Citations

Intramedullary ependymomas are surgically curable tumors. However, their surgical resection poses several challenges. In this intraoperative video we illustrate the main steps for the surgical resection of a cervical intramedullary ependymoma. These critical steps include: adequate exposure of the entire length of the tumor; use of the intraoperative ultrasound; identification of the posterior median sulcus and separation of the posterior columns; Identification of the plane between the spinal cord and the tumor; mobilization and debulking of the tumor and disconnection of the vascular supply (usually from small anterior spinal artery branches). Following these basic steps a complete resection can be safely achieved in many cases. The video can be found here: http://youtu.be/QMYXC_F4O4U .

A long-held dogma in neurosurgery is that parenchymal arteriovenous malformations (AVMs) are congenital. However, there is no strong evidence supporting this theory. An increasing number of documented cases of de novo formation of parenchymal AVMs cast doubt on their congenital nature and suggest that indeed the majority of these lesions may form after birth. Further evidence suggesting the postnatal development of parenchymal AVMs comes from the exceedingly rare diagnosis of these lesions in utero despite the widespread availability of high-resolution imaging modalities such as ultrasound and fetal MRI. The exact mechanism of AVM formation has yet to be elucidated, but most likely involves genetic susceptibility and environmental triggering factors. In this review, the authors report 2 cases of de novo AVM formation and analyze the evidence suggesting that they represent an acquired condition.

Object Flow diversion has emerged as a promising treatment alternative for cerebral aneurysms. As a new device, treatment-related events and complications are currently being characterized. Methods Data on 100 consecutive procedures with the intention to use flow diversion were prospectively collected and analyzed retrospectively. Results Ninety-five aneurysms were treated in 93 patients during 100 consecutive procedures in which the intention was to treat an intracranial aneurysm with flow diversion. Death occurred in 1% and permanent morbidity in 1%. However, periprocedural technical complications occurred in 35% of the procedures and included proximal device migration in 12%, incomplete device expansion in 9%, catheter-induced vasospasm in 6%, and artery perforation from the wire in 3%. Perioperative clinical events were seen in 28% (thromboembolism and access site complications were the most common, being observed in 6.5% of patients). Worsened extraocular motility was seen in 5.4% and resolved in 4/5 patients. Mean clinical follow-up was 17 months. There were no late clinical or technical issues resulting in permanent deficits, although one patient suffered worsening ataxia. Overall, using very strict angiographic criteria, complete angiographic obliteration was 50% at 6 months and 69% after 1 year. Conclusions Flow diversion for intracranial aneurysms is a safe and effective treatment. Technical and clinical events are common in the perioperative period. Careful perioperative care and proper management of technical and clinical events encountered is key to achieving low morbidity and mortality. Late clinical events can occur but are unlikely to result in permanent complications.

It is with great pride that we present this Neurosurgical Focus video supplement on endovascular neurosurgery. We were privileged to view a multitude of outstanding quality videos demonstrating the current state-of-the-art in endovascular neurosurgery. Careful and critical review was required to narrow down the videos to a workable volume for this supplement, though there were many more that we would have liked to have included. This issue consists of several videos that represent modern neuroendovascular techniques for the treatment of cerebrovascular disease. The videos demonstrate the cutting-edge as well as standard endovascular therapies, which will be valuable to both the novice and the expert endovascular neurosurgeons. We are greatly honored to be involved with this project, and are very proud of its content and expert authors. We confidently believe you will enjoy the video content of this supplement.

Background Expansion of the endovascular and surgical workforce in the USA might lead to carotid revascularization procedures being carried out at low volume centers. Objective To evaluate trends in the treatment of carotid stenosis at high volume centers in the USA and compare outcomes by hospital volume. Methods Using the Nationwide Inpatient Sample, we evaluated trends in the proportion of carotid revascularization procedures performed at high volume centers in the USA from 2005 to 2011. High volume was defined as combined endarterectomy/stenting volume ≥130 patients/year, carotid endarterectomy volume ≥117 cases/year and carotid stenting volume ≥38 cases/year. In-hospital mortality, discharge to a long-term facility, intracranial hemorrhage, and postoperative stroke rates were compared between high and low volume centers. Results A total of 181 972 patients were included in this study. Overall, 63 442 patients (34.9%) were treated at high volume centers. The proportion of patients treated at high volume carotid revascularization centers decreased from 38.3% in 2005–2006 to 30.2% in 2010–2011. The proportion of patients treated at high volume centers decreased from 35.7% to 30.0% for carotid endarterectomy (p<0.0001) and 45.2% to 35.1% for carotid stenting. Patients treated at low volume centers had significantly higher rates of discharge to a long-term facility than high volume center patients (6.3% vs 5.0%, p<0.0001). The same was true for endarterectomy patients (6.0% vs 4.7%, p<0.0001) and stenting patients (8.3% vs 6.5%, p<0.0001). Conclusions A trend toward a lower proportion of patients with carotid stenosis being treated in high volume centers from 2005 to 2011 is concerning as these high volume centers had lower complication rates.

The surgical treatment of meningiomas located at the base of the anterior cranial fossa is often challenging, and the evolution of the surgical strategy to resect these tumors parallels the development of craniotomy, and neurosurgery in general, over the past century. Early successful operations to treat these tumors were pioneered by prominent figures such as Sir William Macewen and Francesco Durante. Following these early reports, Harvey Cushing made significant contributions, allowing a better understanding and treatment of meningiomas in general, but particularly those involving the anterior cranial base. Initially, large-sized unilateral or bilateral craniotomies were necessary to approach these deep-seated lesions. Technical advances such as the introduction of electrosurgery, the operating microscope, and refined microsurgical instruments allowed neurosurgeons to perform less invasive surgical procedures with better results. Today, a wide variety of surgical strategies, including endoscopic surgery and radiosurgery, are used to treat these tumors. In this review, the authors trace the evolution of craniotomy for anterior cranial fossa meningiomas.

Background and Purpose— To address the increasing need to counsel patients about treatment indications for unruptured intracranial aneurysms (UIA), we endeavored to develop a consensus on assessment of UIAs among a group of specialists from diverse fields involved in research and treatment of UIAs. Methods— After composition of the research group, a Delphi consensus was initiated to identify and rate all features, which may be relevant to assess UIAs and their treatment by using ranking scales and analysis of inter-rater agreement (IRA) for each factor. IRA was categorized as very high, high, moderate, or low. Results— Ultimately, 39 specialists from 4 specialties agreed (high or very high IRAs) on the following key factors for or against UIA treatment decisions: (1) patient age, life expectancy, and comorbid diseases; (2) previous subarachnoid hemorrhage from a different aneurysm, family history for UIA or subarachnoid hemorrhage, nicotine use; (3) UIA size, location, and lobulation; (4) UIA growth or de novo formation on serial imaging; (5) clinical symptoms (cranial nerve deficit, mass effect, and thromboembolic events from UIAs); and (6) risk factors for UIA treatment (patient age and life expectancy, UIA size, and estimated risk of treatment). However, IRAs for features rated with low relevance were also generally low, which underlined the existing controversy about the natural history of UIAs. Conclusions— Our results highlight that neurovascular specialists currently consider many features as important when evaluating UIAs but also highlight that the appreciation of natural history of UIAs remains uncertain, even within a group of highly informed individuals.

Asymptomatic carotid artery stenosis is a well-recognized risk factor for ischemic stroke, and its prevalence increases with age. In the late 1980s and in the 1990s, well-designed randomized trials established a definite advantage for carotid endarterectomy in reducing the risk of ipsilateral stroke when compared with medical therapy alone. However, medical treatment of cardiovascular disease has improved significantly over the past 2 decades, and this has, in turn, resulted in a decline of the stroke risk in patients with asymptomatic carotid artery stenosis treated medically. This improvement in medical therapy casts doubts on the effectiveness of large-scale invasive treatment in patients with asymptomatic carotid artery stenosis. Several studies have been conducted to identify possible subgroups of patients with asymptomatic stenosis who are at higher risk of stroke in order to maximize the potential benefits of invasive treatment. Ongoing large-scale trials comparing best current medical therapy to available invasive treatments, such as carotid endarterectomy and carotid artery stenting, are likely to shed some light on this debated topic in the near future. In this review, the authors summarize the current controversy surrounding the ideal management of asymptomatic carotid artery stenosis.