Dysphagia can be caused by various mechanisms such as impaired tongue movement, delayed swallowing reflex, decreased pharyngeal peristalsis, incomplete closure of epi-glottis and cricopharyngeal dysfunction. Cricopharyngeal muscle, forming the upper esophageal sphincter, acts as a muscular sling between the pharynx and the esophagus. Normally, it closes constantly at rest and opens during laryngeal elevation through active relaxation on the one hand and passive traction by the antero-cephalad laryngeal movement on the other. If its incoordination or hypertonicity happens, dysphagia can develop. Cricopharyngeal muscle dysfunction is caused by various situations such as neuro-muscular diseases, postoperative changes and stroke, parti-cularly after brainstem stroke. We report a case of isolated dysphagia caused by failure of active relaxation of crico-pharyngeal muscle without aspiration after left lateral me-dullary lacunar infarction. (J Korean Acad Rehab Med 2009; 33: 252-254)

Hypertonicity of the cricopharyngeal muscle often results in dysphagia. Current available treatments for this problem include the mechanical balloon dilation and cricopharyngeal myotomy. Recently, a botulinum toxin injection into the cricopharyngeal muscle has been proved to be a successful approach. The case well proved the effectiveness of botulinum toxin injections as a viable treatment for patients suffering from cricopharyngeal dysphagia. A 58 year-old man, who had right lateral medullary infarction, claimed severe difficulties in swallowing which was complicated by aspiration pneumonia. A videofluoroscopic barium swallow test indicated aspiration and cricopharyngeal hypertonicity. Botulinum toxin was injected into the cricopharyngeal muscle, through endoscopic identification. After treatment, videofluoroscopy showed a significant improvement in the cricopharyngeal muscle opening and no more silent aspiration was seen. This case implicated the effectiveness of endoscopic botulinum toxin injection treatment for cricopharyngeal dysphagia in situations where there was no response to traditional swallowing rehabilitation. (J Korean Acad Rehab Med 2006; 30: 398-401)