Biomedical subjects

János Vajda

Publications and source records attributed to János Vajda.

6 recordsLinked to original sources

PubMed2005

Long-term outcome after temporal lobe surgery--prediction of late worsening of seizure control.

We analyzed possible predictors of late worsening of seizure control in 94 adult patients who had anterior temporal lobectomy (ATL) from the Epilepsy Center of the National Institute of Psychiatry and Neurology, Budapest between 1985 and 2001. We evaluated data regarding epilepsy, presurgical evaluation, pre- and postoperative EEG, structural imaging, histology and operative complications. The mean follow-up was 6.1 years (range: 2-17 years). The outcome was measured as Engel class, the time to the first seizure and the longest seizure free period. Multiple regression analysis was used to assess predictors. Seizure free outcome was achieved in 72% of the patients 1-year after surgery. Eighty-seven percent of them remained seizure free at the second year of follow-up, 74% at the fifth, and 67% at the tenth year of follow-up. After 2 years of follow-up improvement was present in 3%, worsening in 18% of the patients. Factors associated with long-term worsening were: postoperative ipsilateral EEG spikes over the resected side, preoperative bilateral interictal discharges, cortical dysplasia of Taylor's type, and ictal contralateral propagation. In these patients, even in seizure free state, therapy reduction might be inappropriate.

Adolescent↗

PubMed2004

[Surgical treatment of epilepsy].

In this article the possibilities, indications, methods and results of surgery in epilepsy are summarized in general with the Hungarian experience emphasized. Surgery may provide effective treatment in about 5-10% of the epileptic population. Surgical solution nowadays became an essential treatment in medial temporal epilepsy, if hippocampal sclerosis or other lesion is present, in therapy resistant lesional extratemporal epilepsies and in catastrophic childhood epilepsies if the epileptic disorder is restricted to one hemisphere (Rasmussen syndrome, hemimegalencephaly, Sturge-Weber disease and posttraumatic or postencephalitic hemispherial epilepsies). The algorithms of the presurgical evaluation and the current methods for study the pacemaker area, forbidden zones, and hemispherial functions are treated. The currently used type and techniques of surgery, such as lesionectomy, temporal lobe resections, hemispherotomy, callosotomy, multiple subpial transsections and their indications are described. The newest surgical approaches, as deep brain stimulation, vagal nerve stimulation, and irradiation techniques are also briefly touched. Lastly, we deal with prognostical factors of the surgical outcome, reasons of surgical failures and complications. In a brief chapter the importance of postsurgical rehabilitation is emphasized.

Algorithms↗

PubMed2004

In vivo laminar electrophysiology co-registered with histology in the hippocampus of patients with temporal lobe epilepsy.

Laminar multiple microelectrodes have been developed to sample cortical and hippocampal activity in animals. If these measurements are adequately co-registered with the anatomy of the region, they can yield important information about its function and structure. In vivo laminar electrophysiological recordings from the human epileptic hippocampus are rare. However, histological and immunohistochemical analyses are widely used to determine the structural changes associated with temporal lobe epilepsy (TLE). Here we present data obtained by a combined approach: intraoperative recording of laminar field potentials, single and multiple unit activity under anesthesia, accompanied by histology and immunohistochemistry from the same hippocampal region of epileptic patients undergoing temporal lobectomy for drug-resistant TLE. The stability of the electrophysiology and the accuracy of its co-registration with histology were tested successfully. We have found large field potential spikes associated with bursting single units in CA1. Intracortical and subdural strip recordings from the lateral temporal cortex showed similar field potential activation patterns. A prominent oscillatory activity was present in the dentate gyrus with highly localized field potential gradient and multiple unit activity. This pattern could be used as a landmark defining the position of the electrode in the hippocampus. Our findings indicate that some aspects of the local and network epileptiform activity in the hippocampal formation are likely preserved under anesthesia. Electrophysiological identification of the functional state of the hippocampus together with its local structural correlates could further enhance our understanding of this disease.

Action Potentials↗

PubMed2003

[Epilepsy surgery in childhood: theory and practice].

1-1.5% of the Hungarian child population has epilepsy, and around 20% of them produces seizures in spite of modern antiepileptic drugs. A part of the pharmaco-resistant children may benefit from surgical removal of the epileptogenic focus. Presurgical evaluation has been developed a lot since the progress of neuroimaging, video-EEG monitoring, neuropsychology, and neurosurgical techniques in the 1990s. Authors summarize the important steps of presurgical evaluation in epileptic children emphasizing the role of history taking, physical examination, neuroimaging, standard EEG, long term monitoring, and neuropsychology. They describe the surgical treatment of the most important epilepsy syndromes in childhood analyzing the data of 58 epileptic children examined in the Bethesda Children's Hospital and operated in the National Institute of Neurosurgery (Budapest, Hungary). Age of children at surgery was between 16 months and 18 years, dysplasia and benign tumors covered etiology in 59% of the cases. The most frequent intervention was resection; however also some callosotomies and hemispherotomies were completed. Authors emphasize the importance of early surgical intervention of therapy resistant children in order to prevent the deteriorating effects of epilepsy on childhood psychomotor development.

Adolescent↗

PubMed2003

Split laminotomy in pediatric neurosurgery.

TECHNIQUE: A novel technique of multilevel opening of the spinal canal is introduced into pediatric neurosurgery. Split laminotomy helps to preserve the spinal column integrity in cases of posterior exposure of the spinal canal. The spinal processes are cut in the midline and the laminae are separated and retracted while the lesion in the spinal canal is explored. At closure the lamina are simply sutured. RESULTS AND DISCUSSION: Excellent postoperative results were obtained in patients from different age groups. Pediatric peculiarities of the new method are discussed.

Child↗

PubMed2003

Surgery of ventral intradural midline cervical spinal pathologies via anterior cervical approach: our experience.

INTRODUCTION: The surgical removal of the cervical intradural pathologies located ventrally carries a high risk. According to the anatomical situation and the increasing experience with anterior cervical approach and corpectomy revealed the reality to remove the ventral midline pathologies this way. The anterior approach which require corpectomy preferable to cervical intradural lesions located ventrally at the midline. In the literature have described anterior approach for intradural cervical lesions in very limited cases. CASE: The authors present five cases of intradural ventral cervical spinal pathologies, where removal was done via anterior cervical approach with corpectomy. Two of the cases were intradural meningeomas, one intramedullary cavernoma, one ventral arachnoid cyst and one malignant neurogenic tumour. The approach was described elsewhere. The corpectomy gave a relatively wide window to explore the pathologies and under operative microscope the local control of removal was fairly well. After the total removal of tumours and cavernoma, and fenestration of arachnoid cyst to the subarachnoid space watertight dural closure was made and the cervical spine was stabilized with autolog iliac bone graft, plate and screws. The recovery of the patients was well and there were no postoperative complications. CONCLUSIONS: The anterior cervical approach with corpectomy seems to be a real and safe way to explore and remove the cervical ventral midline pathologies. Postoperative MRI has a great value in early control after the surgery and for follow up the patients.

Adult↗