Posterior Fossa Arteriovenous Malformations Research Articles

Posterior Interhemispheric-Transtentorial Approach for Resection of an Arteriovenous Malformation of the Superior Medullary Velum and Fourth Ventricle: 2-Dimensional Operative Video.

Brain arteriovenous malformations (AVMs) of the fourth ventricle represent a rare subtype associated with an aggressive natural course.1,2 In this case, a woman in her early 50s presented with dizziness. An AVM was diagnosed in the left superior cerebellar peduncle extending into the fourth ventricle. The AVM was supplied by superior cerebellar artery branches and classified as a Spetzler-Martin grade III and a Lawton-Young grade III, with a supplemented grade of 6.3,4 Being a single case report, institutional review board approval was not needed. Patient consent was obtained. The lesion was accessed through a torcular craniotomy and posterior interhemispheric-transtentorial approach, employing gravity to naturally retract the parietooccipital lobe.5-7 Dissection continued into the quadrigeminal and ambient cisterns, where the tentorium was incised parallelling the straight sinus to reach the superior vermis. Partial resection of the lingual and central lobules of the vermis facilitated access to the superior medullary velum. The superior cerebellar artery feeders were divided and followed to the superior cerebellar peduncle and through the superior medullary vellum. A vertical incision in the superior medullary velum facilitated entry into the fourth ventricle, where the AVM nidus was dissected circumferentially and resected en bloc. Intraoperative indocyanine green videoangiography and postoperative digital subtraction angiography confirmed complete obliteration of the AVM. After surgery, the patient experienced mild ataxia, but motor symptoms greatly improved during 3-month follow-up. This video illustrates resection of a complex fourth ventricular AVM through a posterior interhemispheric-transtentorial approach, highlighting pivotal considerations of patient positioning and approach selection to optimize treatment outcome for complex posterior fossa AVM resection.

PICA flow-related aneurysms and posterior fossa AVM: rare association and challenging management: case presentation and review of literature

BackgroundThe association of an infratentorial arteriovenous malformations (AVMs) with a PICA aneurysm is very rare and the presence of associated aneurysms was an independent predictive factor of poor outcome at follow-up for posterior fossa AVMs (pfAVMs). We report the case of a 57-year-old female patient admitted to our institution with a challenging management of a pfAVM associated with multiple flow-related aneurysms of the PICA.Case presentationA 57-year-old patient with no medical past history was admitted to our emergency department with a sudden onset headache and severe neck stiffness. A cerebral CT Scan showed a cerebellar hematoma. Digital subtraction angiography demonstrates a right paramedian supero-posterior infratentorial AVM located at the posterosuperior part of the right cerebellar hemisphere with a small compact nidus supplied by branches of the right PICA and the right superior cerebellar artery. Venous drainage being toward the torcular. The AVM is associated with 3 flow-related aneurysms. We opted for surgical treatment of the 2 high-flow aneurysms on the distal branch of the right PICA. Patient was then sent for radiosurgery for the AVM. We opted for observation of the left small aneurysm.ConclusionMicrosurgery for PICA aneurysms is particularly well suited because exposure through a far-lateral craniotomy is excellent. Endovascular embolization can be used to occlude the aneurysm as well as treat the AVM at the same time in certain circumstances. Clipping or coiling the aneurysm should be discussed in a multidisciplinary meeting.

Assessment of endovascular embolization of cerebral arterio-venous malformations in vertebrobasilar domain

BackgroundEndovascular approaches have been widely applied in patients with brain arterio-venous malformations (AVM). However, little is known regarding the risk factors for complications or predictors of procedure success. Herein, we report our experience regarding the outcomes of endovascular embolization of posterior fossa AVM, focusing on how angioarchitectural and hemodynamic characteristics of the AVM affect the post-intervention outcomes. 17 patients diagnosed with posterior cranial fossa AVM were enrolled and scheduled for endovascular interventions by Onyx or Histoacryl.ResultsMost patients had a single session (58.8%), while 29.4% had two sessions, 11.7% had three sessions. Total nidus obliteration was achieved in 52.9% of cases, while 35.3% and 11.8% of them had subtotal and partial occlusion, respectively. Postprocedural hematoma was encountered in 17.6% of cases. All preprocedural demographic characteristics did not have a significant impact on occlusion outcomes. However, some angioarchitecture criteria were associated with partial occlusion including large size, superficial or mixed drainage. No significant association was noted between patients criteria and the incidence of complications.ConclusionEndovascular interventions could be curative for brain AVM, with an accepted periprocedural morbidity rate. Proper knowledge of the angioarchitectural characteristics of these lesions could help us to predict lesions that carry high risk for complications or high chance for cure.

Facilitation of Pediatric Posterior Fossa Vascular Malformation Resection Using Virtual Reality Platform: 2-Dimensional Operative Video.

Pediatric posterior fossa arteriovenous malformations (AVMs) are rare entities that pose significant cumulative lifetime risk of rupture and require treatment. Microsurgical resection remains a good option for definitively treating posterior fossa AVMs in one setting. The drawback of endovascular embolization is the lower rates of nidus obliteration. Although stereotactic radiosurgery is a safe alternative, it takes several years to achieve the treatment goal all the while predisposing the patient to the risk of AVM rupture.1,2 Accurate localization and visualization remain challenging for microsurgical treatment of posterior fossa AVMs.3-5 Small size of a nidus, prone position, and proximity to eloquent areas make these lesions particularly difficult to localize and resect. We present the operative case of a 6-year-old boy with a small, ruptured posterior fossa AVM. After undergoing hematoma evacuation, the patient underwent microsurgical resection of a small right vermian AVM assisted by the virtual reality platform, Surgical Theater (Gates Mills, OH). Our video demonstrates the utility of a virtual augmented reality platform for addressing the challenges posed by a small posterior fossa AVM with respect to the need for precise three-dimensional localization of small lesions. The patient consented to the procedure. The participants and any identifiable individuals consented to publication of his/her image.

Image Characteristicộng sự of Ruptured Arteriovenous Malformations of the Brain on the Multislice Computed Tomography

This study describes the features of the image of the Ruptures Brain Arteriovenous Malformation (AVM) based on films of Multislide Computed Tomography (MSCT) at Bach Mai Hospital. The study used descriptive cross-sectional, prospective and retrospective method to analyze the MSCTs of 40 patients at the Center of Radiology, Bach Mai Hospital, from March 2019 to March 2020. The results show that the common age of the patients was <40 years old and the average age was 33.88 ± 16.27; the ratio of female/male was ≈ 1.11/1; 70% of the patients suffered from headache. On admission, 52.5% of the patients were conscious (glassgow 15 points), 30% of them lost consciousness (glassgow <13 points) and 17.5% were comatose; 47.5% had a syndrome of increased intracranial pressure; 22.5% with detected cerebral AVM but never treated; 77.5% with ruptured cerebral AVM in the upper floor of the cerebellum and 57.5% had it in the highly functional area; 67.5% with cerebral AVM ≤ 3cm in size. Feeding artery ≤ 3 stalks accounted for 85%, of which 1 stem accounted for the majority. Attached aneurysm accounted for 42.5%, mainly in AVM drive aneurysm (32.5%). Pure shallow drainage veins accounted for 50%. Brain parenchymal hemorrhage alone accounted for 60%. Brain parenchymal with ventricular and subarachnoid hemorrhage accounted for 37.5%. The small size hemorrhage volume ratio (<30 mm) and the average size (30-60 mm) accounted for the same percentage of 45%. According to the Spetzler - Martin classification, the cerebral ruptured venous malformation drive with low resolution (I-III) accounted for 85%. Overall, MSCT provides information to help guide the treatment of cerebral hemorrhage caused by cerebral AVM.
 Keywords:
 Arteriovenous malformation of the brain, ruptured cerebral arteriovenous malformations, Multislide Computed Tomography (MSCT).
 References
 [1] R. M. Friedlander, Clinical Practice, Arteriovenous Malformations of the Brain, N Engl J Med, Vol. 356, No. 26, 2007, pp. 2704-2712, https://doi.org/10.1056/nejmcp067192.[2] J. F. Yu, A. D. Nicholson, J. Nelson et al., Predictors of Intracranial Hemorrhage Volume and Distribution in Brain Arteriovenous Malformation, Vol. 24, No. 2, 2018, pp. 183-188, https://doi.org/10.1177/1591019917749819.[3] E. Shotar, M. Debarre, N. A. Sourour et al., Retrospective Study of Long-term Outcome after Brain Arteriovenous Malformation Rupture: the RAP Score, J Neurosurg, Vol. 128, No. 1, 2018, pp. 78-85, https://doi.org/10.3171/2016.9.jns161431.[4] P. M. Thong, N. H. An, The Initial Results of Treatment Mass the Brain Arteriovenous Malformation Rupture with Surgery in Combination with Embolization in Bach Mai Hospital; Vietnam Journal of Medicine, October, No. 1, 2017, pp. 51-56 (in Vietnames). [5] R. F. Speizler, N. A. Martin, A Proposed Grading System for Arteriovenous Malformations, J Neurosurg, Vol. 108, No. 1, 2008, pp. 186-193, https://doi.org/10.3171/jns/2008/108/01/0186[6] M. Majumdar, L. A. Tan, M. Chen, Critical Assessment of the Morbidity Associated with Ruptured Cerebral Arteriovenous Malformations, J Neurointerv Surg, Vol. 8, No. 2, 2016, pp. 163-167, https://doi.org/10.1136/neurintsurg-2014-011517. [7] R. F. Spetzler, D. S. Kondziolka, R. T. Higashida et al., Comprehensive Management of Arteriovenous Malformation of the Brain and Spine, Cambridge University Press, 2015, pp. 78-85, https://doi.org/10.1080/01616412.1998.11740583[8] R. Torné, R. A. Hernández, F. Arikan et al., Posterior Fossa Arteriovenous Malformations: Significance of Higher incidence of Bleeding and Hydrocephalus, Clin Neurol Neurosurg, Vol. 134, 2015, pp. 37-43, https://doi.org/10.1016/j.clineuro.2015.04.003.

Combined treatment for a hemispheric cerebellar AVM

Posterior fossa arteriovenous malformations (AVMs) can be a challenging disease, especially those large in size. AVMs can be treated with a combination of endovascular treatment and microsurgery. Here, the authors present the case of a 16-year-old female patient with progressive dizziness and episodic syncope. The workup of the patient showed a hemispheric cerebellar AVM, Spetzler-Martin grade IV. She underwent combined treatment (endovascular and microsurgery) with no complications and cure of the malformation.The video can be found here: https://youtu.be/rNw_Kyd76Mg

Suboccipital craniectomy with bilateral cerebellomedullary fissure dissection for resection of a ruptured tonsillar/vermian AVM occupying the roof of the fourth ventricle in a pregnant patient.

Posterior fossa arteriovenous malformations (AVMs) in pregnant patients can present unique considerations for surgical treatment, including positioning to minimize pressure on the fetus, minimization of radiation exposure, and ethical considerations regarding emergency surgery. This video outlines surgical treatment of a ruptured tonsillar/vermian AVM performed in a staged fashion after emergent suboccipital craniotomy with posterior fossa decompression in the setting of a life-threatening infratentorial hemorrhage. Later, bilateral cerebellomedullary fissure dissection, exposure and dissection of the tela choroidea and inferior medullary velum, and disconnection of arterial feeders from the posterior inferior cerebellar artery (PICA) allowed resection of this AVM occupying the roof of the fourth ventricle.This study was approved by the UCSF Human Research Protection Program IRB no. 18-26938.The video can be found here: https://youtu.be/rTYUGanopUE

Multimodal treatment of a pediatric posterior fossa arteriovenous malformation employing endovascular and microsurgical techniques

Intracranial hemorrhage is the most common presentation of posterior fossa arteriovenous malformations (AVMs) and may have serious consequences. The authors present a case of a 7-year-old girl with headache, vomiting, dysmetria, and ataxia due to a ruptured cerebellar grade III AVM. After two sessions of embolization, the patient underwent total microsurgical resection through a suboccipital craniotomy. There were no additional postoperative deficits, and the patient improved progressively during 6 months of rehabilitation. These challenging lesions should be removed after rupture, especially in children with long-term cumulative risk of rebleeding. Multimodal treatment reduces the perioperative bleeding, allowing better outcomes for pediatric AVM.The video can be found here: https://youtu.be/HQWnjD8ENZQ

The First Successful Endovascular Management of Posterior Fossa Arteriovenous Malformations in Nepal: Case Series.

Posterior fossa arteriovenous malformations represent 7-15% of all intracranial AVMs. They carry a higher risk of rupture than supratentorial AVMs and are associated with considerable rates of morbidity and mortality. Available treatment options include conservative management, microsurgical resection, radiosurgery, endovascular embolization, or combinations of these modalities. Recent advances in endovascular techniques have revolutionized their management with better clinical outcomes. We illustrate two cases of posterior fossa AVMs treated by endovascular techniques with good clinical outcomes. The first patient also had associated flow-related aneurysms. One of these aneurysms had already ruptured, so it was coiled first followed by AVM nidus embolization using the same microcatheter. The second patient had a diffuse type of posterior fossa AVM for which staged-embolization was planned and the first-stage partial embolization was successfully performed.

Presence of direct vertebrobasilar perforator feeders in posterior fossa arteriovenous malformations and association with poor outcomes after endovascular treatment.

Treatment of posterior fossa arteriovenous malformations (PFAVMs) remains controversial as it is always challenging and may lead to major complications. Nonetheless, these lesions are more likely to bleed and generate poorer outcomes than other brain AVMs. The aim of this study was to evaluate the effect of endovascular treatment on long-term outcomes and identify the patient subgroups that might benefit from endovascular treatment. The authors performed a retrospective analysis of all consecutive cases of PFAVM managed at the Fondation Rothschild Hospital between 1995 and 2018. Clinical, imaging, and treatment data were prospectively gathered; these data were analyzed with respect to long-term outcomes. Among the 1311 patients with brain AVMs, 114 (8.7%) had a PFAVM, and 88 (77.2%) of these patients had a history of bleeding. Of the 114 PFAVMs, 101 (88.6%) were treated (83 ruptured and 18 unruptured). The mean duration of follow-up was 47.6 months (range 0-240 months). Good neurological outcome at last follow-up was achieved in 79 cases (78.2%). Follow-up angiography showed obliteration of the PFAVM in 68.3% of treated cases. The presence of direct vertebrobasilar perforator feeders was associated with neurological deterioration (OR 5.63, 95% CI 11.15-30.76) and a lower obliteration rate (OR 15.69, 95% CI 2.52-304.03) after endovascular treatment. Other predictors of neurological deterioration and obliteration rate were consistent with the Spetzler-Martin grading system. Advances in endovascular techniques have enabled higher obliteration rates in the treatment of PFAVMs, but complication rates are still high. Subgroups of patients who might benefit from treatment must be carefully selected and the presence of direct vertebrobasilar perforator feeders must call into question the indication for endovascular treatment.

Posterior Fossa Arteriovenous Malformations: Experience with 14 Patients and a Systematic Review of the Literature.

The optimal management of posterior fossa arteriovenous malformations (pfAVMs) is a matter of debate. To advance this discussion, we present our clinical series and the results of a systematic literature review according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Fourteen consecutive patients with pfAVMs were admitted between 2007 and 2018. Preoperative status, radiologic parameters, and outcome were assessed. A systematic literature review was performed according to the PRISMA-P guidelines. Ten patients presented with rupture (71%), of whom three had associated aneurysms (AAs). The treatments were microsurgery (n = 4), endovascular (n = 3), radiosurgery (n = 2), a combination of two or three treatment modalities (n = 3), or conservative (n = 2). At discharge, all four patients (100%) with unruptured pfAVMs had a good outcome (modified Rankin Scale [mRS]: 0-2). In contrast, in ruptured pfAVM cases, mRS was 0 to 2 in four patients (40%), mRS 3 to 4 in two (20%), mRS 5 in three (30%), and one patient (10%) died within 30 days after gamma knife treatment due to pancreatitis secondary to chronic alcohol abuse. At discharge, four patients (29%) had persistent preinterventional cranial nerve and/or focal neurologic deficits. The literature review identified 63 articles with 1,753 pfAVM patients. Overall, 66% of pfAVMs presented with rupture, and AAs were found in 20% of the cases, which is higher than in supratentorial AVMs (stAVMs). Because pfAVMs are associated with higher rates of hemorrhagic presentation, higher rates of morbidity and mortality when ruptured, and have a higher incidence of AAs compared with stAVMs, early curative treatment is recommended as soon as the diagnosis is established, regardless of rupture status.

Posterior Fossa Arteriovenous Malformations: Anatomy, Management, and Outcomes

Posterior Fossa Arteriovenous Malformations: Anatomy, Management, and Outcomes

Posterior Fossa Arteriovenous Malformations: Anatomy, Management, and Outcomes

Posterior Fossa Arteriovenous Malformations: Anatomy, Management, and Outcomes

Removal of superior vermian arteriovenous malformation through the occipital transtentorial approach

Abstract Background Arteriovenous malformations (AVMs) of the superior vermis are extremely rare. Although they have a higher rate of hemorrhagic presentations than supratentorial AVMs, the surgical approaches for AVMs at this location remain controversial. Case description We report the case of a 73-year-old man with a hemorrhagic superior vermian AVM that was treated with surgical resection through the occipital transtentorial approach (OTA). This approach, with a direct perpendicular view of the whole lesion, enabled us to control the feeding arteries safely and to finally accomplish a total resection. Conclusions The OTA is an elegant approach for the resection of superior vermian AVMs. Detailed assessment of angiographic features is mandatory in selecting an effective and safe surgical approach for posterior fossa AVMs depending on their location.

Associated Aneurysms in Infratentorial Arteriovenous Malformations: Role of Aneurysm Size and Comparison with Supratentorial Lesions

Background: The natural history and treatment of brain arteriovenous malformations (AVMs) is the object of ongoing debates and discussions. To capture the entirety of these complex lesions, associated vascular pathologies, such as associated aneurysms (AAs), have to be implemented in future risk stratification models, as they are believed to represent additional risk factors for intracranial hemorrhage. The present study aims to determine AA characteristics in posterior fossa AVMs and to compare with AAs accompanying supratentorial AVMs, with special focus on aneurysm size. Methods: Patients with cerebral AVMs, treated in our department between 1990 and 2013, were analyzed retrospectively. Only patients with flow-related AAs of the feeding arteries were evaluated. Thus, patients harboring intranidal, venous or remote aneurysms were excluded. Results: Of 485 patients with cerebral AVM, 76 patients harbored an AVM of the posterior fossa. Among those, 22 individuals exhibited a total of 35 AAs (n = 8 patients with multiple AAs). Most common location of AAs was the posterior inferior cerebellar artery (n = 20, 57%) and mean AA diameter was 7.9 mm (SD 5.5). In the subgroup of patients with a single AA, mean aneurysm size in posterior fossa AVMs was with 7.8 mm (SD 6.0; range 2-25 mm) significantly larger than the mean size of AAs with supratentorial AVMs (4.8 mm, SD 3.0; range 2-20 mm; p = 0.048). Intracranial hemorrhage was found in 18 of 22 patients (82%) with infratentorial AVMs, and of these, 11 patients suffered from aneurysm rupture. In 14 patients bearing a single AA, 8 (57%) had sustained hemorrhage from aneurysm rupture. The mean diameter of AAs was as supposed in the ruptured group with 9.8 mm (SD 6.9; range 4-25 mm) significantly larger than in the unruptured AA group exhibiting a mean of 5.0 mm (SD 3.3; range 2-10 mm; p = 0.038). Patients with posterior fossa AVMs and AAs were significantly older as compared to those patients with supratentorial lesions (57.1, SD 12.6 vs. 45.8 years, SD 15.9 years; p = 0.004), which was also evident in the subgroup of patients with single AAs (55.2, SD 11.7 vs. 45.8 years, SD 14.9 years; p = 0.038). Conclusions: AAs of posterior fossa AVMs are larger in diameter than aneurysms accompanying supratentorial AVMs. AA size influences risk for hemorrhage, which, together with the high number of hemorrhagic events in posterior fossa AVMs, justifies treating these pathologies. The higher age of patients with AVMs of the posterior fossa might be one reason for larger AAs in this cohort, when compared to patients with supratentorial AVMs and AAs.

Trigeminal Neuralgia Caused by Cerebellopontine Angle Arteriovenous Malformation Treated With Gamma Knife Radiosurgery

Trigeminal neuralgia is a facial pain syndrome characterized as sudden onset and lightening-like sensation over somatosensorial branch(es) of fifth cranial nerve. Rarely, some underlying diseases or disorders could be diagnosed, such as multiple sclerosis, brain tumors, and vascular malformations. The authors present a 47-year-old man with trigeminal neuralgia over left V2 and V3 dermatomes. He had a previous transarterial embolization and long use of carbamazepine with partial response to treatment. Gamma knife radiosurgery (GKR) was planned. A marginal dose of 15 Gy was given to 50% isodose line. His pain was relieved by GKR in 1.5 years. Treatment of posterior fossa arteriovenous malformations causing trigeminal neuralgia, with GKR has a very limited use in the literature. It, however, is obvious that success rate as pain relief, in a very challenging field of functional neurosurgery, is satisfactory. Large series, however, are in need to make a more comprehensive statement about efficacy and safety of the procedure in these pathologies.

Endovascular treatment of posterior fossa arteriovenous malformations

Infratentorial arteriovenous malformations (AVM) are rare, representing only 7–15% of cerebral AVM. The concentration of eloquent neurological structures and the high rate of bleeding presentation of AVM in this location complicate the management of such lesions. New therapeutic options, especially in endovascular therapy, have fundamentally modified the treatment strategy and also the outcome of posterior fossa AVM. Between 1999 and 2013, baseline, clinical and angiographic data of cerebral AVM were prospectively collected. We analyzed data from patients treated for a posterior fossa AVM, focusing on risk factors for bleeding, and clinical and angiographic outcomes. Sixty-nine patients (mean age 34years, male to female ratio 2:1) were consecutively treated for an infratentorial AVM. Fifty-seven presented with hemorrhage, six with focal neurologic deficits, and the remaining six patients were diagnosed incidentally. The Spetzler–Martin grade was <3 in 39 (56.5%) patients. Associated aneurysms were noted in 43.5% of patients. All patients were treated using endovascular procedures, associated with microsurgical resection in nine patients and with stereotactic radiosurgery in six. Mean follow-up was 28.5months, with angiographic exclusion of the AVM in 72.5% of patients; 21.7% of patients presented a modified Rankin Score ⩾3 at follow-up. Endovascular embolization seems to be a secure approach for posterior fossa AVM although a large number of sessions are necessary to achieve complete obliteration. Multi-disciplinary discussion and management is crucial to obtain the best cure rate without increasing procedural risks.

Increased prevalence and rupture status of feeder vessel aneurysms in posterior fossa arteriovenous malformations

BackgroundPosterior fossa arteriovenous malformations (AVMs) are considered to have a higher risk of poor outcome, as are AVMs with associated aneurysms. We postulated that posterior fossa malformations may be more...

P-036 posterior fossa arteriovenous malformations: increased prevalence and risk of associated aneurysms

Introduction Posterior fossa arteriovenous malformations (AVMs) are considered higher risk, reported by some to be due to the enclosed space and highly eloquent functional areas contained therein, despite often smaller hematoma volumes after rupture. Associated aneurysms engender a higher risk of poor outcome as well. We suggest that posterior fossa malformations are also more prone to associated aneurysms, specifically feeder vessel aneurysms, leading to a higher risk of hemorrhage and poor outcome. Methods A retrospective review ofAVMs evaluated at our institution was performed with attention paid to locationand presence of aneurysms, designated as a feeder vessel aneurysm, intranidalaneurysm, or both. The hemorrhage status and origin of the hemorrhage was alsoreviewed. Results A total of 570 AVMs wereanalyzed, with a total of 162 associated aneurysms identified (284 ruptured).90 AVMs were located in the posterior fossa, including cerebellar and brainstemlocations. 34 of those malformations (37.8%) had aneurysms: 29 with at leastone feeder vessel aneurysm, 3 with intranidal aneurysms, and 2 malformationswith both. Of the 480 supratentorial AVMs, 126 (26.2%) harbored aneurysms: 82with feeder aneurysms, 37 with intranidal and 7 with both. The overallincidence of aneurysms was appreciably higher in posterior fossa AVMs. Thisassociation was most pronounced for feeder aneurysms, which were evident in34.4% of infratentorial AVMs compared to 18.5% of supratentorial malformations(P When evaluating for rupturesite, 18 hemorrhages in the posterior fossa could be attributed to a feederaneurysm, yielding at least a 58% rupture rate for those aneurysms, andaccountable for 30% of ruptures amongst infratentorial AVMs. In comparison, 17supratentorial hemorrhages could be attributed to a feeder aneurysm, yielding a19% aneurysm rupture rate, and accounting for 7.6% of total supratentorial AVMhemorrhages (p Conclusion Posterior fossa AVMs aremore prone to developing associated aneurysms, specifically feeder vesselaneurysms. Feeder vessel aneurysms are also more likely to be the source ofhemorrhage in the posterior fossa, contributing to the increased morbidity andmortality of these malformations. These high risk features may be appropriatetargets for initial and prompt control by embolization or surgery due to theirelevated threat. Disclosures J. Orning:None. S. Amin-Hanjani: None. Y. Hamade: None. X. Du: None. V. Aletich: None. F.Charbel: None. A. Alaraj: None.

Posterior fossa arteriovenous malformations: Significance of higher incidence of bleeding and hydrocephalus

ObjectiveHydrocephalus associated with different types of intracranial arteriovenous malformations (AVMs) has been scarcely studied. In the present report we investigate this association with posterior fossa AVMs (pfAVMs). We hypothesized that there is an increased risk of hydrocephalus and required permanent cerebrospinal fluid (CSF) shunt in patients with pfAVMs that may be linked to the increased risk of bleeding of these lesions. We also review the factors associated with this increased risk of hemorrhagic presentation and we assess how it affects management strategies and functional outcomes in these patients. MethodsOut of a prospective registry of 374 patients with brain AVMs diagnosed in our center from 1993 to 2013, 60 (16%) had a pfAVM. We described these patients’ demographics, their AVM characteristics, clinical presentation, and hydrocephalus incidence and compared the results with those of the supratentorial AVM (spAVM) patients recorded during the same period. ResultsOut of the 60 patients with pfAVMs, 10 (16.7%) presented AVMs located in the brainstem. Hemorrhagic presentation (49/60; 82%) was significantly higher in pfAVMs than in spAVMs (122/314; 38.8%; p<0.05). Hydrocephalus was a common complication in pfAVM patients who had a statistically significant higher need for both temporary external ventricular drain (EVD) (6.7 vs. 20%; p<0.05) and permanent CSF shunts (3.5 vs. 20%; p<0.05). The initial mortality was high (12/60; 20.3%) and half of these patients died before any treatment option could be offered. However, out of those who survived, 70% (42/60) had already shown good clinical outcome at the 6-month follow-up. ConclusionsHemorrhagic presentation and hydrocephalus have a higher incidence in pfAVM patients, which initially results in more neurological deficits and an elevated mortality even before receiving any treatment. However, a large number of survivors present good functional outcomes at early follow-up, justifying an aggressive management strategy with microsurgery as the first treatment option in most cases, and radiosurgery as an alternative, especially in brainstem AVMs.