Congenital Occlusion of the Foramen of Monro

Abstract

Congenital occlusion of the foramen of Monro is extremely rare. In a review of medical literature, only 6 verified case reports could be found (2, 4, 5, 7, 8,10). From 1964 to 1968, we encountered 4 new cases of proved congenital occlusion of this foramen, which we will report below, emphasizing their radiologic and surgical findings. Case Reports Case I: This 6-month-old girl was admitted to Children's Hospital, Cincinnati, because of numerous brief convulsive seizures since birth. There was slight tenseness of the open anterior fontanel, and the head did not transilluminate. Roentgenographically, the skull appeared asymmetrical with prominence of the right parietal bone. Needle puncture through the fontanel yielded a large amount of yellow fluid from the right lateral ventricle. The left lateral ventricle could not be entered. Ventriculograms showed a huge right lateral ventricle. On pneumoencephalography the next day no air entered the lateral, third, or fourth ventricles (Fig. 1). A large amount of air still remained in the right lateral ventricle from the ventriculography. At craniotomy the right lateral ventricle was found to be enormously dilated. A membrane occluded the right foramen of Monro. An opening was made through the membrane, effecting adequate communication between the lateral and third ventricles. The child died from pulmonary aspiration on the first postoperative day. Case II : This 6-month-old boy was admitted to Children's Hospital, Cincinnati, because of vomiting for two days and a bulging fontanel. A ventriculogram (Fig. 2, A) showed a markedly dilated right lateral ventricle extending across the midline. No communication with the third or left lateral ventricle was evident. A diagnosis of obstruction of the foramen of Monro was made, and at craniotomy no foramen could be detected. Pneumoencephalography performed four days later showed a dilated left lateral ventricle communicating with the third ventricle, but no air entered the right lateral ventricle (Fig. 2, B). A right ventriculojugular shunt was performed a month later with subsequent clinical improvement. Case III: This girl was born with meningomyelocele which was immediately repaired surgically. During the first month of life gradual enlargement of the head was observed, and ventriculography was performed at Children's Hospital. No communication between the two lateral ventricles was demonstrated (Fig. 3, A). Filling both lateral ventricles with air through separate needles showed symmetrical dilatation (Fig. 3, B). Despite a variety of maneuvers the air could not be passed into the third ventricle (Fig. 3, C). A right ventriculopleural shunt was performed. One month later left hemiplegia developed. Ventriculography (again using two needles) showed further enlargement of the left lateral ventricle (Fig. 3, D). A fenestration was made in the septum pellucidum to establish communication between the two lateral ventricles. The child has shown little improvement.