What is Choanal Atresia Correction?
Choanal atresia in horses occurs when the bucconasal membrane, which separates the nose and mouth in the foal in utero, fails to rupture at birth, resulting in an obstruction of one or both of a foal’s nostrils. The obstruction may be membranous or fibrocartilaginous in nature. If only one nostril is affected the condition may not be noticed immediately and, in fact, may not become obvious until the young horse is in training and has difficulty with respiration during performance. However, if both nostrils are blocked, a life-threatening condition occurs. Some foals will learn to mouth breathe immediately, but usually an emergency tracheotomy must be performed to create and airway and allow the foal to breathe. This condition occurs in 1% to 4% of equine births, and owners with pregnant mares should be aware. If choanal atresia is present, the membrane or tissue will need to be resected to allow for normal breathing. Your veterinarian can perform this procedure endoscopically with a laser in a sedated or anesthetized horse or endoscopically with resection by traditional means, which will require general anesthetic. This is not an uncommon procedure in horses and results are generally positive. Stents and nasal tubes are normally placed in the surgically created opening to prevent the collapse of the structures of the opening which would result in further blockage and difficulty breathing.
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Choanal Atresia Correction Procedure in Horses
Resection of the mucosal membrane to open up the young horse's airway is conducted endoscopically and may be performed with a laser or traditional surgical tools. If laser is being used, it may be possible to perform the procedure under heavy sedation, however intravenous anesthetic is more commonly used to immobilize the young horse. The young horses will be sedated or anesthetized and an endoscope, a tube with a video camera, inserted into the nasal cavity to allow the surgeon to visualize the obstruction and aid in the resection procedure. Endoscopic surgical tools or a laser will then be used to make an incision in the blocking membrane or tissue and open the airway. Stents will then be placed into the nasal cavity to ensure that the opening does not collapse when the membrane is removed. Once the membrane is resected a nasotracheal tube is inserted into the nostril and sutured into place to keep the airway open during recovery. Once the procedure is completed, the foal will be aided in recovery from sedation or anesthetic.
Efficacy of Choanal Atresia Correction in Horses
Prognosis for unilateral choanal atresia is good, however, when bilateral condition occurs the ability to quickly diagnose and clear the airway will impact the young horse’s medical condition and affect prognosis. Because of this, bilateral choanal atresia cases are associated with more guarded prognosis. In addition, the surgically created opening can narrow and stricture can result, causing respiratory difficulties to recur. The use of a nasotracheal tube and stents in the nasal passage during healing minimizes this occurrence.
Choanal Atresia Correction Recovery in Horses
During recovery, the young horse will need to be closely monitored to ensure that the nasal tube does not come loose or displaced and repositioning and suturing may be required. The foal should be kept under close observation to ensure that nursing occurs. If irritation of the mare's udder from the tube occurs or if the foal has trouble nursing, they may require assistance. If nasal discharge with blood or signs of infection occur, immediate veterinary assistance should be obtained. The foal will also have to be closely observed after the nasal tube is removed and on an ongoing basis for respiratory difficulties that would indicate stricture of the nasal passages resulting in respiratory difficulty.
Cost of Choanal Atresia Correction in Horses
The cost of correction for choanal atresia depends on the procedure used and requirements for anesthesia. The cost of correction of choanal atresia ranges from $3,000 and up depending on the individual's requirements and the cost of living in your area.
Horse Choanal Atresia Correction Considerations
If bilateral choanal atresia occurs, emergency tracheostomy will need to be performed in most cases, to allow the foal to breathe. This procedure and the trauma caused by lack of air prior to an airway being created can result in a foal with a guarded prognosis due to issues around the lack of oxygen and compromised health of the young horse. Stricture of the nasal passages is common, and long term, additional procedures may be required. Horses experiencing this condition may not be suitable for high performance activities if respiratory compromise is an issue.
Choanal Atresia Correction Prevention in Horses
Although the cause of congenital choanal atresia has not been determined, a hereditary factor may be present, and removal of horses with choanal atresia from breeding programs may need to be considered. Owners of mares expecting foals should be aware of this condition and prepared to deal with bilateral choanal atresia at birth with emergency tracheostomy if required to provide the best outcome for the foal.