoscopic injection.
• The development of fibrous granulation tissue and the migration of fibroblasts and fibrocytes into the implant using bovine collagen suggest some level of stabilization.
• Despite reported good clinical results using PTFE via laryngotomy, this research suggests the material may not be suitable for the transendoscopic technique due to the higher occurrence of complications.