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J Schramm

Publications and source records attributed to J Schramm.

At least 181 records · Page 10Linked to original sources
PubMed1994

Ganglioglioma: a detailed histopathological and immunohistochemical analysis of 61 cases.

Gangliogliomas are tumors composed of intimately admixed neuronal and glial components and account for approximately 1% of all brain tumors. Here we report the histopathological findings in 61 gangliogliomas. Epilepsy was the most common presenting symptom. Most gangliogliomas were located in the temporal lobes (74%). Thirteen percent of the gangliogliomas were associated with glioneuronal hamartias. There was considerable variation in neuronal size and density, presence of binucleated neurons, calcifications, desmoplasia, lymphocytic infiltrate, pilocytic differentiation, Rosenthal fibers, location, or histological uniformity. Fifteen percent of the gangliogliomas contained areas of purely astrocytic differentiation. All tumors were examined immunohistochemically for an aberrant p53 tumor suppressor gene product and for the presence of nuclear antigens associated with cell proliferation (Ki-67, Ki-S1, proliferating cell nuclear antigen). In 45 of 61 cases (74%) labeling indices for Ki-67 were less than 1%. Nuclear labeling for Ki-67 was observed exclusively in the astrocytic component. Gangliogliomas with very large neurons had higher Ki-67 labeling indices and occurred in younger patients than gangliogliomas with small- or intermediate-sized neurons. None of the tumors had an aberrant expression of p53. The observations suggest that gangliogliomas may arise from glioneuronal hamartias through neoplastic transformation of the astrocytic component.

Adolescent↗
PubMed1994

Hippocampal loss of the GABAA receptor alpha 1 subunit in patients with chronic pharmacoresistant epilepsies.

Alterations of gamma aminobutyric acid (GABA)-mediated neurotransmission have been implicated in the pathogenesis of epilepsies. Here we examine the distribution of the GABAA receptor in the hippocampus of 78 surgical specimens from patients with chronic pharmacoresistant focal epilepsies. The receptor was localized immunohistochemically with the monoclonal antibody bd-24 which selectively recognizes the alpha 1 subunit of the GABAA receptor. The results were compared with the receptor distribution of 28 normal hippocampal specimens obtained at autopsy. In the great majority of the surgical specimens a loss of GABAA receptor immunoreactivity was present in CA1 (92.3%), CA4 (78.2%), the dentate granular cell layer (70.5%) and the molecular layer of the dentate gyrus (65.4%). The subiculum revealed a normal staining pattern in all but 4 cases. In no instance did we observe an increase of immunoreactivity in any region or cell population. The decrease of GABAA receptor immunoreactivity was closely related to neuronal loss in the respective specimen and to Ammon's horn sclerosis. There was no correlation between GABAA receptor loss and the patient's age at surgery, duration of seizures, age at onset of seizures and to the presence or absence of secondary generalized tonic clonic seizures. The data suggest that the observed loss of GABAA receptor immunoreactivity is a secondary phenomenon rather than an event that is relevant for the pathogenesis of epileptic seizures.

Adolescent↗
PubMed1994

Subdural and depth electrodes in the presurgical evaluation of epilepsy.

From 1987 to 1992, invasive EEG studies using subdural strips, grids or depth electrodes were performed in a total of 160 patients with medically intractable epilepsy, in whom scalp EEG was insufficient to localize the epileptogenic focus. Dependent on the individual requirements, these different electrode types were used alone or in combination. Multiple strip electrodes with 4 to 16 contacts were implanted in 157 cases through burrholes, grids with up to 64 contacts in 15 cases via boneflaps, and intrahippocampal depth electrodes in 36 cases using stereotactic procedures. In every case, localization of the electrodes with respect to brain structures was controlled by CT scan and MRI. Visual and computerized analysis of extra-operative recordings allowed the localization of a resectable epileptogenic focus in 143 patients (89%), who subsequently were referred for surgery, whereas surgery had to be denied to 17 patients (11%). We did not encounter any permanent morbidity or mortality in our series. In our experience, EEG-monitoring with chronically implanted electrodes is a feasible technique which contributes essentially to the exact localization of the epileptogenic focus, since it allows nearly artefact-free recording of the ictal and interictal activity. Moreover, grid electrodes can be used for extra-operative functional topographic mapping of eloquent brain areas.

Adolescent↗
PubMed1994

Intraoperative SEP monitoring in aneurysm surgery.

Somatosensory evoked potentials (SEP) were monitored during surgical treatment of 282 aneurysms in 226 patients. Significant SEP changes were found in 32 aneurysms (11.3%) mainly referring to accidental or intentional vessel occlusion. Response to these changes included reapplication of aneurysm clips, repositioning of retractors, or removal of temporary clips as followed in 23 cases (8.1%). Stable SEP signals allowed the surgeon to proceed with the surgical course and coincided in all but 2 cases (0.7%) with an uneventful outcome. Despite the limitations of SEP monitoring in certain anatomical locations, it has been found to be helpful in the operative management of some cases such as multilobed aneurysms, giant aneurysms, trapping procedures, and procedures requiring temporary vessel occlusion.

Adolescent↗
PubMed1994

Anaplastic ganglioglioma: case report and review of the literature.

We present the case of a 13-year-old boy who had a 12 year history of complex partial seizures. Recent CT scan and Magnetic Resonance Imaging (MRI) showed a contrast-enhancing lesion of the left temporal lobe, while CT performed 6 years ago was unconspicuous. Extended lesionectomy was performed according to the results of presurgical epileptological evaluation. Histological examination of the specimen showed an anaplastic ganglioglioma (WHO grade III). The clinical, neuroradiological, and histopathological findings of our patient are presented with respect to the literature on malignant gangliogliomas.

Adolescent↗
PubMed1994

Gangliogliomas: clinical, radiological, and histopathological findings in 51 patients.

Clinical, radiological, and histopathological features of 51 surgically treated gangliogliomas were evaluated retrospectively. The most common presenting symptoms were epileptic seizures (47 patients (92%)). Focal neurological deficits occurred in 8% of the patients. The duration of symptoms at the time of operation ranged from three months to 45 years, mean 11 years. The temporal lobe was affected in 43 patients (84%), the frontal lobe in five patients (10%), and the occipital lobe in one patient (2%). Two of the tumours (4%) were localised infratentorially. On MRI, solid tumour parts usually showed a pronounced signal increase on proton density images and a less pronounced signal increase on T2 weighted images, whereas solid components were mainly isointense on T1 weighted images. Contrast enhancement was noted in 16 of 36 patients (44%). Cystic tumour parts were found in 23 of 40 patients (57%), all characterised by signal increase on T2 weighted images and decreased T1 signals. Signal deviation of cystic tumour parts on proton density images was variable. Computed tomography was performed in 17 patients and showed hypodense lesions in 10 (59%), and calcifications in seven (41%) cases. Surgery included complete tumour removal in 44 patients (86%) and partial resection in seven (14%). In six patients (12%) there were transient postoperative complications. One patient (2%) died postoperatively due to pulmonary embolism. Histopathological examination of the surgical specimens showed low grade gangliogliomas in 49 cases (96%) and anaplastic gangliogliomas in two (4%). Control MRI of 31 patients with a mean follow up period of 16 months was uneventful in all but one case of an anaplastic ganglioglioma. In all patients in whom the ganglioglioma was associated with medically intractable seizures the operation resulted in complete relief of seizures or a noticeable improvement of the epilepsy.

Adolescent↗
PubMed1994

[Morphological findings in temporal lobe epilepsy: experience with 216 consecutive surgical specimens].

We have examined 216 consecutive surgical specimens of patients with chronic pharmacoresistant temporal lobe epilepsy. Neoplasms were detected in 75 cases (34.7%). All but two of these tumors were of low histopathological grade (WHO-grade I or II). There were 34 gangliogliomas, 17 pilocytic astrocytomas, 9 oligodendrogliomas, 6 fibrillary astrocytomas, and 6 dysembryoplastic neuroepithelial tumors. Fifty-one specimens contained non-neoplastic focal lesions and an additional 13 cases had both tumors and non-neoplastic focal lesions within the same specimen. The most frequent non-neoplastic focal lesions were microscopic glioneuronal hamartias (32 cases), glioneuronal hamartomas (7 cases) and vascular malformations (13 cases). The hippocampal formation was structurally well preserved in 71 specimens and in 51 of these (71.8%) there was Ammon's horn sclerosis. The findings document that intractable temporal lobe epilepsy is associated with significant structural alterations in the great majority of patients.

Brain Neoplasms↗
PubMed1993

Effects of four intravenous anesthetic agents on motor evoked potentials elicited by magnetic transcranial stimulation.

The influence of four intravenous anesthetic agents on motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (magnetic MEP) was examined in 77 subjects. The patients were anesthetized by a continuous intravenous infusion of one of the following anesthetic agents: propofol, etomidate, methohexital, or thiopental. Comparable anesthetic effects among the four agents were achieved by computing an infusion scheme for each drug. Infusion rates were increased slowly in a step-wise manner in order to reach minimal anesthetic blood concentrations within 15 minutes. During anesthesia induction, magnetic MEPs were recorded every 2 minutes from the abductor pollicis brevis muscle. The patient's level of consciousness was assessed and documented in the alternating minutes. A dose-related reduction of the MEP amplitudes was seen in all drug groups, while the latencies remained constant. Reduction of the amplitude was occasionally so prominent that the MEP was completely abolished before adequate anesthesia was achieved. MEPs were obtainable at the end of anesthesia induction in 14% of the propofol group (n = 22), 57% of the etomidate group (n = 21), 53% of the methohexital group (n = 19), and 20% of the thiopental group (n = 15). Propofol and thiopental showed significantly stronger suppression of MEP, when compared to etomidate (both P < 0.01) and to methohexital (P = 0.01 and 0.05, respectively). Etomidate was the least detrimental anesthetic agent for intraoperative monitoring of magnetic MEP. Nonetheless, the low incidence of 57% of preserved MEP in subjects without motor deficits indicated the inadequacy of this technique for intraoperative monitoring. More effective transcranial stimulation techniques are required for successful intraoperative MEP monitoring.

Adult↗
PubMed1993

Surgical pathology of chronic epileptic seizure disorders: experience with 63 specimens from extratemporal corticectomies, lobectomies and functional hemispherectomies.

The surgical treatment of chronic pharmacoresistant epilepsies is increasing rapidly. Although several studies have reported on histopathological findings in temporal lobe epilepsy, little is known about the surgical pathology of other seizure disorders. Here we report the histopathological findings in 63 consecutive surgical specimens of patients who were operated for chronic pharmacoresistant epileptic seizures other than temporal lobe epilepsy (37 corticectomies, 19 functional hemispherectomies, 5 lobectomies, 1 multilobectomy, and 1 frontal lobe deafferentiation combined with a temporal lobectomy). There were structural lesions in 85.7% of the specimens. In 16 cases (25.4%) the predominant lesions were malformative (focal glioneuronal hamartias and hamartomas, vascular malformations, abundant ectopic neurons in the white matter, microgyria, and arachnoid cyst). Lesions indicating pre- or perinatal necrosis such as porencephaly, ulegyria, and congenital hemiatrophy were present in 7 cases (11.1%). Twelve specimens (19.0%) contained low-grade neoplasms (7 gangliogliomas, 3 astrocytomas, 1 oligodendroglioma and 1 oligoastrocytoma). There were 3 cases of Rasmussen encephalitis, 1 specimen with atrophy and gliosis due to previous herpetic encephalitis and 1 case with an old abscess wall. Posttraumatic or postoperative changes were the predominant finding in 7 specimens (11.1%). In 7 patients there were only nonspecific changes such as cortical atrophy and gliosis or old hemorrhage. No structural alterations were identified in 9 specimens (14.3%). The findings suggest that the structural lesions observed in the great majority of the specimens were closely related to the pathogenesis of intractable seizures.

Adolescent↗
PubMed1993

Outcome and management of intraoperative aneurysm rupture.

The incidence of intraoperative aneurysm rupture (IAR) was studied in a consecutive personal series of 222 patients operated on for a ruptured intracranial aneurysm. In 77 patients subjected to early surgery (operation within 72 h after rupture) IAR was 40.2% and in 145 patients with surgery after 72 h IAR was 20.7%. The mortality and severe morbidity (GOS grade 4 and 5) were 2.6% in the early surgery group, 7.6% in the late surgery group, and 5.85% in the total series despite the fact that there was a significantly higher incidence of IAR in the early surgery group. Aneurysms arising from the anterior cerebral artery (ACA) or anterior communicating artery (ACoA) appeared more prone to IAR--36.9 versus 18.6 and 23.2%--than aneurysms at other locations. There was no correlation between incidence of IAR and preoperative Hunt and Hess grade [8]. IAR affected final outcome only when it occurred prematurely during introduction of anesthesia or during opening of the dura. In conclusion, although IAR occurs more frequently when surgery is undertaken in the early stage after rupture, this complication is in experienced hands not necessarily associated with an increased risk for an unfavorable outcome.

Aneurysm, Ruptured↗
PubMed1993

Surgical pathology of temporal lobe epilepsy. Experience with 216 cases.

The surgical treatment of chronic epilepsies is increasing rapidly. Here we report the histopathologic findings in 216 consecutive surgical specimens of patients with chronic pharmacoresistant temporal lobe epilepsy. In 75 cases (34.7%) there were tumors, all but two of which were of low histopathological grade (WHO grade I or II). The most common tumors were gangliogliomas (34 cases), pilocytic astrocytomas (17 cases), oligodendrogliomas (9 cases), fibrillary astrocytomas (6 cases), and dysembryoplastic neuroepithelial tumors (6 cases). There were 51 cases with non-neoplastic focal lesions and an additional 13 cases with tumors and non-neoplastic focal lesions within the same specimen. The most frequent non-neoplastic focal lesions were microscopic glioneuronal hamartias (32 cases), glioneuronal hamartomas (7 cases), and vascular malformations (13 cases). The hippocampal formation was structurally well preserved in 71 specimens. In 51 of these (71.8%) there was Ammon's horn sclerosis. Presurgical placement of depth electrodes was invariably associated with circumscribed defects of the brain parenchyma. The implantation of subdural electrodes was sometimes followed by chronic inflammatory changes of the leptomeninges. Our findings indicate that in the majority of patients with medically intractable temporal lobe epilepsy there are significant histopathologic findings, many of which are only rarely encountered otherwise.

Adolescent↗
PubMed1993

Modification of cortical stimulation for motor evoked potentials under general anesthesia: technical description.

This pilot study presents a possible modification of direct cortical electrical stimulation technique for the recording of motor evoked potentials under general anesthesia. The exposed primary motor cortex was stimulated by a short train of anodal rectangular pulses at high frequency (300-500 Hz), while the compound muscle action potentials were recorded from the forearm and hand muscles. When compared with the traditional way of eliciting movement of the extremities by applying a train of pulses at lower frequency (50-60 Hz), muscle responses were obtainable at an intensity of much lower charge. It is suggested that this stimulation achieves a repetitive activation of the corticomotoneuronal tract. Responses could be continuously recorded throughout surgery and seemed to respond to surgical manipulation affecting the motor pathways. This technique seems to be applicable for intraoperative monitoring of motor pathways but requires further optimization of stimulation and recording parameters before wider clinical applications are possible.

Anesthesia, General↗
PubMed1993

Complete removal of an oculomotor nerve neurinoma without permanent functional deficit. Case report.

A case of complete operative removal of a neurinoma of the oculomotor nerve with long-time preservation of oculomotor function despite minor signs of aberrant reinnervation is presented. A review of the literature referring to the clinical appearance, radiological features, treatment, and outcome of 22 cases is given, 18 of which involved operations. To our knowledge, this is the first case to prove that complete operative removal of an oculomotor neurinoma without relevant persisting neurological sequelae is possible.

Aged↗