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A Valavanis

Publications and source records attributed to A Valavanis.

At least 73 records · Page 4Linked to original sources
PubMed1993

Surgical therapy of glomus vagale tumors.

Lying between the carotid bifurcation and the jugular foramen, glomus vagale tumors share characteristics with paragangliomas of those two structures, such as invasion of the carotid artery, destruction of the skull base, and cranial neuropathies. This capability for local invasion provides a therapeutic challenge with regard to the proper assessment of tumor extent and the selection of appropriate treatment. In order to clarify an approach to the management of glomus vagale tumors, we reviewed a 10-year experience with 15 patients treated for this tumor at the University of Zürich Department of Otolaryngology, using a new system of classification. This system highlights the relative position of a vagal paraganglioma to the jugular foramen and is helpful in designing the proper therapy. Pitfalis in surgical technique, recommended preoperative evaluation, and the roles of balloon occlusion and irradiation in the treatment of these tumors, are discussed.

Journal Article↗
PubMed1993

[Magnetic resonance imaging in neuroradiology. Indications and applications].

On the basis of own experience with 250 MR-Angiographies and with reference to the literature the authors report on the role MR-Angiography is assuming in neuroradiological diagnostic procedures. As a noninvasive method MR-Angiography contributes to the evaluation of vessel stenosis and occlusion, venous sinus thrombosis and neurovascular compression syndromes. It supports the work-up of space-occupying lesions, as well as arteriovenous malformations and aneurysms. In addition to the diagnosis, follow-up examinations serve as a noninvasive means of therapy control particularly after interventional endovascular procedures. Knowledge of the diagnostic capabilities and limitations, the choice of the correct examination technique and modification of technical variables contribute to establish MR-Angiography as a valuable adjunct to MR imaging.

Aneurysm↗
PubMed1992

[Neuroradiology of the spinal cord].

In recent years MR has assumed a central and key role in neuroradiological evaluation of the spinal cord. Because of its noninvasiveness and high sensitivity in the detection of intramedullary lesions, it represents the method of choice today for the work-up of acute, chronic and traumatic myelopathies. The main limiting factor of MR is its rather low specificity. For this reason the clinical history as well as the neurological and laboratory findings continue to be of major importance in arriving at a definite diagnosis. The method is contraindicated in patients with pacemakers or other intracorporeal paramagnetic devices. It is relatively contraindicated in claustrophobic patients. In these cases MR should be replaced by myelography or CT-myelography. For the diagnosis of vascular diseases of the spinal cord, specifically vascular malformations and hypervascular tumors (e.g. hemangioblastoma), selective spinal angiography represents an essential adjunct to MR. Selective angiography can also be used therapeutically to treat preoperatively or definitely vascular malformations (i.e. interventional neuroradiology).

Angiography↗
PubMed1992

Central neurocytoma: histopathological variants and therapeutic approaches.

The central neurocytoma has recently been added to the differential diagnosis of intraventricular tumors. Histopathologically, this tumor is characterized by a uniform neoplastic cell population with features of neuronal differentiation. Central neurocytomas occur in young adults, develop in the area of the foramen of Monro, and are usually associated with the septum pellucidum. Initial reports appeared to indicate that these tumors are benign lesions with a favorable postoperative prognosis. The authors present clinical and neuropathological findings in a series of eight patients with central neurocytoma. An anterior transcallosal microneurosurgical approach yielded good outcomes. Postoperative radiation therapy was restricted to two patients with a malignant variant of central neurocytoma and one patient with a recurrent tumor. Observations of anaplastic variants of this neoplasm in two cases and local tumor recurrences in three indicate that the biological behavior and postoperative prognosis of central neurocytoma may not always be as favorable as previously assumed.

Adult↗
PubMed1991

Neuroradiology of central neurocytoma.

Central neurocytomas (CN) are rare, usually benign cerebral intraventricular neuroepithelial tumors, which occur in adult patients. Retrospective evaluation of the CT- and MRI-findings in eight cases as well as review of the cases reported in the literature showed that CN usually presents as a primarily slightly hyperdense and/or hyperintense mass within the body of the lateral ventricle with moderate contrast enhancement. The majority of tumors contain both multiple small cysts and calcifications and exhibit a characteristic broad based attachment to the superolateral ventricular wall. We conclude that these criteria appear to be reliable to exclude other intraventricular tumors such as astrocytoma, giant cell astrocytoma, ependymoma, subependymoma, intraventricular oligodendroglioma and meningioma. Preoperative diagnosis of CN may prove of value for planning therapy, because this tumor type seems to have a better prognosis than other intraventricular tumors.

Adult↗
PubMed1991

[Neuroradiologic exploration of cerebral arteriovenous malformations].

MR and superselective neuroangiographic investigation of 223 patients with cerebral arteriovenous malformations (AVMs) were retrospectively analyzed with regard to topography, morphology, vascular architecture and signs of increased bleeding risk. MR proved highly efficient in defining the topography of the lesion and highly sensitive in detecting AVM-induced parenchymal changes. Superselective neuroangiography enables complete endovascular mapping of the AVM and provides relevant information on its intrinsic vascular composition. In addition, this method gives new insights into the venous drainage patterns and the unexpectedly high incidence of associated venous changes. MR-neuroangiographic correlation in each individual case forms the basis for any therapeutic decision and treatment planning. In concordance with previous statements in the literature this study disclosed that the presence of stenotic draining veins or related aneurysms on feeding arteries represents an increased risk for AVM rupture.

Adolescent↗
PubMed1991

[MRT morphology and classification of cerebral cavernomas].

An MRI review of 54 histologically verified cavernomas allowed the introduction of a system classifying this cavernous venous malformation into four types: type I (20%) corresponds to the classic morphology of a cavernoma without hemorrhage; type II (67%) is characterized by intralesional hemorrhage; type III (11%) is associated with an extra-lesional hemorrhage that compresses or displaces the cavernoma itself; and type IV (2%) corresponds to a totally calcified cavernoma. These variable cavernoma types represent different possible stages of the natural evolution of a cavernoma and limit the differential diagnosis, especially in the group of occult or cryptic cerebral vascular malformations.

Adolescent↗
PubMed1990

[Injuries of the large brain-feeding arteries].

Among 2923 severely injured patients in the period 1980-1988, 17 had injuries or large supraaortic arteries. The incidence was 0.58%, with an overall mortality of 53%. In 75% of survivors there was a persistent neurological deficit. We treated 5 penetrating (A. carotis 4, A. vertebralis 1) and 12 nonpenetrating (A. carotis 11, A. vertebralis 1) injuries. In all penetrating carotid injuries (4) repair was performed on admission and mortality was 50%; 1 of 2 survivors has postoperative hemiparesis. Localization of nonpenetrating carotid injuries (11) was intrathoracic (2), in the neck (7) and intracranial (2). Main complication of nonpenetrating extracranial carotid injuries is neurological deficit (7/9) due to thrombosis (3) or stenosis (4) with embolism (2). Surgery was performed in 3 cases comprising pseudoaneurysm in 2 and concomitant aortic rupture in 1. Mortality was 44%, and 80% of survivors had persistent neurological deficits. Extracranial carotid injuries (n = 13) carried a mortality rate of 83% in occluded and 29% in nonoccluded vessels (p less than 0.05). Location of carotid injury in the neck (n = 11) carried a mortality of 55%, and intracranial (n = 2) of 100% respectively. Duplex-Doppler scanning of carotid arteries is a safe, noninvasive method which is essential in blunt carotid artery trauma. Prognosis is dependent upon the size of cerebral infarction. Once neurologic deficit has been established for more than 24 hours, reconstruction of the artery should be postponed and performed only for complications (pseudoaneurysm or embolization). Clamping of arteries without hypothermic circulatory arrest or shunt should be avoided. The danger of rupture in dissection and pseudoaneurysm is slight.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

MRI in Cockayne syndrome type I.

MRI findings are reported from two patients with Cockayne syndrome (CS) type I, aged 11 and 37 years. Changes were compatible with diffuse white matter hypomyelination. Basal ganglia calcification was present in both, marked cerebellar atrophy in the older patient. MRI may support the diagnosis of CS in the appropriate clinical context. The view that CS is a dysmyelinating disorder is further substantiated.

Adult↗
PubMed1989

Neurohypophyseal ectopy in growth hormone insufficiency.

Nuclear magnetic resonance imaging of the hypothalamohypophyseal tract allows the detection and identification of ectopic posterior pituitary lobe tissue by its characteristic high signal intensity. We found this anomaly in 2 boys with growth hormone insufficiency. Neurohypophyseal ectopy may be misdiagnosed as subhypothalamic tumor and such patients risk to be subjected to unnecessary neurosurgery.

Child↗
PubMed1989

The surgical management of extensive nasopharyngeal angiofibromas with the infratemporal fossa approach.

Large juvenile nasopharyngeal angiofibromas are a therapeutic challenge because of their relation to major vasculature and cranial nerves at the base of the skull, and their propensity for recurrence. A classification scheme based on the growth pattern of this tumor is proposed to help the surgeon choose a procedure to access this lesion. This report describes the results obtained with the surgical removal of large (class III and IV) nasopharyngeal angiofibromas through the infratemporal fossa approach. Fourteen patients were cured and one individual developed a recurrence which was totally removed at a second procedure. Surgical morbidity was minimal and there was no mortality. Radiation therapy was necessary in only one patient who had tumor infiltration of the cavernous sinus.

Adolescent↗
PubMed1989

Management of the internal carotid artery in surgery of the skull base.

Management of the internal carotid artery in skull-base surgery can be a difficult problem when disease involves this vessel or resection is anatomically limited by it. The recent radiologic development of the detachable balloon catheter has permitted occlusion of the internal carotid artery in a controlled setting prior to any surgical procedure. An obvious prerequisite to using this technique is the demonstration of adequate collateral blood flow to the brain. Patients are evaluated with arteriography and temporary arterial balloon occlusion while monitoring physical signs and electroencephalography (EEG). Although usually performed preoperatively, internal carotid artery occlusion is needed intraoperatively on occasion. This essential adjuvant technique for the skull-base surgeon will be detailed along with its indications and limitations in 24 patients.

Carotid Artery, Internal↗
PubMed1989

Intracranial abnormalities associated with facial plexiform neurofibromas in neurofibromatosis type 1.

From 1975 to 1988 seventeen patients with neurofibromatosis type 1 and a disfiguring facial plexiform neurofibroma (FPN) were investigated. The FPN was left-sided in 13 patients. It was orbital/periorbital in 4, lower facial in 7 and involved the whole face in 6 subjects. Neuroimaging (n = 13) revealed a tumor (of optic pathways or basal ganglia) in 8, an ipsilateral middle cranial fossa arachnoid cyst in 2, multiple areas of high signal intensity (in T2-weighted magnetic resonance imaging) in 1, and normal findings in 2 patients. In NF-1 patients with FPN there seems to be a high incidence of intracranial tumors and possibly of arachnoid cysts. Our observation has to be confirmed in a larger patient series.

Adolescent↗
PubMed1989

Neural tolerance of iotrolan 300 in ascending cervical myelography: results of a multicenter study.

This study examined the opacification, dose, and tolerance of iotrolan 300 on 231 patients in ascending cervical myelography. The contrast was rated good in 188 (81.4%) of the cases and satisfactory in 40 (17.3%) of the cases. The contrast was poor in only three (1.3%) cases. In 152 patients a dose of 10 ml or less of iotrolan 300 was administered. A good contrast quality was obtained in 84.2% of all examinations. From a total of 231 patients, 146 exhibited no concomitant effects. The intensity of the headache and neck ache was recorded by the patients themselves by means of an analog scale. The frequency and degree of the postmyelographic complaints did not increase with higher doses, i.e., they were not dose dependent. Neurologic irritation, in the form of radicular symptoms, appeared in only 2 of 231 examinations. These data demonstrate that iotrolan 300 is excellent for use in ascending cervical myelography.

Adult↗