Anterior communicating artery aneurysm rupture and functional outcome in short-term: clipping versus coiling.

Our research aims to assess the change in the grade of responsiveness using the Hunt and Hess score as well as the modified ranking scale in patients suffering from anterior communicating artery rupture. We retrospectively analyzed data from 11-patients who suffered from an anterior communicating artery aneurysm rupture that caused a subarachnoid hemorrhage. Severity was assessed using the Hunt and Hess scale grade and modified ranking scale. Anterior communicating artery rupture caused a subarachnoid hemorrhage in 40.81% of all aneurysm ruptures that took place at the Circle of Willis. Unfortunately, 4-patients deceased (3.4%) at a median age of 52-years (range 34-75-years), three of which deceased after coiling and one after clipping. In 71-patients (61.2%) endovascular coiling was performed - 33-males and 38-females - and in the remaining 45-cases, (38.8%) clipping was indicated - 24-males and 21-females. Overall, the pre-interventional median Hunt and Hess scale was 2, which remained after the intervention. When relating the outcome score to the intervention performed, we found that the Hunt and Hess scale score was 3 before coiling and 2 before clipping, whereas afterward, there was a slight increase to 2 and 2, respectively. The modified ranking scale was 2 after clipping, respectively, coiling (P = 0.218). No significant differences were observed between the different groups. Our results show that clipping is as effective as coiling in terms of the Hunt and Hess scale and the rate of mortality in the short-term.

Miyazaki syndrome: Cervical myelo/radiculopathy caused by overshunting. A systematic review.

OBJECTIVES: Miyazaki syndrome is a cervical myelopathy or radiculopathy caused by cervical epidural venous congestion, due to cerebrospinal fluid over-drainage by an implanted ventricular shunt. The complex pathophysiology includes CSF pressure-changes consistent with the Monro-Kellie doctrine and a non-functional Starling resistor, leading to spinal epidural venous plexus enlargement and dilation. This venous congestion may be significant enough to exert compression on the spinal cord or nerve roots. The typical clinical and imaging findings together with a history of ventricular CSF shunting may establish the diagnosis, proven by a successful treatment. The aim of treatment is the abrogation of CSF over-drainage. The eligible interventions may be the followings: the increase of the opening-pressure of the valve system by the insertion of a new programmable valve if necessary, closing or removing the shunt. AIM: We want to call attention to this rare iatrogenic condition with potentially severe consequences. PATIENTS AND METHODS: We perform a systematic literature-review and present our five cases. RESULTS: Once recognized in time, Miyazaki syndrome can be well taken care of. CONCLUSIONS: Patients with chronic ventricular shunt need monitoring for CSF over-drainage to recognise potential complications such as cervical myelopathy or radiculopathy.

Minimally invasive spine surgery: systematic review.

Minimally invasive procedures in spine surgery have undergone significant development in recent times. These procedures have the common aim of avoiding biomechanical complications associated with some traditional destructive methods and improving efficacy. These new techniques prevent damage to crucial posterior stabilizers and preserve the structural integrity and stability of the spine. The wide variety of reported minimally invasive methods for different pathologies necessitates a systematic classification. In the present review, authors first provide a classification system of minimally invasive techniques based on the location of the pathologic lesion to be treated, to help the surgeon in selecting the appropriate procedure. Minimally invasive techniques are then described in detail, including technical features, advantages, complications, and clinical outcomes, based on available literature.

Para-split laminotomy: a rescue technique for split laminotomy approach in exploring intramedullary midline located pathologies.

OBJECTIVE: Conventional posterior approaches, which may involve multilevel laminectomies and facetectomies, may lead to spinal deformities, instability, and subluxation. We developed the multilevel spinous process splitting and distraction laminotomy technique, which is an option for approaching midline intramedullary spinal pathologies with preservation of mechanically relevant bone and muscle structures. In some cases, midline splitting is not feasible or convenient because of anatomical differences of spinous processes and laminas. Our objective was to develop a minimally invasive rescue approach technique that makes it possible to remove intramedullary lesions but does not increase the risk of damage to the crucial posterior stabilizers of the spine. METHODS: We used the para-split laminotomy technique for opening the spinal canal not in the midline but rather in the parasagittal plane. The technique can be combined with the basic split laminotomy technique. This novel technique was used in five adult patients with midline intramedullary pathologies of the cervical and cervicothoracic spine. RESULTS: The operating field under the microscope was sufficient for tumor removal according to the keyhole concept. The approach used did not affect the extent of resection or neurologic outcome. The average number of split laminae was 6 (range: 3-10). Average follow-up was 18 months (range: 13-36 months). Histologic results were as follows: two ependymomas, two astrocytomas, and one primitive neuroectodermal tumor (PNET). To confirm the extension of resection, all patients underwent postoperative magnetic resonance imaging evaluations. The resections were complete in the cases of two ependymomas, subtotal in one astrocytoma, and partial in the other astrocytoma case and the PNET case. Computed tomography scans showed the extension of para-split approaches and the moderately disturbed bony structures. Instability was detected in none of the patients on the flexion-extension lateral radiographs during the follow-up period. CONCLUSION: The minimally invasive multilevel para-split laminotomy approach as a rescue technique for split laminotomy is a safe and effective surgical procedure, suitable for exploring different intramedullary pathologies located in the midline of the spinal canal. This modified surgical approach fulfills the requirements of other minimally invasive techniques and lowers the risk of damage to the crucial posterior stabilizers of the spine; furthermore, disintegration of the vertebral arches and facet joints is reduced.

Novel surgical approach in the management of longitudinal pathologies within the spinal canal: the split laminotomy and "archbone" technique: alternative to multilevel laminectomy or laminotomy.

Multilevel laminectomy to open the spinal canal carries the risk of spinal deformities and instability. With the aim of preserving and reconstructing the posterior structures the authors developed a novel, minimally invasive, multilevel spinous process splitting and distracting laminotomy approach with or without complementary corticocancellous iliac crest or PEEK cage "archbone" grafting. The technique allows exploration of the spinal canal and the removal of intramedullary pathologies. Moderate enlargement of the spinal canal with preservation of the majority of posterior structures is also possible, so that muscle attachments remain intact and postoperative complications are substantially reduced.This surgical approach, while fulfilling the requirements of previous laminotomy techniques, helps to prevent damage to the crucial posterior stabilizers of the spine. In contrast to conventional spinal canal approaches, preservation of the majority of posterior structures is possible, leaving muscle attachments on the spinous processes and laminae completely intact.Furthermore, the procedure for exposure and decompression of the spinal canal is a suitable method for all spinal segments, the cervical, thoracic, and the lumbar spine in all age groups.

Modified surgical approach to cervical neurinomas with intraforaminal components: minimal invasive facet joint sparing "open-tunnel" technique.

BACKGROUND: The conventional posterior approaches, which may involve multilevel laminectomies and facetectomies, may lead to spinal deformities, instability, or subluxation. Our objective was to develop a minimally invasive approach suitable for exploring neuromas with an intraforaminal component in the cervical spine, with the aim of preserving mechanically relevant bone structures and the facet joints as much as possible. METHODS: The authors used the hemi-semi-laminectomy combined with partial lateral facetectomy "open-tunnel" technique in nine adult patients with neuromas of the cervical spine extending into the foramen. RESULTS: The operating field under the operating microscope was sufficient for tumor removal according to the keyhole concept. The approach did not affect the extent of tumor resection or neurological outcome. Complete removal was achieved in all patients, as confirmed by magnetic resonance imaging (MRI). The affected nerve roots included C3 in three cases, C2 and C4 in two, and C5 and C6 in one case. Average follow-up was 12 months, with a range from 8 to 18 months. Histological results were as follows: six schwannomas and three neurofibromas. Computed tomographic scans demonstrated the extension of the keyhole approaches and the moderately affected bony structures and facet joints. Instability was detected in none of the patients on the flexion or extension lateral radiographs during the follow-up period. CONCLUSION: This modified surgical approach fulfills the requirements of other minimally invasive techniques and lowers the risk of damage to the crucial posterior stabilizers of the spine; furthermore, disintegration of vertebral arches and facet joints is reduced. The approach is suitable for exploring and removing neuromas located in the spinal canal and in the neuroforamen.

Split laminotomy and complementary spacer insertion for opening and enlargement of the thoracic spinal canal at infiltrative intramedullary tumor removal.

OBJECTIVE: The author main objective was to improve the previously developed technique of split laminotomy and moderate enlargement of the spinal canal with preservation of the majority of posterior structures, and to avoid the complications of the classic autologous bone grafting procedure. METHODS: A multilevel spinous process splitting and distracting laminotomy technique with complementary spacer insertion between the laminar parts was developed. We used Poly-Ether-Ether-Ketone (PEEK) cages. This improved method was used in five patients to remove malignant intramedullary tumors at the thoracic level. RESULTS: Adequate surgery of the tumors located intramedullary, and permanent decompression of the spinal canal was achieved in all patients using our new modified procedure. The results have been postoperatively confirmed with MRI and CT. The affected spine was the thoracic in all cases. The numbers of split laminae were three to five. Histological results were as follows: four intramedullary astrocytomas, one ependymoma. The ependymoma was completely, while the astrocytomas were only subtotally removed. In all cases heterologous grafts were inserted between the sides of the distracted laminas, to achieve the enlargement of the spinal canal. The mean duration of the whole surgical procedure was 118 minutes (range 91 to 145 minutes). The average follow-up was 11.2 months, with the range from five to 16 months. Upon postoperative neurological follow-up, no complications were revealed related to the newly developed procedure. The postoperative followup CT scans demonstrated bony healing, with a cage between the osteotomized faces. No compression or dislocation of the spacer was seen. Instability was not detected in any of the patients by flexion or extension lateral radiographs. CONCLUSION: This modification of the split laminotomy and heterologous grafting method fulfills the requirements of other laminotomy techniques. The split laminotomy is suitable for removing intramedullary tumors, and the posterior stabilizing structures of the spine, as the vertebral laminae and the longitudinal musculature are completely prevented. Due to use of allograft the complications of the classic hip bone grafting procedures are avoided. The spacers, inserted between the osteotomized faces, provided permanent decompression of the spinal canal, and bony healing--throughout the spacer--of the splitted vertebral laminae, without iliac graft complications.

[New minimally invasive surgical techniques in spinal surgery]. / Új mutéttechnikai eljárások a gerincsebészetben, különös tekintettel a minimálinvazivitásra.

The last decade has brought significant development in spine surgery. As in all field of surgery, introduction of the minimal invasive, atraumatic procedures characterized our activities. The number of short and long-time complications were significantly reduced and the effectiveness of operations were markedly improved by the new technical conditions, for example by the use of neuronavigation, surgical microscope, intraoperative fluoroscopy, high speed drill and the widespread of keyhole concept. The applied multislice CT imaging and the high resolution MRI enabled to improve the accuracy of the planned surgical procedures and to reduce the mortality and morbidity of operations. In our studies technical methods were investigated and new developments were established in the field of minimal invasive spine surgery. The National Institute of Neurosurgery's spinal surgical team pioneers further development and application of novel minimal invasive procedures. Applied methods of vanguard surgical procedures include split laminotomy, the "archbone" technique, the "over the top" decompression, the multilevel hemi-semi laminectomy, the supraforaminal "burr hole", the facet joint sparing "open tunnel" techniques or parasplit minimal invasive approaches. The new innovative surgical techniques are applied in our daily routine and meet international trends by utilizing benefits of minimal invasive spinal surgery. Using our newly developed innovative techniques allow to decompress neural elements in case of spinal canal stenosis and to remove the intramedullary and extramedullary space-occupying lesions located in the spinal canal and spreading extraspinally through the neuroforamen. These techniques are specially tailored to preserve structural integrity and stability of the spinal column, and allow at the same time to minimize resection of and injury to tissues not directly involved in the pathologic processes. In our studies a classification system of spatial localization of pathological lesions and processes in spinal canal was developed by us. Using this classification system enables the surgeon to select and apply the appropriate minimal invasive technique from dorsal direction and to remove the space-occupying lesions located in the spinal canal. The minimal invasive techniques were characterized and summarized. This overview of the minimal invasive techniques can be applied and recommended in the daily routine of spine surgery. We proudly employ novel surgical techniques having been developed in our institution. These techniques are internationally recognized and applied in our practice on daily basis as well.

Gliosarcoma of the pineal region with cerebellar metastasis: case illustration.

A very rare case of gliosarcoma of the pineal region with cerebellar metastasis is presented. A few cases of glioblastoma and fibrosarcoma have already been published however there was no reported case with gliosarcoma at the pineal region even with cerebellar metastases.

Dynamic changes of CB1-receptor expression in hippocampi of epileptic mice and humans.

The endocannabinoid system plays a central role in retrograde synaptic communication, and controls both glutamatergic and gamma-aminobutyric acid (GABA)ergic transmission via type 1 cannabinoid (CB1) receptor. Both in sclerotic human hippocampi and in the chronic phase of pilocarpine-induced epilepsy in mice with sclerosis, CB1-receptor-positive interneuron somata were preserved both in the dentate gyrus and in the CA1 area, and the density of CB1-immunostained fibers increased considerably in the dentate molecular layer. This suggests that, although CB1 receptors are known to be reduced in density on glutamatergic axons, the CB1-receptor-expressing GABAergic axons sprout, or there is an increase of CB1-receptor levels on these fibers. The changes of CB1 immunostaining in association with the GABAergic inhibitory system appear to correlate with the severity of pyramidal cell loss in the CA1 subfield. These results confirm the involvement of the endocannabinoid system associated with GABAergic transmission in human temporal lobe epilepsy (TLE), as well as in the chronic phase of the pilocarpine model in mice. Pharmacotherapy aimed at the modulation of endocannabinoid-mediated retrograde synaptic signaling should take into account the opposite change in CB1-receptor expression observed on glutamatergic versus GABAergic axon terminals.

Loss and reorganization of calretinin-containing interneurons in the epileptic human hippocampus.

Calretinin is expressed mainly in interneurons that specialize to innervate either principal cell dendrites or other interneurons in the human hippocampus. Calretinin-containing cells were shown to be vulnerable in animal models of ischaemia and epilepsy. In the human hippocampus, controversial data were published regarding their sensitivity in epilepsy. Therefore we aimed to reveal the fate of this cell type in human epileptic hippocampi. Surgically removed hippocampi of patients with drug-resistant temporal lobe epileptic (n = 44) were examined and compared to control (n = 8) samples with different post-mortem delays. The samples were immunostained for calretinin and the changes in the distribution, density and synaptic target selectivity of calretinin-positive cells were analysed. Control samples with post-mortem delays longer than 8 h resulted in a reduced number of immunolabelled cells compared to controls with short post-mortem delay. The number of calretinin-positive cells in the epileptic tissue was considerably decreased in correlation with the severity of principal cell loss. Preserved cells had segmented and shortened dendrites. Electron microscopic examination revealed that in controls, 23% of the calretinin-positive interneuronal terminals targeted calretinin-positive dendrites, whereas in the epileptic samples it was reduced to 3-5%. The number of contacts between calretinin-positive dendrites also dropped. The present quantitative data suggest that calretinin-containing cells in the human hippocampus are highly vulnerable, thus inhibition mediated by dendritic inhibitory cells and their synchronization by interneuron-specific interneurons may be impaired in epilepsy. We hypothesize that reorganization of the interneuron-selective cells may be implicated in the occurrence of seizures in non-sclerotic patients, where the majority of principal and non-principal cells are preserved.

Exploration and decompression of the spinal canal using split laminotomy and its modification, the "archbone" technique.

OBJECTIVE: To develop a novel minimally invasive approach suitable for exploring different pathologies located in the spinal canal, allowing moderate enlargement of the canal with preservation of the majority of posterior structures so muscle attachments remain intact and postoperative complications are reduced. METHODS: The authors developed a multilevel spinous process splitting and distracting laminotomy technique with or without complementary corticocancellous iliac crest "archbone" autografting. Technical details are discussed. The multilevel spinous process splitting and distracting laminotomy technique with or without complementary iliac bone grafting was used in 19 patients with different pathologies of the spinal canal. RESULTS: Satisfactory surgery of the lesions located within the spinal canal, especially intramedullary, was achieved in all patients using this new approach. The affected area of the spine was cervical in seven patients, cervicothoracic in four patients, thoracic in five patients, and thoracolumbar in three patients. The average number of split laminae was three (range, 2-6). Histological results were as follows: seven intramedullary astrocytomas, eight ependymomas, two cavernous hemangiomas, one dural arteriovenous malformation, and one hemangioblastoma. Of the eight ependymomas, 75% were removed completely and 25% were partially removed. Of the seven astrocytomas, 28.7% were removed completely, 14.3% were removed subtotally, and 57% were partially removed. The cavernous hemangiomas and the hemangioblastoma were completely removed. The approach used did not affect the extent of resection or neurological outcome. The spinous processes were closed directly in 13; in six cases, a tricortical iliac bone graft was placed between the facing bony parts of the spinous processes. The mean duration of splitting and distracting the spinous process was 16 minutes (range, 11-28 min) for the first process and 8 minutes (range, 5-14 min) for each additional spinous process. The mean duration of the whole surgical procedure, including intraspinal surgery, was 159 minutes (range, 90-290 min). The mean blood loss was 158 ml (range, 48-442 ml). The average length of hospital stay was 7.2 days. The average follow-up period was 15.4 months. Fifty-one of the 57 (89.5%) spinous process computed tomographic scans demonstrated bony healing with or without a graft between the osteotomized faces. Of the 57 spinous process computed tomographic scans, fracture of the spinous process was seen in nine (15.8%) and traumatic bony changes of the body of the vertebra in the midline in three (5.2%); these were without clinical significance and they later showed complete healing. CONCLUSION: This surgical approach fulfills the requirements of other laminotomy techniques and helps prevent damage to the crucial posterior stabilizers of the spine. In contrast to conventional spinal canal approaches, preservation of the majority of posterior structures leaves muscle attachments on the spinous processes and laminae completely intact. Furthermore, the technique for exposure and decompression of the spinal canal is a suitable method for all spinal segments, the cervical, thoracic, and the lumbar spine in all age groups.

[Removal of intraspinal space-occupying lesions through unilateral partial approach, the "hemi-semi laminectomy"]. / A gerinccsatornában elhelyezkedo térfoglaló folyamatok eltávolítása féloldali parciális feltárásból, a "hemi-semi laminectomia".

OBJECTIVE: The conventional dorsal surgical approaches used in removal of intraspinal space-occupying lesions by unroofing the spinal canal, often result the destruction of dorsal bony structures, sacrifice the interspinosus/supraspinosus ligament complexes and stripping of the paraspinal muscles causing a pathologic biomechanical milieu may lead to spinal deformities, instability. Various less invasive techniques exist to save the integrity and to prevent the instability of the spinal column and allow removal of intraspinally located space-occupying lesions at the same time. The authors discuss the experiences with unilateral partial laminectomy approach in removal of intraspinally, mainly lateral, intra- or extradurally located pathologic lesions. METHODS: The unilateral partial laminectomy, in which the laminas were preserved (hemi-semi laminectomy) was performed in 86 symptomatic patients to remove space-occupying intra- or extradurally located lesions of the cervical, thoracic and lumbar spinal canal. Symptoms were local or radicular pain, motor, sensory and vegetative disturbances. RESULTS: Adequate surgery of the lesions located within the spinal canal was achieved in all patients using this approach. The hemi-semi laminectomy was performed at one spinal level in 68 patients, two levels in 15 and three levels in 3. The affected spine was the cervical in 16, the cervico-thoracic in 6, the thoracic in 35, the thoraco-lumbar in 10 and lumbar region in 19 cases. Histological results were as follows: 32 intradural meningiomas, 27 neurinomas, 10 ependymomas, 3 arachnoid cysts, 2 cavernomas and extradurally 4 epidural haemorrhage, 5 epidural abscesses and 3 dural vascular malformations. CONCLUSION: The unilateral partial laminectomy (named hemi-semi laminectomy) approach for the mainly laterally located intra- or extradural lesions, confined to one side, allow to minimize resection of and injury to tissues not directly involved in the pathologic process, while affording a safe and thorough removal of space-occupying pathologies and decompression of neural structures located in a spinal canal. Two additional advantages come from this technique in cases of misjudged level or at re-operation.

Downregulation of the CB1 cannabinoid receptor and related molecular elements of the endocannabinoid system in epileptic human hippocampus.

Endocannabinoid signaling is a key regulator of synaptic neurotransmission throughout the brain. Compelling evidence shows that its perturbation leads to development of epileptic seizures, thus indicating that endocannabinoids play an intrinsic protective role in suppressing pathologic neuronal excitability. To elucidate whether long-term reorganization of endocannabinoid signaling occurs in epileptic patients, we performed comparative expression profiling along with quantitative electron microscopic analysis in control (postmortem samples from subjects with no signs of neurological disorders) and epileptic (surgically removed from patients with intractable temporal lobe epilepsy) hippocampal tissue. Quantitative PCR measurements revealed that CB(1) cannabinoid receptor mRNA was downregulated to one-third of its control value in epileptic hippocampus. Likewise, the cannabinoid receptor-interacting protein-1a mRNA was decreased, whereas 1b isoform levels were unaltered. Expression of diacylglycerol lipase-alpha, an enzyme responsible for 2-arachidonoylglycerol synthesis, was also reduced by approximately 60%, whereas its related beta isoform levels were unchanged. Expression level of N-acyl-phosphatidylethanolamine-hydrolyzing phospholipase D and fatty acid amide hydrolase, metabolic enzymes of anandamide, and 2-arachidonoylglycerol's degrading enzyme monoacylglycerol lipase did not change. The density of CB(1) immunolabeling was also decreased in epileptic hippocampus, predominantly in the dentate gyrus, where quantitative electron microscopic analysis did not reveal changes in the ratio of CB(1)-positive GABAergic boutons, but uncovered robust reduction in the fraction of CB(1)-positive glutamatergic axon terminals. These findings show that a neuroprotective machinery involving endocannabinoids is impaired in epileptic human hippocampus and imply that downregulation of CB(1) receptors and related molecular components of the endocannabinoid system may facilitate the deleterious effects of increased network excitability.

Properties of in vivo interictal spike generation in the human subiculum.

A large proportion of hippocampal afferents and efferents are relayed through the subiculum. It is also thought to be a key structure in the generation and maintenance of epileptic activity; rhythmic interictal-like discharges were recorded in previous studies of subicular slices excised from temporal lobe epilepsy patients. In order to investigate if and how the subiculum is involved in the generation of epileptic discharges in vivo, subicular and lateral temporal lobe electrical activity were recorded under anesthesia in 11 drug-resistant epilepsy patients undergoing temporal lobectomy. Based on laminar field potential gradient, current source density, multiple unit activity (MUA) and spectral analyses, two types of interictal spikes were distinguished in the subiculum. The more frequently occurring spike started with an initial excitatory current (current source density sink) in the pyramidal cell layer associated with increased MUA in the same location, followed by later inhibitory currents (current source density source) and decreased MUA. In the other spike type, the initial excitation was confined to the apical dendritic region and it was associated with a less-prominent increase in MUA. Interictal spikes were highly synchronized at spatially distinct locations of the subiculum. Laminar data showed that the peak of the initial excitation occurred within 0-4 ms at subicular sites separated by 6 mm at the anterior-posterior axis. In addition, initial spike peak amplitudes were highly correlated in most recordings. A subset of subicular and temporal lobe spikes were also highly synchronous, in one case the subicular spikes reliably preceded the temporal lobe discharges. Our results indicate that multiple spike generator mechanisms exist in the human epileptic subiculum suggesting a complex network interplay between medial and lateral temporal structures during interictal epileptic activity. The observed widespread intra-subicular synchrony may reflect both of its intrinsic and extrinsically triggered activity supporting the hypothesis that subiculum may also play an active role in the distribution of epileptiform activity to other brain regions. Limited data suggest that subiculum might even play a pacemaker role in the generation of paroxysmal discharges.

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.

Water dissection technique of Toth for opening neurosurgical cleavage planes.

BACKGROUND: The low-pressure water dissection technique of Toth, first reported in 1987, is a method to cautiously open neurosurgical cleavage planes such as the sylvian fissure or the interhemispheric space, and the interfaces between extraparenchymal masses and the adjacent brain. The aim of this technical report is to present our long-term experience with this simple and elegant asset of microneurosurgery and to promote its widespread use. METHOD: Water is injected under microscopic control by a hand-held syringe with a blunt needle or by an irrigating balloon applying repeated injections of physiological saline into the cleavage plane to open it. FINDINGS AND CONCLUSION: The water dissection technique of Toth has been extensively used in Budapest and Helsinki in thousands of microsurgical cases, in removal of meningiomas and to open sylvian and interhemispheric fissure. In our experience, there have been no noticeable complications, and we recommend this technique for widespread use. It is a very inexpensive, simple, and effective method not requiring any expensive or complicated devices.

[Surgical treatment of epilepsy]. / Az epilepszia mutéti kezelése.

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.

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.