Comprehensive neurosurgical treatment of right occipital arteriovenous malformation with advanced angiographic techniques.

/Summary. A 39-year-old female with a notable medical history of smoking and a familial predisposition to unruptured aneurysms presented with clinical symptoms of intermittent right-sided headaches, flashes of light, and pulsatile tinnitus in the right ear. Diagnostic evaluations, including advanced angiographic techniques, identified a right occipital arteriovenous malformation (AVM). The angiogram revealed significant venous flow voids, emphasizing the need for a comprehensive treatment approach. The Spetzler-Martin grading system classified the AVM as Grade 2, indicating a moderate risk profile. A strategic decision was made to undergo partial embolization of two primary arterial feeders from the right posterior cerebral artery (PCA). Subsequent post-embolization angiograms confirmed a marked reduction in arteriovenous shunting, validating the efficacy of the intervention. The surgical approach encompassed an occipital craniotomy, meticulous subarachnoid dissection, and intraoperative angiography to ensure complete resection. Post-operative assessments showcased a successful and complete AVM resection. The patient experienced a brief, transient headache post-surgery, which resolved on its own. She was discharged on the third post-operative day and has since reintegrated into her professional life. However, she reported a minor visual field deficit, which, while noticeable, did not impede her daily activities. This case underscores the importance of a holistic, patient-centric approach in managing AVMs [1-3]. It challenges the conventional wisdom from the ARUBA trial, advocating for a more nuanced, individualized treatment paradigm, especially for young patients with low-grade AVMs [4].

Hypofractionated stereotactic radiotherapy in Spetzler Martin grades 4 and 5 arteriovenous malformations in the pediatric population: Is it a viable alternative?

OBJECTIVE: To analyze the outcomes of hypofractionated stereotactic radiotherapy (HFSRT) for Spetzler Martin grades 4 and 5 arteriovenous malformations (AVMs) in a pediatric population. METHODS: Fourteen patients with Spetzler Martin (SM) grades IV and V large AVMs who underwent HFSRT between January 2013 and July 2019 were retrospectively reviewed. All patients received HFSRT at a dose of 30-36 Gy in 5 to 6 fractions. They were followed up annually with clinical and imaging assessments to evaluate obliteration rates. RESULTS: The median age at presentation was 15 years (range 8-21 years). Ten (71%) were SM grade 4 AVMs and the rest were SM grade 5 AVMs. The majority presented with headache (8 [57%]), and 3 (21%) presented with bleeding. The median nidus volume was 39.4 cc (IQR, 31.4-52.4). Two (14%) patients had infratentorial AVMs. All of them had deep venous drainage. The median clinical follow-up duration was 75 months (range 31-107 months). There was complete obliteration of the nidus in 3 (21%) patients with a median time to obliteration of 39 months. HFSRT resulted in a reduction of the AVM volume to 12 cc or less in nearly 70% of patients. None of the patients experienced re-bleeding. 79% reported an improvement in their symptoms. CONCLUSION: HFSRT is a highly effective treatment for high-grade AVMs in children, which can result in either complete elimination or significant reduction of the nidus volume or make it suitable for additional treatment, such as single-session stereotactic radiosurgery (SRS).

Stereotactic radiosurgery outcome for deep-seated cerebral arteriovenous malformations in the brainstem and thalamus/basal ganglia: systematic review and meta-analysis.

Deep-seated unruptured AVMs located in the thalamus, basal ganglia, or brainstem have a higher risk of hemorrhage compared to superficial AVMs and surgical resection is more challenging. Our systematic review and meta-analysis provide a comprehensive summary of the stereotactic radiosurgery (SRS) outcomes for deep-seated AVMs. This study follows the guidelines set forth by the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) Statement. We conducted a systematic search in December 2022 for all reports of deep-seated arteriovenous malformations treated with SRS. Thirty-four studies (2508 patients) were included. The mean obliteration rate in brainstem AVM was 67% (95% CI: 0.60-0.73), with significant inter-study heterogeneity (tau2 = 0.0113, I2 = 67%, chi2 = 55.33, df = 16, p-value < 0.01). The mean obliteration rate in basal ganglia/thalamus AVM was 65% (95% CI: 0.58-0.72) with significant inter-study heterogeneity (tau2 = 0.0150, I2 = 78%, chi2 = 81.79, df = 15, p-value < 0.01). The presence of deep draining veins (p-value: 0.02) and marginal radiation dose (p-value: 0.04) were positively correlated with obliteration rate in brainstem AVMs. The mean incidence of hemorrhage after treatment was 7% for the brainstem and 9% for basal ganglia/thalamus AVMs (95% CI: 0.05-0.09 and 95% CI: 0.05-0.12, respectively). The meta-regression analysis demonstrated a significant positive correlation (p-value < 0.001) between post-operative hemorrhagic events and several factors, including ruptured lesion, previous surgery, and Ponce C classification in basal ganglia/thalamus AVMs. The present study found that radiosurgery appears to be a safe and effective modality in treating brainstem, thalamus, and basal ganglia AVMs, as evidenced by satisfactory rates of lesion obliteration and post-surgical hemorrhage.

The Thalamic Arteriovenous Malformations Have Better Prognosis than Basal Ganglia Malformations Regarding Obliteration: Prognostic Factors Analysis.

BACKGROUND: Arteriovenous malformations (AVMs) are rare vascular congenital lesions that affect mainly patients during their productive years of life. In order to obtain a better quality of life for patients with this disease, a multidisciplinary approach is recommended. Radiosurgery is one of the treatment modalities available for AVMs, but many factors may influence the effectiveness of this strategy. Classically, it has been said that deep-seated lesions have a particular behavior compared with AVMs in other regions, but a differentiation between thalamic lesions and those located in the basal ganglia has not been made. METHODS: Institutional records for central core AVMs treated with radiosurgery between January 2004 and January 2014 were retrospectively analyzed. Brainstem lesions were excluded from the analysis. RESULTS: Forty-nine patients with deep-seated AVMs were included. Forty-three (87.8%) were located in the thalamus and 6 (12.2%) in the area of basal ganglia. The nidus mean volume was 4.1 cm3 (SD: 4.1), the maximum diameter mean was of 19.5 mm (SD: 8.0). The prescription dose was 18.2 Gy (SD: 2.1), and the follow-up time was 75.8 months (SD: 32.5). There was a greater obliteration rate in thalamic AVMs compared with those located in the basal ganglia: 81.4% versus 33.3% (P = 0.026), respectively. There was no association between categorical variables and obliteration rate. CONCLUSIONS: Stereotactic radiosurgery is a good option for patients with thalamic and basal ganglia AVMs, but a multidisciplinary approach to decision-making is mandatory in order to achieve the best results.

Thalamus Cavernous Malformation Resection of via Contralateral Anterior Interhemispheric Transcallosal Approach: Two-Dimensional Operative Video.

Thalamic cavernous malformations (CM) are highly challenging surgically. In this illustrative video (Video 1), we present the case of a 36-year-old man with a CM at the left medial thalamus, which was successfully treated by a contralateral anterior interhemispheric transcallosal approach. Informed consent was obtained from the patient. Preoperative imaging demonstrated that the CM appeared to have reached the pial surface superiorly and medially, and diffusion tensor imaging showed the pyramidal tracts to be traveling laterally to the CM. Based on the "Two-point" principle and to avoid pyramidal tract impingement, an anterior interhemispheric transcallosal approach was chosen. Furthermore, to avoid excessive retraction on the ipsilateral hemisphere, we selected the contralateral trajectory over the ipsilateral trajectory. The head was positioned with the right side down; thus, the space between the right hemisphere and the falx could expand because of gravity autoretraction, which could minimize the need of retraction during the interhemispheric dissection. A small incision on the corpus callosum was performed under the guidance of neuronavigation, and the left ventricle was subsequently entered. After a thin layer of hemosiderin-stained pia was opened on the superior surface of the left thalamus, some sandlike old hemorrhagic component was removed for decompression, and the lesion was carefully dissected away from the normal parenchyma within the surrounding gliosis boundary. The CM was removed en bloc, and the deep venous anomaly was well protected. The patient did not experience any intraoperative changes shown by electrophysiologic monitoring, and he recovered well postoperatively.

Stereotactic radiosurgery for arteriovenous malformations of the basal ganglia and thalamus: an international multicenter study.

OBJECTIVE: Arteriovenous malformations (AVMs) of the basal ganglia (BG) and thalamus are associated with elevated risks of both hemorrhage if left untreated and neurological morbidity after resection. Therefore, stereotactic radiosurgery (SRS) has become a mainstay in the management of these lesions, although its safety and efficacy remain incompletely understood. The aim of this retrospective multicenter cohort study was to evaluate the outcomes of SRS for BG and thalamic AVMs and determine predictors of successful endpoints and adverse radiation effects. METHODS: The authors retrospectively reviewed data on patients with BG or thalamic AVMs who had undergone SRS at eight institutions participating in the International Gamma Knife Research Foundation (IGKRF) from 1987 to 2014. Favorable outcome was defined as AVM obliteration, no post-SRS hemorrhage, and no permanently symptomatic radiation-induced changes (RICs). Multivariable models were developed to identify independent predictors of outcome. RESULTS: The study cohort comprised 363 patients with BG or thalamic AVMs. The mean AVM volume and SRS margin dose were 3.8 cm3 and 20.7 Gy, respectively. The mean follow-up duration was 86.5 months. Favorable outcome was achieved in 58.5% of patients, including obliteration in 64.8%, with rates of post-SRS hemorrhage and permanent RIC in 11.3% and 5.6% of patients, respectively. Independent predictors of favorable outcome were no prior AVM embolization (p = 0.011), a higher margin dose (p = 0.008), and fewer isocenters (p = 0.044). CONCLUSIONS: SRS is the preferred intervention for the majority of BG and thalamic AVMs. Patients with morphologically compact AVMs that have not been previously embolized are more likely to have a favorable outcome, which may be related to the use of a higher margin dose.

Recurring Thalamic Symptoms Due to Intracranial Dural Arteriovenous Fistula: Report of Unusual Case and Treatment Outcome.

BACKGROUND: Initial clinical presentation of dural arteriovenous fistula (DAVF) with predominantly thalamic symptoms is rare and has not been reported until now. CASE DESCRIPTION: A young child presenting with complaints of tinnitus and mild right hemiparesis was evaluated with an initial magnetic resonance imaging, which revealed a Borden type 2 DAVF in the right transverse sinus with retrograde venous drainage and cortical venous reflux. Flow-related small aneurysms were also noted in the left basal vein of Rosenthal (BVR). Two days later, his motor power deteriorated and he developed right hemisensory loss and severe thalamic pain. Aphasia was atypical and mimicked the transcortical type. Repeat imaging revealed expanding thrombosed aneurysm of BVR with mass effect and edema on thalamocapsular region. Initial antiedema measures reversed the neurologic deficits; however, they recurred, necessitating an urgent endovascular intervention. Angiogram revealed an extensive high-flow DAVF in the right transverse-sigmoid sinus and torcula with preferential retrograde venous drainage into deep veins and left BVR. He underwent staged embolization of DAVF, resulting in significant obliteration of shunt. Neurologic deficits improved in the postoperative period, and the patient remained clinically asymptomatic at 6 months of follow-up. CONCLUSIONS: DAVF presenting with recurrent predominantly thalamic symptoms is rare. Atypical transcortical aphasia rather than fluent aphasia is an unusual clinical manifestation of thalamic pathology and could result from the involvement of specific thalamic nuclei. Preferential high flow into BVR in the presence of venous anomalies could potentially induce architectural weakness of the venous wall and precipitate aneurysm formation. Embolization of the DAVF can potentially reverse this unusual neurologic condition.

Bilateral Thalamic Edema from Coexisting Choroid Plexus Arteriovenous Malformation and Sinus Thrombosis: Case Report.

Bilateral thalamic dysfunction secondary to venous congestion may result from either venous sinus thrombosis or high flow arteriovenous malformations or a combination of both. We present a case of bilateral thalamic edema resulting from concomitant choroid plexus arteriovenous malformation (AVM) and straight sinus thrombosis and describe our treatment approach. The patient presented with several weeks of progressive confusion and memory deficits. Magnetic resonance imaging and venography (MRI/ MRV) showed bilateral thalamic T2 hyperintensities and straight sinus thrombosis. Subsequent cerebral angiography revealed a choroid plexus AVM within the right lateral ventricle. The patient underwent surgical resection of the AVM resulting in postoperative resolution of bilateral thalamic edema on MRI and improvement of his confusion and memory deficits. This case demonstrates a rare example of reversible bilateral thalamic edema secondary to venous hypertension from both an AVM and sinus occlusion after appropriate treatment of the AVM.

Bilateral Thalamic Edema from Coexisting Choroid Plexus Arteriovenous Malformation and Sinus Thrombosis: Case Report.

Bilateral thalamic dysfunction secondary to venous congestion may result from either venous sinus thrombosis or high flow arteriovenous malformations or a combination of both. We present a case of bilateral thalamic edema resulting from concomitant choroid plexus arteriovenous malformation (AVM) and straight sinus thrombosis and describe our treatment approach. The patient presented with several weeks of progressive confusion and memory deficits. Magnetic resonance imaging and venography (MRI/ MRV) showed bilateral thalamic T2 hyperintensities and straight sinus thrombosis. Subsequent cerebral angiography revealed a choroid plexus AVM within the right lateral ventricle. The patient underwent surgical resection of the AVM resulting in postoperative resolution of bilateral thalamic edema on MRI and improvement of his confusion and memory deficits. This case demonstrates a rare example of reversible bilateral thalamic edema secondary to venous hypertension from both an AVM and sinus occlusion after appropriate treatment of the AVM.

Stereotactic radiosurgery for deep intracranial arteriovenous malformations, part 2: Basal ganglia and thalamus arteriovenous malformations.

The aim of this review is to critically analyze the outcomes following stereotactic radiosurgery (SRS) for arteriovenous malformations (AVM) of the basal ganglia and thalamus. The management of these deep-seated lesions continues to challenge neurosurgeons. Basal ganglia and thalamic AVM show a higher risk of hemorrhage, and an associated devastating morbidity and mortality, as compared to AVM in more superficial locations. Any of the currently available treatment modalities may fail or result in iatrogenic neurologic deterioration. Recent evidence from A Randomized Trial of Unruptured Brain AVM (ARUBA) further deters aggressive approaches that carry a significant risk of treatment-related adverse events. Microsurgical resection, endovascular embolization and SRS all play a role in the treatment of AVM. SRS is an effective therapeutic option for AVM of the thalamus and basal ganglia that are deemed high risk for resection. SRS offers acceptable obliteration rates, with generally lower risks of hemorrhage occurring during the latency period compared to the AVM natural history. Considering that incompletely obliterated lesions still harbor the potential for rupture, additional treatments such as repeat SRS and microsurgical resection should be considered when complete obliteration is not achieved by an initial SRS procedure. Patients with AVM of the basal ganglia and thalamus require continued clinical and radiologic observation and follow-up after SRS, even after angiographic obliteration has been confirmed.

Endovascular Management of Deep Arteriovenous Malformations: Single Institution Experience in 22 Consecutive Patients.

BACKGROUND: The management of arteriovenous malformations (AVMs) in the basal ganglia, insula, and thalamus is demanding for all treatment modalities. OBJECTIVE: To define safety and outcomes of embolization used as a stand-alone therapy for deep-seated AVMs. METHODS: A cohort of 22 patients with AVMs located in the basal ganglia, thalamus, and insula who underwent embolization between January 2008 and December 2013. RESULTS: Eighteen of 22 (82%) patients had anatomic exclusion. The mean size was 2.98 ± 1.28 cm, and the mean number of sessions was 2.1 per patient. Most patients presented with hemorrhage (82%, n = 18), and 3 (14%) patients were in a deteriorated neurological status (modified Rankin Scale >2) at presentation. Sixty-eight percent of ruptured AVMs had size ≤3 cm. A single transarterial approach was performed in 9 (41%) cases, double catheterization was used in 4 (18%), and the transvenous approach was required in 8 (36%) cases. Procedure-related complications were registered in 3 (14%) cases. One death was associated with treatment, and complementary radiosurgery was required in 2 (9%) patients. CONCLUSION: Embolization therapy appears to be safe and potentially curative for certain deep AVMs. Our results demonstrate a high percentage of anatomic obliteration with rates of complications that may approach radiosurgery profile. In particular, embolization as stand-alone therapy is most suitable to deep AVMs with small nidus size (≤3 cm) and/or associated with single venous drainage in which microsurgery might not be indicated.

Thalamic arteriovenous malformation fed by the artery of Percheron originating from the contralateral posterior cerebral artery in a child.

PURPOSE: Artery of Percheron (AOP) is a rare variant of thalamoperforating artery with a single common trunk feeding both thalami and with or without contribution to the rostral midbrain. We report the first case of thalamic arteriovenous malformation (AVM) fed by AOP with hemorrhagic onset. METHODS: A 12-month-old girl suddenly weakened and developed coma. Left thalamic hemorrhage was detected with the third and both lateral ventricles' hematoma. Thalamic AVM was discovered to be fed by an AOP originating from the contralateral posterior cerebral artery. RESULTS: Endovascular embolization of AVM was impossible due to a risk of bilateral thalamic infarction and anatomical inaccessibility. Thalamic AVM was removed by high superior parietal approach without new neurological symptoms. CONCLUSION: The first case of thalamic AVM fed by AOP originating from the contralateral posterior cerebral artery is reported. Surgical removal of AVM would be at the heart of treatment in order to avoid bilateral thalamic infarction.

Deep arteriovenous malformations in the Basal Ganglia, thalamus, and insula: microsurgical management, techniques, and results.

BACKGROUND: Arteriovenous malformations (AVMs) in the basal ganglia, thalamus, and insula are considered inoperable given their depth, eloquence, and limited surgical exposure. Although many neurosurgeons opt for radiosurgery or observation, others have challenged the belief that deep AVMs are inoperable. Further discussion of patient selection, technique, and multimodality management is needed. OBJECTIVE: To describe and discuss the technical considerations of microsurgical resection for deep-seated AVMs. METHODS: Patients with deep AVMs who underwent surgery during a 14-year period were reviewed through the use of a prospective AVM registry. RESULTS: Microsurgery was performed in 48 patients with AVMs in the basal ganglia (n=10), thalamus (n=13), or insula (n=25). The most common Spetzler-Martin grade was III- (68%). Surgical approaches included transsylvian (67%), transcallosal (19%), and transcortical (15%). Complete resection was achieved in 34 patients (71%), and patients with incomplete resection were treated with radiosurgery. Forty-five patients (94%) were improved or unchanged (mean follow-up, 1.6 years). CONCLUSION: This experience advances the notion that select deep AVMs may be operable lesions. Patients were highly selected for small size, hemorrhagic presentation, young age, and compactness-factors embodied in the Spetzler-Martin and Supplementary grading systems. Overall, 10 different approaches were used, exploiting direct, transcortical corridors created by hemorrhage or maximizing anatomic corridors through subarachnoid spaces and ventricles that minimize brain transgression. The same cautious attitude exercised in selecting patients for surgery was also exercised in deciding extent of resection, opting for incomplete resection and radiosurgery more than with other AVMs to prioritize neurological outcomes.

Role of stereotactic radiosurgery in the treatment of high-grade cerebral arteriovenous malformation.

Arteriovenous malformation (AVM) with a small nidus located in the cortical eloquent areas is difficult to surgically resect without neurological complication, but is a suitable target for stereotactic radiosurgery (SRS). However, lesions with large nidus volume or with deeply located nidus are difficult to safely treat, even by SRS. To explore the optimal treatment strategies for such high-grade cerebral AVM, we reviewed treatment outcomes of SRS using gamma knife surgery (GKS) for patients with high-grade AVM at our institute and in published reports. Although lesions in the thalamus and the brainstem carried higher risk of morbidity after SRS, accumulation of technical knowledge and experience about SRS and technological advances in dose planning have enabled safer treatment of AVM in these locations. Large AVM presents another challenge to SRS treatment. Multimodal treatment, including surgery and endovascular treatment, should be considered. In this setting, staged SRS using GKS or CyberKnife may achieve safer treatment of large cerebral AVM. Further progress in SRS is anticipated to enhance the treatment efficacy for high-grade cerebral AVM while reducing treatment morbidity.

Gamma Knife surgery for basal ganglia and thalamic arteriovenous malformations.

OBJECT: Gamma Knife surgery (GKS) has emerged as the treatment of choice for small- to medium-sized cerebral arteriovenous malformations (AVMs) in deep locations. The present study aims to investigate the outcomes of GKS for AVMs in the basal ganglia and thalamus. METHODS: Between 1989 and 2007, 85 patients with AVMs in the basal ganglia and 97 in the thalamus underwent GKS and were followed up for more than 2 years. The nidus volumes ranged from 0.1 to 29.4 cm(3) (mean 3.4 cm(3)). The mean margin dose at the initial GKS was 21.3 Gy (range 10-28 Gy). Thirty-six patients underwent repeat GKS for residual AVMs at a median 4 years after initial GKS. The mean margin dose at repeat GKS was 21.1 Gy (range 7.5-27 Gy). RESULTS: Following a single GKS, total obliteration of the nidus was confirmed on angiograms in 91 patients (50%). In 12 patients (6.6%) a subtotal obliteration was achieved. No flow voids were observed on MR imaging in 14 patients (7.7%). Following single or repeat GKS, total obliteration was angiographically confirmed in 106 patients (58.2%) and subtotal obliteration in 8 patients (4.4%). No flow voids on MR imaging were observed in 18 patients (9.9%). The overall obliteration rates following one or multiple GKSs based on MR imaging or angiography was 68%. A small nidus volume, high margin dose, low number of isocenters, and no history of embolization were significantly associated with an increased rate of obliteration. Twenty-one patients experienced 25 episodes of hemorrhage in 850 risk-years following GKS, yielding an annual hemorrhage rate of 2.9%. Four patients died in this series: 2 due to complications of hemorrhage and 2 due to unrelated diseases. Permanent neurological deficits caused by radiation were noted in 9 patients (4.9%). CONCLUSIONS: Gamma Knife surgery offers a reasonable chance of obliterating basal ganglia and thalamic AVMs and does so with a low risk of complications. It is an optimal treatment option in patients for whom the anticipated risk of microsurgery is too high.