Hemispherical deafferentation: an alternative to functional hemispherectomy.

An alternative technique for so-called functional hemispherectomy has been developed to be used for the classical indications of hemispherectomy or the various modifications of functional hemispherectomy. The technique entails a smaller trepanation, less operation time, and less blood loss, and it leaves more brain tissue in place as compared with other functional hemispherectomy techniques. It starts with either hippocampectomy alone or with hippocampectomy and anterior temporal lobectomy. After this, deafferentation of the white matter of the temporal, occipital, parietal, and frontal lobe, using either a transcortical transventricular approach along the outline of the lateral ventricle or a sylvian key hole approach, is performed. The technique includes a transventricular callosotomy, and it leaves in place only a small portion of the suprainsular cortex and the insular cortex. However, as one modification, removal of the insular cortex can easily be performed, if necessary, and, as a second modification, the entire transventricular deafferentation can be performed through a sylvian key hole. In this report, the technique is described and the surgical experience for the first 13 patients is outlined. The immediate seizure relief with an average follow-up of 12 months was similar to that for patients with functional hemispherectomy, but the follow-up period for these 13 patients is not long enough to allow definite conclusions concerning long-term control of seizures and long-term complications.

Human brain cortex and platelet serotonin2 receptor binding properties and their regulation by endogenous serotonin.

In patients with affective disorder and suicidality up-regulation of the serotonin2 receptor has been observed in brain and on platelets. Although the pharmacological profiles of the receptor in brain synaptosomes and platelet membranes are similar, it is a matter of debate whether the platelet serotonin2 receptor reflects the characteristics of the receptor in the brain and whether serotonin regulates the receptor activity. To answer these questions we measured in healthy human subjects the platelet serotonin2 receptor activity and blood serotonin concentrations. In an attempt to find whether the serotonin2 receptor activity in brain cortex synaptosomes and on platelets is similarly expressed we investigated the receptor's binding characteristics in neurosurgical patients. The results suggest that in men and women increased platelet serotonin concentrations correlate with a decrease in platelet membrane serotonin2 receptor affinity. The affinities of the brain cortex synaptosomal and platelet membrane serotonin2 receptor correlate intra-individually. These data suggest that the platelet serotonin2 receptor affinity appears to be regulated at the cellular level by blood serotonin and that the binding characteristics of the serotonin2 receptor in brain cortex synaptosomes corresponds to that on platelets. The latter finding supports the hypothesis of the platelet as a model for neuronal function.

Activation of the epileptic focus by transcranial magnetic stimulation of the human brain.

To establish whether transcranial magnetic stimulation is able to activate the primary epileptic focus preferentially, 13 patients who had medically intractable complex partial seizures were examined prior to surgical therapy. Single or a series of magnetic stimuli were applied to various regions of the skull. The effects of transcranial magnetic stimulation were monitored via subdurally implanted electrodes. In the process of presurgical evaluation, the dosage of anticonvulsant medication had been reduced in all patients but one. Transcranial magnetic stimulation was able to activate the epileptic focus (or foci) in 12 of the 13 patients. Distinct patterns of focal activation were observed in 3 patients who had several foci. No epileptiform potentials were induced outside epileptic foci, which had been identified by corticographic recordings. In one patient a complex partial seizure that was induced was identical to her habitual seizures. In another patient, a complete transition from a nonactive theta focus to a self-sustained epileptic focus occurred. A facilitation of epileptiform afterdischarge was seen with sequential stimulation. No adverse effects were either reported by the patients or observed by the investigators. In summary transcranial magnetic stimulation is able to activate the epileptic focus (or foci) and consequently may be an additional tool for the localization of epileptic foci in presurgical evaluation.

Pharmacokinetic aspects of cerebrospinal fluid penetration of fosfomycin.

Even today antibiotic therapy of postoperative or posttraumatic meningitis remains a problem. In patients in a neurosurgical intensive care unit, nosocomial microorganisms with high resistance are mainly found. There are no antibiotics available which have simultaneously a good efficacy on the higher resistant nosocomial microorganisms and a good penetration through the blood-brain or blood-cerebrospinal fluid barrier. We analysed the cerebrospinal fluid (CSF) penetration of fosfomycin carrying out the investigations in patients in whom a CSF drainage was required for a neurosurgical indication. The blood-brain barrier was considered to be largely intact (total CSF protein and cell counts with in the normal range). Five or 10 g fosfomycin were administered to adults in 30 min infusions. After administration of 5 g, the CSF concentration formed a plateau between 8.6 and 9.9 micrograms/ml 3 to 6 h after the infusion. Increasing the dose infused (10 g) markedly shortened the latency period between reaching a sufficient concentration of fosfomycin in the CSF. With repeated doses of fosfomycin (3 X 5 g/day) the concentration in the CSF did not fall below the therapeutic level. Even in the presence of an intact blood-brain barrier, fosfomycin in our investigation showed a satisfactory penetration into the CSF. This is attributable to the favourable physicochemical state of fosfomycin (relative molecular mass 182).

Suppression of plasma prolactin in a patient with a pinealocytoma.

Plasma growth hormone (HGH), prolactin (PRL), luteinizing hormone (LH), thyroid stimulating hormone (TSH), cortisol and melatonin were determined during a 24 h period in a pubertal boy with a pinealocytoma. All hormone concentrations were normal with respect to age and time of day, with the exception of PRL which was undetectable. After subtotal removal of the tumor, basal PRL was still undetectable, but could be stimulated moderately by insulin-induced hypoglycaemia or TRH.

Removal of intraponto-mesencephalic spongioblastoma.

Excision of a circumscribed spongioblastoma with intrapontine-intramesencephalic extension was performed via the floor of the fourth ventricle in two girls 14 and 5 years of age. The preoperative neurological deficits (severe hemiparesis, cerebellar, and sixth and seventh cranial nerve disturbances) showed slow but continuous improvement to a satisfying neurological condition, if compared with the preoperative state. The indication for this microsurgical procedure is supported by findings, that indicate the tumour to be benign: (1) a long history, (2) a well circumscribed tumour including a cyst, as seen on CT, and (3) a localized protrusion of the floor of the fourth ventricle on ventriculography.

[The influence of etomidate and thiopentone on the intracranial pressure elevated by nitrous oxide (author's transl)]. / Wirkungen von Etomidat und Thiopental auf den Stickoxydulbedingten intrakraniellen Druckanstieg.

Intracranial pressure (ICP), arterial blood pressure (BP) and the calculated cerebral perfusion pressure (CPP) were investigated under standard conditions in 14 patients with severe brain injury. The influence of etomidate 0.3 mg/kg in comparison with thiopentone 6.0 mg/mg was evaluated both in patients with primarily elevated ICP (group I) and with an increase of ICP produced by nitrous oxide in oxygen (group II). In both groups of patients a marked ICP reduction (42%/26%) was produced by etomidate as well as by thiopentone. Whereas the reduction of CPP caused by thiopentone was enhanced by a moderate fall in BP, no influence on either BP or CPP was observed with etomidate. A regular fall in BP by about 10-15% was observed under nitrous oxide in oxygen alone, subsequently reducing the CPP by about 25%. These results emphasize the importance of the actions and interactions of different combinations of anesthetics in patients with acute brain injury in the prevention of further brain ischaemia. We believe that etomidate like thiopentone has brain protective properties in patients with cerebral hypoxia and must therefore be considered as an important therapeutic agent in such patients.

[The influence of some inhalation anaesthetics on the intracranial pressure with special reference to nitrous oxide (author's transl)]. / Die Wirkung einiger Inhalationsanaesthetika auf den intrakraniellen Druck unter besonderer Berücksichtigung des Stickoxydul.

The influence of inhalation anaesthetics on intracranial pressure (ICP), arterial blood pressure and cerebral perfusion pressure (CPP) was investigated on 12 unconscious patients with head injury having an initial ICP of about 20 mm Hg. Halothane, enflurane and nitrous oxide induced a considerable rise of ICP during a 15 to 25 minute period of observation. The moderate fall in blood pressure caused by halothane and enflurane enhanced the reduction of the calculated CPP. Besides, a regular fall in blood pressure of about 16% was observed under the influence of nitrous oxide, subsequently reducing the CPP in some cases under 40 mm Hg. Inhalation anaesthetics, including nitrous oxide, should therefore not be used in patients with decreased intracranial compliance before the increased ICP is treated.

Immunoelectrophoresis in the diagnosis of neuroectodermal and mesodermal intracranial tumours, especially those of the posterior fossa.

Immunoelectrophoresis of extracts of 200 intracranial tumours against rabbit anti-glioblastoma serum gave positive results (= precipitation) in all cases of tumours of neuroectodermal origin such as glioblastoma, astrocytoma, oligodendroglioma, ependymoma, neurinoma, and spongioblastoma. No immunoelectrophoretic precipitation was seen for any of the tumours of mesenchymal origin, for instance meningioma and metastases of cancer. On the basis of these findings, immunoelectrophoresis is considered to be a reliable method for differentiation between tumour tissue of neuroectodermal and non-neuroectodermal origin. Among the 41 posterior fossa tumours some unusual observations were made. Cerebellar angioblastoma (Lindau tumour) showed an atypically located precipitation line, which for the present is interpreted as an immunological reaction to vascular wall tissue. Furthermore, among the group of so-called medulloblastomas, two subgroups were distinguished on the basis of three parameters. The first of these subgroups comprises tumours whose immunoelectrophoretic pattern resembles that of gliomas, which are histologically characterized by neuroectodermal structures and which occur in younger children (5--10 years). The tumours of the second subgroup, which do not show this neuroectodermal immunoelectrophoretic pattern, have a sarcomatous character histologically, and occur in patients aged between 10 and 50 years. The view that medulloblastoma comprises a number of different types of tumour seems to be confirmed by this finding.

The influence of intravenous anaesthetic agents on primarily increased intracranial pressure.

In the choice of anaesthetics and techniques the danger of a possible progressive increase of intracranial pressure (ICP) should be considered. Therefore the influence of intravenous anaesthetic agents on mean arterial pressure, ICP, and cerebral perfusion pressure (CPP) in patients with primarily increased ICP was observed under standard conditions for 20-40 minutes. Etomidate, thiopentone, propanidid, and ketamine showed remarkable effects on ICP, even in patients with disturbed cerebro-vascular reactivity. Etomidate and thiopentone cause a fall of ICP by 26%. Because of its stabilizing effects on circulation etomidate does not induce a reduction of CPP, whereas thiopentone will do so because of its depressing effect on blood pressure. Propanidid appears to be a less suitable agent when there is raised ICP, because it induces fluctuations of ICP and blood pressure up to the third minute after injection. According to our results, monoanaesthesia with ketamine cannot be recommended when there is increased ICP because it causes a prolonged increase in ICP, and reduction of blood pressure and CPP.

New aspects of cerebrospinal fluid dynamics in humans investigated by sequential gamma camera cisternography, with data evaluation by the digital multichannel analyzer. Part 4: A unifying criterion of the development of hydrocephalic syndrome. Its dynamic basis.

In the final part of this series we present all of the clinical material, and the patients are classified by different cisternographic syndromes on the dynamic basis offered for our method: dynamic disconnection between ventricular system and basal cisterns, brain atrophy, initial dynamic decompensation or prehydrocephalus, communicating hydrocephalus with and without epicortical fluid circulation. A nomogram method for clinical estimation of CSF production based on the mathematical properties of our analysis of the ventricular reflux is proposed. The different normal and pathological characteristics of fluid movements in the spinal canal are given, and their importance as signs of turbulence in the posterior fossa are emphasized. Different aspects of the dynamics of CSF production are shown and discussed, and an evolving conception of hydrocephalus development is presented.

New aspects of cerebrospinal fluid dynamics in humans investigated by sequential gammacamera cisternography, with data evaluation by the digital multichannel analyzer. Part 3: Physiopathology of the ventricular reflux.

Although well described and intensively used for diagnostic purposes, the ventricular reflux as a gammacisternographic phenomen has not yet been satisfactorily explained, and its physiopathology is a subject of controversy. Based on our method of quantitative gammacisternography and gammaventriculography we study the evolution of the tracer concentrations in two main chambers:--the basal cisterns together with the upper cervical canal, considered as a functional unity (the distribution area) and--the ventricular system. We propose the mathematical analysis of a theoretical model which represents the normal and pathological situations of these two chambers, as a method for measuring ventricular volume and ventricular tracer clearance. From the correlation in results with patients and models, we suggest turbulence as the main factor in generating backmixing or total mixing, the appearance of which is called ventricular reflux. We deny the existence of a real inversion of CSF flow. The spinal canal velocity of isotope flow is proposed as additional evidence of turbulence. The normal general dynamics of CSF are delineated, and we propose the following factors that lead to ventricular reflux:--partial obstruction to epicortical CSF flow;--total obstruction to epicortical CSF flow. Their principal characteristics are given, and the importance of using their quantitative parameters in descriptions of patients is stressed. Different aspects in the evolution of hydrocephalus, transependymal resorption, and factors involved in hydrodynamic changes etc. are discussed.

[Clinical and morphological considerations concerning "medulloepithelioma" (author's transl)]. / Klinische und morphologische Betrachtungen über das "Medulloepitheliom"

The clinical course and autopsy findings in a 20 months old child with a so-called medulloepithelioma of the brain stem are reported. The histological features of this tumour are described. Ten previous cases in the literature are reviewed and the controversial problems of this entity are discussed. It seems reasonable to place this malignant tumour in the group of ependymomas; in detail, the definition "embryonic ependymoma"; proposed by Fowler, appears to be the most suitable, because it comprises all morphological and biological features of this rare malignant tumour.

On the development of an aneurysm of the middle cerebral artery.

The development of an aneurysm of the middle cerebral artery within a 12 year interval is documented angiographically in a 49-year-old female patient suspected of having a meningioma of the medial wing of the sphenoid.

[Long-Term Results of Surgical Treatment of Spinal Tumours in Children and Adolescents]. / Langzeitergebnisse in der Behandlung spinaler Tumoren des Kindes- und Jugendalters

Catamneses of children up to the age of 16, operated on spinal tumours, are reported. Spinal tumours of this age account for about 15% of the total (all ages). There are about 50% intradural and 50% extradural tumours. The most frequent extradural tumours are sarcomas, followed by lipomas and dysontogenetic tumours like teratomas. Intradural tumours consist of intramedullary and extramedullary ones, about 50% each. Intramedullary tumours are gliomas, extramedullary ones may be neurinomas, meningeomas and vascular tumours. Time from onset of first diffuse symptoms up to clinical diagnosis depends on growth tendency of the tumour as well as on its localization. Hence, case history in cases of intramedullary gliomas usually covers two years, of sarcomas only a couple of months. In half of the cases, pain was the first symptom, followed by disturbed motor function. In more than 50% of the cases, complete restoration or significant improvement could be achieved by surgery. In the remaining half, there was either no change or even deterioration of the disturbed function. It seems justified to replace the former pessimistic attitude towards therapy of spinal tumours in childhood by a discret optimism. If in addition other spinal diseases like disk herniation are taken into account, prognosis is even more favourable.