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Biomedical subjects

C Munari

Publications and source records attributed to C Munari.

At least 55 records · Page 3Linked to original sources
PubMed1993

Intracerebral low frequency electrical stimulation: a new tool for the definition of the "epileptogenic area"?

Low Frequency (1 Hz) Electrical Stimulation (LFES) has been systematically utilized, during stereo-EEG investigations, in 24 consecutive young adult patients considered for surgical treatment of severe drug-resistant partial epilepsy. Ninety seizures (1-14/patient) identical to the spontaneous ones previously recorded were thus obtained in 19 patients (79%). LFES is less effective for induction of seizures than high frequency (50 Hz) stimulation (5.9% vs 22.9%), and it also provokes less "false positive" responses (1% vs 17%). The main "sensitive" structures to LFES are the hippocampus, the amygdala, and the hippocampal gyrus. However, seizures were also induced by stimulating the temporal lobe white matter, the temporal pole, and the temporal neocortex, as well as the orbito-frontal cortex (in the only patient with fronto-temporal epilepsy). The more frequently observed electrical pattern is a gradual increase of spikes and spikes and waves frequency, with or without occurrence of low voltage fast activity. The high percentage of early "subjective" manifestations similar to the spontaneous ones, the lack of major electrical artifact, and the good visualization of the spatial evolution of the induced-discharge, strongly suggest that LFES is of great help for defining the "epileptogenic area".

Adult↗
PubMed1993

[Electroclinical manifestations elicited by intracerebral electric stimulation "shocks" in temporal lobe epilepsy].

In patients with severe drug-resistant partial epilepsy, undergoing Stereo-EEG investigations, spatial definition of the "epileptogenic area" is mainly based on spontaneous seizures recordings, but also on seizures induced by intracerebral electrical stimulation (ES). Only "trains" ES (TES, 50 pps) are currently used with this aim; "shocks" ES (SES, 1 pps) are principally applied to localize motor pathways. We have shown, during a prospective study concerning 10 temporal lobe epileptic patients, that SES could frequently induce seizures, especially when stimulation is applied in the anterior part of the Ammon's horn. Even if its efficacy seems lower than by TES, this kind of stimulation, in the majority of the cases, does reproduce isolated ictal subjective symptomatology, allowing the visualization of the progressive organisation of ictal electrical discharges, and avoids "unexpected" ("false positive"?) clinical responses.

Adolescent↗
PubMed1992

Stereotactic approach to intracranial lesions.

The diagnostic and therapeutic approach to intracranial lesions must be different considering the different possibilities offered by the various methods. The diagnostic reliability and safety of stereotactic biopsy are often indispensable in order to optimize the subsequent therapy. The results obtained in selected pathologies allow us to propose the stereotactic approach to treat: -various kind of cysts by aspiration and/or Beta endocavitary radiation therapy; -blood or abscessual collections that can be aspirated in a similar way; -arterio venous malformations or tumours by radiosurgery; -tumours by brachicurietherapy or by computer assisted stereotactic surgery. We present some cases treated at the C.H.S.A. of Paris and at the C.H.R.U. of Grenoble utilizing Talairach methodology.

Adolescent↗
PubMed1992

Surgical therapy for frontal epilepsies.

We have described our 25 years experience concerning 100 patients operated on for frontal epilepsy. Results show that 55% of patients are practically cured of their seizures and that 76% benefited from cortectomy (reduction of more than 75% of seizures). These results are the worst in the total series of St. Anne. Reasons for success and especially failure were analyzed in detail: 1. SEEG methods gave good indications along three dimensions of the limits and borders of the cortical excision. 2. When clinical semiology and organization of ictal discharges give evidence for rapid bilateral discharge, with involvement of axial musculature and generalized tonic-clonic manifestations, experience shows that it is necessary to combine cortectomy with a section of the adjacent cortico-subcortical fibers of the corona radiata, as if propagation of ictal discharges were impeded if not interrupted by sectioning such fibers and the primary site were incapable of expressing itself clinically. 3. If the characteristics of seizures suggest the quasisimultaneous involvement of the two frontal lobes and the existence of bilateral multifocal epilepsy, we suggest that a systematized anterior callosotomy might lead to useful results. 4. Finally, we propose general criteria for indications and contraindications for surgery.

Adolescent↗
PubMed1992

[Radiosurgical treatment of minor intracranial arteriovenous malformations by using a linear accelerator].

This study deals with 43 patients with cerebral arteriovenous malformations (AVMs) of a maximum of 20 mm in diameter. All of them were radiosurgically treated with a linear accelerator in stereotatic conditions (UMIC). The delivered doses vary from 20 gys to 50 gys. Thirty-seven were controlled angiographically and 35 of them showed the disappearence of the AVM. Different parameters can modify the results: delivered dose, the size and shape of the lesion, target-volume, peripheral lesion isodosis (75%), location, underestimation of the size or dose. These results show that small lesions are best to treat than larger ones, particularly because their volume enables us to encompass them more easily. The uniformity of this series is related to the homogenous size of the treated AVMs, thus avoiding the discussion of global, unclear, results.

Adolescent↗
PubMed1991

[Introduction to the clinical study of postrolandic epileptic seizures].

We reviewed, in 145 epilectics studied with SEEG, 800 clinical and electrographic seizures originating from the post-rolandic areas (590 spontaneous Sz and 260 induced by stimulation). The intra-cranial electrodes were implanted using a technique described by Talairach et al. (1974). Seizure onsets were recorded in the centro-parietal region (64 patients) in the parietal and in the occipital region. Additionally in 15 patients, mixed Sz onset were recorded. One hundred and eight (108) patients underwent surgical removal of their epileptic focus. (69 on the right, 39 on left.) 65% were cured (Sz free or occas Sz, f/up 3 years). The main ictal cal features are discussed. Emphasis is placed on the role of the operculo-insular cortex in the functional organization in man, based on Sz arising from the supra-temporal (fronto-pariental) cortex. The study of the pattern of onset and spread of seizures originating in the post-rolandic areas and of their clinical correlates allow a topographic differential diagnosis.

Diagnosis, Differential↗
PubMed1989

Differential diagnosis between tumoural and non-tumoural intracranial lesions in children: a stereotactic approach.

The rational management of intracranial lesions should be based on the exact definition of the nature of the lesions and, when it is possible, on their spatial definition. Since External Radiotherapy (ERT) and cytostatic therapy are not free of undue effects, especially in children, such treatments should be used only when a "sure" diagnosis is obtained. The aim of this paper is to study the results allowed by the Talairach's stereotactic methodology in children. During the period January 1979-December 1986, 704 stereotactic procedures including serial biopsies, were performed at the S. Anne Hospital in Paris. One hundred forty-eight procedures (21%) concerned 134 children (78 M; 56 F) aged from 2 to 16 years. The interval between the occurrence of the first clinical symptoms and the stereotactic procedures varied between 1 and 180 months (m: 24 m). Fifty-two (40%) had previous therapeutic procedures without precise diagnosis. The lesions were hemispheric in 46 (34%) and deep seated in 88 (66%). The serial stereotactic biopsies proved the existence of a non-tumoural lesion in 20 children (14.9%): (cryptic vascular malformation: 5, cortical dysplasia: 3, haematoma: 3, ischaemia: 1, granuloma: 1, degenerative pathology: 2, cicatrix: 2, post-ERT alterations: 1, arachnoidal cyst: 2). Four were in the brain stem. In 3 patients (2%), a precise diagnosis was not obtained. The CT scan characteristics of the 20 non-tumoural lesions did not permit to establish a precise differential diagnosis. The therapeutic management was adapted to the diagnosis, avoiding potentially dangerous procedures in the 20 non-tumoural lesions.

Adolescent↗
PubMed1989

Stereotactic investigations in frontal lobe epilepsies.

The aim of a Stereo-EEG investigation is to verify and prove that the hypothesis, done on the basis of the preliminary investigations (clinical, EEG, neuroradiological), are correct. This task is particularly hard in frontal lobe epilepsies, because of anatomical and physiopathological reasons. Among 277 consecutive patients, 86 were explored for a probable frontal epilepsy. The stereotactically introduced electrodes. 1) simultaneously record the electrical activity on both, mesial and lateral cortical areas, and, 2) in 3/4 of cases also investigate extra-frontal, mainly temporal, areas. Two small, non-surgical haematomas were provoked in one patient. The spatial trajectory of the discharges, evaluated with this methodology, permits of limiting the surgical removal in many cases.

Adolescent↗
PubMed1989

Diagnosis and treatment of colloid cysts of the third ventricle by stereotactic drainage. Report on eleven cases.

Between December 1979 and September 1986, 11 patients with colloid cysts of the third ventricle were operated on by a stereotactic procedure with Talairach's system. Stereoscopic angiography and ventriculographic study allowed for a percutaneous (twist-drill hole diameter: 2.5 mm) stereotactic aspiration of the cysts. The operations were successful, and there were no intraoperative or postoperative mortalities but just mild transient morbidity in three cases. Six cysts were evacuated completely, and five only partially. The mean residual volume was 19% of the initial one. Clinical and anatomical results are presented, and the advantages of this stereotactic procedure are discussed.

Adolescent↗
PubMed1989

Stereotactic radiosurgery with the linear accelerator: treatment of arteriovenous malformations.

An original stereotactic radiosurgical approach coupling a) Talairach's stereotactic methodology, b) a specially devised mechanical system, and c) a linear accelerator is detailed. The authors present their preliminary results on 66 patients with nonsurgical intracranial arteriovenous malformations. The doses delivered for treatment varied from 20 to 70 Gy. Doses of no more than 40 Gy were used in 80% of patients. An angiographic study was performed when the computed tomographic scan controls showed relevant modifications of the lesion volume. Total obliteration was obtained in 27 of the 41 patients (65.8%) who were followed up for at least 24 months. The percentage of the cured patients is significantly higher when a) the entire malformation is included in the 75% isodose (96%) and b) the maximum diameter of the lesion is less than 12 mm (81%). Two patients died of rebleeding at 18 and 29 months after treatment.

Adolescent↗
PubMed1989

[Early right posterior cerebral hemispheric lesion and right speech dominance in 2 right-handed female patients].

Two female patients presented a severe partial epilepsy of early onset and an extended right posterior hemispheric lesion of prenatal or perinatal origin. They were right-handed and all their first degree relatives were right-handed. Nevertheless, evidence of right hemispheric speech was documented in both patients, on the basis of a bilateral sodium amytal test in one case, and of a persistent aphasia after neurosurgical treatment in the other. The possible consequences of an early cerebral pathology on cerebral lateralization are discussed, including pathological right-handedness.

Adolescent↗
PubMed1988

[Stereotaxic ventriculocisternostomy in the treatment of triventricular obstructive hydrocephalus. Apropos of 23 cases].

UNLABELLED: During the period January 1975-October 1987, we performed stereotactic ventriculocisternostomy (V.C.S.) on 23 patients (13 M., 10 F.; age: 11-73 years, m: 33). Sometimes used as an isolated therapeutic procedure, V.C.S. may also follow stereotactic biopsies using Talairach's methodology. Serial stereotactic biopsies were performed in 15 out of 23 patients showing 11 tumoral lesion, two arachnoïdal cysts and two cryptic vascular malformations. Eight patients presented with an isolated aqueductal stenosis. Among the 12 non tumoral patients, seven had very large triventricular hydrocephalus (6 with a retroclival dilatation of the third ventricle) and 5 showed significant dilatation. Of the 11 tumoral patients, 7 had significant ventricular dilatation (1 with a protrusion of the floor of the third ventricle) and 4 with modest dilation. V.C.S. is done by creating an opening (diameter: 5-6 mm) in the floor of third ventricle with a fine forceps introduced through a tubular guide (diameter: 2.45 mm). The percutaneous double oblique transfrontal trajectory (drill-hole: 2.5 mm of diameter) passing through the foramina of Monro, avoids superficial and deep vessels visualised on the previous Stereoscopic Tele-Angiographic and Ventriculographic study. A systematic verification of the V.C.S. patency is made intraoperatively by injection of iodine contrast medium into the third ventricle. RESULTS: (non tumoral patients: 12) (m follow-up: 4 years): two patients needed a ventricular shunt after 3 and 1 months respectively, the first one because of an associated communicant hydrocephalus, the second because of a post-operative meningeal infection. Long-term clinical and CT-Scan follow-up showed that complete resolution (7 cases) or partial (2 cases) improvement of symptoms and signs was not accompanied by normalization of ventricular size, even though the dilatation was significantly reduced in 8 cases and to a lesser extent in 2. RESULTS: (tumoral patients: 11) (m follow-up: 3 years). Hydrocephalus was reduced in 6 cases and remained unchanged in 5. Two patients needed a ventricular shunt 2 years after the V.C.S.: 1 patient, because of a tumoral recurrence involving the region of the fenestration, the second patient because of adhesive arachnoiditis following reoperation for suspicion of recurrence, though this was found to be granulomatous inflammation. Two patients died as a result of their tumors at 2 and 6 years. CONCLUSION: Stereotactic V.C.S. is the treatment of choice for triventricular obstructive hydrocephalus even when there is no retroclival dilatation of the floor of the third ventricle.

Adolescent↗
PubMed1988

[Stereotaxic diagnosis and treatment of colloid cysts of the 3d ventricle. Apropos of 7 cases].

The clinical and anatomical results of the treatment of 7 colloid cysts of third ventricle by stereotaxic aspiration are reported. A history of increased intracranial pressure was reported in all patients (4 females aged of 12, 16, 28, 38 years; 3 males aged of 36, 54, 59 years). A ventricular shunting device has been inserted in 4 patients. Pre-operative clinical findings were: signs of increased intracranial pressure (1 case), isolated memory disturbances (3 cases); motor weakness, memory disturbances and psychomotor slowness (2 cases); 1 of the 2 last cases had also thymic disturbances. Clinical examination was normal in 1 patient. CT-Scan revealed 5 hyperdense lesions, 3 with slight enhancement; 1 hypodensity encircled by an hyperdense ring without enhancement, 1 not enhancing isohypodensity. 6 colloid cysts were between the Foramens of Monro, 1 in the posterior third ventricle. Cyst volume ranged from 1.8 to 6.3 cc. (m: 3.4). Biventricular hydrocephalus was present in all but 1 patient. Stereotaxic aspiration of the cyst performed according to Talairach's system resulted in a release of C.S.F. circulation in all cases. 3 colloid cysts were aspirated completely, 4 were reduced to 3%, 11%, 12%, 33% of the initial volume. Post-operatively 2 patients presented with a transient meningeal reaction, 1 with a transient "myoclonic" syndrome. In 1 "completely aspirated" case a control CT-Scan showed, 5 years later, a small hyperdensity corresponding to 4% of the initial cyst volume. All patients lead a normal and useful life (Follow-up: 8-78 months, m: 45). Neurological examination is normal in 6 cases and shows a pre-existent facial asymmetry in 1. Ours results suggest that stereotaxic investigation should be the first safe procedure in order to achieve both diagnosis and treatment of colloid cysts of third ventricle.

Adolescent↗
PubMed1987

Serial stereotactic biopsies and CT scan in gliomas: correlative study in 100 astrocytomas, oligo-astrocytomas and oligodendrocytomas.

Histologic features of 100 supra-tentorial astrocytomas, oligodendrogliomas and oligo-astrocytomas obtained from serial stereotactic biopsies were compared with the corresponding CT scans. Topographic comparisons provided by visualization of the biopsy trajectories on post-biopsy CT scans were available in 24 cases. Areas of contrast enhancement and low attenuation were compared with the histologic grade of malignancy, tumor delimitation and structural type. The latter was determined as follows: Type I-solid tumor tissue without significant peripheral isolated tumor cells; Type II-solid tumor tissue associated with peripheral isolated tumor cells; Type III-isolated tumor cells only. There was a strong correlation between areas of contrast enhancement and tumor microvascularity. In addition, contrast enhancement occurred only in the solid tumor tissue component of the neoplasm. This correlation accounted for the relationship observed between CT images and the structural type of glioma. Contrast enhancement was constant in structural type I gliomas, inconstant in structural type II, and absent in structural type III. No correlation was found between malignancy and contrast enhancement. Contrast enhancement occurred in all grades of malignancy but was a constant feature of grade 4 gliomas. The volume of the tumors could not be reliably determined from CT images alone. Areas of low attenuation on contrast CT scans could correspond to either peritumoral edema or to edematous parenchyma infiltrated by isolated tumor cells. Serial stereotactic biopsies combined with calculations based on the CT scan provided a more precise definition of the tumor volume and identification of structural type. Such classification may prove useful in prospective analysis of various modes of therapy.

Adolescent↗
PubMed1987

[Complementarity of x-ray computed tomography of staged stereotaxic biopsies and of stereo-electroencephalography in the spatial definition of intracranial lesions].

This study concerns 180 patients (132 M; 48 F) (age: 2 to 69 years; m: 33 years) who underwent stereotactic procedures according to the methodology of Talairach and Szikla. Such procedures (stereotactic and stereoscopic angiography in all cases, and ventriculography in 81%) should permit a correct spatial definition of intracranial lesions. The informations provided by the angiography (normal in 7%) and by the ventriculography (normal in 11%) are complementary to those yielded by the TDM and permit an easier and safe stereotactic approach to the lesions. In 43% of patients the lesions were deep-seated (basal ganglia: 24; sellar region: 19; thalamo-peduncular: 13; brain stem: 6, etc.). The histological examination showed: low-grade gliomas in 43%; glioblastomas in 21%; non tumoral lesions in 17%. A precise diagnosis couldn't be obtained in 3.8%. The data provided by the stereo-EEG (in 11 patients suffering also of severe drug-resistant partial epilepsy) did not permit, alone, an histological diagnosis, excepted when electrodes explored a solid tumor. Two patients had a neurological impairment, and two died (one for extracerebral reasons). The authors consider that the TDM data and the informations given by the stereotactic procedures are complementary for obtaining valuable informations on the spatial organization of intracranial lesions and choosing the best treatment.

Adolescent↗
PubMed1987

[Value and technic of translating the data from x-ray computed tomography into the stereotaxic coordinates of the Talairach system].

The neuroradiological stereotactic examinations provide indispensable information to localize many intracranial lesions: the data obtained by the CT-Scan are complementary of the stereotactic ones. The transfer of the routine CT-Scan transverse axial slices into the Talairach stereotactic system needs a precise definition of the inclination of the plan of the slices and a correct evaluation of the mean magnification factor. The inclination of the slices is appreciated using the bony, vascular and ventricular landmarks clearly identified on the CT-Scan and stereoscopic stereotactic images. We compared the spatial "reconstructed" CT-Scan data with the histopathological findings obtained by serial stereotactic biopsies in 48 tumor patients. The error varied from 1.5 to 4.6% (m: 2.7 +/- 1.2) on the sagittal plane; from 1.3 to 10% (m: 5.8 +/- 3.4) on the transversal plane; from 2.5 to 4.3% (m: 3.5 +/- 0.7) on the axial plane. The mean global error was 3.7% +/- 2.3. The CT-Scan directly performed under stereotactic conditions (acrylic frame) seems to be the more useful procedure. Nevertheless considering the good precision obtained with our methodology applied to the Talairach's system, we consider it suitable when: a) the gantry of the CT-Scan apparatus is too narrow for the acrylic frame; b) the exploitation of previous CT-Scan examinations is necessary; c) patient refuses the discomfort of the acrylic frame.

Brain Diseases↗