R. Webster Crowley, Ricky Medel and Aaron S. Dumont
Penetrating injuries to the neck can result in a number of abnormalities that are of interest to neurosurgeons and interventional neuroradiologists. Gunshot or stab wounds may cause damage to the cervical spinal cord, the adjacent osseous and ligamentous structures, and the peripheral or cranial nerves. In addition, a significant percentage of penetrating wounds to this location result in vascular injury. These may present insidiously or acutely and with a variety of symptoms. The authors present the case of a patient in whom an occipital lobe infarction developed roughly 2 months after the patient was struck in the neck by a bullet. He was found to have a complete transection of the left vertebral artery, with an associated vertebral-venous fistula. The fistula was eventually treated endovascularly with a combination of platinum coils and Amplatzer Vascular Plugs. The management is discussed, with specific emphasis on the technical aspects of the case.
Ricky Medel, R. Webster Crowley and Aaron S. Dumont
Spinal vascular malformations represent a complex group of entities whose treatment paradigm continually evolves. Given the ever-increasing role of endovascular therapy, it is the goal of the authors to review the current literature regarding this therapeutic tool and to provide recommendations guiding management. A thorough literature search was conducted using Medline, with subsequent articles being identified through cross-referencing. The analysis revealed that, since its introduction in the 1960s, endovascular therapy has been used to manage the entire spectrum of spinal vascular malformations, during which period it has undergone considerable technological and technical evolution. As such, embolization has proved of growing therapeutic utility, largely resulting from the mounting evidence supporting its safety and efficacy, in addition to the inherent minimally invasive nature. This alternative to surgical intervention will be increasingly used as first-line therapy in spinal vascular malformations.
Aaron S. Dumont, M. Eric Hyndman, Randall J. Dumont, Paul M. Fedak, Neal F. Kassell, Garnette R. Sutherland and Subodh Verma
Object. Insulin resistance and hypertension are independent risk factors for stroke. Endothelial dysfunction in response to risk factors and carotid artery (CA) disease are important in the pathogenesis of stroke. Pravastatin may have cholesterol-independent pleiotropic effects. In the present study the authors examined the effects of short-course pravastatin treatment on endothelial function in CAs obtained in control and insulin-resistant rats with fructose-induced hypertension.
Methods. Thirty rats were divided into two experimental groups, in which 14 were fed a regular diet and 16 were fed a fructose-enriched diet for 3 weeks. The rats were then divided into four groups: control, pravastatin-treated control, fructose-fed, and pravastatin-treated fructose-fed. Pravastatin was administered (20 mg/kg/day) for 2 weeks. Excretion of the urinary nitric oxide (NO) metabolite nitrite (NO2 −) was also assayed. The CAs from all rats were subsequently removed and assessed for endothelium-dependent and -independent vascular reactivity in vitro. The rats in the fructose-fed group were insulin resistant, hyperinsulinemic, and hypertensive relative to the rats in the control and pravastatin-treated control groups and exhibited diminished endothelium-dependent vasomotion and urinary NO2 − excretion (p < 0.05), with preserved endothelium-independent vasomotion. Strikingly, pravastatin treatment restored endothelium-dependent vasomotion and urinary NO2 − excretion in rats in the fructose-fed pravastatin-treated relative to the fructose-fed group (p < 0.05).
Conclusions. The authors report, for the first time, that pravastatin restores endothelial function in CAs from insulin-resistant rats with fructose-induced hypertension. These beneficial effects were ascribed to direct, cholesterol-independent vascular effects of pravastatin and are likely the result of augmentation of NO production. These data provide impetus for further investigation of nonlipid-lowering indications for pravastatin therapy in the prevention and treatment of CA disease.
Paul T. Boulos, Aaron S. Dumont, James W. Mandell and John A. Jane Sr.
Meningiomas are the most frequently occurring benign intracranial neoplasms. Compared with other intracranial neoplasms they grow slowly, and they are potentially amenable to a complete surgical cure. They cause neurological compromise by direct compression of adjacent neural structures. Orbital meningiomas are interesting because of their location. They can compress the optic nerve, the intraorbital contents, the contents of the superior orbital fissure, the cavernous sinus, and frontal and temporal lobes. Because of its proximity to eloquent neurological structures, this lesion often poses a formidable operative challenge. Recent advances in techniques such as preoperative embolization and new modifications to surgical approaches allow surgeons to achieve their surgery-related goals and ultimately optimum patient outcome. Preoperative embolization may be effective in reducing intraoperative blood loss and in improving intraoperative visualization of the tumor by reducing the amount of blood obscuring the field and allowing unhurried microdissection. Advances in surgical techniques allow the surgeon to gain unfettered exposure of the tumor while minimizing the manipulation of neural structures. Recent advances in technology—namely, frameless computer-assisted image guidance—assist the surgeon in the safe resection of these tumors. Image guidance is particularly useful when resecting the osseous portion of the tumor because the tissue does not shift with respect to the calibration frame. The authors discuss their experience and review the contemporary literature concerning meningiomas of the orbit and the care of patients harboring such lesions.
Ricky Medel, Stephen J. Monteith, R. Webster Crowley and Aaron S. Dumont
Although initially described in the 19th century, cerebral venous sinus thrombosis (CVST) remains a diagnostic and therapeutic dilemma. It has an unpredictable course, and the propensity for hemorrhagic infarction produces significant consternation among clinicians when considering anticoagulation. It is the purpose of this review to analyze the evidence available on the management of CVST and to provide appropriate recommendations.
A thorough literature search was conducted through MEDLINE and PubMed, with additional sources identified through cross-referencing. A classification and level of evidence assignment is provided for recommendations based on the American Heart Association methodologies for guideline composition.
Of the publications identified, the majority were isolated case reports or small case series. Few prospective trials have been conducted. Existing data support the use of systemic anticoagulation as an initial therapy in all patients even in the presence of intracranial hemorrhage. Chemical and/or mechanical thrombectomy, in conjunction with systemic anticoagulation, is an alternative strategy in patients with progressive deterioration on heparin therapy or in those who are moribund on presentation. Mechanical thrombectomy is probably preferred in patients with preexisting intracranial hemorrhage.
Effective treatments exist for the management of CVST, and overall outcomes are more favorable than those for arterial stroke. Further research is necessary to determine the role of individual therapies; however, the rarity of the condition poses a significant limitation.
D. Kojo Hamilton, Neal F. Kassell, Mary E. Jensen and Aaron S. Dumont
✓This 34-year-old man with a 10-year history of HIV infection presented with an acute onset of severe headache, fever, nausea, vomiting, and left-sided weakness. Computed tomography (CT) scanning demonstrated diffuse subarachnoid hemorrhage (SAH), and subsequent CT angiography revealed multiple large and giant intracranial aneurysms with diffuse vasculopathy. The patient's CD4-positive cell count was low, although he had been receiving combination antiret-roviral therapy and his viral load was undetectable.
The preponderance of the literature on HIV-infected patients with intracranial vascular involvement has concerned children in whom there is a high viral load. In such children, appropriate antiretroviral therapy may result in the complete resolution of these vascular abnormalities. In the present study, the authors report on the unique case of an HIV-infected adult patient who presented with SAH, diffuse intracranial vasculopathy, and multiple giant and fusiform aneurysms, despite having received adequate antiretroviral treatment and demonstrating an undetectable viral load. Intracranial vascular involvement in these patients may become increasingly common as the management of HIV infection continues to improve and afflicted patients survive for longer periods.
L. Fernando Gonzalez, Nohra Chalouhi, Stavropoula Tjoumakaris, Pascal Jabbour, Aaron S. Dumont and Robert H. Rosenwasser
Multiple approaches have been used to treat carotid-cavernous fistulas (CCFs). The transvenous approach has become a popular and effective route. Onyx is a valuable tool in today's endovascular armamentarium. The authors describe the use of a balloon-assisted technique in the treatment of CCFs with Onyx and assess its feasibility, utility, and safety.
The authors searched their prospectively maintained database for CCFs embolized using Onyx with the assistance of a compliant balloon placed in the internal carotid artery (ICA).
Five patients were treated between July 2009 and July 2011 at the authors' institution. A balloon helped to identify the fistulous point, served as a buttress for coils, protected from inadvertent arterial embolizations, and prevented Onyx and coils from obscuring the ICA during the course of embolization. No balloon-related complications were noted in any of the 5 cases. All 5 fistulas were completely obliterated at the end of the procedure. Four patients had available clinical follow-ups, and all 4 showed reversal of nerve palsies.
Balloon-assisted Onyx embolization of CCFs offers a powerful combination that prevents inadvertent migration of the embolic material into the arterial system, facilitates visualization of the ICA, and serves as a buttress for coils deployed in the cavernous sinus through the fistulous point. Despite adding another layer of technical complexity, an intraarterial balloon can provide valuable assistance in the treatment of CCFs.
Ricky Medel, R. Webster Crowley, D. Kojo Hamilton and Aaron S. Dumont
Pseudoaneurysms are rare lesions with a multitude of causes, including infectious, traumatic, and iatrogenic origins. In addition, there are a number of potential treatment options, all of which require consideration to determine the most appropriate management. Historically, surgical intervention has been the method of choice, but because the histopathological features of these lesions make them largely unsuitable for clipping, trapping or excision is often required. More recently endovascular methods have been used, including coil embolization, stent reconstruction, or parent artery occlusion. Although these methods are often successful, situations arise in which they are not technically feasible. The authors describe such a case in a pediatric patient with an iatrogenic pseudoaneurysm. Onyx was used to embolize the lesion and the results were excellent.
Giuseppe Lanzino, Aaron S. Dumont, M. Beatriz S. Lopes and Edward R. Laws Jr.
Cranial base chordomas are locally invasive tumors that, from a midline, clival location, extend in different directions and display various patterns of skull base invasion. Although histologically benign, their invasive nature makes true “oncological” resection virtually impossible to achieve in most cases, despite modern skull base surgical techniques. Moreover, because of the tumor's location and proximity to critical neural and vascular structures, surgery-related morbidity can be significant when an aggressive resection is undertaken. Cytoreductive surgery assumes a critical role in the management of these lesions. The choice of surgical approach and the extent of resection are dependent on several factors: location and extension of the tumor, the surgeon's philosophy and familiarity with a specific approach, and the patient's preexisting clinical status. Proton-beam radiotherapy seems to be effective as an adjunct to surgery in achieving local tumor control. The timing of radiation therapy, however, remains controversial. Gamma knife surgery has been proposed as an adjunctive therapy, but the limited experience and short follow-up periods do not permit formulation of meaningful conclusions at this time. Recurrences are common, although in a subset of patients prolonged disease-free survival is demonstrated.