The Pen Nib and the Bolt: The Rhomboid Fossa of the Fourth Ventricle or the Symbol of the Censorship of the Press?

✓A membrane obstruction of the foramina of Magendie and Luschka is an uncommon origin of hydrocephalus characterized by unusual clinical symptoms of rhomboid fossa hypertension. Various surgical approaches have been proposed to alleviate this obstruction, including opening the obstructed foramen of Magendie using suboccipital craniectomy, shunting procedures, and more recently, endoscopic third ventriculostomy (ETV). In some cases, however, reshaping of the posterior fossa due to the collapse of the prepontine cistern could make ETV difficult for the surgeon and dangerous to the patient. In these cases, endoscopic opening of the foramen of Magendie by transaqueductal navigation of the fourth ventricle is a suitable and feasible therapeutic option.

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Intraoperative identification of motor areas of the rhomboid fossa using direct stimulation

Journal of Neurosurgery ◽

10.3171/jns.1993.79.3.0393 ◽

1993 ◽

Vol 79 (3) ◽

pp. 393-399 ◽

Cited By ~ 77

Author(s):

Christian Strauss ◽

Johann Romstöck ◽

Christopher Nimsky ◽

Rudolf Fahlbusch

Keyword(s):

Brain Stem ◽

Fourth Ventricle ◽

Complete Removal ◽

Direct Stimulation ◽

Content Type ◽

Rhomboid Fossa ◽

Stem Lesions ◽

Mass Lesions ◽

The Brain ◽

Motor Areas

✓ Intraoperative electrical identification of motor areas within the floor of the fourth ventricle was successfully carried out in a series of 10 patients with intrinsic pontine lesions and lesions infiltrating the brain stem. Direct electrical stimulation was used to identify the facial colliculus and the hypoglossal triangle before the brain stem was entered. Multichannel electromyographic recordings documented selective stimulation effects. The surgical approach to the brain stem was varied according to the electrical localization of these structures. During removal of the lesion, functional integrity was monitored by intermittent stimulation. In lesions infiltrating the floor of the fourth ventricle, stimulation facilitated complete removal. Permanent postoperative morbidity of facial or hypoglossal nerve dysfunction was not observed. Mapping of the floor of the fourth ventricle identifies important surface structures and offers a safe corridor through intact nervous structures during surgery of brain-stem lesions. Reliable identification is particularly important in mass lesions with displacement of normal topographical anatomy.

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Telovelar approach for microsurgical resection of fourth ventricular subependymoma arising from rhomboid fossa: operative video and technical nuances

Neurosurgical Focus: Video ◽

10.3171/2019.10.focusvid.19452 ◽

2019 ◽

Vol 1 (2) ◽

pp. V5

Author(s):

James K. Liu ◽

Vincent N. Dodson

Keyword(s):

Fourth Ventricle ◽

Total Resection ◽

Tela Choroidea ◽

Safe Technique ◽

Microsurgical Resection ◽

Cerebellomedullary Fissure ◽

Telovelar Approach ◽

Ventricular Tumors ◽

Rhomboid Fossa ◽

Neurologically Intact

Fourth ventricular tumors have traditionally been removed via transvermian approaches, which can result in potential dysequilibrium and mutism. The telovelar approach is an excellent alternative to widely expose fourth ventricular tumors without transgressing the cerebellar vermis. This is achieved by opening the cerebellomedullary fissure and incising the tela choroidea and inferior medullary velum, which form the lower half of the roof of the fourth ventricle. In this operative video manuscript, the authors demonstrate microsurgical resection of a fourth ventricular subependymoma arising from the rhomboid fossa via the telovelar approach. The key technical nuance in this video is to demonstrate a gentle and safe technique to identify a dissectable plane to peel the tumor off of the rhomboid fossa using a microspreading technique with fine micro-bayonetted forceps. A gross-total resection was achieved, and the patient was neurologically intact.The video can be found here: https://youtu.be/ZEHHbUGb9zk.

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To the pathological anatomy of the spinal cord in diabetes mellitus

Kazan medical journal ◽

10.17816/kazmj46866 ◽

1901 ◽

Vol 1 (7-8) ◽

pp. 370-380

Author(s):

N. E. Osokin

Keyword(s):

Diabetes Mellitus ◽

Spinal Cord ◽

Fourth Ventricle ◽

Vascular System ◽

Point Of View ◽

Central Channel ◽

Pathological Anatomy ◽

Loose Connective Tissue ◽

Considerable Length ◽

Rhomboid Fossa

Thanks to a number of works by various researchers, it became known that with diabetes, spinal cord disease occurs frequently, and the lesions take part (to a greater or lesser extent) that is very (W. Muller None), then very (Lеісlіtеntrіtt, wіllіаmsоn, Leyden) sub stations, the vascular system or finally the central channel (Diskinson). At that time, when the pathogenesis of the sugar disease was examined only from the point of view of C1. Vegard'a, that is, lesions of the bottom of the fourth ventricle, changes in the spinal cord in most cases were considered primary phenomena, and diabetics - as a consequence of the spread of a painful process from the spinal cord to the rhomboid fossa (Wеbісlісlе). Along with similar observations, which fully fit into the framework of the theory of a sugar injection, there were such cases of diabetes, where, when one or another lesion of the spinal cord was found, the medulla oblongata remained completely intact (Silver and Irvine, W. Miller). It goes without saying that these cases were waiting for their explanation. Dr. W. Muller in the case of diabetes studied by him was in a state to discover, over a considerable length of the spinal cord, the disappearance of the substance at the base of the anterior horns, replacing it with loose connective tissue.

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