摘要:

Summary:Foramen magnum (FM) meningiomas are reviewed from our personal experience of 37 cases over 12 years and a cooperative study done in 1993 in which patients were collected from 21 French departments of neurosurgery over the period 1982–1992. FM meningiomas account for 6.5% of posterior fossa meningiomas and 1.5% of all intracranial meningeal tumors. Historical background and clinical features are presented first. Then reported are the histological and radiological data. Finally, the surgical technique is described, detailing postoperative clinical condition and extent of resection. Important specific points are emphasized: (a) the limits of what is defined as the FM area, which is generally not described in the literature; (b) the high frequency (56%) of psamommatous tumors; and (c) the great value of magnetic resonance imaging (MRI) and angio-MRI in defining the localization regarding the dura (14% of FM meningiomas have an extradural extension), the vertebral artery (48% of FM meningiomas are developed above the vertebral artery), and the anteroposterior location (31% of FM meningiomas are anterior and 56% are lateral). These points are fundamental to choosing the best surgical technique. The technique always includes drilling of the FM lateral wall according to tumor localization, thus providing lateral access to the premedullary spaces. This lateral approach can be posterolateral (a lateral extension of the standard midline approach mainly used to excise intradural tumors) or anterolateral (applied in the excision of extradural tumors). The lateral approach is currently the technique that permits the most complete resection (96%) with minimal mortality and morbidity.

ISSN:1050-6438    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Summary:The posterior fossa is a common site of occurrence of astrocytic tumors in the pediatric population. The two distinct subgroups comprising these tumors are cerebellar astrocytomas and brainstem gliomas. The cerebellar astrocytoma commonly presents with signs and symptoms of increased intracranial pressure. These tumors are generally amenable to total surgical resection, and carry an excellent prognosis. Brainstem gliomas are a heterogeneous group of tumors of which the diffuse pontine glioma is the most common. These tumors are inevitably glioblastoma multiforme, and carry a dismal prognosis. In recent years, subgroups of brainstem tumors have been identified, which are more focal in nature, are of a more benign histology, and carry a better prognosis. These tumors may be amenable to surgical resection.

ISSN:1050-6438    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Summary:Tethered cord syndrome (TCS) is a clinical-neurological condition caused by an abnormally low conus medullaris, frequently defined as a malformative sequence of a dysraphic pathology. Clinical onset generally occurs in early childhood; adult onset is rare, accounting for ˜6% of cases. In the adult form, a triggering factor plays a determining role in the onset of symptoms. The clinical and neuroradiological features of this syndrome are discussed together with surgical outcome, pointing out the differences between the two age groups.

ISSN:1050-6438    

出版商:OVID    

年代:1995

数据来源: OVID

ISSN:1050-6438    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Summary:Intracranial arachnoid cysts have been found in 0.3% of computed tomography (CT) scans and in 0.1% of brain autopsy specimens, more often in children than in adults. Intracranial arachnoid cysts occur prevalently in males, on the left side, and in the temporal fossa. Their occasional association with other hereditary disorders suggests a genetic factor. The majority of temporal arachnoid cysts are of small size and remain so; large arachnoid cysts appear to exhibit a tendency to grow. Communication studies have suggested an inverse correlation between the size of the cyst and the extent of communication with surrounding cerebrospinal fluid (CSF) spaces. The small cysts, in particular, tend to be asymptomatic. Symptomatology may be aspecific, such as headache and epileptic seizures, or focal, including hemiparesis. Progressive symptoms of increased intracranial pressure may be the result of expansion of the cyst, intracystic hemorrhage progressing to subdural hemorrhage (especially with temporal fossa cysts), or obstructive hydrocephalus (associated with cysts at the posterior fossa and intraventricular locations). In children, the presenting symptoms are usually enlargement of the head, seizures, and developmental retardation. In the elderly, arachnoid cysts may present with the symptoms common to normal pressure hydrocephalus. On CT or magnetic resonance imaging (MRI) scans arachnoid cysts have a fluid content identical to CSF, and they are typically extraaxially located. Temporal fossa arachnoid cysts of medium size may show the typical straight-edged triangular or rectangular shape. Communication studies are recommended in the management of arachnoid cysts at the less frequent locations. Intraaxial cysts containing CSF-like fluid, which are not of the ex vacuo type in our classification, may be arachnoid or neuroepithelial cysts, and histological verification of biopsy specimens, including immunocytochemical studies and electron microscopy, may be required. Indications for treatment are the progression of symptoms, and the presence of severe functional disorders, such as hemiparesis, cranial nerve palsies, and endocrinological dysfunction. In children, enlargement of the head and the space-occupying nature of the cyst, which interferes with brain development, may be considered indications for intervention. As to the less specific symptoms of headache and seizures, surgical treatment appears to achieve amelioration in the majority of patients, although seizures may occasionally remain unchanged or even deteriorate. There is considerable controversy as to the primary intervention of choice: shunting or craniotomy with fenestration or excision of the cyst wall. In the presence of hydrocephalus, shunting should involve both the cyst and the ventricular system, using an interconnected shunt. Follow-up of treated patients may include sequential scans because improvement appears to parallel morphological normalization.

ISSN:1050-6438    

出版商:OVID    

年代:1995

数据来源: OVID

ISSN:1050-6438    

出版商:OVID    

年代:1995

数据来源: OVID

ISSN:1050-6438    

出版商:OVID    

年代:1995

数据来源: OVID

ISSN:1050-6438    

出版商:OVID    

年代:1995

数据来源: OVID

ISSN:1050-6438    

出版商:OVID    

年代:1995

数据来源: OVID