Biomedical subjects
Publications and source records attributed to Roberto Leal Silveira.
We describe the unusual case of a 45-year-old male patient harboring an intracranial mass due to cerebral amyloid angiopathy whose clinical and radiological features were those of a low grade glioma. Biopsy revealed cerebral amyloid angiopathy. The clinical, radiological and pathological findings are discussed as we review the available literature.
We report the surgically treated case of a 21-year-old caucasian male harboring a cavernous hemangioma of the right internal auditory canal encasing the seventh and eighth cranial nerves complex. Only 18 cases of cavernous hemangiomas of this location have been previously reported. The clinical features, the differential diagnosis and the treatment are discussed.
Twenty-two patients harboring tumors or vascular lesions (AVMs and aneurysms) located at the posterior aspect of the parahipocampal gyrus and the pulvinar of thalamus operated by supratentorial-infraoccipital approach were analysed. Total resection was achieved in all five AVM patients as well as in six out of fifteen tumor patients. This approach was performed in five anatomical specimens (ten approaches); It results, along with the surgical results, allow this approach to be considered a good option for lesions of the pulvinar of thalamus and postero-medial temporal lobe which are evident at the transverse fissure.
A modification of the supraorbital approach is proposed in order to improve the access to the medial portions of the anterior and middle fossas (supraselar region). It consists of a midline extension of the frontal craniotomy along with an interhemispheric approach: interhemispheric supraorbital or frontopolar approach. The anatomical basis of this approach were studied in eight cadaveric heads. Its results demonstratete that this approach adequaly access the medial structures of the anterior and medial fossas with minimal brain retraction and wide exposure.
We report the case of a 22-year-old man victim of penetrating brain injury due to a 15 x 12 asbestos fragment and a successfully treatment via decompressive craniectomy. Unlike gunshot wounds to the head, penetrating brain injury from low energy objects are unusual. Most cases reported involve cranio-orbitary injuries as well as self inflicted lesions in mentally ill patients. The reported case is noteworthy due to the large dimensions of the foreign body, the treatment via decompressive craniectomy and the good patient functional outcome.
An analysis of the surgical results of 51 patients harboring 55 paraclinoid aneurysms is performed, along with a throughoutful description of its complex microsurgical technique. The anterior clinoid process was removed by the extradural route after sectioning the dural duplication between the superior orbital fissure and the dura of the temporal lobe, and/or by the intradural approach. All 55 aneurysms was excluded. In two cases the clipping was partial and the internal carotid artery were occluded in three cases. The surgical outcome was good in 42 (82%) patients, moderate incapacity occurred in five (10%) and severe incapacity in one patient (2%). Three patients (6%) died due to brain infarction. Seven patients (13,7%) had additional lesion of the optic nerve, being partial in 4 (7,7%) and total in 3 (6%).
A topographic study of posterior surface of the petrous pyramid was performed in 20 human cadaveri heads. The distances between the neurovascular structures were measured in the points where they contact the posterior surface of the petrous pyramid. The study also points out the relationship between the bone landmarks and the transverse and the superior petrous sinuses. The result of this study was correlated with the approaches to the cerebellopontine angle.
A modification of the conventional suction device for microsurgery is described. It consists of a built-in tube in another tube, being the first connected to the suction device and the second to the irrigation. This suction-irrigator device allows to accomplish the suction and irrigation simultaneously and in a precise way.
The knowledge of the craniotopography allows the delimitation of the cranial approaches. In this study the landmarks, defined in relation to the craniometric points and used in the different cranial approaches, were systematized. Twenty two landmarks are described: the first twelve are in relation to the skull base and the remainder are in relation to the skull vertex.
The anterolateral limit of the occipital lobe was studied in anatomical specimens and with neuroimaging. Seven human cadaver heads, 103 normal CT-scan and 104 MRJ of the brain were studied. There was a fold of the dura mater on the transverse sinus (preoccipital tentorial plica) and a bony protuberance related directly to the preoccipital notch. It was also determined the mean distance between the parieto-occipital sulcus and the lambdoid suture. In the imaging studies, especially magnetic resonance, it was possible to identify the preoccipital notch and/or a protuberance in the cranial vault related to this notch, besides the parieto-occipital sulcus and lambdoid suture, making possible, therefore, the definition of the anterolateral limit of the occipital lobe.
We studied the extensions of the lateral suboccipital approach (LSOA) in seven cadaver heads, in the microsurgical laboratory, in order to establish the extensions necessary to approach the anterolateral area of the foramen magnum and the jugular foramen. The extensions (bone resection) were accomplished in five progressive steps: 1) suboccipital retrossigmoid craniectomy (LSOA retrocondylar); 2) extending the craniectomy with removal of half the occipital condyle (LSOA partial transcondylar); 3) extending the drilling of the occipital condyle to open the hypoglossal foramen, followed by removal of the jugular tubercle and opening the jugular foramen (LSOA transcondylar-transjugular); 4) complete drilling of the occipital condyle (LSOA complete transcondylar); 5) LSOA complete transcondylar plus removal of the atlas lateral mass up to the odontoid process (ASOL transcondylar-transjugular). We concluded that the extensions of LSOA should be adapted to the topography of the lesion: the LSOA retrocondylar for the lateral area of the foramen magnum; the LSOA partial transcondylar for the anterolateral portion; the LSOA transcondylar-transjugular to reach the jugular foramen; the LSOA complete transcondylar for the anterior part, and the LSOA complete transcondylar/translateral mass of the atlas for extradural lesions anterior to the foramen magnum.
Focal somatosensory epileptic seizures ipsilateral to a brain tumor is reported and the literature reviewed. It is an exceptional occurrence, having been described only six cases, with several mechanisms being proposed. The proximity of the lesions with the low cerebral convexity (perisylvian) suggests the compromising of the secondary somatosensorial area, seeming to prove the experimental observation of somatosensorial crises originating in this area.
A case of endolymphatic sac adenocarcinoma is reported and the literature is reviewed. The clinical picture was presented by vertigo and progressive hearing loss caused by a tumor of the endolymphatic sac. The surgical removal was complete, via a retro and translabyrinthine approach. Endolymphatic sac tumors are locally invasive, involve the petrous bone and the mastoid. The radical surgery presents good outcome.