Rapid postradiation malignant transformation of a pilocytic astrocytoma in an adult with neurofibromatosis type 1: illustrative case.

Background: Juvenile pilocytic astrocytoma (JPA) is the most common primary brain tumor of childhood and is rarely seen in adults. Neurofibromatosis type 1 (NF1), a common tumor predisposition syndrome, demonstrates a strong association with low-grade gliomas, most notably pilocytic astrocytoma, which are relatively indolent. Unlike its juvenile counterpart, reports of adult pilocytic astrocytoma (APA) vary widely in terms of disease progression from benign to much more malignant courses.

Management of failed flow diversion for intracranial aneurysm beyond the first 6 months of follow-up: an international Delphi consensus.

Objective: The placement of flow-diverting devices has become a common method of treating unruptured intracranial aneurysms of the internal carotid artery. The progressive improvement of aneurysm occlusion after treatment-with low complication and rupture rates-has led to a dilemma regarding the management of aneurysms in which occlusion has not occurred within 6-24 months. The authors aimed to identify clinical consensus regarding management of intracranial aneurysms displaying persistent filling 6-24 months after flow diversion and to ascertain questions that may drive future investigation.

Supracerebellar "Flyover" Approach to Dumbbell Falcotentorial Meningioma Encasing the Galenic Venous System.

Falcotentorial meningiomas involve the tentorial apex and straight sinus, posing challenges when encasing the galenic venous system. Microneurosurgery is considered the best treatment option for large falcotentorial meningiomas because it provides a definitive cure. In contrast, Gamma Knife surgery mainly allows the control of smaller or residual tumors after microsurgical resection.

Multimodality resection of Oliveira Type IIIC* cerebellar AVM: A distinct entity.

Background: Posterior fossa AVMs constitute about 10% of AVMs and are associated with a higher rate of hemorrhage and increased morbidity and mortality rates necessitating treatment with rare exception. Cerebellar AVMs differ markedly from their supratentorial counterparts in that there are no perforating vessels involvement, drainage into the deep cerebral venous system, or presence of eloquent functional area except for the dentate nucleus. While Yaşargil has classified cerebellar AVMs into seven subtypes according to their location, de Oliveira .

Clipping of Multiple Cerebral Aneurysms Through Cranioorbital Zygomatic Approach: 2-Dimensional Operative Video.

Ruptured cerebral aneurysm is a grave disease, with a high morbidity and mortality, mandating securing the aneurysm to eliminate fatal rebleeding.1 Multiple aneurysms are frequent and may occur in approximately 20% of the cases with female prominence.2 The risk of subarachnoid hemorrhage in unruptured aneurysms is higher in patients who had prior ruptured aneurysms.

Cervical to Petrous Carotid Artery High-Flow Bypass for Carotid Artery Pseudoaneurysm Through Zygomatic Approach: 2-Dimensional Operative Video.

Pseudoaneurysms of the cervical internal carotid artery may generate grave risk from catastrophic rupture, thromboembolic stroke, or mass effect. They have many causes, including malignancy, infection, and iatrogenic and most commonly blunt or penetrating trauma.1 These aneurysms require treatment to eliminate their risk.

"Save the Nerve": Technical Nuances for Hearing Preservation and Restoration in Vestibular Schwannoma Surgery: 2-Dimensional Operative Video.

Hearing loss is a significant disability that inflects dysfunction and affects the patient quality of life. Consequently, hearing preservation and the potential of hearing restoration are prized quests in the management of vestibular schwannoma.1 Although small intracanalicular vestibular schwannomas are commonly observed, progressive hearing loss occurs despite the absence of tumor growth; hence, surgical resection can be performed with the sole aim of hearing preservation in well-informed and eager patients.

Comparison of Surgical Outcomes and Recurrence Rates of Cystic and Solid Vestibular Schwannomas.

 Cystic vestibular schwannomas (CVSs) are anecdotally believed to have worse clinical and tumor-control outcomes than solid vestibular schwannomas (SVSs); however, no data have been reported to support this belief. In this study, we characterize the clinical outcomes of patients with CVSs versus those with SVSs.  This is a retrospective review of prospectively collected data.

Medial Acoustic Tumors: Special Considerations: 2-Dimensional Operative Video.

Medial acoustic tumors are a rare distinct type of vestibular schwannoma having distinguished clinical and radiological features.1 Originating medially in the cerebellopontine angle without extending into the lateral internal auditory meatus, they are frequently giant in size at presentation in younger patients with a relatively preserved hearing, while they have other neurological deficits from cerebellar or brainstem compression and associated hydrocephalus. Imaging typically shows a cystic tumor with local mass effect and an internal auditory canal filled with cerebrospinal fluid.

Is Falcine Meningioma a Diffuse Disease of the Falx? Case Series and Analysis of a "Grade Zero" Resection.

Background: Falcine meningiomas have unique characteristics including their high rates of recurrence, association with high grade pathology, increased male prevalence, and potential for diffuse involvement of the falx.

Objective: To address these issues in a substantial series of falcine meningiomas and report on the impact of extent of resection for this distinct meningioma entity.

Methods: Retrospective analysis of characteristics and outcomes of 59 falcine meningioma patients who underwent surgery with the senior author.

Onyx embolization of skull base paragangliomas: a single-center experience.

Background: Skull base paragangliomas are highly vascular tumors that are often embolized before surgical resection; however, the safety and efficacy of preoperative embolization using an ethylene vinyl alcohol copolymer (Onyx; Medtronic, Dublin, Republic of Ireland) in these tumors is unknown. This retrospective cohort study evaluated patient outcomes after preoperative embolization of skull base paragangliomas using Onyx.

Methods: We retrospectively analyzed data from all patients with skull base paragangliomas who underwent preoperative Onyx embolization at our institution (January 01, 2005-December 31, 2017).

Flow diverters as a scaffold for treating direct carotid cavernous fistulas.

Background: Direct carotid-cavernous sinus fistulas (dCCFs) are high flow arteriovenous shunts between the internal carotid artery and the cavernous sinus. Recently, we have used the pipeline embolization device (PED) to treat dCCFs.

Methods: We describe our experience treating patients with dCCFs in whom the PED was placed as the primary treatment modality.

Direct Repair of Iatrogenic Vertebral Artery Injury Associated With Anterior Cervical Corpectomy: 2-Dimensional Operative Video.

Vertebral artery (VA) injury during anterior cervical spine surgery has potentially devastating neurovascular consequences. Our video highlights the operative nuances of exposing and directly repairing the V2 segment of the VA from an anterior approach. A 67-year-old woman undergoing anterior cervical corpectomy at another hospital began briskly bleeding from a suspected VA injury.

Prognostic factors in the surgical treatment of intracanalicular primary optic nerve sheath meningiomas.

Objective: Although meningiomas frequently involve the optic nerve, primary optic nerve sheath meningiomas (ONSMs) are rare, accounting for only 1% of all meningiomas. Given the high risk of vision loss with these tumors, surgical intervention is seldom considered, and radiation or observation is commonly applied. Here, the authors describe the visual outcomes for a series of patients who were treated with surgery aiming at maximal tumor resection and highlight their prognostic factors.

Preoperative Embolization of Skull Base Meningiomas: Outcomes in the Onyx Era.

Objective: Preoperative embolization may facilitate skull base meningioma resection, but its safety and efficacy in the Onyx era have not been investigated. In this retrospective cohort study, we evaluated the outcomes of preoperative embolization of skull base meningiomas using Onyx as the primary embolysate.

Methods: We queried an endovascular database for patients with skull base meningiomas who underwent preoperative embolization at our institution in 2007-2017.

Delayed Carotid Pseudoaneurysms from Iatrogenic Clival Meningeal Branches Avulsion: Recognition and Proposed Management.

Background: Carotid injury during anterior skull base approaches is promptly recognizable and mandates immediate treatment; likewise, development of pseudoaneurysms after such injuries is anticipated and managed.

Methods: We report here on the delayed development of a pseudoaneurysm as the result of avulsion of clival meningeal arteries that manifests as unalarming intraoperative bleeding.

Results And Conclusions: The bleeding is brisk and arterial but easily controlled.

Hybrid Surgery Management of Giant Hypervascular Tumors: Intraoperative Endovascular Embolization with Microsurgical Resection.

Background: Giant hypervascular intracranial tumors represent a formidable challenge because their size limits surgical control of the blood supply and debulking poses the risk of critical blood loss. Embolization facilitates resection but carries the risk of life-threatening tumor infarction, hemorrhage, or swelling if performed preoperatively. Endovascular intraoperative embolization avoids the fatal risk and allows the surgeon to attend instantly if any complication occurs.

Middle meningeal arteriovenous fistulas: A rare and potentially high-risk dural arteriovenous fistula.

Background: Middle meningeal arteriovenous fistulas (MMAVFs) are rare lesions with a poorly established natural history. We report our experience with patients with MMAVFs who presented with intracranial hemorrhage.

Methods: We reviewed our prospectively maintained endovascular database for patients with MMAVFs, who were treated by embolization during a 15-year period.

Low-flow and high-flow neurosurgical bypass and anastomosis training models using human and bovine placental vessels: a histological analysis and validation study.

OBJECTIVE Microvascular anastomosis is a basic neurosurgical technique that should be mastered in the laboratory. Human and bovine placentas have been proposed as convenient surgical practice models; however, the histologic characteristics of these tissues have not been compared with human cerebral vessels, and the models have not been validated as simulation training models. In this study, the authors assessed the construct, face, and content validities of microvascular bypass simulation models that used human and bovine placental vessels.

Treatment of Ruptured Anterior Communicating Artery Aneurysms: Equipoise in the Endovascular Era?

Background: Ruptured anterior communicating artery (ACoA) aneurysms are heterogeneous intracranial aneurysms whose diverse morphological features influence treatment modality.

Objective: To compare clinical outcomes and complications of all ruptured ACoA aneurysms treated by clipping or coiling in a modern institutional trial.

Methods: All patients with ruptured ACoA aneurysms in the Barrow Ruptured Aneurysm Trial were included.