Are spontaneous epidural haematoma in sickle cell disease a rare complication? A report of two new cases.

BACKGROUND: Sickle cell anaemia, an autosomal recessive disease relatively common among the black races, gives rise sometimes to neurological complications. Among these, spontaneous epidural haematoma constitutes a rare event that is not always easy to treat in the Third world conditions. METHODS: Two new cases are described and their pathology is compared with the five already described cases in the literature. A vaso-occlusive pathological process as in the orbital compression syndrome is thought to be implicated in the generation of the spontaneous epidural haematoma. RESULTS: When facing an epidural haematoma as a complication of sickle cell disease in a hospital of the Third world conditions, a cautious attitude towards surgery should be observed because of the high complication rate. If the relation between the haematoma and the anaemia is not immediately apparent, we are in favour of starting treatment with antibiotics.

Vagus nerve stimulation for medically refractory epilepsy; efficacy and cost-benefit analysis.

INTRODUCTION: Vagus nerve stimulation is a novel treatment for patients with medically refractory epilepsy, who are not candidates for conventional epilepsy surgery, or who have had such surgery without optimal outcome. To date only studies with relatively short follow-up are available. In these studies efficacy increased with time and reached a maximum after a period of 6 to 12 months. Implantation of a vagus nerve stimulator requires an important financial investment but a cost-benefit analysis has not been published. PATIENTS AND METHODS: Our own experience with VNS in Gent comprises 15 patients with mean age of 29 years (range: 17-44 years) and mean duration of epilepsy of 18 years (range: 4-32 years). All patients underwent a comprehensive presurgical evaluation and were found not to be suitable candidates for resective epilepsy surgery. Mean post-implantation follow-up is 24 months (range: 7-43 months). In patients with follow-up of at least one year, efficacy of treatment in terms of seizure control and seizure severity was assessed one year before and after the implantation of a vagus nerve stimulator. Epilepsy-related direct medical costs (ERDMC) before and after the implantation were also compared. RESULTS: A mean reduction of seizure frequency from 14 seizures/month (range: 2-40/month) to 8 seizures/month (range: 0-30/month) was achieved (Wilcoxon signed rank test n = 14; p = 0.0016). Five patients showed a marked seizure reduction of > or = 50%; 6 became free of complex partial seizures, 3 of whom became entirely seizure free for more than 12 months; 2 patients had a worthwhile reduction of seizure frequency between 30-50%; in 2 patients seizure frequency reduction has remained practically unchanged. Seizure freedom or > or = 50% seizure reduction was achieved within the first 4 months after implantation in 6/11 patients. Before the implantation, the mean yearly epilepsy-related direct medical costs per patient were estimated to be 8830 US$ (n = 13; range: 1879-31,129 US$; sd = 7667); the average number of hospital admission days per year was 21 (range: 4-100; sd = 25.7). In the 12 months after implantation, ERDMC had decreased to 4215 US$ (range: 615-11,794 US$; sd = 3558) (Wilcoxon signed rank test n = 13; p = 0.018) and the average number of admission days to 8 (range: 0-35) (Wilcoxon signed rank test n = 13; p = 0.023). CONCLUSION: VNS is an effective treatment of refractory epilepsy and remains effective during long-term follow-up. Cost-benefit analysis suggests that the cost of VNS is saved within two years following implantation.

Dipole modelling and intracranial EEG recording: correlation between dipole and ictal onset zone.

This study includes 11 patients (3 males, 8 females) with mean age of 29 years (range: 15-42 years) who underwent a presurgical evaluation for refractory complex partial seizures (CPS). In all patients, neuroimaging (1.5 T optimum-MR) demonstrated intracranial structural abnormalities (space-occupying: n = 2; atrophic: n = 8; dysplastic: n = 1) and video-EEG monitoring showed CPS, because of discrepancies in the non-invasive examinations, all underwent additional intracranial EEG monitoring. After tailored resective procedures, all but one patient became seizure free. Mean follow-up was 30 months (range: 12-52 months). Results of intracranial EEG recording were compared with spatiotemporal dipole mapping of interictal and ictal epileptic discharges. Interictal dipole modelling revealed two distinct dipole patterns. Patients with lesions located in the medial temporal lobe uniformly presented a combined dipole that consisted of a radial and a tangential component with a high degree of elevation relative to the axial plane. Patients with extrahippocampal lesions had a less stable dipole with a predominant radial component. Dipole modelling of early ictal discharges revealed a striking correspondence with the interictal findings in individual patients. Elevation of ictal dipoles was always congruent with localisation based on intracranial EEG recordings. Interictal and ictal dipole mapping of medial temporal lobe sources may limit the number of surgical candidates for refractory CPS that need intracranial EEG recording. Whether ictal dipole modelling can be equally useful in extratemporal epilepsy remains to be proven.

Epilepsy surgery in Belgium, the Flemish experience.

Between January 1992 and June 1995, 160 patients were presurgically evaluated for medically refractory epilepsy by the Epilepsy Monitoring and Surgery Team at the University Hospital of Gent. All these patients underwent a comprehensive presurgical evaluation, including extensive neurological history and examination, video-EEG monitoring of interictal EEG and habitual seizures, CT and optimum MR. In a large subgroup of these patients a comprehensive neuro-psychological examination and interictal 18FDG-PET were performed. After the non-invasive phase of the presurgical evaluation, a bilateral carotid angiography and intracarotid amytal procedure was planned in 27 patients to establish hemispheric language dominance and bilateral memory function. After proper selection, 14 patients underwent invasive video-EEG monitoring with intracranial implantation of parenchymal and/or subdural electrodes to further document the area of seizure onset. From the initial group of 160 potential surgical candidates, 40 patients (20 M, 20 F) with mean age of 31 years (range: 2 months-55 years) and mean duration of uncontrolled seizures of 16 years (range: 2 months-47 years) eventually underwent a surgical procedure. 30/40 patients were on high dose antiepileptic polytherapy. Optimum MR detected structural abnormalities, confined to a limited brain area, in 39 patients. These abnormalities were of space-occupying nature in 21 cases; an atrophic lesion was suspected in 17 patients. Structural abnormalities were most frequently located in the temporal lobe (n = 26) and the frontal lobe (n = 7). Video-EEG monitoring documented complex partial seizures in 32 patients with occasional secondary generalisation in 14. In most of these patients, seizures could be subclassified as being of temporal lobe origin based on clinical and EEG criteria. Two patients had only simple partial seizures. One patient with Sturge-Weber syndrome and a strictly unilateral angioma had hemiconvulsions. A mentally retarded patient with Lennox-Gastaut syndrome had different types of seizures. After non-invasive and invasive exploration, the area of seizure onset could be determined in all patients. Standard or modified temporal lobectomy +/- hippocampectomy were the most commonly performed procedures (n = 26). In 5 patients complete lesionectomies were performed for epileptogenic structural lesions in and outside the temporal lobe. In 2 patients only partial lesionectomies were possible; in 5 patients only biopsies could be performed. Anterior 2/3 callosotomy and hemispherectomy were each performed in one patient. Postsurgical seizure control, after average follow-up of 20 months (range: 6-40 months), was excellent in 27 patients who became seizure-free. In these patients antiepileptic therapy was tapered 2 years after surgery. An additional 4 patients continue to experience non-disabling simple partial seizures only. Patients in whom only biopsies or partial lesionectomies were performed have poor seizure control. Three patients died as a result of the intrinsic malignancy of their space-occupying lesion. Two patients who are seizure free experienced a moderate postoperative hemiparesis with subtotal recovery. Overall quality of life was substantially improved both in patients who became entirely seizure free or who experienced a very significant reduction in seizure frequency. Presurgical evaluation and epilepsy surgery are a labour intensive but rewarding therapeutic alternative for patients with medically refractory epilepsy. Besides providing therapeutic efficacy, comprehensive presurgical evaluation and epilepsy surgery allow for fruitful clinical neurological research.

An MR protocol for presurgical evaluation of patients with complex partial seizures of temporal lobe origin.

PURPOSE: To find an optimal diagnostic protocol for the presurgical MR evaluation of patients with temporal lobe epilepsy. METHODS: MR imaging in 14 healthy subjects and 25 consecutive patients with temporal lobe epilepsy was performed in paracoronal sections perpendicular to the hippocampi with T1-weighted inversion recovery and T2 weighting. Volume measurements of the hippocampus/amygdala complex were performed and a multiecho sequence yielded T2-calculated images. RESULTS: Hippocampal disease was seen in 22 of 25 temporal lobe epilepsy patients on paracoronal T1-weighted inversion recovery images. Four had bilateral abnormalities. Characteristic for hippocampal disease were features such as volume loss, decreased signal, and loss of internal morphology. Only 17 of 25 patients demonstrated hippocampal pathology on T2-weighted images, and in one patient this was bilateral. Patients with only minimal structural loss on T1-weighted inversion recovery had normal T2-weighted images. T2 calculation was no more sensitive than visual assessment on the T2-weighted images. Volume measurements were normal in one patient and misleading in two patients. Lateralization, as compared with clinical and electroencephalographic findings, was most confidently done with paracoronal T1-weighted inversion recovery images and volume measurements. CONCLUSIONS: An optimum MR protocol for temporal lobe epilepsy patients is proposed. Its essential feature is that the hippocampus be evaluated by paracoronal T1-weighted inversion recovery images and volume measurements. T2-weighted imaging can be omitted.

The invasiveness in vitro of brain tumour derived-cells depends on their micro-eco system.

In order to investigate the invasiveness of brain tumours, fragments of freshly resected tumours are transferred into cell culture vessels to form monolayers. The tumour derived monolayer cells are tested in two different in vitro assays for invasiveness: the collagen type I gel and the embryonic chick heart. Nine of the 10 tumour derived cells infiltrated into the collagen gel, independently of their clinical malignancy. Only 4 of the 10 tumour derived cells invaded the embryonic chick heart. Invasion into chick heart in vitro correlated with malignancy in vivo. The results speak for the hypothesis that the micro environment of the embryonic chick heart allows expression of the invasive character of the brain tumour cells, while the collagen type I in contrast indicates only cell motility.

Trans-sternal approach to intraspinal tumours in the upper thoracic region.

The surgical management of ventrally located intraspinal tumours is often difficult, particularly in the upper thoracic region. The anterior approach to these tumours is hindered by anatomical structures. We report our experience using the trans-sternal approach. Three patients with intraspinal tumour between T1 and T4 underwent this approach. The surgical technique, the clinical presentation, the radiological features and the results are presented.

Clinical and neurophysiological correlations in patients with refractory partial epilepsy and intracranial structural lesions.

Twenty patients (13 males, 7 females), who presented with refractory partial epilepsy and a CT and/or MR detected intracranial intra-axial structural lesion were admitted to the University of Gent Epilepsy Monitoring Unit. Mean duration of the epilepsy was 17 years (2-47 years). All patients were enrolled in a comprehensive presurgical protocol including neurological examination, video-scalp-EEG monitoring with prolonged interictal and ictal recording, neuropsychological assessment and positron emission tomography (PET). Intracranial EEG monitoring was performed in 5 patients in whom discrepancies between different tests were found during the non-invasive evaluation. Clinical neurological examination was normal in 16 patients; 4 patients had a mild contralateral hemiparesis. Lesions were mainly located in the temporal lobe (55%). Most patients presented with complex partial seizures (90%). Clinical seizure characteristics correlated well with the lesion location in 55% of patients. Interictal EEG showed focal epileptic activity and focal slowing in respectively 85% and 30% of patients. Interictal EEG lateralization was congruent with the side of the lesion in 17 patients (85%). Interictal EEG localization was congruent with the lobe of the lesion in 13 patients (65%). Ictal EEG lateralized correctly in 14 patients (70%) and localized correctly in 10 patients (50%). Neuropsychological assessment lateralized and localized congruently in respectively 8/17 (47%) and 7/17 (41%) of patients. Interictal PET showed focal interictal hypometabolism, congruent with the lesion, in 13/16 (81%) of patients. Intracranial EEG was congruent with the lesion location in 3 patients but non-congruent in 2 patients. All patients underwent surgical procedures: average follow-up was 14 months (6-24 months). Complete surgical removal of the lesion with free margins resulted in a more than 90% reduction of seizures without postoperative neurological deficit in 12/13 patients.

The development of a decision support system for the pathological diagnosis of human cerebral tumours based on a neural network classifier.

This study describes the use of a topological mapping system in the classification of cerebral tumours and the development of a decision support system based upon that classifier. Fourteen pathological parameters from two hundred primary cerebral tumours are presented as vectors to a topological map. The map, consisting of a grid of neurones, learns the features of each tumour by means of a shortest Euclidean distance algorithm, after which self adaptation of the neurons occurs. An LVQ algorithm performs the final classification. Study of the map reveals that it can correctly classify tumors following their malignancy potential and their cytogenesis. The decision support system uses the network at its core and helps not only in reaching a diagnosis but also in finding the optimal way to reach that diagnosis. The usefulness of such a mapping system lies in the field of education, clinical research and medically acceptable cost reduction.

A multipurpose cerebral endoscope and reflections on technique and instrumentation in endoscopic neurosurgery.

We discuss our experiences concerning our cerebral endoscope with reflections on various techniques used since 1986. During this time we have had experience with four prototypes. This minimal invasive procedure has been successful to a certain extent both in paediatric and adult patients, stereotactically and by freehand method or both. Further modification for flexibility and manipulation of the optic element is under development.

Endoscopic diagnosis and treatment of para- and intra-ventricular cystic lesions.

Different cystic lesions can be located in or around the ventricular system, eventually causing hydrocephalus. Twenty-one patients are described where endoscopic intervention, mainly large fenestration towards the ventricular cavity, has been performed. This treatment can sometimes replace open surgery or extracranial shunting. Most rewarding are the arachnoid and ependymal intra- and paraventricular cysts. With careful and adequate endoscopic technique this procedure is safe and much less invasive than other methods described.

Invasiveness invitro versus clinical evolution of primary and secondary brain-tumors.

Cells of 56 primary cell cultures derived from primary and secondary brain tumours were confronted in vitro with host tissue, embryonic chick heart fragments (PHF). The evolution of the confrontation was followed for one week. Histological analysis of the confrontations demonstrated two different patterns. (i) Survival of host tissue and tumour derived cells without invasion of the last ones into the host. (ii) Invasion of tumour derived cells into the host tissue followed by replacement of the chick heart tissue. Invasion into the host tissue was observed only in the confrontations with primary cell cultures originating from malignant and metastatic tumours. The invasive characters in vitro of primary cell cultures correlated with the malignancy of the tumour in vivo.

Invasiveness of primary and secondary brain tumors in vitro correlated with clinical results.

One hundred fifty-one tumor fragments were collected in the neurosurgical operating amphitheater immediately after removal. Small tumor fragments were transferred into culture flasks and cultured until a confluent monolayer was formed by the outgrowing cells. Flaps of these cell monolayers were mechanically scraped from the culture flasks and confronted with embryonic chick heart tissue in vitro. The evolution of the confrontations was followed for a week. Histological analysis of the confrontations demonstrated three different morphological patterns of interaction between the heart tissue and the tumor-derived cells: 1) progressive engulfment of the tumor-derived cells by the heart tissue (Type I), 2) survival of both the heart tissue and the tumor-derived cells (Type II), and 3) progressive replacement of the heart tissue by tumor-derived cells (Type III). The replacement of the heart tissue by tumor-derived cells was only observed in cells originating from malignant tumors that were invasive and metastatic in vivo. Thus, invasiveness in confrontation culture is correlated with malignancy in vivo.

Invasiveness in in vitro and clinical evaluation of meningiomas.

Fragments of freshly isolated human meningiomas were cultured in vitro to form cell monolayers. These monolayers were confronted with embryonic chick heart fragments in vitro for 1, 2, 4, and 7 days. Microscopically, three different histological patterns were observed. Type I included necrotized meningial cells; type II presented surviving meningial cells; type III included meningial cells that had invaded the host tissue. The clinical analysis included the histopathological diagnosis, the macroscopic situation at surgical intervention, and the follow-up with or without recurrence. Correlation between these clinical parameters and the in vitro results demonstrated that type III confrontations correlated with macroscopic infiltration in the brain parenchyma and tumor recurrence. Invasiveness in vitro was seen in two anaplastic and two transitional meningiomas.

Influence of converting enzyme inhibition on isoflurane-induced hypotension for cerebral aneurysm surgery.

Twenty-five patients (aged 18 to 72 years), who recovered after the first bleed from a cerebral aneurysm, were operated on under neuroleptanaesthesia. Isoflurane was added to induce hypotension. It was found that the required hypotension (51 (SEM 1) mmHg) could be obtained and maintained at much lower isoflurane concentrations (less than 1%) after blockade of the angiotensin converting enzyme activity by enalaprilat (2.5 mg i.v.) than without such inhibition. During the hypotension which lasted 78 (SEM 10) min, only minor adjustments of the isoflurane concentration (0.70 (0.04%) were needed. The desired level of hypotension was obtained with preservation of the cardiac output and without tachycardia. No resistance to the blood pressure lowering effect of isoflurane was observed. On recovery from anaesthesia, a small increase of blood pressure above control values was seen in 16 patients and was easily reversed by small doses of clonidine (mean total dose: 220 (61) micrograms). The operative conditions were excellent and the postoperative recovery was uneventful and complete in 23 patients.

Endoscopic treatment of suprasellar arachnoid cysts.

Four cases of large suprasellar arachnoid cysts in children are described. The authors propose a large fenestration into the lateral ventricles and into the basal cisterns as the treatment of choice. A specific multipurpose cerebral endoscope has been designed by the first author. The endoscopic technique with different instruments and with the use of a laser is illustrated. Results and complications are discussed.

Brain abscess after esophageal dilatation for stenosis.

The case is presented of a 28-year-old female with a brain abscess after esophageal dilatation for stricture, secondary to an acute necrotizing esophagitis. Other causes of brain abscess were excluded. To our knowledge this is the first documented case of brain abscess after dilatation for esophageal stricture in adult life. Some reports in the pediatric literature have been published previously.