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Resume Les techniques utilisees en neurochirurgie pour le traitement des epilepsies partielles pharmaco-resistantes sont multiples. Elles peuvent etre divisees entre chirurgie curatrice (notamment lorsqu’un foyer unique est mis en evidence) et chirurgie palliative. La chirurgie curatrice la plus frequemment realisee concerne les resections du lobe temporal. Les differentes techniques sont brievement decrites, les indications et les complications sont discutees.

We set out to validate the concept of three-dimensional (3D) angiography. We evaluated the sensitivity and the quality of morphological analysis mode possible by an experimental system for imaging cerebrovascular disease versus standard digital subtraction angiography (DSA). The system, the 3D Morphometer, is a computerised X-ray angiography unit capable of acquiring a set of two-dimensional (2D) projections during a rotation and then reconstructing a 3D volume from them. We studied 78 patients with suspected cerebrovascular disease. 3D and 2D images (standard 2D DSA performed during the same procedure), were reviewed blindly to assess detection and display of morphological characteristics of cerebrovascular diseases. We found 53 aneurysms, 22 arteriovenous malformations and two venous angiomas. On 3D angiography we detected two aneurysms we missed on 2D angiography. In 47 aneurysms on which further data were obtained during surgery or embolisation, the 3D angiography allowed more accurate analysis of the neck and surrounding vessels in cases in which the 2D angiographic findings were doubtful. Assessment of arteriovenous malformations was equivalent with both techniques. Under the conditions of our study, the technical constraints being the same for both methods, 3D angiography was superior to 2D angiography. Implementation on C-arm vascular systems is being evaluated.

Frontal lobe epilepsy surgery is the second most common surgery performed for drug-resistant partial epilepsy. We investigated the longitudinal outcome in a cohort of patients investigated since 1990 with SEEG and modern diagnostic techniques. We reviewed 105 patients who underwent surgery between 1990 and 2005 (mean follow-up, six years; range: one to 17 years) and analyzed the year-per-year follow-up according to Engel's classification. Favorable outcome (Class I) was observed for 70% and this result was stable at least five years after surgery. More than 90% of patients with lesion-related epilepsies (focal cortical dysplasia and dysembryoplastic neuroepithelial tumors) became seizure-free. Less than 50% of patients classified as having cryptogenic epilepsy (defined as normal imaging and neuropathology on surgical specimen) had a favorable outcome. Permanent neurological sequelae were subtle and rare, especially after surgery for dysplasia in eloquent cortex (primary motor cortex). Our data indicate that frontal surgery is a successful treatment in patients when electrophysiological and morphological investigations demonstrate a well-defined epileptogenic zone or lesion to be surgically resected. Progress in electrophysiological and brain-imaging techniques will further improve the selection of frontal lobe epilepsy surgery candidates.

Many different surgical procedures are performed for medically refractory partial epilepsy. Some surgical therapies are performed to cure the epilepsy (for example unifocal epilepsy), others are palliative procedures. To cure epilepsy, temporal lobectomy is the most common surgical procedure. The different techniques are shortly described, indications and complications are discussed.

A system devoted to the localization and treatment of small cerebral lesions that can not be reached by surgery is presented. The method is based on the use of a stereotactic approach to localize the target and to guide the multibeam radiation therapy treatment. The approach and the pipeline software modules developed to process and control the radiation therapy planning are described. The application presented here is a first approach to computer-aided radiation planning and treatment. >

We report scalp EEG and ictal SPECT findings in epileptic (complex partial) and non-epileptic seizures in three patients who experienced both types of event during presurgical investigation of medically intractable epilepsies. In all three patients, ictal SPECT showed localizing changes in cerebral blood flow during epileptic seizures, but showed no change during pseudoseizures. In two patients, the physical manifestations of the pseudoseizures were similar to those of the epileptic seizures, supporting the contention that physiological activation is unlikely to mimic ictal perfusion changes. In one patient, the EEG recording was rendered difficult to interpret by muscle artefact, while SPECT was clear and showed no change. SPECT is not a primary tool for diagnosis of pseudoseizures, but when patients undergoing presurgical investigation are injected during pseudoseizures, then SPECT is unlikely to show misleading perfusion changes due to activation effects, and may aid diagnosis where there is muscle artefact on EEG.

We report scalp EEG and SPECT findings in a young patient who experienced gelastic seizures; clinical, EEG and scintigraphic data strongly suggested a frontal focus in a context of cryptogenic epilepsy. Few cases of gelastic seizures originating in the frontal lobe have been reported in the literature, most of them involving a diencephalic hamartoma or a temporal focus although, no clinical pattern has been found to be specific for each of these three anatomical regions. The ictal laughter is of variable nature, unmotivated or associated with feelings of mirth, forced or natural, except in the case of a frontal focus where the laughter seems consistently described as forced and unmotivated. However, mirth and laughter are two dissociable clinical elements; their genesis probably involves distinct mechanisms. Anatomical considerations lead to several hypotheses concerning laughter generation: it could be a simple reactional behavior in response to a modified cognitive process, an automatic behavior or a forced action. In a few cases with a temporal focus, laughter seems directly related to a disorganization of the associative temporal cortex and may be considered as a reactional behavior. In cases with frontal focus, anterior cingulate and orbital structures would be particularly implicated in laughter genesis, although with possible different pathophysiological routes: in the first case by disconnection within the premotor mesial system or by an imbalance between premotor mesial and premotor lateral systems, and in the second case by activation of a previously conditioned orbital region.

The RETAIN project (Radiological Examinations Transfer on an ATM Integrated Network) has aimed at testing videoconferencing and DICOM image transfers to get advice about difficult radiological cases over an asynchronous transfer mode (ATM)-based network, which affords a more comfortable interface than narrow-band networks and allows exchange of complete image series using the DICOM format of studies. For this purpose, an experimental ATM network was applied between six university hospitals in four different countries. An assessment of the functionalities of the system was performed by means of log-file analysis, video recording of the sessions and forms filled out by the participants at the end of each session. Questionnaires were answered by the users at the end of the project to bring out perspectives of utilisation and added value. We discussed 43 cases during 20 sessions. For technical or organisational problems, only 20 of the 36 planned sessions took place. The throughput over ATM (10.5 Mbit/s, 20 times faster than six ISDN B-channels) was adequate. Despite the experimental configuration of the network, the system was considered as satisfactory by all the physicians. In 72 % of the sessions, the expected result (answer to the question) was gained. By common consent, videoconferencing was unanimously regarded as a prominent tool in improving the interaction quality. Asynchronous transfer mode is an efficient method for fast transferring of radiologic examinations in DICOM format and for discussing them through high-quality videoconferencing.

The main purpose of our study is to combine three different methods of brain activity recordings: depth recordings (stereotactic EEG: SEEG) and surface recordings (EEG/MEG) in order to improve localizations of the sources of the brain activity. We present here the first step of this study. We built a model of a region of interest (ROI) within the brain based on MRI information. Our goal was to obtain an accurate description of the surface of the ROI. According to this model, we defined realistic dipole layers in respect to the anatomy (orientation, shape, extension). By activating those dipole layers we produced SEEG, EEG and MEG theoretical signals. In order to validate this concept on a physiological point of view, we chose the auditory cortex as the ROI. We compared the simulations with in vivo signals (Auditory evoked potential (AEP)) for which Liegeois-Chauvel et al [1] studied the localization of the middle latency components using SEEG. We performed the validation by taking into account the auditory cortex anatomy and built the simulations for each patient studied. We then compared the theoretical results with the real SEEG data. Furthermore we used those simulations to test the reliability of several MEG sources modeling algorithms.

We report an unusual case of spontaneous acute spinal subdural hematoma. To date, only a few cases of magnetic resonance imaging (MRI) demonstration of such a pathology have been reported in the medical literature. We analyse the pathogenesis, clinical presentation, magnetic resonance imaging results, intraoperative findings and prognosis of this rare condition. We would like to stress that prompt and non-invasive diagnosis by MRI sagittal sections leads to efficient surgical treatment.

The need for medical images which can directly contribute to therapeutic decision making has led to the development of 3D visualization techniques. With this objective, a procedure capable of producing 3D volume reconstructions using isotropic voxels from digitalized 2D films obtained by rotation around the object has been developed: 3D morphometry. The technique has been assessed from 1993 through 1996 for vascular malformations in the brain, particularly aneurysms. Recognition of collateral vessels originating at the malformation was helpful in better identifying the lesions and evaluating possible therapeutic difficulties. The morphometric sequence thus is a possibility for the future assessment of neurovascular arches.

Multimodal sensory properties of the prefrontal cortex have been extensively studied in monkeys, while little is known of such functions in humans. We report electrophysiological evidence for auditory and visual representations in the dorsolateral prefrontal cortex, as inferred from intracerebral ‘depth’ recordings of focal, sensory-evoked spike-wave complexes (SWC) in an epileptic patient. In addition to clinical monitoring, the patient participated in behavioural evoked potential studies involving auditory and visual discrimination tasks. Inspection of evoked potential recordings from different medial-to-lateral prefrontal sites revealed overlapping, but non-identical topographies of evoked SWC for the two sensory modalities. The maximal activity of sensory-evoked SWC was located 7 mm more medially for visual than for auditory stimuli, and occurred later for visual presentations (mean = III ms following stimulus onset) than for auditory ones (mean = 87 ms). Effects of sensory habituation were seen. Evoked SWC were less likely to occur following repeated presentations of an unchanging tone than when tones alternated in pitch, or when a tone followed an omission in stimulus presentation. Visual hemifield effects were found, with greater prefrontal responsiveness to presentations in the contralateral visual hemifield. These results are consistent with electro-physiological findings in animals indicating overlapping auditory and visual representations in the dorsolateral prefrontal cortex.

A new system has been designed and built to validate the concept of 3D computerized Χ-ray angiography. It addresses all the difficulties met from the acquisition of raw data on a patient to the display of the reconstructed volume. The first in vivo results obtained with this system are presented.

Extracorporeal circulation with circulatory arrest and deep hypothermia in surgery on certain giant intracranial arterial aneurysms or on aneurysms difficult to access is described. The series includes a giant left carotid aneurysm, an aneurysm of the basilar artery bifurcation, a patient with two aneurysms, one on the right middle cerebral artery and the other at the end of the basilar artery, and a fourth patient with two aneurysms, one on the right middle cerebral and the other on the right carotid. Closed-thorax extracorporeal circulation with femoral cannulation was performed on all the patients. Surgical procedure is described and the advantages and disadvantages discussed. Results are encouraging. The authors suggest that the technique be used during surgical treatment of certain intracranial aneurysms that are in awkward positions or are very large in size. They emphasize that the procedure should be confined to exceptional cases.

The authors emphasize the advantages of stereotaxic methodology in the management of 200 brain tumors. Nowadays computerized tomography is the first stage of radiologic diagnosis. Both CT scan and stereotaxic examination have been carried out in more than 35% of these tumors. Rather than a comparison of the two examinations, the authors' purpose is to attempt to demonstrate their complementarity in the assessment of location, volume, and nature of the lesion and eventually in the choice of a therapeutic attitude. Analysis of topographic data and staged biopsies, gathered from the 'stereotaxic space,' provides the neurosurgeon with accurate information for planned surgical excision or interstitial irradiation.

Both surgical (236 aortic valve replacements) and anatomical (62 dissections) studies have defined the aortic annulus diameter. Measurements (23.5 mm for women; 26 mm for men) are more considerable than established values. Furthermore, surgical study allows the authors to compare these results to several variables, more especially corporeal surface and stature: the height's increase perhaps explains the large sizes discovered.

Stereotaxic angiography offers many advantages over conventional techniques for the diagnosis of cerebral tumours: three dimensional analysis of the vascular pedicles supplying thetumours; precise identification of the structures with which certain cortical vascular loops are connected; early detection of small pathologic displacements; pre-planning of a precise surgical procedure, and finally a radiographic control of each intervention under the same circumstances.

Report on two cases of spontaneous, intermittent and long lasting spinal fluid rhinorrhea. The lesion responsible of the spinal fluid fistula is a glio-arachnoid expansion of the convexity of the frontal pole, contained into a fibrous pedicle ; it crosses the dura mater and penetrates, through a well individualized bone orifice, into the posterior wall of the frontal sinus or into an ethmoid-frontal cell. This arachnoid diverticle is not associated with an hydrocephalon. In the absence of any traumatic past history, its congenital nature may be admitted. No para-clinical investigation makes possible to detect such a minor abnormity ; the isotopic transit of the spinal fluid may remain silent, when performed at a moment of drying up of the nasal flow. Surgical exploratory study of the anterior level has to be complete, while numerous independent diverticles may coexist.

The natural history of malignant gliomas is compared to the mean survival duration after surgery alone and/or surgery associated with radiotherapy and chemotherapy. In the state of the art a combined treatment by surgery and roentgentherapy offers the best prognosis but does not allow for more than 35% of expectation of life at the end of the first year. According to the severity of the general prognosis the present authors advocate a strict care for the functional integrity. An improved knowledge in the biology of cerebral gliomas justifies further consideration in the surgical treatment preparing the expected effects of radiotherapy and chemotherapy.

The habenular complex of 11 cats and 13 rats was injected with horse Radish peroxydase (HRP) (30% solution, 0,05--0,4 microliter). Retrograde labelling of cells was visualized after a survival period of 24 to 48 hours by means of the method of Lavail et al. (1973). The resultats obtained with this method suggest significant species differences regarding the habenular afferents in cats and rats. One of the most striking differences is that the entopeduncular nucleus of the cat contains very few HRP labelled cells after lateral habenular nucleus injection in comparison to the entopeduncular nucleus of the rat which can be shown to be the major source of afferents to the lateral habenular nucleus by the same method.

The respective role of surgical ablation versus palliative methods (i.e. shunting followed by irradiation) in the treatment of tumors of pineal region is still questionnable and must take into account the variability of their pathology. Thus, knowledge of tumoral type in each case is the first step to therapeutic discussion. The stereotactic methods allow a faithful biopsy, easy to interpret and without major risks.

The authors describe an exceptional case of aspergillosis from sphenoidal sinus showed by oculomotar palsy its follow up simulates a malignant tumour.

A new case of thoracopagus twins is reported. Radiological, hemodynamical and surgical explorations showed a communication between the two hearts, situated at the atrial level and associated with digestive and cardiovascular malformations. These abnormalities were definned by the anatomical study realized after vascular injection:hypoplastic pulmonary artery (associated with a persistent atrio-ventricular canal in one case, with a tricuspid atresia in the other case), a large fused liver, common pancreas and ileum. A bibliographic study allows the authors to define surgical separation possibilities. The prognosis depends essentially on cardiovascular abnormalities associating abnormal connections between the twins' hearts with malformations often too severe for surgical repair.

Seventy tests of stimulation with hypothalamic thyreotrophic hormone liberation factor, and 35 bromocriptine inhibition tests were carried out on a routine basis in patients with latent or frank hyperprolactinaemia. Pathological hyperprolactinaemia does not have a single clinical pattern: frank, it takes the form either of an exteriorised pituitary adenoma (14 cases), or of an amenorrhoea-galactorrhoea syndrome with or without micro-adenoma (12 cases); latent, it takes the form either of isolated amenorrhoea (17 cases) or of dysovulatory sterility (16 cases). Amongst the dynamic tests available, it is worthwhile to make a choice, and in the case of frank hyperprolactinaemia, the authors propose use of the bromocriptine inhibition test in the first instance. The TRH test is reserved for verification of the results of neurosurgery. As far as latent hyperprolactinaemia is concerned, it may be identify only by the TRH test, with the resultant possibility of specific treatment.

After a double study (anatomical--50 dissections--and radiological--100 arteriograms) the following points can be stressed: the femoral tripod is only found in 38 per cent of the cases. One or several nutrient arteries of the thigh originate often separately (62% of cases). Their origine is situated highup in a number of cases (at 3 cm below the inguinal ligament). The collateral network develops from each of the arteries forming a complete "profunda femoris system". Two surgical consequences deserve to be underlined: 1. The approach to all the branches is possible by a transverse incision in the fold of the groin. 2. Surgical revascularisation must concern the whole of the "profunda femoris" network.

Stereotactic examinations with CT scan have previously demonstrated their performances but the specific interest of MRI in the neurooncology field requires the transposition of a well established CT scan method into NMR technology (2,3,6). Main problems concern the material included in the stereotactic frame (without any ferromagnetic substances), the position of the patient in the imaging system and the visibility of constrast substances in MRI. Regarding these three demands, we have developed a convenient stereotactic frame for both MRI and CT scans. This frame is of very simple use according to the atraumatic fixation on the patient head and allows short time examination compatible with routine use of imaging.

From a necropsy series of 14 kidneys, it is very easy to prove, that there is a quite good correlation between the theorical calculated volume of the kidney and its real volume. It is possible to compare the kidney to an ovoid, and to calculate its volume, knowing the 3 dimensions which are its length, its width, its depth. In this way, by echotomography it is possible to estimate these three parameters at the level of the transplanted and to calculate the volume and if, after two successive examinations of control, the kidney volume is found to be enlarged (over 20%) a reject phenomenon must be diagnozed.

The authors emphasize the advantages of stereotaxic methodology in the management of 200 brain tumors. Nowadays computerized tomography is the first stage of radiologic diagnosis. Both CT scan and stereotaxic examination have been carried out in more than 35% of these tumors. Rather than a comparison of the two examinations, the authors’ purpose is to attempt to demonstrate their complementarity in the assessment of location, volume, and nature of the lesion and eventually in the choice of a therapeutic attitude. Analysis of topographic data and staged biopsies, gathered from the ‘stereotaxic space,’ provides the neurosurgeon with accurate information for planned surgical excision or interstitial irradiation.

The treatment of tumours of the pineal region is the subject of keen controversy between advocates of surgical excision and those of radiotherapy with ventricular shunting. The proponents of these extremes often seem to ignore the wide pathological variety of tumours of this site. Attempted excision of a germinoma invading the walls of the 3rd ventricle is as futile and dangerous as irradiation of a teratoma. Stereotaxic biopsy provides precise pathological diagnosis and thus allows more specific management; the procedure is safe and no serious complications were experienced in 25 cases.

Agenesis of the internal carotid artery was discovered during emergency cerebral angiography carried out on a comatose 28 year old man. The left cerebral hemisphere was supplied from the controlateral carotid artery, via a large vessel running through the sphenoid bone, between the intracavernous portions of the internal carotid arteries. Postmortem examination showed that death resulted from massive haemorrhagic infarction of the cerebellum and brain stem. Absence of the cervical and petrosal portions of the left internal carotid artery was confirmed. The anastomotic vessel was found to run through the spongiosa below the dorsum sellae. The heart, major vessels and circle of Willis were otherwise normal. An intercarotid anastomosis of this type has been reported on three previous occasions, in none of which was there anatomical confirmation.