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BackgroundThe aim of this publication is to provide a detailed update on the diagnosis, treatment, and endovascular techniques for posterior circulation emergent large vessel occlusion (pc-ELVO).MethodsWe performed a review of the literature to specifically evaluate this disease and its treatments.ResultsData were analyzed, and recommendations were reported based on the strength of the published evidence and expert consensus.ConclusionWhile many questions about pc-ELVO remain to be studied, there is evidence to support particular practices in its evaluation and treatment.

The history of vascular neurosurgery is as rich and complex as any other field in medicine. Its birth and development emerged from the necessity, creativity, and technology needed to care for patients with potentially life-threatening lesions. Its growth and technological changes have influenced many other subdisciplines of our field. As a matter of fact, of the numerous evolutionary and revolutionary advances in the practice of neurological surgery, most have arisen from this need to treat and cure vascular disease of the brain and spinal cord. From anatomy to pathophysiology, from preoperative imaging to intraoperative optics, from creative microsurgical approaches to innovative endovascular techniques, vascular neurosurgery has brought a plethora of challenges to the practitioners of this art and science, and throughout its history, the neurosurgeon and the many collaborators and scientists have responded.

The cavernous sinus is a rich and fascinating anatomic structure, serving as a major conduit between the intradural and extradural cranial milieu. Because of the many connections the cavernous sinus has with other structures of the head and neck, diseases of this structure can have a myriad of presentations. Vascular pathology in particular produces a myriad of symptoms and signs that are quite unique. One of the most recognizable of these lesions is the carotid-cavernous fistula (CCF). Dramatic or slowly indolent in its presentation, it can progress to become devastating to vision, cranial nerve function, and potentially cognition. The complexity of lesions in this territory is historically very difficult to treat, carrying significant morbidity and mortality. Though surgical lesions were the initial method by which to effect a cure, advances in endovascular technology have changed the treatment paradigm. This chapter will describe significant historical aspects, the anatomy and presentation of CCF and the endovascular treatment options for these lesions.

Control of bleeding in the confined area of the skull is imperative for successful neurosurgery and the prevention of devastating complications such as postoperative hemorrhage. This paper reviews the historical evolution of methods to achieve successful hemostasis in neurosurgery from the early1800s to today. The major categories of hemostatic agents (mechanical, chemical and thermal) are delineated and discussed in chronological order. The significance of this article is in its detailed history of the kinds of hemostatic methods that have evolved with our accumulating medical and surgical knowledge, which may inform future innovations and improvements.

Background Decompressive hemicraniectomy to control medically refractory intracranial hypertension and cerebral edema and evacuate mass lesions in traumatic brain injury is a widely accepted treatment paradigm. However, the critical specifications of the bone flap size necessary to control the intracranial pressure (ICP) and provide improved patient outcomes is unknown. We assessed the effect of craniectomy size on the outcomes in surgical decompression for traumatic brain injury. Methods From 2003 to 2011, 58 cases of decompressive hemicraniectomy were performed for evacuation of hematoma and treatment of refractory ICP in adult patients with traumatic brain injury. The surface area of the decompressive bone flaps was calculated from the postoperative computed tomography scans and correlated with the ICP and Glasgow Coma Scale scores immediately postoperatively and during long-term follow-up. Results Decompressive craniectomy led to a statistically significant continued reduction in the preoperative ICP values (24.5 mm Hg; range, 5–30 mm Hg) compared with the postoperative ICP (16.7 mm Hg; range, 1–30; P = 0.006). However, no significant improvement in the preoperative Glasgow Coma Scale (7.47 mm Hg; range, 3–15; vs. 7.50 mm Hg; range, 3–15; P = 0.96) was observed with hemicraniectomy. Conclusion For surface areas of 7000–16,000 mm2, size was an independent factor in ICP reduction but not for the overall neurologic outcome.

With the increased reliance on the Pipeline embolization device (PED) for the treatment of complex intracranial aneurysms, our experience in managing intraoperative complications and challenges continues to accumulate amid a scarcity of reports on rescue strategies and innovative techniques. We describe the case of a 50-year-old woman who presented for elective repeat embolization of a right posterior communicating artery aneurysm with some residual aneurysmal filling. During the procedure the patient developed severe vasospasm due to vessel irritation and this led us to proceed to deploy the PED through a biaxial construct composed of the 6 French Envoy MPD DA XB, and the Marksman catheters. The biaxial construct in select patients may provide the required stability while eliminating the need for an intermediate catheter, minimizing embolic risk, and allowing for less irritation to the vessel. Larger studies are required for further validation.

The American Revolution was a gruesome warthat resulted in the independence of the United States of America from the British crown and countless casualties to both belligerents. However, from these desperate times, the treatment of traumatic head injury was elucidated, as were the origins of American neurosurgery in the 18th century. During the war, the surgical manual used by military field surgeons was titled Plain Concise Practical Remarks on the Treatment of Wounds and Fractures, by Dr. John Jones. This manual explains the different types of cranial injuries understood at that time as well as the relevant surgical treatment. This article seeks to review the surgical treatment of head injury in the Revolutionary War as outlined by Dr. Jones’s manual.

Arteriovenous malformations (AVMs) in the pediatric population are relatively rare but reportedly carry a higher rate of rupture than in adults. This could be due to the fact that most pediatric AVMs are only detected after rupture. We aimed to review the current literature regarding the natural history and the clinical outcome after multimodality AVM treatment in the pediatric population, as optimal management for pediatric AVMs remains controversial. A multidisciplinary approach using multimodality therapy if needed has been proved to be beneficial in approaching these lesions in all age groups. Microsurgical resection remains the gold standard for the treatment of all accessible pediatric AVMs. Embolization and radiosurgery should be considered as an adjunctive therapy. Embolization provides a useful adjunct therapy to microsurgery by preventing significant blood loss and to radiosurgery by decreasing the volume of the AVM. Radiosurgery has been described to provide an alternative treatment approach in certain circumstances either as a primary or adjuvant therapy.

Physicians and scientists can use fractal analysis as a tool to objectively quantify complex patterns found in neuroscience and neurology. Fractal analysis has the potential to allow physicians to make predictions about clinical outcomes, categorize pathological states, and eventually generate diagnoses. In this review, we categorize and analyze the applications of fractal theory in neuroscience found in the literature. We discuss how fractals are applied and what evidence exists for fractal analysis in neurodegeneration, neoplasm, neurodevelopment, neurophysiology, epilepsy, neuropharmacology, and cell morphology. The goal of this review is to introduce the medical community to the utility of applying fractal theory in clinical neuroscience.

BackgroundWhile a growing number of reports offer evidence for the potential of drug eluting stents (DES) in treating atherosclerotic stenosis of the extracranial vertebral artery, their efficacy when compared with bare metal stents (BMS) is uncertain due to the lack of a large prospective randomized trial.MethodsA search strategy using the terms ‘stents’, ‘drug-eluting stents’, ‘atherosclerosis’, ‘vertebral artery’, and ‘vertebrobasilar insufficiency’ was employed through Medline. Five studies met the criteria for a comparative meta-analysis. The technical/clinical success, periprocedural complications, target vessel revascularization (TVR), rates of restenosis, recurrent symptoms, and overall survival were compared.ResultsThere was no significant difference in the technical success (OR=1.528, p=0.622), clinical success (OR=1.917, p=0.274), and periprocedural complications (OR=0.741, p=0.614) between the two groups. An OR of 0.388 for no restenosis in the BMS to DES arms (p=0.001) indicated a significantly higher restenosis rate in the BMS group relative to the DES group (33.57% vs 15.49%). When compared with the DES group, the BMS group had a significantly higher rate of recurrent symptoms (2.76% vs 11.26%; OR=3.319, p=0.011) and TVR (4.83% vs 19.21%; OR=4.099, p=0.001).ConclusionsA significantly lower rate of restenosis, recurrent symptoms, and TVR was noted in the DES group compared with the BMS group.

Cerebrovascular injuries after blunt or penetrating head and neck trauma often lead to significant disability from ischemic stroke, hemorrhagic stroke and uncontrolled extracranial hemorrhage. Trauma causes carotid or vertebral dissection, occlusion, pseudoaneurysm, arteriovenous fistula, vessel transection, traumatic epistaxis, venous sinus thrombosis and carotid cavernous fistula. The rapid development of neuroendovascular techniques over the past two decades has led to effective therapies for each of these injuries. Controlled lesion embolization may use coils, liquid embolics (onyx or n-butyl cyanoarcrylate), polyvinyl alcohol particles or detachable balloons; there is stent angioplasty with uncovered, overlapping and covered stents or mechanical thrombolysis using stent-retrievers or aspiration catheters and the use of balloon occlusion tests and supraselective angiography to delineate safety of vessel sacrifice and to diagnose occult lesions respectively. Furthermore, the proliferation of stroke centers has increased local availability of rapid neuroendovascular expertise at many major trauma centers. Neuroendovascular therapies are less invasive than surgery, can often preserve the injured parent vessels and aid in treating conditions where surgery may be limited. In the absence of randomized controlled trials we present a narrative review of current endovascular therapeutic applications for each of these injuries. This expands the therapies at trauma teams' disposal in the continued effort to control bleeding, reduce secondary injury and prevent disability after trauma. Further research is necessary to inform the role of endovascular techniques after trauma. In particular, comparative studies are necessary to quantify the risk and benefits in conditions where surgical options also exist.

Stroke is the leading cause of adult disability in North America and is the fifth most common cause of death.1 ,2 The natural history of patients with acute ischemic stroke and occlusion of a major intracranial vessel such as the internal carotid artery (ICA), middle cerebral artery (MCA), or basilar artery is dismal, with high rates of mortality and low rates of disability-free survival.3 ,4 We introduce the term ‘Emergent Large Vessel Occlusion (ELVO)’ to describe this clinical scenario. Among acute ischemic stroke, ELVO accounts for the greatest proportion of patients with long-term disability. For the past two decades the use of endovascular therapy has been performed in many centers across the world. The therapies have spanned from infusion of thrombolytic agents5 ,6 to mechanical embolectomy with the introduction of first-generation devices,7 ,8 aspiration-based embolectomy techniques,9 ,10 and the use of stent-retriever based procedures.11 ,12 However, these embolectomy trials were single-arm trials demonstrating safety of the procedure and technique or superiority over another, without direct comparison with standard medical therapy alone. In the past 3 years, several major trials have been published comparing endovascular therapy with standard medical therapy alone. The purpose of this document is to summarize the results of these trials and synthesize the level of evidence supporting the use of embolectomy in patients with ELVO. This document was prepared by the Standards and Guidelines Committee of the Society of NeuroInterventional Surgery, a multidisciplinary society representing the leaders in the field of endovascular therapy for neurovascular disease. The strength of the evidence supporting each recommendation was summarized using a scale previously described by the American Heart Association. ### Role of intravenous thrombolysis In 1996 the FDA approved the use of recombinant tissue plasminogen activator (tPA) for the treatment of acute ischemic stroke …

Objective The natural history intracranial aneurysms (IA) remains poorly understood despite significant morbidity and mortality associated with IA rupture. Hemodynamic impingement resulting in elevations in wall shear stress and wall shear stress gradient (WSSG) has been shown to induce aneurysmal remodeling at arterial bifurcations. We investigate the hemodynamic environment specific to side-wall pre-aneurysmal vasculature. We hypothesize that fluid impingement and secondary flow patterns play a role in side-wall aneurysm initiation. Methods Eight side-wall internal carotid artery aneurysms from the Aneurisk repository were identified. Pre-aneurysmal vasculature was algorithmically reconstructed. Blood flow was simulated with computational fluid dynamic simulations. An indicator of isolated fluid impingement energy was developed by insetting the vessel surface and calculating the impinging component of the fluid dynamic pressure. Results Isolated fluid impingement was found to be elevated in the area of aneurysm initiation in 8/8 cases. The underlying fluid flow for each area of initiation was found to harbor secondary flow patterns known as Dean’s vortices, the result of changes in momentum imparted by bends in the internal carotid artery (ICA). Conclusion Isolated fluid impingement and secondary flow patterns may play a major role in the initiation of side-wall aneurysm initiation. We are unable to determine if this role is through direct or indirect mechanisms but hypothesize that elevations in isolated fluid impingement mark areas of cerebral vasculature that are at risk for aneurysm initiation. Thus, this indicator provides vascular locations to focus future study of side-wall aneurysm initiation.

A 56-year-old female patient with a past medical history of hypertension and type II diabetes mellitus undergoes a diagnostic aneurysm at 1 year after coil embolization of an anterior communicating artery aneurysm. Fortunately, the aneurysm had been coiled prior to rupture, and the patient had not suffered any neurological deficits. Other than some difficulty in gaining access to the right common carotid artery, the angiogram went without any particular setback. In the post-procedure recovery unit, the patient complained of left arm weakness. Upon examination, the patient was unable to move her left arm, and it had no tone. She was rushed back to the angiography suite, where she was discovered to have a thrombus in a distal MCA branch, unable to be treated. MRI showed an MCA territory infarction. She was sent back to the recovery unit, where the attending physician explained the undesired outcome and the steps which would be taken to optimize her long-term outcome with hope of regaining some function in the left arm. Was this a medical error resulting in neurological deficit, or was this a complication of the procedure?

Background: Developmental venous anomalies (DVAs) are variations of normal transmedullary veins draining white and gray matter. In the vast majority of cases, DVAs are diagnosed incidentally and should be considered as benign entities. In extremely rare circumstances, DVAs may become symptomatic due to mechanical or flow-related etiologies. Thrombosis of the collector vein of a DVA is a rare type of a flow-related complication with only 29 cases reported in the literature, the majority of which are supratentorial. Infratentorial thrombosed DVAs are thus extremely rare and the few cases reported have typically caused symptoms due to venous ischemic infarctions. Summary: We report a case of an infratentorial DVA with a thrombosed drainage vein in a patient with nonhemorrhagic, noninfarcted venous congestive edema, which was successfully treated with high-dose glucocorticoids and short-term anticoagulation. We review the pertinent venous anatomy of the posterior fossa as well as the literature of symptomatic infratentorial thrombosed DVAs. Key Message: The presented case of an infratentorial thrombosed DVA with cerebellar and pontine venous congestive edema is extremely rare. A working knowledge of posterior fossa venous anatomy and possible pathomechanisms responsible for the rarely symptomatic lesion will aid in the timely and efficacious treatment of such lesions.

Acute ischemic stroke (AIS) is the fifth leading cause of death, and remains the leading cause of disability in the USA.1 There are an estimated 680 000 new strokes per year in the USA, with a mortality rate of 53–94%, and with an even greater morbidity.2 It is estimated that 3–22% of these patients are candidates for endovascular therapy.3–6 In addition to baseline stroke severity, emergent large vessel occlusion (ELVO) has been shown to be an independent predictor of poor outcome at 6 months.3 4 While intravenous recombinant tissue plasminogen activator (IV r-tPA) has proven efficacious predominantly for small cerebral vessel occlusions, endovascular therapies, including stent retriever based, aspiration based mechanical thrombectomy techniques, and intra-arterial administration of thrombolytic agents, have been shown to achieve higher rates of recanalization in patients with ELVO.7–10 The purpose of this document is to provide an update and critical assessment of technical aspects of the mechanical thrombectomy procedure. This document was prepared by the Standards and Guidelines Committee of the Society of NeuroInterventional Surgery (SNIS), a multidisciplinary society representing the leaders in the field of endovascular therapy for cerebrovascular disease. A review of the English language literature published between January 1998 and March 2016 was conducted using search terms that included: ‘stroke,’ ‘ischemic stroke,’ ‘large vessel occlusion,’ ‘thrombectomy,’ ‘mechanical thrombectomy,’ ‘neurointerventional,’ ‘tPA,’ and ‘technique.’ Additionally, we incorporated already existing guidelines published by the American Heart Association (AHA) and the SNIS.11–15 The strength of the evidence supporting each recommendation was summarized using a scale previously described by the AHA guideline panels, and by the University of Oxford, Centre for Evidence Based Medicine.13 15–18 Much of our current practice in mechanical thrombectomy derives from recent randomized controlled trials (RCTs) which provide a foundation for treatment goals. The online supplementary tables 1-3 provide details of these thrombectomy trials, and …

Surgery of the mind has a rather checkered past. Though its history begins with the prehistoric trephination of skulls to allow “evil spirits” to escape, the early- to mid-20th century saw a surge in the popularity of psychosurgery. The 2 prevailing operations were topectomy and leukotomy for the treatment of certain mental illnesses. Although they were modified and refined by several of their main practitioners, the effectiveness of and the ethics involved with these operations remained controversial.In 1947, Dr. J. Lawrence Pool and the Columbia-Greystone Associates sought to rigorously investigate the outcomes of specific psychosurgical procedures. Pool along with R. G. Heath and John Weber believed that nonexcessive bifrontal cortical ablation could successfully treat certain mental illnesses without the undesired consequences of irreversible personality changes. They conducted this investigation at the psychiatric hospital at Greystone Park near Morristown, New Jersey.Despite several encouraging findings of the Columbia-Greystone project, psychosurgery practices began to decline significantly in the 1950s. The uncertainty of results and ethical debates related to side effects made these procedures unpopular. Further, groups such as the National Association for the Advancement of Colored People and the American Civil Liberties Union condemned the use of psychosurgery, believing it to be an inhumane form of treatment. Today, there are strict guidelines that must be adhered to when evaluating a patient for psychosurgery procedures. It is imperative for the neurosurgery community to remember the history of psychosurgery to provide the best possible current treatment and to search for better future treatments for a particularly vulnerable patient population.

Recent trials have proven the benefits of endovascular treatment for patients with stroke from emergent large vessel occlusions (ELVOs).1–5 Optimal management of these patients involves attention to pre-procedural, intra-procedural, and post-procedural elements. However, many of the ideal treatment approaches following endovascular stroke therapy remain controversial. This document synthesizes current recommendations from the best available evidence to provide guidance in the post-procedural management of a patient undergoing stroke thrombectomy. This document was constructed by the Standards and Guidelines Committee of the Society for NeuroInterventional Surgery, a multidisciplinary committee composed of practitioners with backgrounds including neuroradiology, vascular neurosurgery, stroke neurology, and neurocritical care. We reviewed electronic databases for publications related to the management of acute stroke patients post-procedure, using both broad and narrow search terms. We subsequently evaluated those results for papers with randomized clinical results, which were given the highest priority. The remaining papers were assessed on the basis of individual methodology, and recommendations were made based on the data available. In the absence of supporting adequate clinical trial evidence, the committee made consensus recommendations. Each recommendation is graded, where possible, with a level of evidence utilizing the American Heart Association/American Stroke Association grading system.6 This document represents one of a continuum related to acute stroke intervention, including other documents on prehospital management, training standards for thrombectomy, and management of ELVO patients.7–9 ### Post-thrombectomy care environment ELVO patients require careful monitoring in a stroke unit or intensive care unit. Stroke units provide dedicated, specialized, multidisciplinary inpatient care for ELVO patients. Patients treated in this environment are more likely to survive, regain independence, and return home than those receiving less organized service.10 Stroke units are characterized by protocol guided care, adherence to guidelines, and coordination of care provided by various services.11–14 Furthermore, a dedicated stroke unit is preferable to a mobile consultative …

Acute occlusions of the extracranial internal carotid artery (ICA) and a major intracranial artery respond poorly to intravenous tissue plasminogen activator (tPA) and present an endovascular challenge. The aim of our study was to retrospectively delineate the feasibility of the combined use of emergent carotid stenting and intra-arterial (IA) Abciximab with intracranial revascularization in the setting of acute ischemic stroke and carotid occlusions at our institution.Eleven patients with complete cervical carotid occlusion with or without concomitant intracranial ICA and/or MCA occlusion were identified from a single center, retrospective review of patients admitted to the Stroke unit. We evaluated all cases for complications of emergent cervical ICA recanalization employing carotid stenting and IA Abciximab.All patients had complete cervical carotid occlusion with (n = 8) or without (n = 3) concomitant intracranial ICA and/or MCA occlusion. Successful emergent cervical ICA recanalization was achieved in all cases. All patients were administered IA Abciximab (dose range 6-17 mg, average 11.4 mg) immediately following the cervical carotid stenting. There was complete recanalization in all patients with no procedural morbidity or mortality. A single case (1/11, 9%) developed asymptomatic hemorrhagic transformation. Upon discharge, 9 patients (9/11, 82%) had a mRS of 0-2 and 2 patients (2/11, 18%) had a mRS of 3.In acute ICA-MCA/distal ICA occlusions, extracranial stenting followed by intracranial IA Abciximab and thrombectomy appears feasible, effective, and safe. Further evaluation of this treatment strategy is warranted.

Over the past decade there has been a growing use of intracranial stents for the treatment of both ischemic and hemorrhagic cerebrovascular disease, including stents to assist in the remodeling of the neck of aneurysms as well as the use of flow diverting devices for aneurysm treatment. With this increase in stent usage has come a growing need for the neurointerventional (NI) community to understand the pharmacology of medications used for modifying platelet function, as well as the testing methodologies available. Platelet function testing in NI procedures remains controversial. While pre-procedural antiplatelet assays might lead to a reduced rate of thromboembolic complications, little evidence exists to support this as a standard of care practice. Despite the routine use of dual antiplatelet therapy (DAT) with aspirin and a P2Y12 receptor antagonist (such as clopidogrel, prasugrel, or ticagrelor) in most neuroembolization procedures necessitating intraluminal reconstruction devices, thromboembolic complications are still encountered.1–3 Moreover, DAT carries the risk of hemorrhagic complications, with intracerebral hemorrhage (ICH) being the most potentially devastating.4 ,5 Light transmission aggregometry (LTA) is the gold standard to test for platelet reactivity, but it is usually expensive and may not be easily obtainable at many centers. This has led to the development of point-of-care assays, such as the VerifyNow (Accumetrics, San Diego, California, USA), which correlates strongly with LTA and can reliably measure the degree of P2Y12 receptor inhibition.6–9 VerifyNow results are reported in P2Y12 reaction units (PRUs), with a lower PRU value corresponding to a higher level of P2Y12 receptor inhibition and, presumably, a lower probability of platelet aggregation, and a higher PRU value corresponding to a lower level of P2Y12 receptor inhibition and, hence, a higher chance of platelet activation and aggregation. While aspirin resistance is perhaps less common, clopidogrel resistance may be more challenging as …

Elevated intracranial pressure in patients with chronic renal failure has several potential causes. Its rare occurrence secondary to the hemodynamic effects of hemodialysis is described and the findings support a multifactorial etiology (“two hits”).

BACKGROUND Recently, the use of intraoperative magnetic resonance imaging (ioMRI) has evolved in neurosurgery. Challenges related to ioMRI-augmented procedures are significant, since the magnetic field creates a potentially hazardous environment. Strict safety guidelines in the operating room (OR) are necessary. Checklists can minimize errors while increasing efficiency and improving workflow. OBJECTIVE To describe the Zurich checklists for safety in the ioMRI environment. METHODS We summarize the checklist protocol and the experience gained from over 300 surgical procedures performed over a 4-yr period using this new system for transcranial or transsphenoidal surgery in a 2-room high-field 3 Tesla ioMRI suite. RESULTS Particularities of the 2-room setting used at our institution can be summarized as (1) patient transfer from a sterile to a nonsterile environment and (2) patient transfer from a zone without to a zone with a high-strength magnetic field. Steps on the checklist have been introduced for reasons of efficient workflow, safety pertaining to the strength of the magnetic field, or sterility concerns. Each step in the checklist corresponds to a specific phase and particular actions taken during the workflow in the ioMRI suite. Most steps are relevant to any 2-room ioMRI-OR suite. CONCLUSION The use of an ioMRI-checklist promotes a zero-tolerance attitude for errors, can lower complications, and can help create an environment that is both efficient and safe for the patient and the OR personnel. We highly recommend the use of a surgical checklist when applying ioMRI.

The artery of Percheron (AOP) is a rare anatomic variant of the paramedian thalamic-mesencephalic arterial supply, arising as a solitary arterial trunk from the P1 segment of the posterior cerebral artery. Its occlusion, commonly caused by cardioembolism, leads to distal bilateral paramedian thalamic ischemia, oftentimes affecting the midbrain and/or the anterior thalamus. AOP occlusion presents with a clinical triad of altered mental status, vertical gaze palsy, and memory impairment, along with other associated symptoms. Digital subtraction angiography is effective for detecting AOP, while diffusion weighted MRI is best for diagnosis of its occlusion. Our extensive literature search sought to determine the best forms of treatment for uncomplicated AOP occlusion, with the inclusion criterion of implementation of medical treatment or other forms of therapy in patient recovery from this condition. We conclude that intravenous heparin and thrombolysis with tissue plasminogen activator are effective firstline treatment options for emergent AOP occlusion followed by a prescription of long term anticoagulants, while non-emergent cases without midbrain involvement could be treated through rehabilitation and continual monitoring by medical staff. Clinical trials of higher power are needed for a more comprehensive analysis of the treatment options for AOP occlusion.

Every year almost 800 000 people in the USA suffer a new or recurrent stroke, and stroke is the third leading cause of death with over 140 000 deaths in the USA in 1995.1 Additionally, stroke is a leading cause of long-term disability with an estimated cost of $68.9 billion in 2009. The relationship between carotid artery disease and stroke was first described by Fisher in 1951,2 and it is estimated that about one-third of ischemic strokes are due to carotid artery thromboembolic disease.3 ,4 Several trials have established carotid endarterectomy (CEA) as an excellent surgical technique for revascularization and prevention of future stroke, with a reasonable safety profile. Over the last 10–15 years, carotid artery stenting has been studied as an alternative and potentially less invasive revascularization method. Early trials of carotid artery stenting struggled with high complication rates but, as experience has grown and techniques improved, more recent trials have shown complication rates comparable to CEA. The goals of this document are to suggest standards of practice for patients treated with carotid artery angioplasty and stenting (CAS) and to provide a reporting framework for series of patients treated with CAS. Our evidence-based treatment recommendations were assessed according to criteria published by the American Heart Association/American Stroke Association (AHA/ASA) and the University of Oxford's Center for Evidence Based Medicine (CEBM). The development of treatment guidelines for CAS is facilitated by several large clinical trials that have already investigated surgical treatment for extracranial carotid stenosis as well as trials that have compared CAS with the established surgical treatment (CEA). In addition to this standards document, we would also recommend previously published guidelines for the use of CAS.5 Note that this document is not addressing the use of angioplasty with or without stenting in the setting of acute ischemic …

Vertebroplasty and kyphoplasty are minimally invasive image-guided procedures that involve the injection of cement (typically polymethylmethacrylate (PMMA)) into a vertebral body. Kyphoplasty involves inflation of a balloon tamp to create a cavity within the vertebral body into which cement is subsequently injected. The majority of these vertebral augmentation procedures are performed to relieve back pain from osteoporotic or cancer-related vertebral compression fractures and to reinforce the vertebral body with neoplasm or vascular tumor. The primary goal of vertebroplasty and kyphoplasty is to reduce back pain and to improve patient's functional status, and the secondary goal is stabilization of a vertebra weakened by fracture or neoplasia. ### Osteoporotic vertebral fractures Osteoporosis is a common disease that causes significant morbidity and incurs a significant healthcare cost to the community. The major osteoporotic fractures involve the hip, vertebra, proximal humerus and distal forearm; the lifetime osteoporotic fracture risk at age 50 is approximately one in two women and one in five men.1 The lifetime incidence of symptomatic osteoporotic vertebral fractures in women at age 50 is estimated at 10–15%1; once a vertebral fracture occurs, there is a 20% risk of another vertebral fracture within 12 months.2 Most osteoporotic vertebral compression fractures are asymptomatic or result in minimal pain; only a third of vertebral fractures result in medical attention.3 Conservative medical therapy is therefore appropriate for the vast majority of vertebral compression fractures since most acute back pain symptoms are mild and subside over a period of 6–8 weeks as the fracture heals. The goals of conservative therapy are pain reduction (with analgesics and/or bed rest), improvement in functional status (with orthotic devices and physical therapy) and prevention of future fractures (with vitamin D, calcium supplementation and antiresorptive agents). However, conservative treatment for those with severe pain or limitation of function is not benign. It …

Intracranial aneurysms (IAs) affect 2% to 5% of the population and can have catastrophic results on rupture, accounting for 80% all of subarachnoid hemorrhages (SAHs).1–4 This medical and surgical emergency carries a 40% to 50% mortality rate, with 12% of individuals expiring before receiving any medical attention.5 Survivorship is fraught with socioeconomic challenges because two thirds of patients are left with some form of permanent neurological deficit.4 Although most IAs do not cause clinical symptoms during life,6,7 the substantial mortality rate with initial presentation underscores the importance of early diagnosis and intervention in high-risk groups. Advances in neuroimaging, microsurgical clipping, and minimally invasive endovascular modalities have helped reduce the burden of these morbid events; however, patient selection remains controversial given the unpredictable nature of aneurysm progression. Likewise, appropriate management is confounded by complex influences from environmental and genetic factors. Individuals aged 40 to 60 years are at highest risk for IAs, with women affected more than men by a 3:2 ratio.7,8 Other modifiable risk factors are hypertension, atherosclerosis, smoking, and alcohol consumption.9,10 In addition to aneurysm size and location within the cerebrovasculature, these factors are used clinically to assess rupture risk.7 Certain inherited syndromes predispose individuals to the formation of IAs, including Autosomal Dominant Polycystic Kidney Disease and Ehlers–Danlos syndrome.11–13 Although individuals with these syndromes should be screened with computed tomography or magnetic resonance angiography when there is family history of stroke or SAH, they account for only 10% of all cases.14 In the absence of known predisposing genetic mutations, individuals with first-degree relatives with IAs are 4× more likely to develop IAs themselves.15 Moreover, evidence shows that these aneurysms present earlier in life and rupture at smaller sizes compared …

The field of neurointerventional surgery has grown in recent years. Endovascular therapies for both ischemic stroke and intracranial aneurysms have become important components in the multimodal treatment of these conditions. Familiarity with these treatment options by general neurologists is important for patient care. This article reviews recent trials and devices representing important advances in the field.

Objectives/Hypothesis Patients are increasingly using the Internet as a source of information on medical conditions. Because the average American adult reads at a 7th- to 8th-grade level, the National Institutes of Health recommend that patient education material be written between a 4th- and 6th-grade level. In this study, we assess and compare the readability of patient education materials on major surgical subspecialty Web sites relative to otolaryngology. Study Design Descriptive and correlational design. Methods Patient education materials from 14 major surgical subspecialty Web sites (American Society of Colon and Rectal Surgeons, American Association of Endocrine Surgeons, American Society of General Surgeons, American Society for Metabolic and Bariatric Surgery, American Association of Neurological Surgeons, American Congress of Obstetricians and Gynecologists, American Academy of Ophthalmology, American Academy of Orthopedic Surgeons, American Academy of Otolaryngology–Head and Neck Surgery, American Pediatric Surgical Association, American Society of Plastic Surgeons, Society for Thoracic Surgeons, and American Urological Association) were downloaded and assessed for their level of readability using 10 widely accepted readability scales. Results The readability level of patient education material from all surgical subspecialties was uniformly too high. Average readability levels across all subspecialties ranged from the 10th- to 15th-grade level. Conclusions Otolaryngology and other surgical subspecialties Web sites have patient education material written at an education level that the average American may not be able to understand. To reach a broader population of patients, it might be necessary to rewrite patient education material at a more appropriate level. Level of Evidence N/A. Laryngoscope, 124:405–412, 2014

Background Recent studies have documented the high sensitivity of computed tomography angiography (CTA) in detecting a ruptured aneurysm in the presence of acute subarachnoid hemorrhage (SAH). The practice of digital subtraction angiography (DSA) when CTA does not reveal an aneurysm has thus been called into question. Objective We examined this dilemma from a cost-effectiveness perspective by using current decision analysis techniques. Methods A decision tree was created with the use of TreeAge Pro Suite 2012; in 1 arm, a CTA-negative SAH was followed up with DSA; in the other arm, patients were observed without further imaging. Based on literature review, costs and utilities were assigned to each potential outcome. Base-case and sensitivity analyses were performed to determine the cost-effectiveness of each strategy. A Monte Carlo simulation was then conducted by sampling each variable over a plausible distribution to evaluate the robustness of the model. Results With the use of a negative predictive value of 95.7% for CTA, observation was found to be the most cost-effective strategy ($6737/Quality Adjusted Life Year [QALY] vs $8460/QALY) in the base-case analysis. One-way sensitivity analysis demonstrated that DSA became the more cost-effective option if the negative predictive value of CTA fell below 93.72%. The Monte Carlo simulation produced an incremental cost-effectiveness ratio of $83 083/QALY. At the conventional willingness-to-pay threshold of $50 000/QALY, observation was the more cost-effective strategy in 83.6% of simulations. Conclusion The decision to perform a DSA in CTA-negative SAH depends strongly on the sensitivity of CTA, and therefore must be evaluated at each center treating these types of patients. Given the high sensitivity of CTA reported in the current literature, performing DSA on all patients with CTA negative SAH may not be cost-effective at every institution.

Introduction: Immune dysregulation has long been implicated in the development of delayed cerebral ischemia (DCI) following aneurysmal subarachnoid hemorrhage (aSAH). The neutrophil-lymphocyte ratio (NLR) is an established prognostic marker in patients with cancer, cardiac disease, or sepsis. This study sought to determine whether there is a relationship between NLR and DCI in SAH patients. Methods: We evaluated 340 aneurysmal SAH patients between 2002 and 2015 enrolled into a single center, retrospective, observational cohort study. Admission NLR was analyzed using a ≥10 cutoff. DCI from cerebral vasospasm was defined as (1) clinical deterioration (i.e., a new focal deficit, decrease in level of consciousness, or both), and/or (2) a new infarct on CT that was not visible on the admission or immediate postoperative scan, when the cause was thought by the research team to be vasospasm. Logistic regression models were generated. Results: We found that 132 (39%) patients had an admission NLR ≥ 10. Admission NLR predicted development of DCI (OR: 1.7; 95% CI: 1.1- 2.5, p=0.008) after controlling known predictors including age and incidence of rebleed. Conclusions: This study shows that the admission NLR provides further evidence to the association between inflammation and DCI. Admission NLR is a readily available biomarker that may be a clinically useful tool for prognostication when evaluating SAH.

Central retinal artery occlusion (CRAO) is an ophthalmologic emergency due to the sudden cessation of circulation to the inner retinal layer. Without immediate treatment, permanent blindness may ensue. Several treatment options exist, ranging from noninvasive medical management to thrombolysis. Nonetheless, ongoing debate exists regarding the best therapeutic strategy.The authors present the case of a 78-year-old woman with a medical history of hypercholesterolemia and rheumatoid arthritis who experienced complete loss of vision in her left eye. Following ophthalmologic evaluation demonstrating left CRAO, anterior chamber paracentesis was performed. Endovascular intervention was performed via local intra-arterial fibrinolysis with alteplase. Her vision returned to 20/20 following the procedure. In general, conventional therapies have not significantly improved patient outcomes.Several management options exist for CRAO. In general, conservative measures have not been reported to yield better patient outcomes as compared to the natural history of this medical emergency. Endovascular approaches are another option as observed with this case reported. In cases of CRAO, therapeutic strategies such as intra-arterial fibrinolysis utilize a local infusion of reactive tissue plasminogen activator directly at the site of occlusion via catheterization of the ophthalmic artery. Although several case series do show promising results after treating CRAO with intra-arterial fibrinolysis, further studies are required given the reports of complications.

Treatment of complex aneurysms using microsurgical and other conventional neuroendovascular techniques remains challenging. As a result, stent- and balloon-assisted coiling are instead performed to treat morphologically complex aneurysms, which include giant, wide-necked, and fusiform aneurysms. While these techniques have had success in treating these complex aneurysms, recanalization rates associated with these techniques are still problematic. In the constant effort to improve the outcome of complex aneurysm treatment, flow-diverting stents (FDSs) have emerged in recent years as the preferred treatment. Instead of directly obstructing the flow of blood into the aneurysmal sac, as is the case for stent- and balloon-assisted coiling, FDSs are placed in the parent blood vessel to divert blood flow away from the aneurysm itself. Subsequent to the diverting away of blood from the aneurysm, a thrombotic cascade ensues that ultimately results in the closure of the aneurysm while the parent vessel's perforators are preserved. Current known risks for this procedure include vessel rupture or perforation, in-stent thrombosis, perforator occlusion, procedural or delayed hemorrhages, and perianeurysmal edema. In this review, we will evaluate the mechanisms of actions, clinical applications, complications, and ongoing studies for FDSs.

Background Temporomandibular joint (TMJ) ankylosis causes disability through impaired digestion, mastication, speech, and appearance. Surgical treatment increases range of motion with resultant functional improvement. However, substantial perioperative blood loss can occur (up to 3 L) if the internal maxillary artery (IMAX) is injured as it traverses the ankylotic mass. Achieving hemostasis is difficult because of limited proximal IMAX access and poor visualization. Our aim is to investigate the technical feasibility and preliminary safety of preoperative IMAX embolization in patients undergoing TMJ ankylosis surgery. Methods Case series using chart reviews of 2 patients who underwent preoperative embolization before TMJ ankylosis surgery. Results Both patients were women (28 and 51 years old) who had severely restricted mouth opening. Embolization was performed using general anesthesia with nasal intubation on the same day of TMJ surgery. Both patients underwent bilateral IMAX embolization using pushable coils (Vortex, Boston Scientific) of distal IMAX followed by n-butyl-cyanoacrylate (Trufill, Cordis) embolization from coil mass up to proximal IMAX. There were no complications from the embolization procedures. Both patients had normal neurologic examination results. TMJ surgery occurred with minimal operative blood loss (≤300 mL for each surgery). Maximum postoperative mouth opening was 35 mm and 34 mm, respectively. One patient had a postoperative TMJ wound infection that was managed with antibiotics. Conclusions Preoperative IMAX embolization before TMJ ankylosis surgery is technically feasible with encouraging preliminary safety. There were no complications from the embolization procedures and surgeries occurred with low volumes of blood loss.

Recent randomized clinical trials1–5 established the superiority of endovascular recanalization techniques, specifically mechanical embolectomy, compared with best medical therapy alone for the treatment of patients with emergent large vessel occlusion (ELVO) stroke. ELVO stroke is defined as a stroke secondary to anterior circulation large vessel occlusion (LVO) of the internal carotid, middle cerebral (M1 segments) arteries documented by imaging, without large completed infarct and presenting within 6 hours of symptom onset.6 Given the overwhelming clinical evidence provided by these trials, recent American Heart Association (AHA) guidelines concluded that “embolectomy needs to be performed as rapidly as possible for the greatest clinical benefit, and is best when performed within 6 h from onset of symptoms” (AHA class I, level of evidence A).6 In addition, cost modeling derived from trial outcomes data and claims databases in the USA strongly suggests that cost-effectiveness and an overall societal benefit is associated with investment in access to these endovascular techniques.7 Rapid access to endovascular services depends upon optimization of prehospital stroke care and transport within stroke systems of care, focusing on the unique needs of patients with ELVO through their diagnostic investigation and treatment pathway. The Society of NeuroInterventional Surgery (SNIS) proposed process time metrics for ELVO stroke treatment, including door to IV tissue plasminogen activator (t-PA) of

Acute ischemic stroke continues to be one of the leading causes of morbidity and mortality worldwide. Recent advances in mechanical thrombectomy techniques combined with prereperfusion computed tomographic angiography for patient selection have revolutionized stroke care in the past year. Peri- and postinterventional neurocritical care of the patient who has had an emergent large-vessel occlusion is likely an equally important contributor to the outcome but has been relatively neglected. Critical periprocedural management issues include streamlining care to speed intervention, blood pressure optimization, reversal of anticoagulation, management of agitation, and selection of anesthetic technique (ie, general vs monitored anesthesia care). Postprocedural critical care issues that might modulate neurological outcome include blood pressure and glucose optimization, avoidance of fever or hyperoxia, fluid and nutritional management, and early integration of rehabilitation into the intensive care unit setting. In this review, we sought to lay down an evidence-based strategy for patients with acute ischemic stroke undergoing emergent endovascular reperfusion.

The Civil War era was an age-defining period in the history of the United States of America, the effects of which are still seen in the nation today. In this era, the issue of head injury pervaded society. From the president of the United States, Abraham Lincoln, to the officers and soldiers of the Union and Confederate armies, and to the population at large, head injury and its ramifications gripped the nation. This article focuses on 3 individuals: Major General John Sedgwick, First Lieutenant Alonzo Cushing, and Harriet Tubman, as examples of the impact that head injury had during this era. These 3 individuals were chosen for this article because of their lasting legacies, contributions to society, and interesting connections to one another.

Direct carotid-cavernous fistulas (CCFs) are rare complications of flow diversion and have typically been documented in a subacute time frame after treatment. We present the first reported case of an intraprocedural direct CCF that developed immediately after flow diversion for treatment of a symptomatic paraclinoid right internal carotid artery aneurysm with a neck involving the cavernous segment. Endovascular treatment of such direct fistulas typically involves either transarterial obliteration of the fistulous site or transvenous embolization of the cavernous sinus. Our case was successfully treated with further immediate flow diversion without additional transvenous intervention. There are few reports on the use of flow diversion for treatment of such direct CCFs, and in all but one of these cases, flow diversion was combined with concomitant transvenous embolization. Thus, the presented case is not only the first reported case of an immediate CCF after flow diversion, but it is also only the second reported case of a direct fistula to be successfully treated using solely flow diversion, without additional transvenous intervention. We review the literature of direct CCFs after flow diversion, the pathophysiology of development of CCFs after flow diversion, the literature on treatment of CCFs with flow diversion as well as all other current treatment options.

bilateral thalamic infarctions are rare and usually caused by vascular occlusions. When symptomatic, it is important to make a distinction between different vascular etiologies in order to provide an effective and timely therapeutic response. Clinical presentations may not adequately differentiate between the vascular etiologies alone. It is therefore important to use imaging technologies to distinguish appropriately the origin of the infarct so that proper treatment can be administered. Advanced imaging techniques, such as CT angiography and MR angiography, have proved useful for distinguishing between arterial and venous causes of bithalamic infarctions. Bilateral thalamic venous infarctions can be treated with anticoagulation medication and with thrombolysis in more severe cases. Bilateral thalamic arterial infarctions may be treated with thrombolysis.