Anatomía microquirúrgica en 3D de la superficie cerebral / Microsurgical anatomy in 3D of the brain cortex

Introducción: El estudio de la superficie externa del cerebro es analizado desde diferentes puntos espaciales, es decir unasuperficie lateral, medial y basal. La superficie lateral del cerebro se distingue por la presencia de dos puntos de referencia quedividen a cada hemisferio cerebral en lóbulos. Estos dos puntos son la fisura de Silvio (fisura lateral) y el surco de Rolando (surcocentral). Estos dos surcos dividen a cada hemisferio en lóbulo frontal (superior a la fisura de Silvio y anterior al surco de Rolando),el lóbulo temporal (inferior a la fisura de Silvio) y lóbulo parietal (superior a la fisura de Silvio y posterior al surco de Rolando). Ellóbulo occipital se ubica por detrás del surco parietooccipital, y el lóbulo de la ínsula que se sitúa en la profundidad de la fisurade Silvio. Objetivo: Describir la anatomía Microquirúrgica de la superficie cerebral en imágenes estereoscópicas anaglíficas tridimensionales.Material y Métodos: La superficie cerebral fue examinada en 30 cerebros humanos con la ayuda de microscopioquirúrgico D.F. Vasconcellos M900 con una magnificación de 16x y 40x, el equipo fotográfico marca Nikon modelo D60, lenteAF-S VR Micro-Nikkor 105 mm f/2.8G IF-ED de Nikon, instrumental de microcirugía y sistema de vernier calibrado en décimasde milímetros. Resultados: La superficie cerebral de cada hemisferio esta dividida por medio de la fisura de Silvio y el surco deRolando en; Lóbulo frontal que se localiza superior a la fisura de Silvio y anterior al surco de Rolando, el lóbulo temporal que sesitúa inferior a la fisura de Silvio, lóbulo parietal de localización superior a la fisura de Silvio y posterior al surco de Rolando, el lóbulooccipital se ubica por detrás del surco parietooccipital. En la profundidad de la fisura de Silvio se encuentra el lóbulo de la ínsula...

Introduction: Brain cortex is studied from different views: lateral, medial and basal surfaces. The brain lateral surface is distinguished by the presence of referential points and sulci. Those specific surgical points consist of the Sylvian fissure (lateral fissure) and the Rolandic sulcus (central sulcus). Those sulci divide each hemisphere in frontal lobe (superior to the Sylvian fissure and anterior to the Rolandic sulcus), temporal lobe (inferior to the Sylvian fissure), and parietal lobe (superior to the Sylvian fissure and posterior to the Rolandic sulcus). The occipital lobe is located posteriorly to the parietooccipital sulci, and the insular lobe is located deep into the Sylvian fissure. Objetive: To describe the microsurgical anatomy of the brain cortex in tridimensional surface imaging reconstruction. Material and Methods: Human cadaveric speciments of 30 human brains were studied through the surgical microscopy D.F. Vasconcellos M900, 16x and 40x magnification, Nikon D60 camera, AF-S VR Micro-Nikkor 105 mm f/2.8G IF-ED lens, and microsurgical instruments. Results: Brain surface is divided in each hemisphere basically through the Sylvian fissure and the Rolandic sulcus in frontal lobe, superiorly to the to the Sylvian fissure and anteriorly to the Rolandic sulcus, temporal lobe, inferiorly to the Sylvian fissure, parietal lobe, superiorly to the Sylvian fissure and posteriorly to the Rolandic sulci, and occipital lobe behind the parietooccipital sulci. Deep into the Sylvian fissure is located the insular lobe...

Intracranial aneurysm and arachnoid cyst: a rare association between two cerebral malformations.

Intracranial aneurysms and arachnoid cysts are cerebral disorders of a high prevalence. However, association between both malformations is a rare finding. The aim was to analyse this association with regard to the different clinical presentations according to the haemorrhage types, as well as the pathogenesis of this association. We searched the English language literature in MEDLINE database in order to include all manuscripts in which this association was found. A new case of a 55-year-old man with a large posterior communicating artery aneurysm and a middle cranial fossa arachnoid cyst presenting with headache and seizure was added to review of the literature and presented as an illustrative case. Nine cases were found. Six were male and three were female. The mean age was 42 years (range 29-66 years). All but one arachnoid cysts were located at middle cranial fossa, aneurysms arose from middle cerebral artery in three cases, internal carotid artery bifurcation in two cases, posterior communicating segment of carotid artery in two cases, anterior communicating artery in one case and azygos pericallosal artery in one case. Clinical presentation was related to aneurysmal rupture in six cases (subarachnoid haemorrhage in four, subdural haematoma in one and intracystic haematoma in two) and related to arachnoid cysts in three cases, where the most common symptoms were seizures and headache. Association between intracranial aneurysms and arachnoid cysts is a rare finding that can present with signs and symptoms related to aneurysm rupture, or with mass effect and seizures related to the cyst. The aneurysmal haemorrhage may be atypical, since it can be into the subarachnoid space, into the arachnoid cyst, or into the subdural space.

Compound osteosynthesis in the thoracic spine for treatment of vertebral metastases. Technical report.

Metastases to vertebrae often cause bone destruction leading to instability and neural compression. Anterior surgical approaches allow tumor resection and direct neural decompression. For patients with a short life expectancy, vertebral body replacement with methyl-methacrylate polymerized in situ can be used for load sharing in the axial plane. Screws hung from the rod into the corpectomy site are incorporated into the acrylic cement. The technique described in this article allows for immediate spinal stabilization and provides a protective environment for the neural elements. All the patients tolerated the procedure well and were able to ambulation without an orthoses.

Skull base chordomas: a management challenge.

Because of their critical location, invasive nature, and aggressive recurrence, skull base chordomas are challenging and, at times, frustrating tumors to treat. Both radical surgical removal and high-dose radiation therapy, particularly proton beam therapy, reportedly are effective in tumor control and improve survival rates. The authors posit that these tumors are best treated with radical surgery and proton-photon beam therapy. During the last 5 years, they treated 25 patients (15 females and 10 males) who harbored pathologically diagnosed skull base chordomas. The mean age of the patients was 38.4 years (range 8-61 years). Previous surgery or radiation therapy was performed at other institutions in seven and two patients, respectively. The authors performed 33 surgical procedures on 23 patients. Radical removal (defined as absence of residual tumor on operative inspection and postoperative imaging) was achieved in 10 patients; subtotal resection (defined as resection of > 90% of the tumor) was achieved in 11 patients; and partial resection (defined as resection of < 90% of the tumor) was achieved in two patients. Radical surgical removal included not only the excision of soft-tumor tissue, but also extensive drilling of the adjacent bone. Adjuvant therapy consisted of postoperative combined proton-photon beam therapy (given to 17 patients and planned for one patient) and conventional radiation therapy (two patients); three patients received no adjunct therapy. To date, four patients have died. One patient who had undergone previous surgery and sacrifice of the internal carotid artery died postoperatively from a massive stroke; one patient died from adenocarcinoma of the pancreas without evidence of recurrence; and two patients died at 25 and 39 months of recurrent tumor. Permanent neurological complications included third cranial nerve palsy (one patient) and hemianopsia (one patient); radiation necrosis occurred in three patients. Of the 21 patients followed for more than 3 months after surgery, 16 have had no evidence of recurrence and five (including the two mortalities noted above) have had recurrent tumors (four diagnosed clinically and one radiologically). The mean disease-free interval was 14.4 months. A longer follow-up period will, hopefully, support the early indication that radical surgical removal and postoperative proton-photon beam therapy is an efficacious treatment. The use of skull base approaches based on the tumor classification introduced in this paper is associated with low mortality and morbidity rates.

Cranial chordomas in children and adolescents.

Chordomas are rare tumors that usually occur in adults. This report describes four cases of intracranial chordomas treated in patients 20 years of age or younger by the senior author (O.A.M.) during a 4-year period. The authors also reviewed the literature on pediatric patients, which revealed that the clinical presentations, histological patterns, and behaviors of these tumors differ considerably depending on whether the patient is younger or older than 5 years of age. The younger population had a wider range of presenting symptoms, a greater prevalence of atypical histological findings with aggressive behavior, a greater range of cellularity than the classic chordomas, and a higher instance of metastasis; it showed no chondroid component compared to a 17.1% instance in the older patients. The prognosis for patients with a chordoma is related directly to the histological pattern of the tumor; the atypical chordoma carries a poor prognosis. The prognoses for children older than 5 years of age with a classic or chondroid tumor were not significantly different (p=0.788). At follow up, the difference in survival rates between patients undergoing surgery plus radiation therapy and those who had surgery alone was statistically significant (p=0.00446). No correlation was found between radical resection or radiation therapy and an improved prognosis for patients younger than 5 years of age who had a tumor with an atypical histological pattern. This study identifies and delineates the distinction between these age groups and provides a review of the potential prognostic factors.

Intravagal paragangliomas: report of four cases.

The intravagal paraganglioma is a very rare tumor of the head and neck that accounts for only 5% of the paragangliomas in that area. A painless mass in the high neck with extension into the peripharyngeal space is the most common characteristic of this tumor. Malignant paragangliomas with invasion of the cervical lymph nodes and carotid artery have been reported, but the presence of metastasis, rather than the histological findings, is the only parameter for classifying them as malignant tumors. Despite the numerous descriptions of the efficacy of radiation therapy, the histological findings of irradiated specimens have shown little effect of radiation therapy on the chief cells. The only curative therapy for intravagal paragangliomas is the total resection of the tumor. Using the supra-adventitia dissection plane, we were able to achieve total resections in four cases of complex intravagal paraganglioma. The surgical management of these cases was complex because of the following: 1) misdiagnosis as a carotid body tumor, 2) previous radiation therapy and surgical procedure, 3) association with glomus jugulare, and 4) a giant tumor with invasion of the temporal bone and encasement of the internal carotid artery. We report the surgical management of intravagal paragangliomas and the role of radiation therapy, hormonal secretion, and rehabilitation care.

The transcondylar approach to extradural nonneoplastic lesions of the craniovertebral junction.

Ventral extradural lesions at the craniovertebral junction are commonly exposed through the transoral or transmaxillary approach. The disadvantages of these approaches include: 1) difficulty in reaching laterally located lesions; 2) ineligibility of patients with an intradental distance of less than 25 mm or severe macroglossia; 3) the need for a separate procedure for stabilization and fusion; and 4) the risk of infection from transgressing a contaminated field. In this report, the authors describe the use of the transcondylar approach to extradural nonneoplastic lesions of the anterior craniovertebral junction for decompression and stabilization. Advantages of this approach include: 1) a short distance to the lesion; 2) a wide surgical envelope; 3) direct visualization of the dural sac, eliminating manipulation of the brainstem or upper spinal cord; 4) easy identification and control of the ipsilateral vertebral artery; 5) direct visualization and preservation of the lower cranial nerves; and 6) a sterile field. In addition, occipitocervical fusion and instrumentation can be performed during the same procedure. The transcondylar approach, based on anatomical studies in cadavers, was used to treat eight patients with ventral nonneoplastic lesions at the craniocervical junction. The technique and results are described.

Paracoccidioidomycosis of the central nervous system: CT findings.

A retrospective analysis of six cases of central nervous system paracoccidioidomycosis, all but one proven by biopsy and surgery, was carried out to study the CT and clinical data and pathological correlation. Most of the patients were from the country. Headache, vomiting, seizures and hemiparesis were the most frequent symptoms. Papilloedema was present in four patients with raised intracranial pressure. Five patients had chronic lung disease and two with advanced systemic disease, skin and mucous membrane lesions were also observed. The neurological disturbance was sometimes the presenting features and the diagnosis was discovered incidentally after surgery. Both solitary and multiple parenchymal lesions were observed and the cerebral hemispheres were more commonly involved in four patients. Local meningeal involvement was observed in one with a single cortical granuloma. We emphasise the usefulness of CT, showing a rounded or lobulated mass with an isodense or radiolucent centre after contrast enhancement, surrounded by an irregular wall of varying thickness. There was always moderate oedema, extending peripherally. Other infections or neoplastic diseases may present similar findings. Preoperative diagnosis should rest on integration of clinical data, chest films, laboratory and neuroimaging studies.