Intracranial Arteriovenous Malformations Research Papers (original) (raw)

Traditionally, decisions regarding treatment and outcomes for patients with cerebral arteriovenous malformations (AVM) have made use of the Spetzler-Martin grading scale. The latter has withstood the test of time in clinical practice for AVM patients managed surgically and even when comparing studies involving other modalities of treatment. Recent awareness on the applicability of the grading system for risk assessment and outcome determination in cases of treatment by neuroendovascular means has emerged. We propose a preliminary grading system for neuroendovascular procedures based on a revision of the available literature. A literature search using the keywords 'arteriovenous malformation', 'embolization' and 'outcome' was done. Articles studying the factors involved in complications and outcome determination for endovascular cerebral AVM patients were reviewed. These were tabulated and those dealing with anatomical, radiological and hemodynamic description...

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- Risk assessment, Risk Assessment, Intracranial Arteriovenous Malformations

The uncommon simultaneous occurrence of an exuberant, angioma-like proliferation of superficial cerebral microvessels along with absence of the kidneys has been proposed to constitute a syndromic complex for which the term "meningocerebral angiodysplasia (or angiomatosis) with renal agenesis" (MCA-RA) is being descriptively used. We observed this constellation in one of a pair of dichorionic male twins following postpartal death in the 38th week of pregnancy. General autopsy revealed rudimentary metanephric anlagen made up of few residual glomeruli, cysts lined by flattened tubular epithelium, and islands of cartilage -corresponding to renal aplastic dysplasia. Largely inconspicuous with respect to its gyral pattern, as well as the configuration of the ventricular system, the brain microscopically showed extensive replacement of the cortex by a lattice of proliferating capillaries with necrosis of the intervening parenchyma. Minute foci of calcified necrosis were scattered in the deep subcortical white matter as well, while the ventricular ependyma and the subventricular germ cell layer remained remarkably intact. The cerebellum and brain stem appeared unaffected as well. Karyotyping of skin fibroblasts indicated a normal chromosome set of 46XY without gross structural anomalies. We interpret these findings as ones apt to being reasonably accommodated within the spectrum of MCA-RA. Although exceedingly rare, accurate identification of individual cases of MCA-RA is relevant both to differential diagnosis from its prognostically different look-alike "proliferative vasculopathy and hydranencephaly-hydrocephaly" (PVHH), and to refine the nosology of unconventional pediatric vascular malformations, for which the rather nonspecific label "angiodysgenetic necrotizing encephalopathy" is still commonly used.

- by Carla Rocha
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- Pregnancy, Practice, Central Nervous System, Differential Diagnosis
- by Feres Chaddad-neto and +2
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- Cognitive Science, Magnetic Resonance Imaging, Clinical Sciences, X ray Computed Tomography

BACKGROUND occurred predominantly in patients who suffered ischemit strokes. The average age of patients who used cocaine and presented with SAH secondary to a ruptured intracerebral aneurysm was 32.8 years with an average aneurysm diameter of 4.9 mm versus an average age of 52.2 years with an average aneurysm diameter of approximately 11.0 mm in noncocaine users. Population differences were statistically significant at the p < 0.05 level. Mortality was 27.3% for patients who presented with neurovascular sequelae of their cocaine use, with 77.8% of deaths occurring in patients who presented with W-l.

- by Richard Fessler
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- Cocaine, Subarachnoid hemorrhage, Brain Ischemia, Clinical Sciences

The authors sought to assess the relationship between obliteration rate and different dose parameters following fractionated radiotherapy for arteriovenous malformations (AVMs). A comparison of the results of radiosurgery and radiotherapy for AVMs was made to calculate the best fit alpha/beta value, which would then be used as a model for predicting the treatment outcome, independent of the number of fractions applied.

- by Michael Söderman
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- Neurosurgery, Radiosurgery, Treatment Outcome, Clinical Sciences

In 2008 we witnessed a rapid advancement in stent technology, which is reflected in the high number of case reports, publications of case series, and randomized trials. Stents not only served for a combined intrasaccular and extrasaccular treatment of challenging aneurysms but also assisted the revascularization in acute and chronic ischemic conditions of the neurovascular system. Although a self-expanding nitinol semiopen cell stent is currently used for intracranial occlusive disease, a new retrievable closed-cell designed stent is widely used for aneurysms because of its easy delivery through a microcatheter in frequently tortuous head and neck as well as cerebrovascular circulation (Figure 1). However, despite numerous publications in the field, the widespread acceptance of the use of stents to routinely treat carotid stenosis awaits the results of the multicenter randomized clinical trials that should be available in 2009. The role of interventional neuroradiology in the treatment of acute ischemic stroke continues to expand and excite interest. (Stroke. 2009;40:e305-e312.

- by Ajay Wakhloo
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- Neurology, Radiology, Stents, Stroke

Summary: We present the case of an unusually located in-tracranial lipoma in a 17-year-old patient with partial ep-ilepsy who was being controlled with medication. The li-poma was located deep in the left sylvian fissure, in the inferior parietal lobule, associated with cortical dysplasia of the surrounding supramarginal gyrus. Abnormal vas-culature was detected adjacent to and within the adipose mass. The findings of the imaging studies that included CT, MR imaging, and MR angiography, are described along with a brief review of the literature. Intracranial lipomas are rare lesions, assumed to be resulting from abnormal persistence and maldif-ferentiation of the meninx primitiva, as first pro-posed by Verga (1) and then supported by Truwit and Barkovich (2). The majority of the lesions oc-

- by Aytekin Besim
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- Magnetic Resonance Imaging, Adolescent, Case Report, Cerebral Cortex

Transcranial color-coded duplex sonography (TCCD), magnetic resonance angiography (MRA), and computed tomography angiography (CTA) are novel noninvasive or minimally invasive techniques for the study of the intracranial circulation. TCCD is relatively inexpensive and permits bedside examination. It improves the accuracy and reliability of conventional transcranial Doppler studies. The main limitation of TCCD are the ultrasonic windows. They restrict the area of insonation to the major cerebral arteries and the proximal part of its branches, lower the spatial resolution, and may prevent transtemporal insonation. Using MRA, both large and small intracranial arteries and veins can be imaged by selecting the appropriate imaging parameters. MRA provides morphologic information about the cerebral vessels, relying on blood flow as the physical basis for generating contrast between stationary tissues and moving spins. MRA is highly sensitive for the detection of occlusive disease in large intracranial arteries. However, with bright blood techniques the degree of stenosis tends to be exaggerated. Flow direction, eg, in collaterals, can be determined by selective or phase-contrast MRA. Perfusion imaging techniques provide information about blood flow at the capillary level. Diffusion imaging depicts molecular motion. TCCD and MRA used in combination or alone may eliminate the need for intra-arterial digital subtraction angiography (DSA) in most patients studied for occlusive cerebrovascular disease. DSA may be reserved for those patients where there is disagreement among the noninvasive techniques, and for the diagnosis of cerebral aneurysms and arteriovenous malformations. CTA relies on spiral CT technology and intravenous contrast injection. To date, intracranial use has been predominantly for the diagnosis of aneurysms. The role of CTA for the detection of nonaneurysmal intracranial vascular disease has yet to be established. 0 1995 John Wiley & Sons, Inc.

- by Rune Aaslid
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- Clinical, Clinical Sciences, Aged, Blood Flow

This is an update of the Royal Adelaide Hospital radiosurgery experience between November 1993 and December 2004 comprising 165 patients with 168 intracranial lesions. Including re-treatment, there were 175 treatment episodes (163 radiosurgery and 12 stereotactic radiotherapy) at an average of 1.3 per month. The commonest lesions were acoustic neuroma (65), arteriovenous malformation (58), solitary brain metastasis (23) and meningioma . The clinical features, treatment details and outcome are described. Our results continue to be well within the range reported in the published work. Radiosurgery provides an elegant, non-invasive alternative to neurosurgery and conventional external beam radiotherapy for many benign and malignant brain tumours.

- by Daniel Roos
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- Radiosurgery, Survival Analysis, Adolescent, Hospitals

Purpose: To evaluate the efficiency of transvaginal ultrasound in the early diagnosis of ovarian cancer. Methods: Screening transvaginal ultrasound has been annually performed during the last 2 years in asymptomatic women without familial history of ovarian cancer. When abnormalities were detected, the procedure was repeated after 4-6 weeks. If the findings disappeared, the study was repeated after 1 year. If the abnormality persisted, study was complemented with tumor markers, computed tomography and laparoscopic surgery. The findings were compared with a control group of women in whom ovarian transvaginal ultrasonography was formally indicated. Results: A total of 26007 transvaginal ultrasound were performed: 8813 (33.8%) belonged to the screening group and 17194 (66.2%) to the control group. In 14 patients of the screening group, a malignant tumor was diagnosed and histologically confirmed. The mean age of these patients was 45 years old (SD 12). Eleven of these tumors were stage I (seven Ia, and four Ic), two stage IIIc and one was a metastatic melanoma in both ovaries. Six lesions were borderline tumors (five serous and one mucinous). In the control group, 27 ovarian cancers were diagnosed in patients with a mean age of 48 years (SD 17). In this group, 11 tumors were in stage I, and six were borderline. Conclusions: Although consensus about the benefits of using transvaginal ultrasound as a screening procedure is not conclusive, our data reveals that tumors detected in patients screened with transvaginal ultrasound are in earlier stages when compared with those diagnosed in the control group. No differences were found in age and number of borderline tumors between both groups. Additional studies are needed to support this preliminary findings.

- by regina ximenes
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- Obstetrics, Pregnancy, Newborn Infant, Three Dimensional

Vein of Galen aneurysmal malformations are a rare and diverse group of entities with a complex anatomy, pathophysiology, and serious clinical sequelae. Due to their complexity, there is no uniform treatment paradigm. Furthermore, treatment itself entails the risk of serious complication. Offering the best treatment option is dependent on an understanding of the aberrant anatomy and pathophysiology of these entities, and tailored therapy is recommended. Herein, the authors review the current concepts related to vein of Galen aneurysmal malformations and suggest a new classification system excluding mesodiencephalic plexiform intrinsic arteriovenous malformations from this group of malformations.

- by Martin Mortazavi
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- Aneurysm, Intracranial Arteriovenous Malformations

Arteriovenous malformations (AVMs) may be cured by injecting liquid embolic agents such as Onyx. Reflux, however, can sometimes be difficult to control and may jeopardize a complete embolization. The pressure cooker technique (PCT) was designed to create an anti-reflux plug by trapping the detachable part of an Onyx-compatible microcatheter with coils and glue in order to obtain wedge-flow conditions, thereby enabling a better understanding of macrofistulous AVMs and a more comprehensive, forceful and controlled Onyx embolization. The PCT might enlarge the range of AVMs amenable to endovascular cure. Three illustrative cases are presented.

- by Pascal Mosimann
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- Treatment Outcome, Neuroradiology, Young Adult, Pressure

- by Jacob Szejnfeld
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- Obstetrics, Pregnancy, Newborn Infant, Three Dimensional
- by Italo Linfante
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- Catheterization, Stroke, Clinical Sciences, Polyethylenes

In one year, cerebral angiograms were performed for intracranial haemorrhage (ICH) on 334 patients. No cause for haemorrhage could be identified in 41 (12 %), 30 of whom had predominantly subarachnoid (SAH) and 11 predominantly parenchymal haemorrhage (PH). These patients were prospectively examined by cranial MRI 1-6 weeks after the ictus. The MRI studies were positive in 7 patients (17 %). In the 30 patients examined after SAH, 2 studies were positive, showing an aneurysm in one case and a brain stem lesion of uncertain aetiology in the other. In those examined after PH, cavernous angiomas were shown in 2, a tumour in 1 and a vascular malformation in another; useful diagnostic information was thus obtained in 36 % of this group.

- by James Byrne
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- Prospective studies, Neuroradiology, Exploration, Subarachnoid hemorrhage

Two babies with severe cardiac failure caused by a large arteriovenous malformation of the vein of Galen were evaluated with 2-dimensional ultrasound, pulsed and colour Doppler techniques. In both cases similar findings were recorded: dilated right cardiac chambers with high cardiac output in superior vena cava and ascending aorta; retrograde diastolic flow in descending aorta and continuous forward flow in arch arteries reflecting low resistance to flow in cerebral arteries; recirculation of microbubbles through the superior vena cava after passage unchanged through the cerebral malformation following contrast injection of saline into a peripheral vein or an arterial ombilical line. In addition, colour Doppler study of the brain clearly showed the malformation and the dilated straight sinus. Arteriovenous malformation of the vein of Galen can be noninvasively and easily detected by ultrasound studies of the heart and the brain.

- by Pierre Mauran
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- Ultrasound, Heart Failure, Ultrasonography, Newborn Infant
- by Michel W Bojanowski and +1
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- Hydrocephalus, Clinical Sciences, Pineal Gland, Cerebral Hemorrhage

We propose an angioarchitectural classification of intracranial vascular lesions as arteriovenous, arteriolovenous and arteriolovenulous fistulae. In order to validate this classification, 99 intracranial arteriovenous lesions were reviewed in 98 patients. Arteriolovenulous fistulae included 39 isolated brain arteriovenous malformations (AVMs) and 1 AVM associated with a giant arteriovenous fistula (AVF). Arteriovenous fistulae included 8 giant AVFs of the brain, 6 vein of Galen aneurysms and 10 direct caroticocavernous fistulae. Arteriolovenous fistulae included i isolated brain AVM, 4 vein of Galen aneurysms and 30dural AVMs. The angioarchitectural classification has three advantages. It is simple and accurate, with no reference to the congenital or acquired nature of the lesion. It allows separate identification of a special group, the arteriolovenous fistulae. It also indicates the endovascular approach: arteriolovenulous fistulae should be treated via the arterial route only, while arteriovenous and arteriolovenous fistulae can be treated via transarterial or transvenous approaches.

Purpose: To unravel biological mechanisms potentially resulting in the obliteration process after radiosurgery (RS) of human cerebral arteriovenous malformations (AVMs) by investigating molecular signatures on the transcriptomic level in peripheral blood of patients. Patients and Methods: Venous blood samples were obtained at definite points of time before and after RS. The samples were tested for radiation-induced changes regarding biological markers (mRNA) using cDNA and oligo-microarray technology. The corresponding expression profiles were correlated with clinical data and obliteration signs in radiologic imaging.

- by Fujio Kayama
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- Toxicology, Radiosurgery, Treatment Outcome, Oxidative Stress

Background and Purpose-Childhood intracerebral hemorrhage is mainly attributable to underlying brain arteriovenous malformations (bAVMs). Multimodal treatment options for bAVMs include microsurgery and embolization, allowing an immediate cure, and radiosurgery, entailing longer obliteration times. Follow-up data on pediatric ruptured bAVMs are scarce, making it difficult to assess the risk of subsequent intracerebral hemorrhage. Our aim was to assess the clinical and angiographic outcome and to analyze risk factors for rebleeding during and after combined treatment of pediatric bAVMs. Methods-A prospectively maintained database of children referred to our institution between January 1997 and October 2012 for bAVMs was retrospectively queried to identify all consecutive ruptured bAVMs treated by surgery, embolization, and radiosurgery. The impact of baseline clinical and bAVM characteristics on clinical outcome, rebleeding rate, annual bleeding rate, and bAVM obliteration was studied using univariate and multivariate Cox regression analysis. Results-One hundred six children with ruptured bAVMs were followed up for a total of 480.5 patient-years (mean, 4.5 years). Thirteen rebleeding events occurred, corresponding to an annual bleeding rate of 2.71±1.32%, significantly higher in the first year (3.88±1.39%) than thereafter (2.22±1.38%; P<0.001) and in the case of associated aneurysms (relative risk, 2.68; P=0.004) or any deep venous drainage (relative risk, 2.97; P=0.002), in univariate and multivariate analysis. Partial embolization was associated with a higher annual bleeding rate, whereas initial surgery for intracerebral hemorrhage evacuation was associated with a lower risk of rebleeding. Conclusions-Associated aneurysms and any deep venous drainage are independent risk factors for rebleeding in pediatric ruptured bAVMs. Immediate surgery or total embolization might be advantageous for children harboring such characteristics, whereas radiosurgery might be targeted at patients without such characteristics. (Stroke. 2014;45:1664-1671.)

- by Michel ZERAH
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- Adolescent, Stroke, Child, Follow-up studies
- by Peter Rivera
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- Neurosurgery, Magnetic Resonance Imaging, Treatment Outcome, Adolescent

Background: The treatment of large and high-grade (Spetzler-Martin III-V) AVMs remains a challenge. There is a paucity of literature addressing the efficacy of radiosurgery in this group. We retrospectively analyze our experience with repeat radiosurgery with such AVMs. Methods: Between 1989 and 2004, 14 patients with large and high-grade AVMs deemed to be nonoperative candidates were treated with repeat radiosurgery. Patients were treated either on a LINAC or c knife-based system at 2-to 3-year intervals with targeting of the entire nidus with each treatment. Patients who did not receive their full treatment course or follow-up at the institution were excluded. Results: Mean follow-up was 18 months. The complete obliteration rate was 35.7%, with a mean volume reduction of 53% in the remaining lesions. Twenty percent of grade III and 50% of grade IV lesions experienced cure. Complications included persistent headaches (2 patients). Statistical analysis revealed no difference between obliterated and partially obliterated groups with regard to mean pretreatment volume (24.87 cm 3 ), median Spetzler-Martin grade (IV), mean follow-up (30.5 months), total delivered dose (3550 cGy), mean dose per stage (13 Gy), median number of stages (2), or mean interval between treatment stages (40 months). Conclusion: The present study demonstrates the potential role of repeat radiosurgery in the treatment of this cohort in the context of our short follow-up. The benefits of repeat therapy could be derived from using lower doses per session and repeat targeting of the lesion in an effort to increase response and decrease complication rates. D

- by Gustavo Pradilla
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- Magnetic Resonance Imaging, Radiosurgery, Adolescent, Child

Abbreviations used in this paper: AChA = anterior choroidal artery; AVM = arteriovenous malformation; DS = digital subtraction; GOS = Glasgow Outcome Scale; ICA = internal carotid artery; MCA = middle cerebral artery; PCA = posterior... more

- by Feres Chaddad-neto and +1
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- Neurosurgery, Microsurgery, Adolescent, Anatomy

We present 26 consecutive cases of nongalenic pial arteriovenous malformations (PAVMs) diagnosed in the neonatal period or in infancy. No diagnosis was made antenatally. Presenting symptoms in neonates were systemic cardiac manifestations (54%), seizures (31%), and hemorrhages (15%). In infants, hemorrhagic strokes and hydrodynamic disorders (external or internal hydrocephaly, macrocephaly, atrophy) both occurred in 38% of cases. Systemic cardiac manifestations and seizures were rare at that age (respectively 16% and 8%). Sixty-two percent of neonates and 31% of infants already had neurocognitive disorders (assessed by pediatric neurocognitive testing: Brunet-Leizine and Denver tests) when referred. The venous drainage and its anomalies (ectasias, stenoses, thromboses) were the main causes of symptoms. Atrophy and leukomalacic lesions occurred rapidly; they express local hydrovenous disorders and are specific to this population group. Untreated neonates and infants have a poor prognosis. Endovascular treatment, although partial and challenging in all instances, represents the treatment of choice in our series. Of the eight neonates treated, one improved to normal (12.5%), while four remained stable (50%): two neurologically normal, two with mild neurological deficit. Three (37%) died despite embolization (heart failure, multiorgan failure, postoperative death). Transient neurological complications occurred in two cases (25%): hemiparesis in one patient with a rolandic and in one with a thalamic AVM. Of the eight infants successfully embolized, one was significantly improved (12.5%) and is now neurologically normal, while five remained stable (62.5%): four neurologically normal, one with mild neurological deficit. One died between two sessions of embolization from intracerebral hemorrhage (12.5%). Hemianopsy occurred in one case (12.5%) after embolization of an occipital AVM. In one additional case in a normal child we failed to embolize the last small pial AVM of four after the three others had spontaneously thrombosed. With a minimal follow-up of 18 months and a maximum of 7 years, the review of our series shows 53% of the initial group of neonates and infants growing neurologically normal after therapeutic management in our institution; 23.5% died despite treatment, and the remaining 23.5% present minor neurological deficit. When targeted at the points of angioarchitectural weakness, embolization contributes to stabilizing a lesion. It should be undertaken rapidly to avoid loss of brain substance secondary to hemorrhage, atrophy, or leukomalacia, and to allow neurocognitive recovery and normal brain maturation. In our experience, theses lesions are the most aggressive ones for the maturating brain, and the most difficult to approach technically. They represent a new therapeutic field and have their own specific anatomy and physiology.

- by Michel ZERAH
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- Magnetic Resonance Imaging, Adolescent, Heart Failure, Hydrocephalus
- by Tetsuo Tani
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- Social Interaction, Magnetic Resonance Imaging, Reading, Fluency disorders
- by Adnan Qureshi
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- Stents, Catheterization, Stroke, Glioma

A 39-year-old man developed retrograde and anterograde amnesia following haemorrhage from an arteriovenous malformation situated near the splenium of the corpus callosum. MRI studies demonstrated damage to the splenium, and to a region containing the retrosplenial cortex and the cingulate bundle. The fornix was anterior and inferior to the site of maximal damage, but may have been involved; the stria terminalis was probably spared. Structures known to be important in memory but spared by the lesion included the hippocampus, thalamus, and basal forebrain. The retrosplenial cortex receives input from the subiculum and projects to the anterior thalamus, thus providing an alternative route between hippocampus and thalamus. Perhaps more importantly, medial temporal structures involved in memory receive anterior thalamic input directly via the cingulate bundle and indirectly through a relay in the retrosplenial cortex. We suggest that this thalamocortical portion of Papez' circuit may be important in memory, and that lesions of the cingulum and retrosplenial cortex may cause amnesia by disrupting this pathway.

- by Dawn Bowers
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- Magnetic Resonance Imaging, Brain, Corpus Callosum, Amnesia

The cumulative experience worldwide indicates complete radiosurgical obliteration rates of brain arteriovenous malformations (AVMs) ranging from 35 to 90%. The purpose of this study was to propose a strategy to increase the obliteration rate for AVMs through the dynamic definition of the key target volume (KTV). A prospective series of patients harboring an AVM was assessed using digital subtraction angiography in which a digital counter was used to measure the several stages of the frame-by-frame circulation time. All the patients were analyzed using dynamic measurement planning to define the KTV, corresponding to the volume of the shunt with the least vascular resistance and the earliest venous drainage. All patients underwent catheter-based angiography, a subgroup was additionally assessed by means of a superselective catheterization, and among these a further subgroup received embolization. The shunts were also categorized according to their angioarchitectural type: fistulous, p...

- by Angel Lee
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- Neurosurgery, Radiosurgery, Treatment Outcome, Adolescent
- by Randall Porter
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- Neurosurgery, Magnetic Resonance Imaging, Adolescent, Child

A combinAtion of endovascular embolization, SRS, and resection has been used in the therapy of brain AVMs. 9,17,23,25 Recent reports have indicated that AVMs with a nonplexiform component such as a highflow AVF appear to be more resistant to radiosurgery than other lesions. 6,8,19 It is also known that AVMs with high-flow shunts are associated with an increased incidence of perioperative complications such as intra-or postoperative bleeding. 4,18,31 Therefore, the endovascular occlusion of those high-flow fistulas plays an important role in perioperative radiosurgery management. 28,32 Recently, Haw et al. 11 reviewed a large series of patients with brain AVMs treated with embolization and concluded that the presence of a high-flow fistula or fistulous component of the AVM increases the risk of complications. Although much has been described about the angiographic characteristics of the fistulous component of AVMs, 12,16,36 there have been very few studies that specifically addressed the treatment risk of embolizing highflow fistulas in AVM and the complications related to this aspect of surgery.

- by Catharina Klijn
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- Neurosurgery, Magnetic Resonance Imaging, Adolescent, Complication

Arteriovenous malformation (AVM) is the most common cause of spontaneous intraparenchymal hemorrhage in children, excluding hemorrhages of prematurity and early infancy. Because most children diagnosed with an AVM undergo initial treatment emergently, the natural history of AVMs in the pediatric population is not well understood. Most pediatric AVMs do not come to clinical attention unless they hemorrhage. Therefore, their optimal management remains controversial. Children with intracranial AVMs represent a special challenge in that they harbor unacceptable lifelong risks of hemorrhage and potential neurologic deficits. Patients should be evaluated on a case-by-case basis to determine the best multidisciplinary treatment regimen that can be used to preserve neurologic function and eradicate the AVM with the lowest risk of mortality. Successful treatment depends on the location and size of the AVM, its hemodynamic properties, the clinical condition of the patient, and the treatment m...

- by Paul Klimo
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- Surgery, Radiosurgery, Treatment, Treatment Outcome

A combinAtion of endovascular embolization, SRS, and resection has been used in the therapy of brain AVMs. 9, Recent reports have indicated that AVMs with a nonplexiform component such as a highflow AVF appear to be more resistant to radiosurgery than other lesions. It is also known that AVMs with high-flow shunts are associated with an increased inci-dence of perioperative complications such as intra-or postoperative bleeding. 4,18,31 Therefore, the endovascular occlusion of those high-flow fistulas plays an important role in perioperative radiosurgery management. Recently, Haw et al. 11 reviewed a large series of patients with brain AVMs treated with embolization and concluded that the presence of a high-flow fistula or fistulous component of the AVM increases the risk of complications. Although much has been described about the angiographic characteristics of the fistulous component of AVMs, there have been very few studies that specifically addressed the treatment risk of embolizing highflow fistulas in AVM and the complications related to this aspect of surgery.

- by Alexandre Laurent
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- Neurosurgery, Magnetic Resonance Imaging, Radiosurgery, Risk
- by Arundhati Biswas
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- Treatment Outcome, Polymers, Head and Neck, Child

A new curative embolization technique with Onyx for selected small and medium-sized superficially located brain AVMs was developed, which consists of obliteration of the nidus, including incremental occlusion of the draining veins. We... more

- by Guus Beute and +1
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- Treatment Outcome, Adolescent, Child, Young Adult

The association of posterior inferior cerebellar artery (PICA) aneurysms with posterior fossa arteriovenous malformation (AVM) is uncommon. Over the past 3 years, five patients with this condition were treated at this institution. A review of the clinical history of these and other reported cases has illuminated common threads in the presentation, treatment, and outcome of these lesions.

- by Huy Do
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- Neurosurgery, Treatment Outcome, Cerebellum, Neuroradiology

The following subjects will appear in serial pub-lications in STROKE, although not necessarily in the order listed: Epidemiology

BACKGROUND: The supplementary grading system for brain arteriovenous malformations (AVMs) was introduced in 2010 as a tool for improving preoperative risk prediction and selecting surgical patients. OBJECTIVE: To demonstrate in this multicenter validation study that supplemented Spetzler-Martin (SM-Supp) grades have greater predictive accuracy than Spetzler-Martin (SM) grades alone. METHODS: Data collected from 1009 AVM patients who underwent AVM resection were used to compare the predictive powers of SM and SM-Supp grades. Patients included the original 300 University of California, San Francisco patients plus those treated thereafter (n = 117) and an additional 592 patients from 3 other centers. RESULTS: In the combined cohort, the SM-Supp system performed better than SM system alone: area under the receiver-operating characteristics curve (AUROC) = 0.75 (95% confidence interval, 0.71-0.78) for SM-Supp and AUROC = 0.69 (95% confidence interval, 0.65-0.73) for SM (P , .001). Stratified analysis fitting models within 3 different follow-up groupings (,6 months, 6 months-2 years, and .2 years) demonstrated that the SM-Supp system performed better than SM system for both medium (AUROC = 0.71 vs 0.62; P = .003) and long (AUROC = 0.69 vs 0.58; P = .001) follow-up. Patients with SM-Supp grades #6 had acceptably low surgical risks (0%-24%), with a significant increase in risk for grades .6 (39%-63%). CONCLUSION: This study validates the predictive accuracy of the SM-Supp system in a multicenter cohort. An SM-Supp grade of 6 is a cutoff or boundary for AVM operability. Supplemented grading is currently the best method of estimating neurological outcomes after AVM surgery, and we recommend it as a starting point in the evaluation of AVM operability.

- by Dr. Michael Lawton
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- Neurosurgery, Microsurgery, Treatment Outcome, Risk assessment

OBJECT Onyx, an ethylene-vinyl alcohol copolymer mixed in a dimethyl sulfoxide solvent, is currently one of the most widely used liquid materials for embolization of intracranial arteriovenous malformations (AVMs). The goal of this study was to define the risks and benefits of stereotactic radiosurgery (SRS) for patients who have previously undergone partial AVM embolization with Onyx. METHODS Among a consecutive series of 199 patients who underwent SRS between January 2007 and December 2012 at the University of Virginia, 25 patients had Onyx embolization prior to SRS (the embolization group). To analyze the obliteration rates and complications, 50 patients who underwent SRS without prior embolization (the no-embolization group) were matched by propensity score method. The matched variables included age, sex, nidus volume before SRS, margin dose, Spetzler-Martin grade, Virginia Radiosurgery AVM Scale score, and median imaging follow-up period. RESULTS After Onyx embolization, 18 AVM...

- by Zhiyuan Xu
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- Neurosurgery, Magnetic Resonance Imaging, Radiosurgery, Treatment Outcome

Objective The purpose of this study is to assess the role of endoscopic third ventriculostomy (ETV) in the treatment of hydrocephalus in children under 1 year of age. The authors analyzed data of ETV in their institution. Methods Between January 1995 and December 2008, 52 ETV procedures were performed for the treatment of hydrocephalus in 49 infants (32 male and 17 female). Their age ranged from 6 days to just under 12 months (mean age 6.2 months). The cause of hydrocephalus was occlusive in 43 patients (aqueduct stenosis in 31, Chiari II malformation in eight, Dandy-Walker cyst in two, quadrigeminal lipoma in one, and cerebellopontine angle arachnoid cyst in one patient). Communicating hydrocephalus was caused by intraventricular hemorrhage, meningitis, and/or ventriculitis in six patients. Results The overall success rate was 69.4% with mean follow-up period of 68.2 months. Patients with aqueduct stenosis had a higher success rate of ETV which was 77.4%. Seven infants were born preterm, six of them required a permanent ventriculoperitoneal shunts (VPS; P=0.003). Malfunctioned VPS was removed in two patients following ETV. There was one death from intracranial hemorrhage, two cerebrospinal fluid leaks, and one meningitis. Conclusion Endoscopic third ventriculostomy can be considered a possible treatment procedure alternative to VPS for the treatment of occlusive hydrocephalus in infants. ETV was effective in full-term infants while the results in low birth weight, preterm infants were poor. Success of ETV is not only age dependent but also etiology dependant. Infants with occlusive hydrocephalus treated with VPS, who present with shunt failure, could be treated by ETV and removal of the shunt device.

- by Wayne Li
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- Cognitive Science, Computed Tomography, Magnetic Resonance Imaging, Treatment Outcome

creased risk of BAVM (p = 0.006), which persisted after adjusting for multiple comparisons (p = 0.03). After adjustments for age and sex, carriers of the minor allele (A) remained at higher risk for BAVM compared to noncarriers (odds ratio, OR = 1.56; 95% confidence interval, CI = 1.01-2.41; p = 0.046) and risk of BAVM was increased with increasing copy of the minor A allele (OR = 1.49, 95% CI = 1.03-2.15; p trend = 0.03). Five common haplotypes (frequency 1 1%) were inferred; overall haplotype distribution differed between BAVM cases and controls ( 2 = 12.2, d.f. = 4, p = 0.02). Neither SNPs (p 1 0.05) nor haplotype distribution ( 2 = 1.1, d.f. = 4, p = 0.89) were associated with risk of ICH among BAVM cases. Conclusion: A synonymous SNP in ANGPTL4 and haplotypes carrying it are associated with risk of BAVM but not with ICH presentation in BAVM cases.

- by Pui-yan Kwok
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- Genetics, Epidemiology, Risk assessment, California

Na operacijama aneurizmi je prikazivanje anatomskih detalja je sredstvo koje vodi cilju, a ne samo sebi svrha. Podatke o onim detaljima sa kojima se hirurzi sre}u u toku rada i koji im ponekad ine pote{ko}e prilikom tuma~enje angiografskih nalaza i planiranje operacije, kao i intraoperativne orijentacije i identifikacije elemenata. U~estalost pojave ovakvih anatomskih detalja i anomalija mo'e da bude sasvim druga~ija od one koju nam pokazuju obdukcione serije. Njihovo poznavanje, hirurzima olak{ava i daje potrebnu dozu sigurnosti prilikom operacija. Stoga smo se opredelili da sprovedemo klini~ku, mor-folo{ku studiju na osnovu angiografskih i operativnih analiza eksplorisanih segmenata Wilisovog kruga. Studija je sprovedena na 344 bolesnika Instituta za neurohirurgiju tokom 2 godine koji su imali kompletnu angiografsku dijagnostiku i operativnu eksploraciju. Na{i nalazi potvrdjuju razlike u lokalizaciji aneurizmi po polu. Aneurizme na prednjem komunikantnom kompleksu su u velikoj meri udru'ene sa anomalijama prednjeg dela Willisovog kruga.

- by Lukas Rasulic and +1
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- Adolescent, Child, Morphological Analysis, Clinical Sciences

Background and Purpose-To assess the frequency, severity, and predictors of neurologic deficits following adjuvant embolization for cerebral arteriovenous malformations (AVMs). [1997][1998][1999][2000][2001][2002][2003][2004][2005][2006] 202 of 275 AVM patients received embolization prior to microsurgery (n=176) or radiosurgery (n=26). Patients were examined before and after endovascular embolization, and at clinical follow-up (mean 43.4±34.6 months). Outcome was classified according to the modified Rankin Scale (mRS). New neurological deficits after embolization were defined as minimal (no change in overall mRS), moderate (mRS≤2), or significant (mRS>2).

- by Robert Starke and +1
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- Treatment Outcome, Adolescent, Multivariate Analysis, Stroke
- by Paul Summers
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- Cerebrovascular Disease, Exploration, Clinical Sciences, Spectrum

Purpose: To better predict permanent complications from arteriovenous malformation (AVM) radiosurgery. Methods and Materials: Data from 85 AVM patients who developed symptomatic complications following gamma knife radiosurgery and 337 control patients with no complications were evaluated as part of a multiinstitutional study. Of the 85 patients with complications, 38 patients were classified as having permanent symptomatic sequelae (necrosis). AVM marginal doses varied from 10 -35 Gy and treatment volumes from 0.26 -47.9 cc. Median follow-up for patients without complications was 45 months (range: 24 -92). Results: Multivariate analysis of the effects of AVM location and the volume of tissue receiving 12 Gy or more (12-Gy-Volume) allowed construction of a significant postradiosurgery injury expression (SPIE) score. AVM locations in order of increasing risk and SPIE score (from 0 -10) were: frontal, temporal, intraventricular, parietal, cerebellar, corpus callosum, occipital, medulla, thalamus, basal ganglia, and pons/midbrain. The final statistical model predicts risks of permanent symptomatic sequelae from SPIE scores and 12-Gy-Volumes. Prior hemorrhage, marginal dose, and Marginal-12-Gy-Volume (target volume excluded) did not significantly improve the risk-prediction model for permanent sequelae (p > 0.39). Conclusion: The risks of developing permanent symptomatic sequelae from AVM radiosurgery vary dramatically with location and, to a lesser extent, volume. These risks can be predicted according to the SPIE location-risk score and the 12-Gy-Volume.

- by John Flickinger
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- Radiosurgery, Forecasting, Risk assessment, Multivariate Analysis

Stereotactic radiosurgery uses a single fraction high dose radiation while stereotactic radiotherapy uses multifractionated lower dose focused radiation. Radiosurgery used rigid CRW head frame while stereotactic radiotherapy utilized GTC or HNL relocatable frames. Stereotactic planning and radiation involved Radionics X-plan and LINAC system. Since December 2001, we have treated 83 lesions from 77 patients using either radiosurgery or fractionated stereotactic radiotherapy. Eighty six percent (86%) of our treated lesions showed favourable outcomes with median follow-up of 32 months (0-7 years). Our lessons from LINAC precision radiation therapy uphold its value as a promising and effective tool in treating a range of nervous system pathologies.

- by I. Badrisyah and +2
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- Radiosurgery, Adolescent, Child, Aged
- by Robert Rosenwasser
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- Management, Neuroimaging, Radiosurgery, Adolescent

Neuropathological findings in children who had died of cerebral arteriovenous malformation under 6 years of age were contrasted with those of children aged 6 to 15 years. In all subjects, the abnormalities were more marked in the shunting vessels and veins distal to the arteriovenous shunt than in the arteries. Fibrous thickening, calcification and adherent thrombus of vessel wall, and gliosis and haemosiderin in contiguous neural tissue were more common in the older than the younger children. Children less than 1 week old with vein of Galen malformations presented with congestive heart failure and "watershed" cerebral infarction; most of those over one week old had hydrocephalus and venous thrombosis with haemorrhagic infarction.

- by Carol Millar
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- Radiosurgery, Natural History, Treatment Outcome, Adolescent
- by Harris Cohen
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- Pediatrics, MRI, Choroid Plexus, Newborn Infant

Accessory anterior cerebral artery (ACA), which is a type of median artery of anomalous triplicate ACA, is not rare, but aneurysmal formation is extremely rare. We report a rare case with ruptured aneurysm arising from a distal accessory ACA. We discuss the characteristics and causes of this type of aneurysm and classification of this anomaly. A 63-year-old man suddenly developed severe headache and then loss of consciousness and paraplegia. Computed tomography disclosed thick and diffuse subarachnoid hemorrhage and interhemispheric hematoma. Subsequent bleeding occurred 2 hours after the first hemorrhage. Cerebral angiography disclosed a saccular aneurysm arising from the distal accessory ACA. Neck clipping of the aneurysm was performed 22 hours after the second episode, using an interhemispheric approach. Although transient paraplegia occurred 8 days after onset, the patient recovered well after surgery without neurological deficit. The characteristics of the aneurysm arising from distal accessory ACA are considered similar to those of distal ACA aneurysm. There is, however, some confusion regarding the terminology of the anterior communicating artery complex anomalies, which we discuss.

- by Christopher Ogilvy
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- Neurosurgery, Complication, Distal, Subarachnoid hemorrhage