[Hemorrhage in arteriovenous malformations: clinical and anatomic data]. / L'hémorragie dans les malformations artério-veineuses cérébrales.

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.

[Characteristics of epileptic seizures associated with cerebral arteriovenous malformations]. / Caractéristiques des crises d'épilepsie associées aux malformations artério-veineuses cérébrales.

PURPOSES: The purpose of this study is to analyze the characteristics of epileptic seizures associated with cerebral arteriovenous malformations treated by radiosurgery. PATIENTS AND METHODS: Seven hundred and two patients are studied (406 men, 296 women) with a mean age of 33 when radiosurgery was performed. 210 patients had epileptic seizures; those seizures either uniquely revealed the arteriovenous malformation or were associated with other clinical signs. Seizures occurring after an hemorrhage were excluded from the study. We studied the age category upon seizures occurrence, the malformation localization, type of seizure (partial, generalized, or partial secondary generalized), the history related to the epileptic seizures, the clinical topographical correlation, the number of seizures, their duration prior to the radiosurgery, antiepileptic treatment provided, electroence-phalographic characteristics, angiographic characteristics, prior endovascular or surgical treatment, and factors associated with severe seizure. RESULTS: Epileptic seizures revealed the arteriovenous malformations in 30% of the cases; they predominated between 10 and 40 years (80.5%) with a peak between 20 and 30 years. The malformation localization most frequently associated with seizures were temporal and rolandic for partial seizures, whereas frontal or sylvian localization were predominantly associated with generalized seizures. The type of seizure was, in all cases, related to the malformation localization because of the initial signs seizure. 47.6% of the patients showed a limited number of seizures (between 2 and 20), 27.6% showed only a single seizure, and 24.7% suffered from severe epilepsy. Generalized seizures are unique in the majority of cases (61.8%) whereas partial seizures were severe in 47.6% of the cases. The majority of patients are under a single-drug therapy (79%). The EEG patterns showed a small increase of slow and sharp localized waves in patients presenting seizures compared with the global population (27% and 15% respectively). Severe seizures predominated between 10 and 19 years of age; seizures were exclusively partial in 59.6% of the cases and secondary generalized in 40.4%, their frequencies were between 1 to 4 per month in the majority of cases (59.1%), the delay was often more than 10 years (57.7%), status epilepticus was rare (5.8%), temporal and rolandic localization were predominant, social and professional insertion of the patient was preserved in 87.5% of the cases, and seizures did not provoke any death. The angiographic characteristics associated with seizures were: superficial localization, volume, superficial venous drainage, recruitment and venous divergence. CONCLUSION: Anatomic and topographic characteristics of cerebral arterio-venous malformations may provide information on the features of seizures associated with them.

[Characteristics of headache associated with cerebral arteriovenous malformations]. / Caractéristiques des céphalées associées aux malformations artério-veineuses cérébrales.

BACKGROUND: and purposes. The purpose of this study was to identify the specific characteristics of headaches associated with cerebral arteriovenous malformations in order to differentiate them from other known entities of headaches such as migraine, cluster headache, and trigeminal neuralgia. This differentiation allows an early diagnosis of cAVM and a treatment to be administrated before any cerebral hemorrhage. PATIENTS AND METHODS: The study included 700 patients with cAVM and treated by radiosurgery. Out of this series, only 109 (48 males, 61 females, mean age of 33) presented with headaches. Headaches were studied as a possible revelation mode of a cAVM, either as an isolated sign, preceding an epileptic seizure, a cerebral hemorrhage, or associated with a neurological deficit. Analysis concerned 13 clinical parameters and 30 anatomic parameters based on angiography. RESULTS: Headaches were found in 15.6%; they were isolated in 6%. They preceded a cerebral hemorrhage in 12.6%, constituting an early alarm signal when increasing in intensity, frequency and duration. They were associated with seizures or a neurological deficit in 9.6%. We found a predominant female sex-ratio (0.78) and occurrence at a young age (72.3% between 10 and 40 years). Headaches were non-pulsating in 95.3%; nausea, vomiting, light or sound phobia were only found in 4.7%. Headaches were unilateral and homolateral to the malformation in 80%, corresponding to the malformation topography in 97.4% in posterior location and 80% in anterior location. Associated neurological symptoms existed in 20.2%; related to the malformation and lasting 5 to 30 minutes. Duration of pain episodes was less than 3 hours in 77% with a frequency of 1 to 2 per month in 82.5%. Pain was mild and responded to simple analgesics. A family migraine was found in only 3 patients. The angiographic characteristics of the malformations were meningeal afferences, superficial venous drainage and posterior location. CONCLUSIONS: Headaches associated with cerebral arterio-venous malformations form a distinct category that can be determined from specific characteristics; this should help an early diagnosis of cerebral arterio-venous malformations in order to start a treatment before the occurrence of cerebral hemorrhage.

[Progressive neurological deficits in cerebral arteriovenous malformations]. / Les déficits neurologiques progressifs dans les malformations artério-veineuses cérébrales.

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.

[Radiosurgery of cerebral arteriovenous malformations: target definition strategy]. / Radiochirurgie des malformations artério-veineuses cérébrales: stratégie de définition de la cible.

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.

[Prospects and future: evolution of stereotactic methodology for planning]. / Perspectives et avenir: évolution de la méthodologie stéréotaxique de repérage.

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.

[Cerebral arteriovenous malformations treated by radiosurgery: a series of 705 cases]. / Résultats de la série de 705 malformations artério-veineuses cérébrales traitées par radiochirurgie.

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.

[Radiosurgery of choroidal and cisternal cerebral arteriovenous malformations]. / Radiochirurgie des malformations artério-veineuses cérébrales choroïdiennes et cisternales.

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.

[Radiosurgery for large cerebral arteriovenous malformations]. / La radiochirurgie des malformations artério-veineuses de grande taille.

BACKGROUND AND PURPOSE: Treatment of large cerebral arteriovenous malformations is a challenge for embolization, surgery and radiosurgery too. The purposes of this study is to review results of RS for these large cerebral arteriovenous malformations and to study recent methods which can allow to improve results. PATIENTS: and method. From our series, 112 patients had cerebral arteriovenous malformations higher than 30 mm or 10 cc at time of the radiosurgery. Revelation mode was hemorrhage in 47%, seizures in 42%, headaches in 16%, and progressive neurological deficits in 7%. Discovery was fortuitous in 2.7% of cases. Before radiosurgery, 57% were embolized, 5% were operated, 4.5% were reirradiated and 1.8% were operated and embolized. Distribution according to Spetzler & Martin's grade was following: 0% in grade I, 12% in grade II, 41% in grade III and 46% in grade IV. No patient was in grade V. RESULTS: Global obliteration rate was 39% for large cerebral arteriovenous malformations. In multivariate analysis, only recovering (positive correlation), and previous embolization (negative correlation) were correlated with obliteration rate. CONCLUSION: Current procedures of radiosurgery allow obliteration in a limited number of large cerebral arteriovenous malformations treated. Other strategies as fractioned irradiation, multileaf microcollimators with single isocenter, radiosurgery before surgery or radiosurgery with protons should improve obliteration rate.

[Radiosurgery of cerebral arteriovenous malformations in children]. / La radiochirurgie des malformations artério-veineuses de l'enfant.

BACKGROUND AND PURPOSE: Radiosurgery has been used in a few cases of cerebral arteriovenous malformations in children. From data of our series and from literature, we tried to determine the place of this therapeutic modality for treatment of pediatric cAVMs. PATIENTS AND METHOD: From the whole series of 705 patients treated by radiosurgery between January 84 and December 1998, 55 were under 15 years of age. Revelation mode was hemorrhage (70.9%), seizures (12.7%), headaches (10.9%) and neurological progressive deficits (1.8%). Size ranged from 5 to 50 mm (mean: 22 mm) and volume ranged from 1 to 16 cc (mean: 4 cc). Treatments prior radiosurgery were embolization alone (28%), surgery alone (16.7%), embolization plus surgery (5.5%). Distribution of cerebral arteriovenous malformations according to Spetzler & Martin's grading were 10% in grade I, 35% in grade II, 40% in grade III, 15% in grade IV and 0% in grade V. RESULTS: Overall obliteration rate was 59% with an exaustibility rate of 80%. Obliteration rate was dependent on size and volume (100% for<1 cc cerebral arteriovenous malformations sized, 73% from 1-4 cc, 40% from 4-10 cc and 100% (but n=1)>10 cc; p=0.019), sex (84.2% for boys and 40% for girls), of angioarchitecture and Dmin (p=0.01). After multivariate analysis, only Dmin was nearly correlated with the obliteration rate (b=0.462 7; SE=0.244 0; p=0.057). Actuarial risk of hemorrhage was 2.12% per year per patient. Patients with seizures were seizure-free without any drugs after radiosurgery in 80% of cases. Parenchymal changes were mainly hypersignals spT2 in MRI. CONCLUSION: Radiosurgery seems to be an efficient treatment with a low morbidity for cerebral arteriovenous malformations in children.

[Retrospective analysis of failures in radiosurgery treatment of cerebral arteriovenous malformations]. / Analyse rétrospective des échecs de la radiochirurgie dans le traitement des malformations artério-veineuses cérébrales.

The aim of this paper is to analyze retrospectively the reasons for the failure in cerebral arteriovenous malformations radiosurgery. Several factors are evoked and discussed mainly: inaccurate target, intentional partial irradiation, repermeabilization of a previously embolized cerebral arteriovenous malformation. The results suggest the necessity of a complete irradiation of the nidus. The strategy of partial volume irradiation should be avoided, even if it necessitates lowering of the doses in large cerebral arteriovenous malformations. Accuracy in the target determination is required and a complete stereoangiography is necessary.

[Re-irradiation of cerebral arteriovenous malformations. Experience of the Sainte-Anne-Tenon Group]. / Ré-irradiation de malformations artério-veineuses cérébrales. Expérience du Groupe Sainte-Anne-Tenopn.

BACKGROUND AND PURPOSE: Between 20 to 50% of cerebral arteriovenous malformations treated with radiosurgery (RS) fail to obliterate 2 to 5 years after irradiation. Patients are not protected against the risks leading to treatment. Two therapeutic options can be used to eradicate the persisting nidus: micro-surgery and a second irradiation. Our group has reirradiated 39 such patients. MATERIAL: From 1989 to 2000, 39 patients have been reirradiated (14 females and 25 males; median age 31 years). There were more left lesions: 59% than right (35%) and 5% on midline. The most frequent locations were: temporal 12 cases; parietal 8 cases; frontal 7 cases; thalamus 7 cases. The predominant first symptoms were hemorrhage (68.5%) and seizure (15.8%). Prior RS, 21/39 patients had embolization (53.8%) and 3 surgery. Method. Treatment has been performed with the same system for the first and the second radiosurgery for 37 patients. Planification and dosimetry improved during that period. The level of dose was similar for the 2 RS. MRI has been used as a non invasive follow-up tool. RESULTS: Only 28 patients were evaluable because 7/39 patients had the second radiosurgery in 1999 or in 2000 and data were lacking at the time of writing for 4 patients. Obliteration rate was 17/28 (60.7%). Nine patients bled between the two radiosurgery procedures. COMPLICATIONS: 4 new regressive deficits occurred after the second radiosurgery. The rate of parenchymal changes were higher, after the second radiosurgery. Except one patient who died of a non-related affection 2 years after obliteration of his cerebral arteriovenous malformation, thus 38/39 patients were alive. CONCLUSION: This series was small compared to the potential number of candidates suffering from failure of the first radiosurgery, but the results are promising.

[Second treatment of cAVMs after radiosurgery]. / Le deuxième traitement des malformations artério-veineuses cérébrales.

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.

[Hemorrhage after radiosurgery of cerebral arteriovenous malformations]. / Hémorragie après radiochirurgie des malformations artério-veineuses cérébrales.

BACKGROUND AND PURPOSE: Obliteration is progressive after radiosurgery of cerebral arteriovenous malformations. Thus the hemorrhage risk still remains until obliteration. Purposes of this study are to appreciate severity of post-radiosurgery hemorrhages, actuarial risk of hemorrhage and parameters associated with it. PATIENTS: and method. Over 705 patients treated, 46 (6.5%) had one or several hemorrhages. Clinical, anatomic, dosimetric parameters and obliteration rates before hemorrhage were studied. Then, actuarial risks per patient and per hemorrhage were calculated. Correlations between parameters and risk were searched by uni and multivariate analysis by drawing hemorrhage-free survival curves (limit-product Kaplan-Meier) and Cox model. RESULTS: Except one pure ventricular hemorrhage causing death of one patient, only parenchymal hemorrhages were associated with morbidity (80% of cases with 45% of permanent deficits). Overall mortality rate by hemorrhage was 6.5%. Overall morbidity rate was 34.8% and 13.6% for permanent deficit. Mean obliteration rate before hemorrhage was 25%. Actuarial hemorrhage rate were 2.98% per patient and 3.24% per hemorrhage. Actuarial rate per patient increased from 1.46% first year to 5.95% 4(th) year after radiosurgery. Parameters correlated with hemorrhage risk were in univariate analysis size (p=0.01), Spetzler and Martin's grade (p<0.001), dose to reference isodose (p=0.03), Dmin (p=0.08), intra or paranidal aneurysms (p<0.001), and recoverage (p<0.001). After multivariate analysis, only intra or paranidal aneurysms, recovering and Dmin were significantly associated with hemorrhage-free survival after RS. CONCLUSIONS: Post-radiosurgery hemorrhages are often sum of hemorrhage risk factors of the cerebral arteriovenous malformation and factors predicting low rate of obliteration. They can be in some cases foreseen but rarely avoided.

[Evolution of epileptic seizures associated with cerebral arteriovenous malformations after radiosurgery]. / Evolution des crises d'épilepsie associées aux malformations artério-veineuses cérébrales après traitement par radiochirurgie.

The goal of this study is to evaluate the response of epileptic seizures associated with cerebral arteriovenous malformations following radiosurgery and determine the factors associated with a positive outcome. The series included 210 patients (123 men, 87 women) with a mean age of 33. One hundred seventy three patients out of 210 were controlled after radiosurgery. Seizures completely disappeared in 58% of cases and decreased in 18%. Anti-epileptic treatment was stopped in 44%. Sex and age upon seizure appearance were not found as determining factors in patients whose seizures disappeared after radiosurgery. Generalized seizures disappeared following radiosurgery in 90.7%, partial secondary generalized seizures in 53.5%, and partial seizures in only 39.6%. Frontal or temporal malformations are associated with a better response after radiosurgery than sylvian or rolandic location. Seizure disappearance was maximal in case of isolated seizure prior to the radiosurgery (84.4%), was reduced to 61.2% when seizures were limited to 2 to 20, and disappeared in 21.4% in severe seizures. Epilepsy present less than 3 years prior to radiosurgery disappeared in 71.9%; was reduced to 45% when the delay was over 3 years. Seizures disappeared in 64.4% when the malformation was obliterated, they were reduced to 46.9% when malformations persisted. The persistence of severe seizures following radiosurgery was linked to persistence of the malformation. On the other hand early seizures occurred in 3.3% during the first 48 hours following radiosurgery; they disappeared in 72.2% after that period. De novo seizures also occurred in 1.7% and disappeared in all these cases. In conclusion, seizures associated with cerebral arteriovenous malformations respond well to radiosurgery; the malformation obliteration evokes its association with the seizure; the seizure disappearance in spite of persistence of the malformation evokes the positive effect of radiotherapy on epileptic seizures.

[Course of headaches associated with cAVMs after radiosurgery]. / Evolution des céphalées associées aux malformations artério-veineuses cérébrales après radiochirurgie.

The purpose of this study is to evaluate the response of headaches associated with cerebral arteriovenous malformations following radiosurgery and determine the factors that are associated with a positive outcome. From our series of 700 patients whose cAVM was treated by radiosurgery, this study includes 109 patients (48 males, 61 females) with a mean age of 32 when radiosurgery was performed. Headaches resolved in 37 patients (53.7%), decreased in 14 patients (20.3%), persisted in 16 patients (23.2%), and even increased in frequency in 2 (2.9%). Headaches disappeared 2 years following radiosurgery in the majority of patients (31 out of 37: 83.3%). The disappearance rate of headaches was better when it was the only sign of the malformation (64%) or preceded an epileptic seizure (60%) with respect to the case when it preceded cerebral hemorrhage (34.8%). Headaches having the best response were those with 1 to 2 episodes per month (64.9%) and whose episode duration was less than 3 hours (67.6%). Unilateral headaches accounted for 86.5% of resolved headaches whereas bilateral headaches were only 8.1% and even less were the diffuse ones (5.4%). The best evolution was obtained for those associated with a parietal location of the cerebral arteriovenous malformation, followed by rolandic (respectively 55.5% and 50%). Occipital malformation was associated with headache disappearance in 38.1% and temporal with 34.3%, whereas frontal location was associated with headache disappearance in only 25% of the cases. Headache disappearance was often correlated with cerebral arteriovenous malformation outcome after radiosurgery (64.9% of disappearance in case of complete obliteration). However, in 24.8%, headaches disappeared prior to the malformation obliteration and were associated with a decrease of the flow, of the nidus volume or with the nidus disappearance with the persistence of a precocious venous drainage. Headaches disappeared in spite of the malformation persistence in 5.4% of the cases. We found de novo headaches in one patient one year following RS. Another patient presented an episode of headache 12 hours following RS. The course of headaches associated with cerebral arteriovenous malformations after radiosurgery is positive in the majority of cases and correlated to the malformation outcome. This correlation suggests a link between cerebral arteriovenous malformations and headaches and the equal benefit of radiosurgery on both of them.

[Parenchymal changes after radiosurgery of cerebral arteriovenous malformations. Clinical and MRI data]. / Réactions parenchymateuses après radiochirurgie des malformations artério-veineuses cérébrales. Données cliniques et IRM.

BACKGROUND AND PURPOSE: Purposes of this study are to describe different parenchymal changes seen after radiosurgery of cerebral arteriovenous malformations and the clinical symptoms which can be associated, and risk factors correlated with them. PATIENTS: and method. From the whole population of 705 patients with a cerebral arteriovenous malformations treated by radiosurgery between 1984 and 1998, clinical from 615 patients and post radiosurgery MRI data from 367 patients were reviewed. Neurological deficit occurred in 5.37% of cases and was still persistant in 1.46% of cases. Delay of occurrence of deficits ranged from 6 to 83 months (mean: 27 months, median: 15 months). Parenchymal changes seen in MRI were classified in 4 grades: 1 without parenchymal changes, 2 hypersignal in sp T2, 3=2 with homogenous enhancement with gadolinium, 4 with hyposignal in spT1 and annular irregular enhancement. Several parameters (size, volume, angioarchitecture of the cerebral arteriovenous malformation, dosimetric parameters) were studied and correlations were searched by uni and multivariate analysis with occurrence and delay of occurrence of deficits or parenchymal changes. RESULTS: In multivariate analysis, only size was significantly correlated with occurrence of parenchymal changes (p=0.0016); only size of the malformation was significantly correlated with delay of occurrence of parenchymal changes (p=0.0082); only grade 4 was correlated with occurrence of neurological deficit (p<0.00001). However, when only "a priori" parameters (known before radiosurgery) are introducted in logistic model, size taille (p=0.02) and hypoplasy of a sinus (p=0.0049) are significantly correlated with occurrence of neurological deficit. Only parenchymal changes grade 4 was significantly correlated with delay of occurrence of a neurological deficit (p<0.00001). However, when only a priori parameters (known before radiosurgery) are introducted in logistic model, only arterial steal (p=0.054) was significantly correlated with delay of occurrence of a neurological deficit. CONCLUSION: Parenchymal changes are various in expression, signification and clinical symptoms associated with them. They must be known and recognized for better prevention and symptomatic treatment as well.

[Treatment of cerebral arteriovenous malformations: decision making strategy]. / Traitement des malformations artério-veineuses cérébrales: la stratégie décisionnelle.

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.

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

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.