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J F Meder

Publications and source records attributed to J F Meder.

At least 55 records · Page 3Linked to original sources
PubMed2001

[Hemorrhage in arteriovenous malformations: clinical and anatomic data].

BACKGROUND AND PURPOSE: Potential severity of hemorrhage often leads to treat a cerebral arteriovenous malformation. Consequences can be very various and serious. Our first purpose is to define the different types of hemorrhage. Our second purpose is to appreciate more precisely individual hemorragic risk of a cerebral arteriovenous malformation with the study of his angioarchitecture. We performed a prospective study in order to validate a logistic model and a classification previously described. PATIENTS: and method. From the whole series of 705 patients, 57% (n=394) suffered a parenchymal, subarachnoid or ventricular hemorrhage. Logistic model and classification of the hemorrhagic risk were prospectively tested on a consecutive population of 78 patients. Comparisons of theorical (calculated hemorrhagic risk) and real (hemorrhage or not) were performed by non parametric tests. RESULTS: Characteristics and clinical consequences of the hemorrhage were analyzed. Results of the prospective study confirmed data of the classification and showed a hemorrhage risk increasing with the grade: grade Ia 0%, grade Ib 30%, grade II 44%, grade III 57%, grade IV 88%. CONCLUSION: The study of the angioarchitecture of a cerebral arterio-venous malformation allowed to assess with accuracy his individual hemorrhagic risk. However, this precision may be improved by the study of other parameters of intracranial arteriovenous malformation.

Adolescent↗
PubMed2001

[Progressive neurological deficits in cerebral arteriovenous malformations].

Progressive neurological deficits are uncommonly associated with cerebral arteriovenous malformations. We present 25 cases (3.54%) from our series of 705 patients treated by radiosurgery. Common characteristics were preferentially: large cerebral arteriovenous malformations, arterial steal, arterial recruitment, venous reflux and deep location. After multivariate analysis, only arterial steal was significantly associated with neurological deficits. Course after treatment was variable and correlated with cerebral arteriovenous malformations regression. Different pathophysiologic hypotheses and their therapeutic consequences are discussed.

Adolescent↗
PubMed2001

[Toward an anatomoclinical classification for arteriovenous malformations?].

This brief study tends to point out that each clinical symptom (hemorrhage, seizures or epilepsy, headaches and progressive neurological deficits) related to cerebral arteriovenous malformations cerebral arteriovenous malformations can be correlated with the anatomy and the angioarchitecture of the cerebral arteriovenous malformations. The most dramatic data were the bipolar-like correlations between hemorrhage and seizures: each parameter correlated positively with hemorrhage was correlated negatively with seizures and vice versa. These data seem to show that cerebral arteriovenous malformations causing seizures have a low risk of hemorrhage, and cerebral arteriovenous malformations with a high hemorrhage risk have a low risk of seizures (excepting with an hematoma). For headaches and progressive neurological deficits, anatomoclinical correlations can improve knowledge of their pathophysiology.

Adolescent↗
PubMed2001

[Diagnostic imaging of brain arteriovenous malformations].

The goals of the imaging work-up of cerebral arteriovenous malformations are not only the diagnosis of malformations but also their radioanatomic characterization in order to define an appropriate treatment plan for a given lesion, to evaluate and to compare results of treatment modalities, to look for parameters correlated with a high risk of bleeding and to identify indications of radiosurgery. In this review, the diagnostic value of imaging techniques is discussed: CT scan, MR imaging, vascular explorations. Radioanatomic parameters most useful for therapeutic discussion are defined: feeding arteries, associated aneurysms, size and topography of nidus, draining veins.

Analog-Digital Conversion↗
PubMed2001

[Radiosurgery of cerebral arteriovenous malformations: target definition strategy].

BACKGROUND AND PURPOSE: Description and critical review of our procedure of definition of the target of irradiation of a cerebral arteriovenous malformations. PATIENTS: and method. Fixation of the stereotactic frame, performing of stereotactic angiography and CT scanner were described, and the target including nidus and venous collectors of the a cerebral arteriovenous malformations defined. CONCLUSION: The use of several three-dimensional imaging techniques can improve and simplify the method of delineating target with a reduction of radio-induced complications.

Cerebral Angiography↗
PubMed2001

[Prospects and future: evolution of stereotactic methodology for planning].

We have been using the stereotactic methodology of Talairach for Linac radiosurgery of cerebral arteriovenous malformations since 1984, and updated it with addition of CT and MR images into the stereotactic space. The target remains defined, as in most other centers, by stereotactic angiography. However, tridimensional configuration of cerebral arteriovenous malformations is better defined using MR or CT-angiography. Therefore, pre-radiosurgical imaging tends to combine multimodal images oriented into the stereotactic space. Frame-based radiosurgery, with invasive frame placement, will be replaced in the future by frameless irradiation with real-time tracking of the patients head, as performed by the recently described Cyber-knife. Intraoperative X-ray will be no longer long-distance fixed equipments but mobile, short-distance fluoroscopic systems integrated in the surgical workstation environment. Finally, biplane conventional angiography performed for cerebral arteriovenous malformations identification will be replaced by CT and MR-angiography, except in some cases who could still require DSA for accurate target identification.

Algorithms↗
PubMed2001

[Cerebral arteriovenous malformations treated by radiosurgery: a series of 705 cases].

BACKGROUND AND PURPOSE: After a review of the main radiosurgical published series, to evaluate our own series of 705 patients with cerebral arteriovenous malformations treated by radiosurgery alone or in combination with embolization or surgery. PATIENTS: and method. From January 1984 to December 1998, 705 patients were treated by a multidisciplinary team including neurosurgeons, neuroradiologists, radiophysicians and radiotherapists. Age of revelation of the cerebral arteriovenous malformations ranged between birth to 73 years (mean 27, median 25). Age at time of radiosurgery ranged between 7 and 75 years (mean 33, median 31). There were 410 males for 295 females (sex- ratio 1.4). Symptoms of revelation were hemorrhage for 59%, seizures for 23%, headaches for 14% and progressive deficits for 4%. Discovery of cerebral arteriovenous malformation was fortuitous in 4% of cases. Repartition following Spetzler's grading was 12% in grade I, 36% in grade II, 40% in grade III, 12% in grade IV and 0% in grade V. Maximal size ranged between 4 and 60 mm (mean 23, median 20). Volume ranged between 0.2 and 24.3 cc (mean 3.8, median 2.8). Majority of cerebral arteriovenous malformations were large size (42% with size higher than 25 mm) and large volume (54% higher than 10 cc. 54% of patients had treatment prior radiosurgery: 38% had embolization, 10% were operated, 4% were treated by radiosurgery (reirradiation) and 3% were operated and embolized. RESULTS: Overall complete obliteration rate was 55%. The obliteration rate was correlated with size (77% for cAVMs lower than 15 mm, 62% for cerebral arteriovenous malformations between 15 and 25 mm, and 44% for cerebral arteriovenous malformations higher than 25 mm), with volume (94% for cerebral arteriovenous malformations lower than 1 cc, 64% between 1 and 4 cc, 48% between 4 and 10 cc, and 62% for cerebral arteriovenous malformations higher than 10 cc), dose at reference isodose, minimal dose, morphological parameters (presence of dural components, arteriolovenous fistula, plexiform angioarchitecture, arterial steal, arterial recruitment, deep exclusive drainage, venous plicature, venous confluence, venous ectasia, venous reflux), sectional topography and good recovery of the target. Embolization was a confusion factor not associated with obliteration rate. After multivariate analysis, only Dmin and complete coverage of the cerebral arteriovenous malformations were correlated with obliteration rate. Delay of obliteration was significantly correlated after multivariate analysis with Dmin, complete coverage, arteriolovenulary angioarchitecture (positive correlation) and venous ectasia (negative correlation). CONCLUSION: Overall complete obliteration rate is unreliable data to assess efficacy of radiosurgical method in the tretment of cerebral arteriovenous malformations. The obliteration rate must be interpretated after stratification on several morphological and dosimetric parameters.

Adolescent↗
PubMed2001

[Radiosurgery of choroidal and cisternal cerebral arteriovenous malformations].

PURPOSE: Cerebral arteriovenous malformations surrounded by cerebrospinal fluid seemed to exhibit worse response to radiosurgery than others. We searched to verify if this is was true and to find causes. MATERIAL: and methods. From our series of 705 patients with cerebral arteriovenous malformations treated by radiosurgery, 3,8% (27/705) had choroidal or cisternal arteriovenous malformations. Revelation mode was hemorrhage in 86% of cases but sometimes headaches occurred before hemorrhage; thus overall hemorrhage rate was 96%. Mean age of revelation was 24. Mean size was 20 mm, mean volume was 4 cc. Spetzler & Martin's grades were 35% in grade II, 43% in grade III and 22% in grade IV. Location was ventricular in 63% of cases and cisternal in 37%. Mean dose at reference isodose was 24 Gy with a higher rate of monoisocenters. We looked for differences between this population of arteriovenous malformations and the rest of the series for patients, treatments prior radiosurgery, cerebral arteriovenous malformations's characteristics, dosimetric parameters and complications. Statistical analysis was done with a Pearson chi2 test and Spearman non parametric correlation test. RESULTS: Obiteration rate was 47.6% with a mean delay of 26 months. Differential characteristics of choroidal or cisternal arteriovenous malformations were: younger age of revelation, higher frequency of hemorrhage, of intra or paranidal aneurysms, of deep unique drainage, a higher Spetzler grade and a smaller rate of complete recovering. Mortality and clinical morbidity due to radiosurgery were 0%. Actuarial rate of hemorrhage after radiosurgery was 4,34% per year and per patient or per hemorrhage. This rate was higher than in the global series. Parenchymal changes seen on MRI were less frequent (26,6%) and less serious (no grade 4 radionecrosis-like parenchymal changes). CONCLUSION: Choroidal or cisternal arteriovenous malformations seem to respond less to radiosurgery than others. One potential explanation is the higher frequency of multiafferences of these arteriovenous malformations with anastomoses of anterior and posterior choroidal arteries. However, radiosurgery still stay a treatment of choice for these arteriovenous malformations with little adaptations of the irradiation strategy.

Adolescent↗
PubMed2001

[Second treatment of cAVMs after radiosurgery].

Risks of bleeding from partially or unobliterated cerebral arteriovenous malformations remain unchanged. A complementary treatment should be indicated after radiosurgery. In this brief review the following data are discussed: the reasons of second treatment, imaging follow-up of cerebral arteriovenous malformations after radiosurgery, types of cerebral arteriovenous malformations to be treated, timing and therapeutic modalities.

Case Management↗
PubMed2001

[Embolization of cerebral arteriovenous malformations].

Embolization is an important therapeutic tool for the treatment of cerebral arteriovenous malformations and is a part of the therapeutic strategy. In selected cases, it may lead to a total and permanent cure per se, but in most cases it will be an adjunctive therapy to radiosurgery. The authors review techniques of embolization, perioperative care, complications and applications of the treatment.

Cerebral Angiography↗
PubMed2001

[Treatment of cerebral arteriovenous malformations: decision making strategy].

We have evaluated our therapeutic strategy through the results of modalities used alone or in association. Should the place of each modality be modified? What could be the influence of the first consulting physician? We feel at the present time that small cerebral arteriovenous malformations could be treated by radiosurgery, surgery and embolization according to their characteristics and location. For middle size and some large cerebral arteriovenous malformations, we consider that embolization and/or surgery are adjuvant modalities, specifically when the cerebral arteriovenous malformation is located in an eloquent area.

Case Management↗
PubMed2001

[Endovascular treatment using endoprosthesis and metallic stents for aneurysmal dissection of the intracranial vertebral artery].

Dissecting aneurysms of the intracranial vertebral artery represent a more frequently recognized cause of subarachnoid hemorrhage. The poor natural history of the ruptured dissecting aneurysms indicate a surgical or endovascular treatment. Endovascular treatment usually consists of balloon occlusion of the vertebral artery. This treatment however can lead to hemodynamic complications especially when the treated artery is unique or dominant. We report two cases of ruptured dissecting aneurysms of the intracranial vertebral artery treated by intravascular stent and endosaccular GDC coils. The first patient suffered from bilateral dissection with spontaneous occlusion of the right vertebral artery and development of a pouch on the left side. The second patient suffered from a dissection of the left vertebral artery which was dominant. The stenting-coiling technique was efficient in the two cases. The patients are free of symptoms with a respective follow up of 24 and 8 months. The stenting-coiling association seems to be an interesting therapeutic option in case of intracranial dissecting aneurysms which allows a preservation of the arterial flow and selective occlusion of the aneurysmal pouch.

Adult↗
PubMed2001

Dysembryoplastic neuroepithelial tumors: CT, MR findings and imaging follow-up: a study of 53 cases.

PURPOSE: To evaluate CT and MRI features and long term imaging follow-up of a large series of dysembryoplastic neuroepithelial tumors (DNTS). PATIENTS AND METHODS: We retrospectively analyzed CT (100%) and MR imaging (83%) findings of 53 patients with complex (n = 14), simple (n = 6) or non specific histological forms (n = 33) of DNTS. All patients underwent epilepsy surgery for the treatment of drug resistant partial seizures. Preoperative radiological follow-up from two to 10 years (81%) and a post-operative follow-up from one to 13 years (92%) were available. RESULTS: DNTs are intracortical tumors with no mass effect and no peritumoral edema. An associated deformity of the overlying skull was observed in 44% of the 34 patients with a cortical lesion of the convexity. We found a contrast enhancement of the lesion in 21% of cases, a calcic hyperdensity in 36% of cases and a cystic part in 7.5% of cases. DNTs were hypodense (82%) on CT examinations and had a decreased signal on the T1 Weighted Images (95%) and a hypersignal in T2 Weighted Images (100%) on MR imaging. Eighty-one percent of patients had a mean preoperative radiological follow-up of four years and the tumor was stable in size in all cases; 92% of patients had a mean post-operative radiological follow-up of 4.5 years and no recurrence was seen. CONCLUSION: Three radiological features of DNTs are helpful for the diagnosis: cortical location, absence of mass effect and no surrounding edema. Clinical, radiological and histopathological findings have to be considered together in order to assess the diagnosis and to differentiate DNTs, which are stable lesions from gliomas.

Adult↗
PubMed2000

Linac radiosurgery for cerebral arteriovenous malformations: results in 169 patients.

PURPOSE: To present the SALT group results using Linac radiosurgery (RS) for AVM in 169 evaluable patients treated from January 1990 thru December 1993. METHODS AND MATERIALS: Median age was 33 years (range 6-68 years). Irradiation was the only treatment in 55% patients. Other treatment modalities had been used prior to RS in 45%: one or more embolizations in 36%, surgery in 6%, and embolization and surgery in 3% patients. Nidus were supratentorial in 94% patients, infratentorial in 6% patients. Circular 15 MV x-ray minibeams (6-20 mm) were delivered in coronal arcs by a GE-CGR Saturne 43 Linac. Patient set-up included a Betti arm-chair, a Talairach frame. Prescribed peripheral dose was 25 Gy on the 60%-70% isodose (max dose 100%). Arteriographic results were reassessed in December 1997 at 48 to 96 months follow-up. RESULTS: The overall obliteration rate (OR) was 64% (108/169). AVM volumes ranged from 280 to 19,920 mm(3), median 2460 mm(3). OR was 70% for AVM </= 4200 mm(3) 4200 mm(3) (p 25 mm (p = 0.04). OR was 71%, in the absence of embolization, vs. 54% for previously embolized nidus (p = 0.03). OR was 71% for monocentric RS vs. 54% for multi-isocenters (p 28 Gy vs. 55% for values </= 28 Gy (p 79% vs. 57% for lower values (p 17 Gy, vs. 59% for mLd </= 16 Gy (p 40%, vs. 54% for mLi </= 40% (p 85% vs. 60% for CR </= 84% (NS). For patients treated according to our protocol, i.e., 24-26 Gy on the 60%-70% isodoses, OR was higher (68%) than for other patients (47%) (p = 0.02). After multivariate analysis, absence of previous embolization and mono isocentric-irradiation were independent factors predicting obliteration. Complications were: recurrent hemorrhage, 4 patients (1 patient died); brain necrosis on MRI, 2 patients; subsequent epilepsy, 4 patients; other subsequent neurologic deficits, 3 patients. CONCLUSION: Overall OR was 64% (48-96 months follow-up). After monovariate analysis higher ORs were associated with smaller volumes </= 4200 mm(3), smaller nidus size </= 25 mm, absence of prior embolization, monoisocentric RS, higher values for mean and minimum lesion doses and compliance to our protocol. Higher values for the peripheral dose and isodose tended to give better results. Multivariate analysis showed that the absence of prior embolization and monoisocentric irradiation were independent factors predicting successful irradiation.

Adolescent↗
PubMed1999

Intracranial dural arteriovenous fistulae with perimedullary venous drainage. Anatomical, clinical and therapeutic considerations.

We report five cases of intracranial dural arteriovenous fistula (DAVF) with perimedullary venous drainage. All the patients presented with rapidly progressive myelopathy and three had autonomic disorders. The DAVF were on the tentorium cerebelli (two cases), sigmoid (one), superior petrosal (one), and cavernous sinus (one). Slow venous drainage was directed through dilated perimedullary cervical veins. The transverse sinus was occluded in two cases. MRI, performed in four cases, demonstrated high signal on T2-weighted spin-echo sequences in the medulla oblongata and upper cervical spinal cord consistent with oedema, which signal resolved after complete cure of the DAVF in three cases. Embolisation was performed in all cases. It was followed by clinical deterioration in two cases and in the dramatic improvement in the other three, with complete clinical cure in two. Extensive venous thrombosis may explain the deterioration observed in one case.

Adult↗
PubMed1999

Radiosurgery of cerebral arteriovenous malformations: is an early angiogram needed?

BACKGROUND AND PURPOSE: Radiosurgical treatment of arteriovenous malformations (AVMs) has slow and progressive vasoocclusive effects. We sought to determine if early posttherapeutic angiography provides relevant information for the management of radiosurgically treated AVMs. METHODS: Between 1990 and 1993, the progress of 138 of 197 cerebral AVMs treated by linear accelerator (Linac) was regularly followed by angiographic study. On each posttherapeutic angiogram ("early," 6-18-month follow-up; "intermediate," 19-29-month-follow-up; and "late," > 30-month follow-up), the degree of reduction across the greatest diameter of the nidus and hemodynamic modifications were analyzed. Each cerebral AVM was qualitatively classified into one of the following categories after early angiographic study: 0%-reduced, 25%-reduced, 50%-reduced, 75%-reduced, and 100%-reduced or "complete obliteration." Vasoocclusive progress for each category was then studied over time. RESULTS: Three (10%) of the 30 0-25%-reduced, eight (38%) of 21 50%-reduced, and 27 (84%) of 32 75%-reduced cerebral AVMs showed complete obliteration after further follow-up. The three 0-25%-reduced AVMS that went on to complete obliteration underwent very early angiography (6-7 months). Fifty-five cerebral AVMs showed complete obliteration on early angiograms (40%). In this group, more follow-up, when performed, confirmed complete obliteration in all cases (n = 17). CONCLUSION: An early angiogram is needed to predict the effectiveness of radiosurgery. Important AVM changes seen on early angiograms are highly correlated with treatment success. Moreover, no or minor changes seen on early angiograms are highly predictive of radiosurgical failure. For these patients, further treatment should be discussed promptly.

Adolescent↗
PubMed1999

[What is your diagnosis? Aneurysm of the abdominal aorta destroying the lumbar spine].

A 58 year old woman suffering from lumbalgia over 3 years is admitted for bilateral cruralgia. Ten years before, she was treated for cervix carcinoma by hysterectomy, pelvic and lumbo-aortic radiotherapy and chemotherapy. On admission, physical examination reveals L2 level hypoesthesia and abolition of deep tendon reflexes. Plain films and CT scan show a lysis of L3, L4 and L5 vertebral bodies and a cuneiform appearance of vertebral body of L2 due to a large abdominal aortic aneurysm.

Aortic Aneurysm, Abdominal↗