Histological evaluation of the equine larynx after unilateral laser-assisted ventriculocordectomy.

This research article is about how trans-endoscopic laser surgery, specifically unilateral laser-assisted ventriculocordectomy (LVC), impacts the laryngeal tissues of horses. The study finds that this procedure caused acute thermal damage to nearby soft tissues, but the laryngeal cartilages showed no signs of histological modification six months post-surgery.

Objectives and Methods

• The research was conducted to understand the histological effects of laser surgery on laryngeal tissues in horses after undergoing LVC used to treat laryngeal hemiplegia (LH).
• The study involved 6 horses, 4 of which had intentionally induced LH, who had then received the LVC treatment 6 months prior to euthanasia. The remaining two were control horses.
• One control horse, with naturally occurring LH, was observed to study neuropathy’s effects without surgery. The other control horse was euthanized immediately after LVC to analyse the acute effects of the surgery.
• All the larynxes were sectioned transversely at 5mm intervals post-mortem with a band saw and evaluated histologically.

Results

• The research found that the laser surgery results in immediate thermal damage to the soft tissues surrounding the area of operation. However, it did not affect the histology of the laryngeal cartilages.
• Six months after LVC, the histological evaluation showed no alterations in the laryngeal cartilages, indicating no long-term tissue damage due to the surgery.
• Also noticed was the squamous metaplasia of the healed laryngeal mucosa, suggesting the recovery and restitution of the mucosal integrity after the surgical intervention.

Conclusions

• LVC, if performed using a diode laser in direct contact mode at a 20 W energy level, allows the removal of the laryngeal vocal fold and the ventricle without causing damage to the laryngeal cartilages.
• The study concludes that laryngeal chondritis, an inflammation of the laryngeal cartilages, is an unlikely outcome of LVC.
• These findings support the increasing use of LVC as a less invasive procedure for treatment not requiring general anesthesia or a laryngotomy incision.