Implementation of a prototype dynamic laryngoplasty system in standing sedated horses provided arytenoid abduction control at seven days postoperatively.

The research evaluates a prototype dynamic laryngoplasty system (DLPS) in horses as a possible solution for laryngeal hemiplegia. The study reports no perioperative complications, successful implantation of the DLPS, and the potential to adjust the level of arytenoid abduction seven days after surgery.

Research Methodology

• The research was conducted as an in vivo experiment on seven healthy Standardbred horses.
• A standing surgical procedure was performed on the horses to induce complete laryngeal hemiplegia, a condition that was then treated using the DLPS.
• The tested DLPS was activated via an injection port that either exited from the horse’s skin or was placed subcutaneously.
• Endoscopic examinations of the horses’ upper respiratory tract were regularly carried out before surgery, during the operation, and seven days postoperatively.
• The researchers calculated left-to-right quotient ratios during inactive and active states using images of the rima glottidis taken on day seven following surgery.
• Three out of the seven horses had the device intentionally overinflated to check for potential device failure. On the seventh day, postmortem examinations were conducted on these horses.
• For the remaining four horses, an additional endoscopy was carried out one month postoperatively, with no follow-up postmortem examinations.

Research Outcomes

• No complications occurred during the perioperative period.
• All horses successfully received the DLPS implant while under standing sedation.
• The left-to-right quotient ratio showed changes after seven days from the operation, moving from a resting position of 0.76 to a maximum of 0.97. This indicates successful adjustment of the degree of arytenoid abduction postoperatively.
• The researchers, however, noted that the degree of arytenoid abduction couldn’t be significantly altered one month after device implantation due to suspected peri-implant fibrosis. This means the ability to adjust the level of abduction may reduce over time because of fibrosis around the implant location.
• No instances of coughing or tracheal contamination were observed at any point during the research or during DLPS inflation.

Conclusions

• The study concluded that the DLPS could potentially offer a way to adjust the degree of arytenoid abduction seven days postoperatively in selective cases.
• While the immediate postoperative results were promising, the research also highlighted the need for further studies due to the suspected onset of peri-implant fibrosis, which could limit the device’s effectiveness in the long term.