Isolated Bilateral Hypoglossal Palsy Complicating a Fourth Ventricle Ependymoma Surgery.

Abstract

Isolated bilateral hypoglossal palsy is a rare condition that has never been described after surgery in the lower part of the fourth ventricle. In this article, we discuss various possible etiologies and relevant anatomy considerations of the rhomboid fossa. We describe a case of bilateral hypoglossal palsy with tongue ptosis following surgery of an ependymoma in the lower part of the fourth ventricle. Immediate postoperative imaging showed ischemic lesions in both hypoglossal nuclei, not compatible with any known arterial territory. Two etiologies could be identified: a venous medullary infarct of the medulla oblongata or direct injury of both hypoglossal nuclei due to their midline position. Finally, the patient improved progressively and returned to normal. Intraoperative neurophysiologic monitoring of hypoglossal nerves, in addition to facial nerves, should be performed for tumors in this location.