Transoral, endoscopic assisted closure of cleft palate in a foal

Abstract

The repair of cleft palate in foals has compared with humans another weightness and importance. Due to the anatomical differences of oro- and hypopharynx between horses and humans, clefting in equines results not only in an insufficient absorption of nutrients by nasal milk escape but also, following aspiration, in a life-threatening aspiration pneumonia. Current reports suggest that cleft palate repair in foals is technically difficult and is accompanied by a high complication rate. In spite of successful cleft repair, aspiration pneumonia existing before the operation can be fatal. The distance between a foal's front teeth and palate is too large to perform a transoral approach like that done in humans. Until now, therefore, an extraoral access was applied by means of a symphysiotomy of the mandible, often in combination with a pharyngotomy. Hence, the vast soft tissue wound led predominantly to uncontrollable infections and asphyxia. To avoid these complications, we decided to take a transoral approach using endoscopic instruments and technologies to bridge the distance. In a five-week-old stallion, milk out-flow off the nose during sucking was observed from birth. Increasing inflammation- parameters and subtotal lung field shadowing in the lateral chest roentgenography proved the diagnosis of an aspiration pneumonia. The endoscopic investigation of the oropharynx confirmed the suspicion of palatoschisis in the form of on uvula bifida and a submucous cleft palate. After suitable presurgical preparation, the surgical procedure was performed in back position of the foal under general anaesthesia. Due to the limited overview of the performed transoral approach, endoscopic optics were introduced, providing a view control on a screen during the proceedings. So by the far less traumatic endoscopically assisted transoral approach, the problem of exposure of the operation field was easily managed. In analogy to the set-up of cleft palate repair in humans, we performed an intravelar myoplastic of the Mm. levator veli palatini in the foal. Until now this procedure has not explicitly been applied to horses, probably because when the function of the Mm. levator palatini in horses is discussed there is controversy regarding the active raising of the extremely long soft palate. However, a layerwise closure of cleft palate should decrease sore healing disturbances with dehiscences and would raise the static stability of the palate. After closure of the oral layer with 2-0 and 3-0 resorptive sutures, the foal recovered well from anaesthesia. After post- surgical treatment, the foal was returned to the mother and was able to drink normally. Following antibiotic therapy with Gentamycin and Penicillin/Streptomycin, at 8 days post-operation the lateral chest roentgenography proved clearly falling findings. The inspection of the situs showed at that time a first-in first-out sore healing. The foal developed normally up to the last control, 18 months post operation. Nevertheless, the precise value of this operation technique must be evaluated based on the results in other cases.