Management of bilateral choanal atresia in a foal.

This study is about the successful treatment of a 1-day-old foal suffering from severe respiratory obstruction, diagnosed as bilateral choanal atresia, using transendoscopic laser fenestration and other surgical techniques. Despite complications like recurring stenosis, the foal recovered and was able to participate in athletic activities without any respiratory issues after a year.

Initial Diagnoses and Treatment

• The research focuses on a 1-day-old Standardbred foal that was presented with a severe upper airway obstruction leading to respiratory distress after its birth.
• Due to the foal’s critical condition, the referring veterinarian had placed a temporary tracheostomy tube to mitigate the distress.
• Upon initial examination, the foal was found to have symptoms indicative of hypoxic-ischemic syndrome, a condition where the brain does not get enough oxygen, a side effect of asphyxia during birth.
• The use of endoscopy revealed that the obstruction was at the level of the choanae (the rear openings of the nasal cavity) in both nostrils, leading to a diagnosis of bilateral choanal atresia (a dense layer of tissue blocking the choanae).

Surgical Intervention

• Under anaesthesia, the foal was subjected to a procedure known as transendoscopic laser fenestration to cut through the blocking membranes.
• Three weeks post the surgery, cicatricial narrowing in the choanae was observed, signalling scar formation and contraction which was corrected through another round of membrane ablation.
• Since the stenosis (narrowing) occurred repeatedly, multiple revision surgeries were conducted which included laser ablation coupled with the topical administration of mitomycin (a medicine to slow tissue growth), radial incisions into the stenotic tissue, and bougienage (a method of widening a passage in the body) with an endotracheal tube.

Post Treatment Progress

• While the treatment helped reduce the stenosis, there was still mild evidence of it even a year later. However, this did not inhibit the growth of the foal or its athletic activities.
• The foal’s choanae were more than 85% open, and it was deemed to have a normal size for its age and had entered training.
• Even though mild stenosis was evident in the review after a year, the horse displayed no exercise intolerance or respiratory problems.

Conclusion

• The study puts forth its successful experience in treating a case of bilateral choanal atresia in a foal by using transendoscopic fenestration of the buccopharyngeal membranes, and handling post-operative complications such as recurrent stenosis.
• This implies that horses suffering from this severe respiratory condition can still expect to recover and be productively involved in athletic activities with the necessary intensive and prolonged treatment.