Resection Of Arteriovenous Malformations Research Articles

Arteriovenous malformations of the brain in children: treatment results for 376 patients

Cerebral arteriovenous malformations (AVM) are increasingly detected in children. To estimate the risk of hemorrhage in children with AVM before and after treatment and evaluate the outcomes of various methods of AVM management in children. This study included 376 patients with various cerebral AVM under the age of 18 years. There were 273 patients with intracranial hemorrhage (72.6%). Recurrent hemorrhages within the first month were registered in 1.1% of patients with angiomatous AVM prior to treatment and in 15.4% of patients with fistulous AVM. Microsurgical resection of AVM was performed in 135 (35.9%) patients. Total resection was achieved in 97.8% of cases. There were no mortality after microsurgical procedures. Endovascular treatment was applied in 79 (21%) patients. Total embolization was achieved in 29.1% of patients. One patient (1.3%) died after endovascular procedure. Radiosurgery was performed in 140 (37.2%) patients with total obliteration after a single fraction in 64.4% of patients. Favorable long-term outcomes (GOS grades V-IV) were achieved in 89.6% of patients with available follow-up data (n=182). Recurrent hemorrhages were registered in 6% of patients (3.3% after radiosurgery, 2.7% after endovascular treatment). One patient with recurrent hemorrhage died after radiosurgery. Early relapses of hemorrhage are not characteristic for children with cerebral AVM. Therefore, there are no indications for urgent surgery except for cases of intracerebral hematoma. In children, microsurgical treatment is preferred for angiomatous AVM, endovascular treatment - for fistulous AVM. Radiosurgery also ensures favorable outcomes. However, it is unreasonable to postpone AVM radiosurgical treatment in children with increased risk of recurrent hemorrhage considering relatively long period of post-radiation obliteration of AVM.

Cervical 7-Thoracic 3 Laminoplasty for Resection of Arteriovenous Malformation: 2-Dimensional Operative Video.

Symptomatic spinal arteriovenous malformations (AVMs) are most frequently associated with hypoperfusion of the spinal cord, either from venous congestion or vascular steal, and are less frequently associated with hemorrhage. This patient had a large cervicothoracic spinal AVM and presented with right hemibody sensory deficit with intact motor function. The AVM had significant preoperative mass effect on the dorsal spinal cord with cord signal change. Preoperative digital subtraction angiography demonstrated a left supreme intercostal feeding artery and left thyrocervical feeding artery, which was embolized preoperatively. A laminoplasty was performed from cervical 7 to thoracic 3 to allow for adequate visualization. The lesion demonstrated an intradural extramedullary presence, which made preservation of the pia mater paramount during the resection. The AVM was disconnected and removed in its entirety as determined by operative visualization and postoperative imaging. The patient gave informed consent for surgery and video recording. Institutional review board approval was deemed unnecessary. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Commentary: A Virtual-Reality, 360-Degree Fly-Through of an Arteriovenous Malformation Resection: 2-Dimensional Operative Video.

Commentary: A Virtual-Reality, 360-Degree Fly-Through of an Arteriovenous Malformation Resection: 2-Dimensional Operative Video.

Application of Indocyanine Green During Arteriovenous Malformation Surgery: Evidence, Techniques, and Practical Pearls.

Indocyanine green (ICG) is a fluorescent molecule that enables visualization of hemodynamic flow through blood vessels. The first description of its application to the resection of arteriovenous malformations (AVMs) did not occur until 2007. Since then, industry leaders have rapidly integrated this optical technology into the intraoperative microscope, and the use of ICG videoangiography (VA) has since become routine in AVM surgery among some academic centers. A number of case series have been published since the introduction of ICG VA to AVM neurosurgery. These early reports with small sample sizes were largely qualitative, assigning to the technology “usefulness” and “benefit” scores as perceived by the operators. This lack of objectivity prompted the development of FLOW 800 software, a proprietary technology of Carl Zeiss Meditec AG (Oberkochen, Germany) that can quantify relative fluorescence intensity under the microscope to generate color maps and intensity curves for ad hoc and post hoc analyses, respectively. However, subsequent case series have done little to quantify the effect of ICG VA on outcomes. The available literature predominately concludes that ICG VA, although intuitive to deploy and interpret, is limited by its dependence on direct illumination and visualization. The subcortical components of AVMs represent a natural challenge to ICG-based flow analysis, and the scope of ICG VA has therefore been limited to AVMs with a high proportion of superficial angioarchitecture. As a result, digital subtraction angiography has remained the gold standard for confirming AVM obliteration. In this review, we provide an overview of the existing literature on ICG VA in AVM resection surgery. In addition, we describe our own experiences with ICG VA and AVMs and offer the senior author's surgical pearls for optimizing the marriage of fluorescence flow technology and AVM resection surgery.

Role of the Checklist in Neurosurgery, a Realistic Perspective to “The Need for Surgical Safety Checklists in Neurosurgery Now and in the Future - a Systematic Review”

Gross total resection of arteriovenous malformations (AVMs) of the central nervous system confirmed by formal angiography is accepted as a cure for patients. In some cases, this may not be possible. Even though in these cases other treatment modalities such as endovascular embolization and radiotherapy can be used, long-term follow-up is lacking in the literature.Here we report a case of a 57-year-old woman with history of a right-sided parieto-occipital/periatrial AVM, initially treated with a combination of endovascular embolization and radiotherapy.The patient subsequently presented (12 years later) with a symptomatic, enlarging, contrast-enhancing mass at the same location that was angiographically occult but ultimately proven to be an AVM on a background of reactive changes on pathology.

Nontraumatic Pediatric Intracerebral Hemorrhage.

Nontraumatic Pediatric Intracerebral Hemorrhage.

Spontaneous appearance of de novo intracranial arteriovenous malformation in hepatic cirrhosis

BackgroundIntracranial arteriovenous malformations (AVMs) are rare lesions that can be congenital or acquired in early childhood, with fatal outcome in approximately 30% of cases. De novo formation during adulthood without established predisposing vascular pathology or previous brain insult is even less frequent. Case DescriptionWe present a case of de novo brain AVM in an alcoholic Child-B cirrhosis setting. Thirty previously reported cases presented de novo AVM in patients of all ages that had another previous brain pathology or insult, such as AVM resection. Seventeen of those cases occurred in adult patients, with only 2 showing no significant predisposing factor. The present pathophysiological review covers and completes Mullan's hemodynamic “two-hit” model, associating probable thrombotic predisposition to AVM with brain insult triggering a later stage based on angiogenic stimuli. ConclusionsThis case report and literature review renews previously discussed hemodynamic theories and contributes to a fuller understanding of the pathogenesis and progression of AVM. We postulate a causal link between hepatopathy and de novo AVM, which should be strengthened and interpreted based on recent genetic data and future prospective studies.

Outcome of Microsurgery for Arteriovenous Malformations in a Resource-Restricted Environment: Single-Surgeon Series from Vietnam

The health care expenditure in Vietnam is equivalent to 1% of that in the United States. For most patients with brain arteriovenous malformations (AVM), surgery is the only available treatment modality. This study reports on the outcomes on AVM microsurgery in this resource-restricted environment. This is a prospectively collected, retrospectively analyzed case series of consecutive patients who underwent surgical resection of AVM by a single surgeon in Vietnam. All surgeries were performed in a 3-year period in Hanoi. The primary endpoints were obliteration of the AVM and surgical morbidity (modified Rankin Scale [mRS] > 1). There were 86 patients and 62% presented with hemorrhage. Only 2 patients had preoperative embolization, and 47 patients (54%) had preoperative digital subtraction angiography. All patients underwent microsurgical resection of their AVM. Excluding the 4 patients who died, the AVM obliteration rate was 98%. The mean follow-up was 20.1 months. Before surgery, 36% of patients had at least some disability (mRS > 1). Postoperatively, this was reduced to 10% (McNemar P= 0.007). For the overall cohort, neurologic status was improved from initial encounter to final assessment (P= 0.001). Because of resource restrictions, some patients with hemorrhage experienced delays in treatment. There was no difference in outcome between patients who were admitted before or after 24 hours post ictus (P= 0.6). The days spent waiting for surgery did not correlate with final mRS in univariate regression (R2= 0.01). Notwithstanding the limitation in health care resources in Vietnam, surgery for AVMs was successful in eliminating the malformation, with obliteration rates and morbidity comparable with international standards.

Does eloquence subtype influence outcome following arteriovenous malformation surgery?

Although numerous arteriovenous malformation (AVM) grading scales consider eloquence in risk assessment, none differentiate the types of eloquence. The purpose of this study was to determine if eloquence subtype affects clinical outcome. This is a retrospective review of a prospectively collected clinical database of brain AVMs treated with microsurgery in the period from 1997 to 2017. The only inclusion criterion for this study was the presence of eloquence as defined by the Spetzler-Martin grading scale. Eloquence was preoperatively categorized by radiologists. Poor outcome was defined as a modified Rankin Scale (mRS) score 3-6, and worsening clinical status was defined as an increase in the mRS score at follow-up. Logistic regression analyses were performed. Two hundred forty-one patients (49.4% female; average age 33.9 years) with eloquent brain AVMs were included in this review. Of the AVMs (average size 2.7 cm), 54.4% presented with hemorrhage, 46.2% had deep venous drainage, and 17.0% were diffuse. The most common eloquence type was sensorimotor (46.1%), followed by visual (27.0%) and language (22.0%). Treatments included microsurgery alone (32.8%), microsurgery plus embolization (51.9%), microsurgery plus radiosurgery (7.9%), and all three modalities (7.5%). Motor mapping was used in 9% of sensorimotor AVM cases, and awake speech mapping was used in 13.2% of AVMs with language eloquence. Complications occurred in 24 patients (10%). At the last follow-up (average 24 months), 71.4% of the patients were unchanged or improved and 16.6% had a poor outcome. There was no statistically significant difference in the baseline patient and AVM characteristics among the different subtypes of eloquence. In a multivariate analysis, in comparison to visual eloquence, both sensorimotor (OR 7.4, p = 0.004) and language (OR 6.5, p = 0.015) eloquence were associated with poor outcomes. Additionally, older age (OR 1.31, p = 0.016) and larger AVM size (OR 1.37, p = 0.034) were associated with poor outcomes. Unlike visual eloquence, sensorimotor and language eloquence were associated with worse clinical outcomes after the resection of eloquent AVMs. This nuance in AVM eloquence demands consideration before deciding on microsurgical intervention, especially when numerical grading systems produce a score near the borderline between operative and nonoperative management.

Seizure Presentation in Patients With Brain Arteriovenous Malformations Treated With Stereotactic Radiosurgery: A Multicenter Study

Abstract INTRODUCTION Seizures are the second most common clinical presentation in patients with brain arteriovenous malformations (AVMs), and they are the most common presentation of unruptured AVMs. The aim of this multicenter, retrospective cohort study was to identify predictors of seizure presentation in AVM patients treated with stereotactic radiosurgery (SRS). METHODS We performed a retrospective review of AVM patients treated with SRS at 8 participating International Radiosurgery Research Foundation sites. Patient and AVM characteristics were compared between those with versus without a seizure presentation in univariable and multivariable models. Subgroup analysis of patients with cortical AVMs was performed. RESULTS The study cohort comprised 2333 AVM patients, including 419 (18%) with and 1914 (82%) without a seizure presentation. Prior AVM resection (OR = 7.65, P = .001), lack of prior AVM hemorrhage (OR = 0.004, P < .001), cortical AVM location (OR = 1559.42, P < .001), lower Spetzler-Martin (SM) grade (OR = 0.51, P = .007), and higher Virginia Radiosurgery AVM Score (VRAS; OR = 1.46, P = .008) were independent predictors of seizure presentation. The rate of seizure presentation in patients with cortical AVMs was 27%. Prior AVM resection (OR = 8.36, P < .001), lack of prior AVM hemorrhage (OR = 0.004, P < .001), and temporal AVM location (OR = 4.15, P < .001) were independent predictors of seizure presentation for cortical AVMs. CONCLUSION We identified multiple factors associated with seizure presentation in AVM patients selected to undergo SRS. Prior AVM resection, cortical AVM location, and lack of prior AVM hemorrhage were the strongest predictors of pre-SRS seizures. SM grade and VRAS may have a role in seizure risk stratification. Among cortical AVMs, temporal lobe localization was predictive of seizure presentation.

Neuroangiography patterns of the middle cerebral artery: Study of 554 cerebral angiography results

The middle cerebral artery (MCA) is the largest and most complex of cerebral arteries because the cerebral neocortex is significantly developed in humans [1,2]. The MCA covers a large part of the cerebral hemispheres; therefore, it is exposed during surgical intervention in that area. Aspects of the cerebral branches tend to vary, and different branching patterns can be described. In the past, surgical interest in the MCA has been directed at avoiding damage to its branches during surgery performed within its territory. Microsurgical techniques have made reconstruction and bypass to the MCA, surgical approaches to MCA aneurysms and resection of arteriovenous malformations (AVMs) related to MCA branches common procedures in vascular neurosurgery. The vascular territory of the MCA includes some of the most eloquent cortical areas for motor and sensory functions. That territory encompasses the receptive and expressive components of language, abstract thought and other faculties of higher cognitive functioning. Moreover, the perforating branches of the proximal MCA supply the basal ganglia and important descending and corticospinal tracts. Anatomical variations of the MCA have to be recognised when planning interventions in order to avoid damage or occlusion of the perforating vessels that arise from the MCA and to assess their contribution to the perfusion of the deep MCA territory. Descriptions of the origins and possible common trunks of the MCA branches are still lacking in the literature. While bifurcation and trifurcation types of MCA branching are usually described, most studies fail to mention the different subtypes. Moreover, there is still some confusion about the criteria used to determine the different branching subtypes. Thus, the present study aimed to review the neuroangiography patterns of the MCA.

Management of arteriovenous malformation of the ear: A protocol for resection and reconstruction.

Arteriovenous malformations (AVM) of the ear show unique features. Progressive growth or inadequate management of AVMs may lead to bleeding, infection, cartilage exposure, and ultimately loss of structure. Total ear amputation is an alternative; however, due to the structural complexity of the ear, reconstruction is technically challenging. This study presents a treatment algorithm based on a clinical series, with treatment options including resection and immediate and late reconstruction. Between 2004 and 2018, 12 patients with auricular AVMs were treated with AVM resection and ear reconstruction at our hospital. Among these 12 patients, seven were women, and patients' ages ranged between 4 and 34 years. Parameters considered before resection and reconstruction were compromised ear extension (partial, total, or extra-auricular involvement), thickness (cutaneous and cartilaginous), symptoms (bleeding, infection, ulceration, and/or cartilage exposure), and preoperative embolization. Total resection of AVMs was planned as the first step in all cases, followed by primary closure. AVM resection was categorized into a partial or total procedure, resulting in partial or total ear defects. Reconstruction was categorized as immediate or delayed. Preoperative embolization was performed in 10 patients. AVMs were totally removed, resulting in seven total ear amputations. In six of these patients, total ear reconstruction was performed 6 months later, and all patients were recurrence-free. Only one patient did not undergo ear reconstruction. Regrowth was not observed in any reconstructed ear. Treatment of ear AVMs requires a planned approach to achieve favorable clinical outcomes and for concomitant safe and definitive reconstruction. 4 Laryngoscope, 130:1322-1326, 2020.

One-Stage Surgical Resection of Giant Intracranial Arteriovenous Malformations in Selected Patients: A Novel Diffusion Tenser Imaging Score

The effective treatment of giant cerebral arteriovenous malformations (gAVMs) is challenging. The aim of this study was to determine the risk factors for 1-stage resection of gAVM and develop a reliable indicator for patient selection. A prospectively maintained database of patients with AVM in our hospital was reviewed. The neuroradiological findings and clinical characteristics of the patients and lesions were analyzed with respect to postoperative functional deficits (FD). A novel blood oxygen level-dependent functional magnetic resonance imaging score and a diffusion tensor imaging (DTI) score were created to predict surgical outcomes. Furthermore, the long-term outcomes of gAVMs treated by other methods in the literature were reviewed. A total of 35 patients with 35 gAVMs were included. The mean diameter of the gAVMs was 64.8 ± 4.9 mm. In the univariate analysis, the functional magnetic resonance imaging score (P= 0.022) and DTI score (P=0.003) were both significantly associated with long-term FD. The Spetzler-Martin score (P= 0.092) trended toward significance. Multivariate analysis revealed that a high DTI score (odds ratio, 2.19; 95% confidence interval, 1.08-4.46; P= 0.030) was the only independent risk factor that was correlated with long-term FD. The predictive effect of the DTI score (area under the curve= 0.822) is superior to that of the Spetzler-Martin score (area under the curve= 0.640) according to the receiver operating characteristic analysis, and the cutoff point was 2.5 (sensitivity= 0.860 and specificity= 0.867). One-stage surgical resection of gAVMs in patients with a low DTI score (0-2) seems to be feasible. The DTI score could be a reliable indicator for patient selection.

The effect of preoperative embolization and flow dynamics on resection of brain arteriovenous malformations.

Preoperative embolization of brain arteriovenous malformations (AVMs) is performed to facilitate resection, although its impact on surgical performance has not been clearly defined. The authors tested for associations between embolization and surgical performance metrics. The authors analyzed AVM cases resected by one neurosurgeon from 2006 to 2017. They tested whether cases with and without embolization differed from one another with respect to patient and AVM characteristics using t-tests for continuous variables and Fisher's exact tests for categorical variables. They used simple and multivariable regression models to test whether surgical outcomes (blood loss, resection time, surgical clip usage, and modified Rankin Scale [mRS] score) were associated with embolization. Additional regression analyses integrated the peak arterial afferent contrast normalized for the size of the region of interest (Cmax/ROI) into models as an additional predictor. The authors included 319 patients, of whom 151 (47%) had preoperative embolization. Embolized AVMs tended to be larger (38% with diameter > 3 cm vs 19%, p = 0.001), less likely to have hemorrhaged (48% vs 63%, p = 0.013), or be diffuse (19% vs 29%, p = 0.045). Embolized AVMs were more likely to have both superficial and deep venous drainage and less likely to have exclusively deep drainage (32% vs 17% and 12% vs 23%, respectively; p = 0.002). In multivariable analysis, embolization was not a significant predictor of blood loss or mRS score changes, but did predict longer operating times (+29 minutes, 95% CI 2-56 minutes; p = 0.034) and increased clip usage (OR 2.61, 95% CI 1.45-4.71; p = 0.001). Cmax/ROI was not a significant predictor, although cases with large Cmax/ROI tended to have longer procedure times (+25 minutes per doubling of Cmax/ROI, 95% CI 0-50 minutes; p = 0.051). In this series, preoperative embolization was associated with longer median resection times and had no association with intraoperative blood loss or mRS score changes.

The future of open vascular neurosurgery: perspectives on cavernous malformations, AVMs, and bypasses for complex aneurysms.

Despite the erosion of microsurgical case volume because of advances in endovascular and radiosurgical therapies, indications remain for open resection of pathology and highly technical vascular repairs. Treatment risk, efficacy, and durability make open microsurgery a preferred option for cerebral cavernous malformations, arteriovenous malformations (AVMs), and many aneurysms. In this paper, a 21-year experience with 7348 cases was reviewed to identify trends in microsurgical management. Brainstem cavernous malformations (227 cases), once considered inoperable and managed conservatively, are now resected in increasing numbers through elegant skull base approaches and newly defined safe entry zones, demonstrating that microsurgical techniques can be applied in ways that generate entirely new areas of practice. Despite excellent results with microsurgery for low-grade AVMs, brain AVM management (836 cases) is being challenged by endovascular embolization and radiosurgery, as well as by randomized trials that show superior results with medical management. Reviews of ARUBA-eligible AVM patients treated at high-volume centers have demonstrated that open microsurgery with AVM resection is still better than many new techniques and less invasive approaches that are occlusive or obliterative. Although the volume of open aneurysm surgery is declining (4479 cases), complex aneurysms still require open microsurgery, often with bypass techniques. Intracranial arterial reconstructions with reimplantations, reanastomoses, in situ bypasses, and intracranial interpositional bypasses (third-generation bypasses) augment conventional extracranial-intracranial techniques (first- and second-generation bypasses) and generate innovative bypasses in deep locations, such as for anterior inferior cerebellar artery aneurysms. When conventional combinations of anastomoses and suturing techniques are reshuffled, a fourth generation of bypasses results, with eight new types of bypasses. Type 4A bypasses use in situ suturing techniques within the conventional anastomosis, whereas type 4B bypasses maintain the basic construct of reimplantations or reanastomoses but use an unconventional anastomosis. Bypass surgery (605 cases) demonstrates that open microsurgery will continue to evolve. The best neurosurgeons will be needed to tackle the complex lesions that cannot be managed with other modalities. Becoming an open vascular neurosurgeon will be intensely competitive. The microvascular practice of the future will require subspecialization, collaborative team effort, an academic medical center, regional prominence, and a large catchment population, as well as a health system that funnels patients from hospital networks outside the region. Dexterity and meticulous application of microsurgical technique will remain the fundamental skills of the open vascular neurosurgeon.

General Principles for Preoperative Planning and Microsurgical Treatment of Pediatric Brain Arteriovenous Malformations: 2-Dimensional Operative Video.

Children with arteriovenous malformations (AVMs) are at cumulative, life-long risk of debilitating and fatal intracranial hemorrhage, especially with syndromes such as hereditary hemorrhagic telangiectasia. Cerebral angiography is the gold standard for diagnosis and allows simultaneous adjunctive embolization limiting radiation and contrast exposure and intraoperative blood loss, important in pediatric patients with low blood volume. Microsurgical resection of low-grade AVMs offers cure with minimal morbidity. The plasticity of the pediatric brain may allow resection of AVMs near eloquent regions. Multidisciplinary care offers the best outcomes in these cases. Discussion of the operative plan with all team members at the start of surgery is carried out. Confirmation that blood products are present and that the microscope, additional suction, and surgical clips are available is performed. A generous craniotomy is created, adequately exposing the lesion. The dura is carefully opened to avoid injury to draining veins. Circumferential dissection and isolation of the AVM is performed, coagulating small arterial feeders, dissecting to the lesion's apex to coagulate, and divide major deep feeders. Once all feeders have been obliterated, venous drainage is disconnected. Indocyanine green distinguishes arterial feeders from arterialized veins and confirms complete resection. Since 2008, all of our patients undergo perioperative angiography in our dedicated suite, greatly improving resection rates. Strict blood pressure control and close neurological monitoring in the intensive care unit is performed postoperatively. In conclusion, microsurgical resection of AVMs can be performed safely with low rates of morbidity. Protocols for preoperative evaluation and planning appear to improve outcomes. Anonymous video is permitted when done without identifying patient related information.

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.

Results of Surgery for Low-Grade Brain Arteriovenous Malformation Resection by Early Career Neurosurgeons: An Observational Study.

For sustainability of arteriovenous malformation (AVM) surgery, results from early career cerebrovascular neurosurgeons (ECCNs) must be acceptably safe. To determine whether ECCNs performance of Spetzler-Ponce Class A AVM (SPC A) resection can be acceptably safe. ECCNs completing a cerebrovascular fellowship (2004-2015) with the last author were included. Inclusion of the ECCN cases occurred if they: had a prospective database of all AVM cases since commencing independent practice; were the primary surgeon on SPC A; and had made the significant management decisions. All SPC A surgical cases from the beginning of the ECCN's independent surgical practice to a maximum of 8 yr were included. An adverse outcome was considered a complication of surgery leading to a new permanent neurological deficit with a last modified Rankin Scale score >1. A cumulative summation (Cusum) plot examined the performance of each surgery. The highest acceptable level of adverse outcomes for the Cusum was 3.3%, derived from the upper 95% confidence interval of the last author's reported series. Six ECCNs contributed 110 cases for analysis. The median number of SPC A cases operated by each ECCN was 16.5 (range 4-40). Preoperative embolization was performed in 5 (4.5%). The incidence of adverse outcomes was 1.8% (95% confidence interval: <0.01%-6.8%). At no point during the accumulated series did the combined cohort become unacceptable by the Cusum plot. ECCNs with appropriate training appointed to large-volume cerebrovascular centers can achieve results for surgery for SPC A that are not appreciably worse than those published from high-volume neurosurgeons.

WITHDRAWN: Multimodal treatment and microsurgical resection of basal ganglionic and thalamic arteriovenous malformations

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Transtentorial Approach for Parahippocampal Gyrus Arteriovenous Malformation Resection: 3-Dimensional Operative Video.

Medial temporal basal arteriovenous malformations (AVMs) have complex anatomy. They usually drain to the basal vein of Rosenthal, and arterial feeders can arise from the anterior choroidal artery and its branches, or from the posterior cerebral artery. If the AVM is more posterior in the parahippocampal gyrus, there is a predominance of arterial feeders arising from P2P or P3 segments of the posterior cerebral artery. As posterior AVMs are difficult to reach using anterior approaches, the supracerebellar transtentorial approach provides a direct pathway to the malformation, allowing better visualization and exposure of the vascular anatomy. In this video, we present a 29-yr-old woman with a left parahippocampal AVM with P2P arterial feeders and Rosenthal basal vein drainage. The patient had three months of moderate headache and two abrupt seizures before admission. Emergency computed tomography showed intraventricular hemorrhage. Magnetic resonance imaging and cerebral angiography revealed an AVM located in the parahippocampal gyrus, posterior to pulvinar thalamus. The patient underwent microsurgical treatment in semi-sitting position using a supracerebellar and infratentorial approach with transtentorial resection. The AVM was completely removed, and the patient recovered without neurological deficits. The authors present a 3-dimensional video of the microsurgical steps required to perform a transtentorial approach for AVM resection in the parahippocampal gyrus. The patient signed the Institutional Consent Form, which allows the use of his/her images and videos for any type of medical publications in conferences and/or scientific articles.