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Biomedical subjects

J Zentner

Publications and source records attributed to J Zentner.

At least 73 records · Page 4Linked to original sources
PubMed1996

Head injuries from bicycle accidents.

This study comprises a total of 159 victims from bicycle accidents treated as inpatients at the Department of Neurosurgery, University of Bonn between January 1987 and June 1995. It was our aim to define the severity and features of bicycle-related head injuries in a defined population. Our results show that 33% of admitted bicycle victims sustained severe head injuries (Glasgow Coma Score 3-8). Neurosurgical operations were performed in 49% of patients and were mainly related to the evacuation of an extracerebral hematoma. Of the 159 bicycle victims, 112 (70%) made a good recovery, 11 (7%) remained moderately and 4 (3%) severely disabled, and 26 (16%) had died at follow-up (mean 2 years). In conclusion, our data indicate that bicycle-related trauma accounts for a substantial proportion of all head injuries requiring neurosurgical treatment. Active (e.g. traffic regulations, education of riders) and passive measures (e.g. safety helmets) can be expected to reduce both incidence and severity of head injuries among bicyclists.

Accidents, Traffic↗
PubMed1996

Subarachnoid hemorrhage of unknown etiology.

During a 10-year-period, 80 of 510 (16%) patients with primary subarachnoid hemorrhage (SAH) had negative angiographic studies. On admission, 70 of 80 patients (88%) were in grades I-II according to Hunt and Hess, 9 (11%) in grade III, and 1 (1%) in grade IV. The most frequent CT feature was preponderance of subarachnoid blood in the peripontine cistern as observed in 35 of 51 cases (69%) in whom blood was visible on CT. During hospitalization, 3 patients (4%) rebled, and 3 others (4%) had an infarction. However, in all of these complicated cases maximum hemorrhage was outside the peripontine cistern. Outcome after hospitalization as assessed by the Glasgow-Outcome-Scale (GOS) was favorable (GOS 1 and 2) in all patients who had maximum blood in the peripontine cistern, but only in 62% showing preponderance of blood outside the peripontine cistern, and 4 of them (25%) had died (GOS 5). These differences are statistically significant (p < 0.001). Long-term outcome of 56 patients as graded according to the Activities of Daily Living (ADL) system was favorable in 88% of cases with peripontine hemorrhage who returned to normal activities (ADL 1). At the same time, another patient with diffuse hemorrhage had died. Thus, overall mortality was 8.9% at a mean observation time of 5.5 years. In conclusion, SAH of unknown etiology generally has a good prognosis, although a nonneglegible percentage of patients have persistent minor side-effects. In our experience, maximum blood in the peripontine cistern particularly indicates a favorable outcome, since all patients with this CT pattern survived in a good condition.

Adult↗
PubMed1996

Surgical treatment of extratemporal epilepsy: clinical, radiologic, and histopathologic findings in 60 patients.

PURPOSE AND METHODS: The aim of this study was to analyze clinical, radiologic, and histopathologic findings in 60 consecutive patients with medically intractable extratemporal epilepsy who were operated on between November 1987 and May 1993. RESULTS: Histologically, there were distinct structural abnormalities in 50 (83%) of the surgical specimens. Signal abnormalities on magnetic resonance imaging (MRI) were present in all patients with neoplastic lesions (n = 17) and in 94% of patients with nonneoplastic focal lesions (n = 32). Overall, structural abnormalities were detected by MRI in 47 (96%) of 49 patients with focal lesions. During a mean follow-up of 4 years, 30 (54%) patients remained completely seizure free, 11 (20%) had < or = 2 seizures per year, seven (12%) showed a seizure reduction of > or = 75%, and eight (14%) had < 75% reduction in seizure frequency. The fraction of seizure-free patients was 12 (80%) of 15 in patients with neoplastic lesions, 16 (52%) of 31 in patients with nonneoplastic focal lesions, and two (20%) of 10 for those without histopathologic abnormalities. The differences in seizure outcome between patients with and without focal lesions were statistically significant (p < 0.05), if seizure-free outcome was compared with persistent seizures. CONCLUSIONS: Focal lesions and particularly neoplasms are associated with improved postoperative seizure control compared with patients without histopathologic abnormalities. We advise caution in considering surgery to treat extratemporal epilepsy in patients who have normal MRI scans, because the outcome with the approach described in this study is poor in such cases.

Adolescent↗
PubMed1996

Clinical, radiological, and therapeutic features of pleomorphic xanthoastrocytoma: report of three patients and review of the literature.

Two out of three patients with pleomorphic xanthoastrocytoma were initially misdiagnosed and correctly interpreted only at tumour recurrence, with progression to malignancy in one. The third patient presented with a remarkably long history of epilepsy. Pleomorphic xanthoastrocytoma is a low grade astrocytoma that is still confused with other tumours. Because pleomorphic xanthoastrocytoma can become malignant even after many years of benign behaviour, a long term follow up is necessary.

Adolescent↗
PubMed1996

Intrinsic tumors of the insula: a prospective surgical study of 30 patients.

Intrinsic insular tumors are frequently excluded from surgical treatment. The authors propose a more extensive approach to these lesions based on the results of this prospective series. From September 1993 to January 1995, 30 patients (18 males and 12 females; mean age 42 years) harboring benign (15 patients) or malignant (15 patients) tumors involving the insula underwent surgical treatment. The dominant and nondominant hemispheres were both affected in 15 cases. Two groups were defined on the basis of preoperative magnetic resonance (MR) imaging: 14 lesions were restricted to the insula and the corresponding opercula; the other 16 lesions also involved other mesocortical and/or allocortical areas. Most patients displayed only mild preoperative symptoms. The median score according to the Karnofsky performance scale was 90. Microsurgical removal was achieved via a transsylvian approach in nine cases and via a frontal and/or temporal approach in 21 cases. According to early postoperative MR imaging, complete tumor removal (100%) was seen in five patients, nearly complete (> 80%) in 21, and incomplete resection (50%-80%) in four patients. There was no operative mortality; 19 patients (63%) experienced immediate postoperative morbidity, including reduced performance. After a mean follow-up review of 8.5 months two of 21 patients suffered permanent deficits, accounting for an overall operative morbidity of 10%. At the mean time of review, three patients with Grade IV tumors had died of tumor recurrence. The authors conclude that low-grade intrinsic insular tumors, as well as Grade III tumors, can be removed with favorable results in the majority of patients. Surgery to excise glioblastomas should only be considered for patients with good preoperative performance and young age.

Adult↗
PubMed1996

Functional results after resective procedures involving the supplementary motor area.

In this article, the authors report their experience with surgically induced supplementary motor area (SMA) deficiency syndrome in a prospective clinical trial of 28 patients who underwent surgery for tumorous (19 patients) or nontumorous (nine patients) lesions. The dominant side was affected in 17 patients and the nondominant side in 11 patients. The primary presenting symptoms included seizure activity (23 patients), hemiparesis (four patients), and aphasia (one patient). Functional topographic mapping, achieved by phase reversal of somatosensory evoked potentials, allowed precise localization of the central sulcus in 25 of the 28 patients. Motor evoked potential (MEP) monitoring, which was performed successfully in 13 of 15 cases during the resective procedure, showed no significant changes in the potentials in any patient. Immediately after surgery, 25 (89%) of the 28 patients displayed additional neurological deficits (aphasia and/or hemiparesis) that depended on the extent of the SMA resection. In 12 patients the SMA was resected completely: nine of these patients demonstrated a complete and three an incomplete deficit. In 16 patients the SMA resection was incomplete: 13 of these patients displayed an incomplete deficit, whereas three had no deficit. Neurological disorders resolved completely within 3 to 42 days (mean 11 days), except for a minimal disturbance of fine motor and/or speech function in complex tasks or at high speed. Electromagnetically elicited MEPs, examined postoperatively in five patients, were initially absent but recovered with improvement of motor function. In conclusion, although the SMA is known to control important functions such as initiation of motor activity or speech, our findings show that unilateral SMA removal can be accomplished without resulting in significant permanent deficits. Functional topographic mapping and monitoring facilitate the exact delineation of the adequate resection plane along the precentral sulcus, and postoperative magnetic resonance imaging allows precise correlation of clinical and anatomical data.

Adolescent↗
PubMed1995

Subclassification of presynaptic 5-HT autoreceptors in the human cerebral cortex as 5-HT1D receptors.

Human cerebral cortical synaptosomes were used to determine the 5-hydroxytryptamine (5-HT) receptor subtype to which the inhibitory presynaptic 5-HT autoreceptor belongs. The synaptosomes preincubated with [3H]5-HT were superfused and tritium overflow was stimulated by high K+. The K(+)-evoked tritium overflow, which was Ca(2+)-dependent but tetrodotoxin-resistant, was concentration-dependently inhibited by the nonselective 5-HT 1D alpha/1D beta receptor agonist, 5-carboxamidotryptamine. Ketanserin at a concentration which should block the 5-HT 1D alpha but not the 5-HT 1D beta receptor failed to antagonize the inhibitory effect of 5-carboxamidotryptamine. In contrast, the nonselective 5-HT 1D alpha/1D beta receptor antagonist, methiothepin, at a concentration which should block both the 5-HT 1D alpha and the 5-HT 1D beta receptor abolished the effect of 5-carboxamidotryptamine. It is concluded that the presynaptic 5-HT autoreceptor, which has previously been classified as 5-HT 1D, belongs to the 5-HT1D beta subtype.

Adult↗
PubMed1995

Antibiotic prophylaxis in cerebrospinal fluid shunting: a prospective randomized trial in 129 patients.

The efficacy of a single dose of cefotiam, a cephalosporin of the second generation, as prophylaxis for postoperative infection was analyzed in a prospective randomized study of 129 patients undergoing cerebrospinal fluid shunting. The main focus of interest was the rate of shunt infection requiring operative shunt removal. Data were evaluated in the total group and subgroups formed for normal and high risk patients, respectively. The overall rate of shunt infection was 7.5% in the cefotiam group and 12.9% in the control group. In the high risk subgroup infection rate was 14.3% with and 26.3% without cefotiam as opposed to 4.3% and 6.9%, respectively, in the normal risk subgroup. Although our results do not reach statistical significance, there is a noticeable difference of infection rate between those patients who receive the antibiotic and those who do not. Therefore, we favor single dose antibiotic prophylaxis in shunting procedures.

Adolescent↗
PubMed1995

Percutaneous needle trephination for external CSF drainage: experience with 226 punctures.

We report on our experience with 226 percutaneous needle trephinations in a total of 192 consecutive patients. Trephination was performed with a hand-driven drill. A special puncture needle was inserted into the anterior horn of the lateral ventricle. The main indication for this procedure was the treatment of occlusive hydrocephalus in an emergency. Duration of drainage ranged from 1 to 34 days and was 7 days on the average. We encountered 14 cases of infection (6.2%) and one case of symptomatic bleeding (0.4%). All these complications eventually resolved without permanent sequelae. In our opinion, ventricle puncture with this device is a simple and effective method and can especially be recommended for external CSF drainage in cases of emergency.

Adolescent↗
PubMed1995

The clinical and prognostic relevance of the postictal slow focus in the electrocorticogram.

Electrocorticograms of 192 complex partial seizures which were recorded via chronically implanted subdural electrodes during presurgical evaluation of 64 patients with medically intractable epilepsy were visually analysed. The objective was to assess the diagnostic and prognostic relevance of postictal slow foci (PISF) in the electrocorticogram which were defined as focal isoelectric activity or as a focal burst-suppression pattern. The following results were obtained: (1) PISF were seen in a total of 114 of 192 seizures (59.4%), (2) 48 of 64 patients (75%) demonstrated at least 1 PISF in 3 seizures, (3) PISF were more frequent in seizures of temporal lobe origin (66%) than in those of extratemporal origin (33.3%), (4) no PISF developed if the electrographic seizure duration was < 32 sec, (5) PISF were (predominantly) localized in the lobe of seizure origin in 85% of the seizures, (6) there was a strong correlation between frequent occurrence of temporal PISF and favourable seizure outcome following temporal lobe surgery. In conclusion, PISF contribute valuable data as to the localization of the epileptogenic zone during presurgical evaluation of epilepsy and indicate favourable seizure outcome following temporal lobe surgery.

Adolescent↗
PubMed1995

Surgical treatment of temporal lobe epilepsy: clinical, radiological, and histopathological findings in 178 patients.

The surgical treatment of pharmacoresistant temporal lobe epilepsy is increasing rapidly. The correlation of preoperative MRI, histopathological findings, and postoperative seizure control is reported for 178 patients with chronic medically intractable temporal lobe epilepsy who were operated on between November 1987 and January 1993. Histopathologically there were distinct structural abnormalities in 97.2% of the surgical specimens. Signal abnormalities on MRI were present in 98.7% of patients with neoplastic lesions (n = 79), 76.6% of patients with non-neoplastic focal lesions (n = 55), and 69.2% of patients with Ammon's horn sclerosis (n = 39). Overall, structural abnormalities were detected by MRI in 82.7% of all patients. The mean postoperative follow up period was three years. Some 92% of the patients benefited from surgery: 103 patients (61.7%) were seizure free, 26 (15.5%) had no more than two seizures a year, and 24 (14.4%) showed a reduction of seizure frequency of at least 75%. Fourteen patients (8.4%) had a < 75% reduction of seizure frequency. The percentage of patients who were completely free of seizures after operation was 68.5% for patients with neoplastic lesions, 66.7% for Ammon's horn sclerosis, and 54.0% for patients with non-neoplastic focal lesions. By contrast, none of the patients in whom histopathological findings were normal became seizure free postoperatively. The data show that the presence of focal lesions or Ammon's horn sclerosis as determined by histopathological examination is associated with improved postoperative seizure control compared with patients without specific pathological findings. Brain MRI was very sensitive in detecting neoplasms; however, its sensitivity and specificity were limited with respect to non-neoplastic focal lesions and Ammon's horn sclerosis. Improvement of imaging techniques may provide a more precise definition of structural lesions in these cases and facilitate limited surgical resections of the epileptogenic area rather than standardised anatomical resections.

Adolescent↗
PubMed1995

Spinal epidural lipomatosis as a complication of prolonged corticosteroid therapy.

We present the case of a 42-year-old man who complained of low back pain radiating into the posterior aspect of both thighs. There were no neurological deficits, while general medical examination revealed a Cushing's syndrome due to corticosteroid therapy for rheumatic polyarthritis. Myelography showed irregular and circumferential narrowing of the dural sac from L-3 to S-1 caused by abundant epidural fat as demonstrated by MRI. Surgical decompression produced immediate relief of symptoms. The literature of epidural spinal lipomatosis is reviewed and therapeutic considerations are discussed.

Adrenal Cortex Hormones↗
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

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

Increased GABA release in the human brain cortex as a potential pathogenetic basis of hyperosmolar diabetic coma.

Human cerebral cortical slices preincubated with [3H]GABA, [3H]noradrenaline, or 5-[3H]hydroxytryptamine and superfused with Krebs solution or Mg(2+)-free Krebs solution were used to investigate the influence of increased D-glucose concentrations on the release of these [3H]-neurotransmitters evoked by high K+ content or NMDA receptor activation, respectively. An increase in level of D-glucose (normal content, 11.1 mM) by 32, 60, and/or 100 mM (a range characteristic for hyperosmolar diabetic coma) increased the [3H]GABA release and inhibited the [3H]noradrenaline release evoked by both methods of stimulation. The K(+)-induced 5-[3H]hydroxytryptamine release was also inhibited by high D-glucose content. Blockade of GABAB receptors by p-(3-aminopropyl)-p-diethoxymethylphosphinic acid (CGP 35348) attenuated the inhibitory effect of high D-glucose content on the K(+)-evoked release of [3H]noradrenaline and 5-[3H]hydroxytryptamine, suggesting that the effect on monoamine release is, at least to a major part, the result of the increased GABA release and, as a consequence, of an increased GABA concentration at inhibitory GABAB receptors. The membrane-impermeable sorbitol mimicked the increasing effect of D-glucose on [3H]GABA release and its inhibitory effect on 5-[3H]hydroxytryptamine release. However, dimethyl sulfoxide, which is known to permeate rapidly through biological membranes, had no effect at concentrations equiosmolar to D-glucose. It is concluded that a reduction in brain cell volume caused by increased extracellular, compared with cytoplasmic, osmolarity is crucial for the changes in neuronal function observed at high D-glucose and sorbitol content.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
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↗