[Surgical management of peripheral hypoglossal nerve palsy caused by abnormal external carotid artery].

It is known that there are a number of variation and anomalies in the bifurcation of the external and internal carotid arteries. It has also been reported that the lateral position of the external carotid artery, which was formerly considered extremely rare, is not so unusual. However, there are few reports that the lateral position of the external carotid artery has caused neurological signs. In this paper, an unusual case of peripheral hypoglossal nerve palsy, attributed to the vascular compression by lateral position of the external carotid artery and abnormally high position of the bifurcation of the external and internal carotid artery was reported. A forty-nine year old man was admitted complaining of tongue deviation and dysarthria. Atrophy and fasciculation of the right lingual muscle were observed. In a right carotid angiogram, lateral position of the external carotid artery was noticed and the bifurcation of the external and internal carotid arteries was abnormally high (upper margin of C2 vertebra). The proximal portions of both arteries were very tortuous and dilated like a megadolichoartery. A right neck surgery was performed and the bifurcation of the external and internal carotid artery was exposed. The hypoglossal nerve was running just above the bifurcation. Owing to the lateral position of the external carotid artery and the tortuous dilatation of the proximal portion of the external and internal carotid arteries, the hypoglossal nerve was markedly compressed and extended laterally. The external carotid artery was ligated and cut at its origin. Inflammatory lymph nodes near the bifurcation were also removed.(ABSTRACT TRUNCATED AT 250 WORDS)