OROPHARYNGEAE DYSPHAGIAS IN THE DOG: A CINEFLUOROGRAPHIC ANALYSIS OF EXPERIMENTALLY INDUCED AND SPONTANEOUSLY OCCURRING SWALLOWING DISORDERS

Cinefluorography and videoflurography were used to record and analyze the functional swallowing deficits of nine dogs with spontaneous oropharyngeal swallowing problems. Based on the clinical and radiographic signs observed in one dog with experimentally induced bilateral hypoglossal palsy and comparison with cinefluorograms of normal dogs, the nine spontaneous dysphagias were divided into five oral dysphagias and four pharyngeal dysphagias. Dogs with oral dysphagias had problems with tongue control and in prehending and transporting food and fluid to the oropharynx. On cinefluorograms, a poor closure of the oral egress led to the loss of contrast medium from the mouth, and a weak tongue-thrust action caused retention of contrast medium in the oropharynx. The clinical and radiographic signs could be duplicated by hypoglossal neurectomy. In contrast to the pharyngeal dysphagias, aspiration pneumonia was noticeably absent in oral dysphagias. The dogs with pharyngeal dysphagia had severe difficulties in transporting the food from the oropharynx to the laryngopharynx owing to a poor contractility of the pharyngeal muscles. The latter resulted in contrast medium retention in the pharynx and laryngotracheal aspiration. The need was stressed for a careful differentiation between oral and pharyngeal dysphagias on one hand, and cricopharyngeal dysphagias on the other hand. In oral dysphagias, cricopharyngeal myotomy appeared of no use. In pharyngeal dysphagias, cricopharyngeal myotomy severely aggravated the clinical signs by causing a cricopharyngeal chalasia.