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Biomedical subjects

H G Eder

Publications and source records attributed to H G Eder.

17 recordsLinked to original sources
PubMed2003

Ventriculopleural shunt: thoracoscopic placement of the distal catheter.

Ventriculopleural shunting is usually reserved for patients with limited options for shunt revisions. We report the case of a 16-year-old boy with posthemorrhagic hydrocephalus who required numerous shunt procedures. At the age of 6 years, a ventriculopleural shunt was inserted by an intercostal thoracotomy, and 4 years later replacement of the distal catheter was necessary. Recently, he presented again with a shunt malfunction due to migration of the pleural catheter. We describe a technique for performing the placement of the distal catheter under direct thoracoscopic vision by a peel-off needle into the unscarred thoracic cavity despite two previous pleural procedures. The postoperative course was uneventful. Thoracoscopic assistance in ventriculopleural shunt placement appears to be a safe and effective technique, offering several advantages over the open procedure: it is less invasive, allows a precise positioning of the thoracic catheter under visual control, and confirms appropriate function.

Adolescent↗
PubMed2002

Gamma-Knife radiosurgery of mesiotemporal tumour epilepsy observations and long-term results.

PURPOSE: The efficacy of radiosurgery in cases of mesiotemporal tumours associated with long standing epilepsy has not clearly been documented up to now. The authors present a retrospective analysis of 19 cases treated by Gamma-Knife radiosurgery (GKRS) for mesiotemporal tumour epilepsy. METHODS: Between 1992 and 1997 19 patients (12 male and 7 female) with a mean age of 31 years (5-72) and mesiotemporal tumour-induced epilepsy of a mean duration of 8.6 years (0.9-28) were treated by GKRS. All tumours were within the mesiotemporal structures and the pathohistology proven by biopsy or resective procedure revealed 15 (79%) low grade astrocytomas, 3 (16%) gangliogliomas and 1 (5%) cavernoma. Beside tumour control, the main aim of GKRS was alleviation of epilepsy by irradiating the presumed epileptic foci outside the tumour volume. The 50% isodose volumes surrounding the tumours measured a mean of 6.2 ccm (1.1-18 ccm). Doses given at marginal isodoses ranged from 12 to 30 Gy (mean 17.3 Gy). The outcome with respect to epileptic seizures was evaluated by the Engel classification. RESULTS: After a follow-up (FU) of 1.7 to 9.7 years (mean 6.5 years) 11 patients (57.9%) were significantly ameliorated (Engel I and Engel II), 7 patients (36.8%) worthwhile improved (Engel III) and 1 patient (5.3%) unchanged. In 11 patients (58%) radiosurgically induced image changes were seen on MRI. INTERPRETATION: Although microsurgical approach guided by electrocorticography (EcoG) is the state of art for treatment of mesiotemporal tumour epilepsy, GKRS can be used as a non-invasive, safe and effective alternative to resective surgery for selected cases.

Adolescent↗
PubMed2001

The role of gamma knife radiosurgery in children.

OBJECTS: Despite advances in microneurosurgery, the surgical management of deep-seated lesions is still associated with a high risk. Gamma knife radiosurgery (GKRS), however, has improved the outcome of cerebral tumors and arteriovenous malformations (AVMs) in delicate areas. METHODS: Between March 1992 and June 1998, 50 children (age 1-16 years) with intracranial lesions were treated with GKRS. There were 12 low-grade gliomas, 12 high-grade gliomas, 7 craniopharyngiomas, 3 hamartomas, 2 meningiomas of the skull base, 2 vestibular schwannomas, 1 pituitary adenoma, 1 choroid plexus papilloma, and 10 AVMs. The mean size of the pathologies was 4.6 cm3 (range: 0.21-25.5 cm3). A mean marginal dose of 16 Gy (8-25 Gy) was applied to a mean isodose surface of 50% (35-90%). Clinical and neuroradiological follow-up were analyzed for outcome. Follow-up periods of 45 of these patients ranged from 8 to 79 months (mean 36 months); 5 patients were lost to follow-up. Neoplasms decreased in size in 15 cases (41%), remained unchanged in 13 patients (35%), and increased in 9 cases (24%). AVMs obliterated in 3 children (38%) within 24 months. Neurological follow-up demonstrated improved clinical status in 7 patients (15.5%), stable neurological status in 31 cases (69%) and clinical deterioration in 7 patients (15.5%). The treatment was well tolerated and no complications occurred. CONCLUSIONS: GKRS represents a safe and effective treatment option for benign neoplasms or AVMs in pediatric patients and may extend survival times of children with malignant lesions.

Adolescent↗
PubMed2001

Outcome and long-term side effects after synchronous radiochemotherapy for childhood brain stem gliomas.

Between 1993 and 1999, 11 children with histologically confirmed diffuse and exophytic brain stem glioma (BSG) were treated with intensive induction chemotherapy and simultaneous external beam irradiation. Chemotherapy was performed according to the German/Austrian Pediatric Brain Tumor Study HIT '91 and included two cycles of ifosfamide (days 1-3), etoposide (days 4-6), methotrexate (days 15 and 22), cisplatin (days 29-31) and cytarabine (days 29-31), separated by a 3-week interval. Maintenance chemotherapy with carmustine, carboplatin and vincristine (8 cycles over a 1-year period) was given in those patients who responded clinically or radiographically to induction chemotherapy. Six of 11 patients showed an objective reduction in tumor size on magnetic resonance imaging and 4 of 11 are alive in good general condition >22, >22, >90 and >92 months, respectively, after diagnosis without radiographic evidence of tumor progression (1 complete remission, 2 partial remissions, 1 stable disease), but suffer from moderate to severe long-term side effects. Three patients died due to disease progression after having achieved a partial remission which lasted 5, 6 and 18 months, respectively, whereas only short-term stabilization was observed in 4 patients who died within 1 year after diagnosis. Acute hematologic toxicity was severe but manageable. This intensive combined modality treatment was toxic but yielded objective responses in more than 50% and long-term survivors in one third of childhood BSG patients.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

Traumatic brain stem lesions in children.

Glasgow Coma Scale (GCS) scores on admission may be predictors of outcome in patients with brain injuries. This study correlated the outcomes of children with traumatic brain stem lesions with their initial GCS scores and morphological patterns of injury as shown on computed tomography (CT) or magnetic resonance (MR) imaging. During the last 16 years, we have treated 1,108 children with brain injuries. The entire series included only 21 (1.9%) children who had clinical signs of brain stem lesions with morphological correlates on CT or MR imaging. Clinical findings were assessed according to the GCS and compared with scores on the Glasgow Outcome Scale (GOS). Of these 21 children, 16 (76%) had morphological lesions seen on CT scans. In 5 (24%) of the children only the MR images revealed brain stem lesions and their CT scans were negative. Generalized severe brain swelling was present in 6 cases (28%). There was a significant difference in GOS scores between patients with initial GCS scores of 3 and 4 and those with GCS scores between 5 and 7 (P < 0.02). Children with intracranial pressure higher than 40 mmHg had poorer outcomes than patients whose intracranial pressure was lower, but the differences were not significant. Outcome did not correlate significantly with morphological patterns of injury or the presence of extracranial injuries. The GCS is a reliable indicator of severity of injury and of outcome in children with brain stem injuries. MR imaging was more sensitive than CT in detecting brain stem lesions.

Adolescent↗
PubMed2000

An automated drug delivery system for focal epilepsy.

Previous studies have demonstrated the ability to stop seizures in animal models with injection of antiepileptic medication directly onto the seizure focus. The present experiments describe automated detection and focal therapy for seizures in the laboratory setting. Focal seizures were created in Sprague-Dawley rats using bicuculline, a GABA antagonist. Computerized detection of seizures was linked to a programmable infusion pump to deliver either diazepam (DZP) or pH-balanced vehicle (VEH) directly onto the seizure focus. Mean numbers of seizures following initial delivery of drug were 2.9+/-1.45 for the VEH-treated group and 0.2+/-0.42 for the DZP-treated group (P<0.0001, Student's t-test, nonpaired, one-tailed). In another series of experiments, early injection of DZP shortened seizure duration. Three DZP-treated animals died. This model provides proof-in-principle for the development of a clinically applicable treatment for intractable partial epilepsy. Such therapy might avoid some of the problems inherent to systemic administration of antiepileptic drugs.

Animals↗
PubMed1999

Corpus callosotomy with radiosurgery.

OBJECTIVE: Corpus callosotomy is a surgical option for medically uncontrolled generalized epilepsy in appropriate patients. Because numerous complications related to open callosotomy are still reported, we performed radiosurgical corpus callosotomy with the gamma knife. METHODS: Between October 1992 and June 1995, three patients underwent stereotactic radiosurgery to ablate the anterior third of the corpus callosum. The patients had intractable epilepsy: two had Lennox-Gastaut syndrome, and one had multifocal epilepsy with atonic, tonicoclonic, and atypical absence seizures. The history of seizures ranged from 20 to 37 years' duration. Stereotactic radiosurgery was performed with a cobalt-60 gamma knife using a 4-mm collimator, targeted to the rostrum, genu, and anterior third of body of the corpus callosum. Two patients were treated once with 150 and 160 Gy at maximum, respectively, and one patient was treated in two stages with 50 Gy and then 170 Gy at maximum. RESULTS: The severity and frequency of seizures were significantly reduced in all three patients. The types of seizures associated with the most improved outcome were atonic and generalized tonicoclonic seizures. The mean follow-up period was 38 months. Hospitalization required for this procedure was 3 days. No complications related to irradiation were recorded except transient headache in one patient. CONCLUSION: The outcomes suggest that radiosurgical corpus callosotomy may be a promising alternative treatment to open callosotomy.

Adult↗
PubMed1998

Intracranial aneurysms: a review of endovascular and surgical treatment in 248 patients.

We reviewed the medium-term results of endovascular treatment of intracranial aneurysms and compared patient selection and results with those of open surgery. Between January 1992 and December 1995, a total of 248 consecutive patients were treated for 297 aneurysms (61 unruptured and 236 ruptured). 162 aneurysms in 142 patients (mean age, 48.5 years) were treated microsurgically and 134 aneurysms in 106 patients (mean age, 54.2 years) were treated by endovascular embolization with Guglielmi detachable coils (GDC). The mean follow-up was 2.6 years (range, 1.5 to 4.5 years). There was no significant difference in patient population and selection in terms of age, sex or location of aneurysms between both methods. Both modalities achieved excellent results (defined as no neurological deficit) in patients with unruptured aneurysms and with no or minor deficits after subarachnoid hemorrhage (SAH) between 71% and 88%. Patients with moderate deficits after SAH had excellent outcomes in 49% after open surgery, and 47% after embolization. Poor grade patients had, equally, as well an acceptable as a pour outcome, between 0% and 50%. There was no significant difference between the outcome of surgical or endovascular patients. We conclude that GDC embolization is not associated with a higher risk of morbidity and mortality than open surgery. This risk may even be lower for lesions in surgically unfavorable locations. The GDC technique is a less invasive, effective option to prevent re-bleeding in early stage, even in poor-grade patients. However, these encouraging medium-term results have to be confirmed by a longer observation period.

Adult↗
PubMed1998

Radiosurgery in lesional epilepsy: brain tumors.

The purpose of this study was to examine the effects of different doses of radiation to the brain tissue immediately adjacent to tumors which were associated with epilepsy. From April 1992 to December 1995, 26 patients with medically intractable tumor epilepsy (mean duration 6.9 years, range: 1-27 years) have been treated with Gamma Knife radiosurgery (GKRS). Clinical and imaging controls were available for 24 patients with a mean follow-up of 2.25 years (range: 1-4.4 years). Tumor control had been achieved in all patients. The patients were divided into two groups according to the volume of tissue outside the tumor which had received 10 Gy or more. This volume was assessed by measuring the ratio of the tumor and the ratio of the volume within the isodose containing 10 Gy (10G/Tum ratio). 54 percent of all the 24 patients achieved an excellent result according to the Engel classification (class I or II). The patients were divided into two groups. In group I were 12 patients, and the 10G/Tum ratio was 3 or less. In group II there were 12 patients and the 10G/Tum ratio was more than 3. In group I the mean value for the 10G/Tum ratio was 2 (range 0.86 to 2.9). In group II the mean value of the ratio was 11.1 (range 3.13 to 63.2). In group I only 42% of patients achieved an excellent result compared with 66% in group II. Moreover, the location of the tumor had an effect on the results, in that temporal tumors were associated with excellent results in 64% of cases as opposed to 40% in extratemporal tumors. Finally, if the epilepsy had lasted for 2.5 years or less there were excellent results in 70% of patients, as opposed to 43% excellent results for patients who had suffered epilepsy for more than 2.5 years.

Adolescent↗
PubMed1998

Treatment of cerebral radionecrosis by hyperbaric oxygen therapy.

Clinically observed adverse radiation effects (ARE) are rather uncommon, but modern imaging reveals that they are more common after radiosurgery than previously believed. Little is known about the pathogenesis, and current treatment is mostly empirical. The benefit of hyperbaric oxygen therapy (HBO) on radiation-induced bone and soft tissue necrosis is known in lesions in the maxillofacial area, the mouth and in the head and neck. HBO raises the tissue pO2 and initiates a cellular and vascular repair mechanism. This forms the basis for the hypothesis that it might also help alleviate the results of cerebral radionecrosis. This study is a preliminary attempt to test this hypothesis. Two patients with arteriovenous malformations (AVMs) were chosen for the study. They had been treated with Gamma Knife radiosurgery (GKRS) and had developed imaging signs consistent with ARE. They were treated by breathing 100% oxygen at 2.5 atmospheres absolute (250 kPa) in sessions of 60 minutes per day. This treatment was repeated 40 times in cycles of ten sessions. Both responded well to HBO, one lesion disappeared and the other was reduced significantly in size. No adjuvant steroids were given. These results give evidence that HBO has a potential value in treating ARE but further experience will be needed to confirm its definite benefit.

Adult↗
PubMed1997

Complications after shunting isolated IV ventricles.

An isolated IV ventricle in chronically shunted patients is being reported with increasing frequency. Complications associated with posterior fossa shunting, however, have seldom been described. Between January 1986 and December 1995, we treated 292 children younger than 16 years for hydrocephalus: 7 (2.4%) developed an isolated IV ventricle, and 5 of these were symptomatic with posterior fossa signs. These 5 patients required posterior fossa shunting, after which their neurological status improved. However, 1 week and 6 weeks after surgery, respectively, 2 patients developed new cranial nerve deficits related to a slit-like IV ventricle with secondary irritation of the brain stem by the IV ventricular catheter. Shortening the catheter and replacing the valve eliminated the cranial nerve palsies, implying that these complications were not caused by direct injury of the brain stem during placement of the shunt. Alternative surgical techniques and the use of different (flow-regulating) valves may avoid such complications.

Adolescent↗
PubMed1997

Interictal and ictal activity in the rat cobalt/pilocarpine model of epilepsy decreased by local perfusion of diazepam.

We investigated the efficacy of focal perfusion of diazepam (DZP) in reducing seizures produced by focal cobalt and systemic pilocarpine in the rat. Cobalt chloride crystals (3.5 mg/kg) were inserted stereotactically into the left hippocampus and recording electrodes affixed to the head of 23 rats. Focal spiking was evident within 5-7 days of implantation. Occasional ictal electrographic events were observed with cobalt alone, but consistent ictal events could be produced by intraperitoneal injection of pilocarpine hydrochloride (60 mg/kg) into the cobalt-treated animals. When rhythmical spiking was observed, the animals were treated either with DZP (0.25 mg in 50 microliters) or a vehicle (VEH) delivered into the left hippocampus. Blinded spike counts before and after injection showed spiking at 133.3 +/- 53.4% of baseline (mean +/- SD, n = 8) for the VEH-treated animals and 2.7 +/- 3.3% (n = 8) for the DZP-treated animals. Ictal events occurred in seven of the eight VEH-treated and two of the eight DZP-treated rats. Mean time to the first ictal event was 5.9 +/- 6.9 min for VEH-treated animals and 24 +/- 32.6 min for DZP-treated animals. DZP injected into the hippocampus contralateral to the cobalt did not reduce spiking. Systemic levels of DZP were unmeasurable in nine of ten tested animals. Focal perfusion of DZP therefore effectively reduced spiking in this cobalt chloride/pilocarpine model of focal and secondarily generalized epilepsy. This model, while involving GABAergic mechanisms, does not entirely depend upon GABAergic mechanisms. The findings therefore broaden the possibility of using focal DZP as a treatment for partial seizures.

Animals↗
PubMed1997

Local perfusion of diazepam attenuates interictal and ictal events in the bicuculline model of epilepsy in rats.

PURPOSE: We evaluated the efficacy of local perfusion of diazepam (DZP) in suppression of EEG spikes and behavioral seizures produced by bicuculline methiodide (BMI) applied to rat sensory motor cortex and hippocampus. METHODS: Data were obtained from 37 rats implanted with EEG head plugs and perfusion cannulas. BMI 4 mM, 5 microliters was infused on neocortex through the epidural space in 23 rats. BMI 0.1 mM, 2 microliters was infused into the left hippocampus in 14 rats. RESULTS: DZP 0.75-1.0 mg markedly reduced the spiking to a level of 9.9 +/- 15.8% of baseline for DZP as compared with 90.2 +/- 57.9% of baseline for vehicle-treated rats. DZP reduced spiking in a hippocampal BMI focus to 1.9 +/- 2.4% of baseline spiking, as compared with 98.0 +/- 95.6% of that in vehicle-treated animals. The amount of spread of solution was estimated with methylene blue (MB) injections. Ictal events also were attenuated. In most of the animals, systemic levels of DZP were unmeasurable and injection on the contralateral side did not reduce spiking. CONCLUSIONS: These findings suggest that focal application of antiepileptic drugs (AEDs) in brain may be a useful new avenue for therapy of intractable partial seizures.

Administration, Topical↗
PubMed1995

Localization of superficial cerebral lesions using a magnetic resonance imaging-guided localizer.

The localization of superficial cerebral lesions may be difficult even if they reach the surface of the cerebral cortex. Intraoperative ultrasound often fails to detect subcortical lesions. A localization device using multiplanar MR-imaging has been designed to project such lesions to the scalp. This device is a hood-shaped grid made of polyethylene tubing filled with paramagnetic contrast agent. In this hemispherical grid the tubes are arranged at a distance of 15 to 30 mm so that the MR-plane always slices perpendicular to the axis of the tubing and depicts a bright spot per tube. It is rapidly filled prior to each MR-examination, placed on the patient's head, and taped to his forehead to avoid unintentional displacement during and after the examination until the projection of the lesion is marked on the skin.

Brain Neoplasms↗
PubMed1993

Cervical cord compression in hereditary multiple exostoses.

A seven year old girl, known to have hereditary multiple exostoses, developed moderate gait disorders at the age of six years. Deterioration of myelopathy initiated the clinical investigation including spinal computed tomography (CT) and magnetic resonance imaging (MRI). These examinations demonstrated a coneshaped exostosis originating from the posterior arch of C2. The spinal canal was markedly narrowed with significant compression of the spinal cord at the C2 level. The girl underwent laminectomy of C2 with total removal of the exostosis. Postoperative deterioration of neurological symptoms correlated with a hypointense lesion on T1 weighted imaging in the cord at the same level, but no further cord compression on follow-up MRI. The spastic tetraparesis has improved considerably within 12 months thereafter.

Child↗