Publications by authors named "Darren Orbach"

Background: Spetzler-Martin (SM) Grade III brain arteriovenous malformations (BAVMs) represent a transitional risk zone between low- and high-grade BAVMs, characterized by diverse angioarchitecture. The primary treatment options are endovascular embolization, microsurgical resection (MS), and stereotactic radiosurgery (SRS). This study compares the efficacy and outcomes of MS and SRS.

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Pediatric cerebrovascular diseases have distinct clinical presentations, pathophysiology, and management compared to the adult counterparts. This introductory article discusses the imaging techniques and neurovascular conditions unique to each age group from the fetal stages through childhood, including vascular malformations, arteriopathy, and strokes. The article also underscores the importance of genetic factors and the need for a multidisciplinary approach in the diagnosis and treatment of pediatric neurovascular disorders.

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Objective: To assess whether white matter injuries differ in symptomatic vs asymptomatic moyamoya-affected hemispheres using diffusion magnetic resonance imaging since there is controversy regarding when or if to revascularize children with asymptomatic moyamoya.

Study Design: We conducted a cross-sectional study of children with moyamoya who underwent diffusion magnetic resonance imaging before revascularization surgery as well as controls without moyamoya. We measured the fractional anisotropy, mean diffusivity, radial diffusivity, and axial diffusivity of white matter tracts in the watershed regions.

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Background: Arteriovenous malformations (AVMs) are uncommon cerebral lesions that can cause significant neurological complications. Surgical resection is the gold standard for treatment, but endovascular embolization and stereotactic radiosurgery (SRS) are viable alternatives.

Objective: To compare the outcomes of endovascular embolization versus SRS in the treatment of AVMs with Spetzler-Martin grades I-III.

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Article Synopsis
  • Four types of vascular anomalies affect the fetal brain, including vein of Galen malformations and dural sinus malformations, and they typically don't manifest after birth.
  • * MRI is crucial for diagnosing these conditions, evaluating potential brain injuries, and planning treatments, especially for high-risk cases.
  • * A new investigational procedure involves transuterine embolization for vein of Galen malformations, offering a promising treatment alternative to conventional methods.
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  • Vein of Galen malformation (VOGM) is a serious congenital issue leading to high death rates and cognitive challenges, necessitating better diagnostic tools.
  • This study aimed to analyze brain blood flow in VOGM patients using 4D flow MRI, focusing on blood inflow to the brain and specific sinus flows, while relating these to age and other clinical factors.
  • Findings showed that blood flow in VOGM patients was consistently higher than normal, and significant correlations were found between various blood flow metrics and the size of pathological structures, aiding future treatment monitoring.
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Background: Mechanical thrombectomy (MT) is a well-established treatment modality for large vessel occlusion (LVO) in adults, but there are limited data in the pediatric population. The rarity of the condition makes prospective trial design difficult, and therefore evaluation of MT devices and outcomes is sparse. In pediatric LVO cases, some newer devices may be appropriate for use in revascularization procedures.

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Background: Infantile-type dural arteriovenous shunts (IDAVS) are rare and heterogeneous vascular lesions, complicating their classification and management. The current tripartite classification of pediatric dural arteriovenous shunts (DAVS) into dural sinus malformation, infantile-type, and adult-type, does not stand up to scrutiny, given the variable presentations of the latter two types in children. We estimate the prevalence of IDAVS and evaluate the long term outcomes after endovascular treatment (EVT).

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To elucidate the pathogenesis of vein of Galen malformations (VOGMs), the most common and most severe of congenital brain arteriovenous malformations, we performed an integrated analysis of 310 VOGM proband-family exomes and 336,326 human cerebrovasculature single-cell transcriptomes. We found the Ras suppressor p120 RasGAP (RASA1) harbored a genome-wide significant burden of loss-of-function de novo variants (2042.5-fold, p = 4.

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Objective: Optimal choroid plexus tumor (CPT) treatment involves gross total resection; however, intraoperative hemorrhage risk remains significant given tumor vascularity. This study describes pediatric CPT management and identifies patients most likely to benefit from preoperative embolization.

Methods: CPTs resected from 1997 to 2021 were included.

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Purpose: To describe a surgical technique for posterior cerebral revascularization in pediatric patients with moyamoya arteriopathy. Here, we describe the clinical characteristics, surgical indications, operative techniques, and clinical and radiographic outcomes in a series of pediatric patients with moyamoya disease affecting the posterior cerebral artery (PCA) territory.

Methods: A retrospective single-center series of all pediatric patients with moyamoya disease who presented to our institute between July 2009 through August 2019 were reviewed.

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Background And Importance: Vein of Galen malformations (VOGMs) are complex arteriovenous malformations in neonates and young children. Recent advances in endovascular interventions have drastically improved treatment and clinical outcomes in what was previously high-morbidity, high-mortality disease. The high-flow shunt pathophysiology in VOGMs can lead to dynamic changes in the malformation angioarchitecture, and over time patients can develop jugular bulb stenosis.

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Computational fluid dynamics (CFD) assess biological systems based on specific boundary conditions. We propose modeling more advanced hemodynamic metrics, such as core line length (CL) and critical points which characterize complexity of flow in the context of cerebral vasculature, and specifically cerebral veins during the physiologically evolving early neonatal state of vein of Galen malformations (VOGM). CFD has not been applied to the study of arteriovenous shunting in Vein of Galen Malformations but could help illustrate the pathophysiology of this malformation.

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Over the last 10 years, there has been a rise in neurointerventional case complexity, device variety and physician distractions. Even among experienced physicians, this trend challenges our memory and concentration, making it more difficult to remember safety principles and their implications. Checklists are regarded by some as a redundant exercise that wastes time, or as an attack on physician autonomy.

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Article Synopsis
  • - An 18-month-old child had masked congestive heart failure (CHF) due to an unrepaired vein of Galen malformation and a superior sinus venosus defect.
  • - After surgery to repair the superior sinus venosus defect, the child's CHF worsened and became severe and difficult to treat.
  • - A partial transvenous coil embolization procedure for the vein of Galen malformation successfully alleviated the child's CHF symptoms.
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Objective: Neurosurgical outcomes are not well defined in the management of pediatric patients with cerebral venous sinus thrombosis (CVST) following acute mastoiditis. Specific notable sequelae are otogenic (otitic) hydrocephalus and CVST management. Correspondingly, the aim of this study was to integrate the currently published metadata to summarize these outcomes.

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Article Synopsis
  • Moyamoya disease leads to narrowing of the cerebral arteries, resulting in strokes or silent brain injuries, primarily identified through MRI studies showing abnormal white matter characteristics.
  • In a study involving 15 children with moyamoya, specific white matter tracts were found to have lower fractional anisotropy and higher mean diffusivity, indicating potential unrecognized injuries.
  • The affected tracts, including key pathways like the uncinate and arcuate fasciculus, were situated in vascular watershed regions, suggesting that the abnormalities may stem from reduced blood flow rather than immediate infarctions.
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  • This study evaluates the link between pulmonary hypertension (PH) and mortality in infants and children with vein of Galen malformation (VOGM), analyzing data from 49 patients admitted to Boston Children's Hospital between 2007 and 2020.
  • It was found that overall hospital survival rates were significantly higher for older children (age >60 days, 96%) compared to younger infants (age ≤60 days, 50%), with high output PH being a critical factor for those under 60 days.
  • The resolution of PH is strongly tied to survival outcomes, while certain treatments like inhaled nitric oxide showed limited benefit in patients, emphasizing the need for effective management strategies in this patient group.*
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Article Synopsis
  • The study focused on understanding vein of Galen malformations (VOGMs), which are severe congenital brain abnormalities, by analyzing the genetic data from 310 affected individuals and their families, as well as a large database of human cerebrovascular cells.
  • Researchers identified significant genetic mutations, particularly in the gene p120 RasGAP and the Ephrin receptor-B4, which play roles in limiting Ras activation and are key to VOGM development.
  • Experiments on mice with specific genetic alterations revealed that abnormal activation of signaling pathways in endothelial cells leads to developmental issues in blood vessel formation, providing insights into both the biology of VOGMs and potential clinical applications for treatment.
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Background: Digital subtraction angiography (DSA) assesses revascularization in pediatric moyamoya patients after surgery, but MRI and angiography (MRI/A) may provide comparable data.

Objective: To evaluate DSA and MRI/A with respect to clinical utility in postoperative follow-up, complication profile, and relative cost at 1 year.

Methods: All pediatric moyamoya patients who received bilateral indirect revascularization between 2011 and 2020 were retrospectively reviewed at 1 institution.

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Background: Vein of Galen malformation (VOGM) is a rare, life-threatening vascular malformation in neonates and is treated with embolization. However, even at the most experienced centers, patients face high mortality and morbidity. In utero treatment options have been limited by lack of animal models or simulations.

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