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Biomedical subjects

J Vajda

Publications and source records attributed to J Vajda.

At least 37 records · Page 2Linked to original sources
PubMed1988

Contralateral approach to bilateral and ophthalmic aneurysms.

In a previous survey, we found a high incidence of fatal rupture of an unclipped aneurysm in patients with multiple aneurysms. To deal with this problem, we introduced a more vigorous technique that accesses aneurysms previously considered unapproachable during one operating session. Attempts were made to clip middle cerebral and ophthalmic aneurysms contralateral to the operative exposure. We have successfully clipped contralateral aneurysms of the posterior communicating artery when bilateral aneurysms were present. We have also used this contralateral approach successfully with single ophthalmic and proximal carotid aneurysms that pointed medially. We review the cases of 39 patients with 43 intracranial aneurysms operated from the contralateral side and present the surgical technique in relation to the angiographic findings.

Adult↗
PubMed1987

Investigation of trigeminal SEP with scalp and deep electrodes.

A special technique for stimulating and recording trigeminal somatosensory evoked potential (SEP) is described. Eleven healthy subjects and seven patients with chronically implanted deep electrodes have been investigated. Characteristic polyphasic waves were repeatedly observed. The recording of somatosensory evoked potential following trigeminal stimulation is a more difficult technique. This paper describes data in control subjects with scalp electrodes and data on patients with electrodes in the nucleus ventralis posteromedialis and cortical white matter. Depth recording may provide useful information about the origin, nature, and properties of trigeminal SEP.

Electrodes, Implanted↗
PubMed1987

Plasticity of the brain in respect of functional restoration after subarachnoid haemorrhage.

Subarachnoid haemorrhage caused by aneurysmal rupture constitutes a great impact on the brain and on the intracranial content as a whole, with emphasis on the subarachnoid spaces and arteries. The rupture is followed by a wide range of pathological alterations in the neural function and an outcome varying from neglected signs subsiding in a few days to immediate death. Two main factors seem to influence the different events after subarachnoid bleeding. One is the rupture itself which can be extremely variable in severity and in its immediate as well as late consequences. The other is the ability of all parts of the intracranial content to recover. In order to understand either of both the other should also be looked at and both have to be dealt with if we are to treat patients with an aneurysmal rupture properly. For this reason a grading of rupture will be given in respect of some characteristic events in the light of neural restoration. Clearing of CSF, resolution of brain oedema, restoration of impaired CBF, absorption of cisternal and parenchymal haematoma are all of importance. The majority of lesions which developed after the rupture are not fatal or irreversible and even the neural tissue destroyed by the impact or late ischaemia can be functionally replaced. Possible methods of treatment for attaining this functional restoration will be discussed.

Animals↗
PubMed1987

Separation of the tumor and brain surface by "water jet" in cases of meningiomas.

In the surgery of meningiomas one of the most delicate problems is the separation of the tumor from the brain surface. The authors generally recommend microsurgery to preserve the brain surface anatomically and functionally. For this purpose we have developed a new surgical technique according to our concepts of tissue care. After excavating the tumor from inside the tumor brain surface was separated by repeated "water jets" into the tumor arachnoideal space. The "water jet" was produced by an ordinary bulb syringe. The front pressure of the jets was 300-1000 mm of water and the side pressure 100-300 mm of water. In the tumor-arachnoideal space the spreading water (phys. NaCl) separates the brain from the tumor with utmost care. We operated on 55 meningiomas of different types with the "water jet" technique. The immediate results were anatomically excellent. Intraoperative and postoperative acute and late edemas appeared only in a few cases. The functions of the nearby brain were generally preserved. The surgery was uneventful when the tumor surface was smooth and the tumor was spherical. When the tumor surface was uneven, one part of the tumor extended under the dura as a thin layer or the tumor was multilobulated with expanded vessels between the lobules, more microseparation was necessary. We compared the results of the "water jet" technique with the results of the "pre-water jet" series. The surgery with the "water jet" technique was much shorter and its results were better than those of microsurgery alone.

Brain↗
PubMed1986

Surgical treatment of multiple intracranial aneurysms.

Patients with multiple intracranial aneurysms present a great challenge to neurosurgical practice. The presence of one or more additional aneurysms, whether recognized or unrecognized, along with the source of the haemorrhage profoundly changes the outcome. It also alters the timing and strategy of surgery. In this study the experiences gained from 138 cases with a total of 317 aneurysms are discussed. The analysis of the clinical data, our results and the factors influencing the outcome suggest that the risk of clipping all aneurysms simultaneously are less than the risk of a rebleed from an untreated, previously silent sac even in the early postoperative period.

Adolescent↗
PubMed1986

The surgery of middle cerebral artery aneurysms.

Aneurysms of the middle cerebral bifurcation represent an interesting entity among intracranial saccular aneurysms. Their shape, size, situation, and in particular their relation to the middle cerebral trunk and its branches show wide variations. Topographical analysis of the angiograms offers a great deal of interest in planning surgery. Our experience with 289 patients with middle cerebral artery aneurysms operated on since 1977 are presented. Factors such as number of previous haemorrhages, timing of surgery, preoperative condition, major intraoperative bleeding or brain oedema and delayed postoperative deterioration play a major role in the outcome. Others such as severity of the subarachnoid bleed, age, size of the sac seem to have much less influence.

Adult↗
PubMed1985

Gangliosides in human chronic lymphocytic leukaemia.

Gangliosides were analysed by elaborated overpressured thin-layer chromatography (OPTLC) in 6 cell samples from 5 patients with chronic lymphocytic leukaemia (CLL) of B-cell origin, and 4 individual lymphocyte preparations from normal blood donors. The principal difference in the ganglioside profile between these two counterparts appears to be the presence of GD3 and the predominance of the less polar compounds (GM3, GM2, GM1) in CLL cells. Qualitatively, GD3 accounted for about 5.5% of the total CLL gangliosides, whereas it was not detectable in normal lymphocytes. Quantitatively, GM3 constituted more than 81% of the total CLL gangliosides, a proportion more than twice as high as that found in normal lymphocytes. Three other minor gangliosides were isolated from CLL cells; these were shown to be GM2 (trace amounts), GM1 (7.7%), and GD1 (4%). The expression of individual gangliosides varied greatly among the various CLL samples obtained from different patients, and even from the same patient, if examined at different times. No gangliosides were found in the supernatant collected from CLL cells subjected to a temperature shift (0 degrees C to 37 degrees C) or in the cell-free medium harvested from the CLL cells kept in overnight culture.

Aged↗
PubMed1985

The spread of somatosensory-evoked potentials within the nervous system.

Four thalamic and cortical recordings were carried out in 5 patients. The thalamic-evoked potentials were typical and revealed a triphasic complex, but their latencies showed a relatively high standard deviation. They could be divided into two groups according to their latencies, both of which had low SD. These data suggested that there could be two types of latency of thalamic SEP, because the 4 patients' body sizes were very similar. More detailed surface, cortical and depth recordings are needed to resolve these questions.

Afferent Pathways↗
PubMed1984

Late reopening of an interposed vein graft for EC/IC bypass.

The authors report a case of EC/IC bypass with venous interposition between the external carotid artery and the middle cerebral artery cortical branch without function in the first eight months after surgery but, after the reopening of the graft, very good revascularization of the brain could be seen. The possible causes are discussed.

Brain Ischemia↗
PubMed1984

Transoral surgery for craniocervical space-occupying processes.

Although the number of reports concerning the transoral approach to anteriorly placed lesions of the craniocervical junction are increasing, the development of this technique is still in its early stages. The indications and surgical methods vary widely, and there is much room for discussion of the technical details. Eight cases operated on via transoral surgery during the last 4 years are presented in support of the transoral approach to tumors in the craniocervical region.

Adenoma↗
PubMed1984

Surgical experiences with giant intracranial aneurysms.

A series of 35 patients with 36 giant aneurysms is presented. Thirteen patients presented following subarachnoid hemorrhage (SAH) and 22 with evidence of a space-occupying lesion without recent SAH. The preferred technique of temporary trapping of the aneurysm, evacuation of the contained thrombus, and occlusion of the neck by a suitable clip is described. The danger of attempted ligation in atheromatous vessels is stressed. Intraoperatively, blood pressure was adjusted to keep the general brain circulation within autoregulatory limits. Direct occlusion of the aneurysm was possible in over 80% of the cases. The mortality rate was 8% in 36 operations. Six percent of patients had a poor result. Considerable improvement in visual loss was evident in six of seven patients in whom this was a presenting feature, and in four of seven with disturbed eye movements.

Adolescent↗
PubMed1983

Distribution of vagus nerve fibres in the stomach wall.

The distribution of vagus nerve fibres and their connections with the intrinsic nerve elements and effector cells were studied following vagotomy at the cardia. Degenerated nerve fibres were found in all layers of the stomach wall 2 days after the operation. No regional difference was noted in the density of degenerated fibres. They could be subdivided into groups on the basis of their vesicle content. Fibres in synaptic junction with an intrinsic nerve cell or with its processes were rare. There were several degenerated fibres also in the inner muscle layer in connection with the smooth muscle cells. Two months after the operation 90-95% of the nerve fibres in the stomach wall remained intact, and several synapses could be observed. It was concluded that although the vagus nerve is indirectly coupled to the nerve elements of the myenteric plexus the intrinsic nerve cells are decisive for gastric functions.

Animals↗
PubMed1982

Dependency on bypass circulation: a case study.

In a case of consecutive occlusion of both internal carotid arteries bilateral STA-MCA anastomoses were established. Since a series of angiographic examinations were undertaken, dynamics and probable efficacy of both natural and artificial collateral circulations could be followed up in a two-year period. Objectively in the evaluation of anastomoses was enhanced by direct percutaneous STA-angiography (STAG), in order to delineate the vascular territory irrigated exclusively by the anastomosis. By demonstrating exactly the functional capacity of anastomoses in correlation with the clinical course, dependency on bypass circulation could be assessed.

Arterial Occlusive Diseases↗