Prediction of Outcomes for Ruptured Aneurysm Surgery.

Background and Purpose- Predicting long-term functional outcomes after intracranial aneurysmal rupture can be challenging. We developed and validated a scoring system-the Southwestern Aneurysm Severity Index-that would predict functional outcomes at 1 year after clipping of ruptured aneurysms. Methods- Ruptured aneurysms treated microsurgically between 2000 and 2014 were included. Outcome was defined as Glasgow Outcome Score (ranging from 1, death, to 5, good recovery) at 1 year. The Southwestern Aneurysm Severity Index is composed of multiple prospectively recorded patient demographic, clinical, radiographic, and aneurysm-specific variables. Multivariable analyses were used to construct the best predictive models for patient outcomes in a random 50% of the cohort and validated in the remaining 50%. A scoring system was created using the best model. Results- We identified 527 eligible patients. The Glasgow Outcome Score at 1 year was 4 to 5 in 375 patients (71.2%). In the multivariable logistic regression, the best predictive model for unfavorable outcome included intracerebral hemorrhage (odds ratio [OR], 2.53; 95% CI, 1.55-4.13), aneurysmal size ≥20 mm (OR, 6.07; 95% CI, 1.92-19.2), intraventricular hemorrhage (OR, 2.56; 95% CI, 1.15-5.67), age >64 (OR, 3.53; 95% CI, 1.70-7.35), location (OR, 1.82; 95% CI, 1.10-3.03), and hydrocephalus (OR, 2.39; 95% CI, 1.07-5.35). The Southwestern Aneurysm Severity Index predicts Glasgow Outcome Score at 1 year with good discrimination (area under the receiver operating characteristic curve, derivation: 0.816, 95% CI, 0.759-0.873; validation: 0.803, 95% CI, 0.746-0.861) and accurate calibration ( R2=0.939). Conclusions- The Southwestern Aneurysm Severity Index has been internally validated to predict 1 year Glasgow Outcome Scores at initial presentation, thus optimizing patient or family counseling and possibly guiding therapeutic efforts.

Spinal vascular malformations: treatment strategies and outcome.

Spinal vascular malformations (SVMs) are a heterogeneous group that can cause acute, subacute, or chronic spinal cord dysfunction. The majority of the patients present to neurosurgical attention after a protracted course with severe neurological dysfunction. Spinal vascular lesions comprise approximately 3-4 % of all intradural spinal lesions. They are pathologically similar to their intracranial counterparts, but their clinical impact is often comparatively worse. Early, correct recognition of the pathology is mandatory to halt the progression of the disease and minimize permanent spinal cord injury. The first clinical observation of a SVM was published in 1890, but it was not until 1914 that the first successful surgical treatment of a spinal vascular malformation was reported. Intervention-either by microsurgical or endovascular means-aims to halt or reverse the progressive neurological deterioration by eliminating flow through the abnormal fistulous or nidal connections, and restoring normal spinal cord perfusion and intravascular pressures. In fact, complex spinal arteriovenous malformations (AVMs) and arteriovenous fistulas (AVFs) frequently require a multimodality approach that utilizes both microsurgery and endovascular embolization effectively. The goal of this review is to describe the various types of vascular malformations of the spine, their pathophysiology, clinical presentation, treatment strategies, and outcome. For purposes of discussion on the current manuscript, vascular malformations of the spine were divided into arteriovenous fistulas (AVFs) and arteriovenous malformations (AVMs). Spinal cord aneurysms are extremely rare, and the majority of the lesions that come to the neurosurgeon's attention are concomitant to a spinal AVM.

Neurosurgical Emergencies in Sports Neurology.

PURPOSE OF REVIEW: Athletic neurosurgical emergencies are injuries that can lead to mortality or significant morbidity and require immediate recognition and treatment. This review article discusses the epidemiology of sports-related traumatic brain injury (TBI) with an attempt to quantify the incidence of neurosurgical emergencies in sports. Emergencies such as intracranial hemorrhage, second impact syndrome, vascular injuries, and seizures are discussed. RECENT FINDINGS: The incidence of sports-related TBI presenting to level I or II trauma centers in the USA is about 10 in 100,000 population per year. About 14 % of the adult sports-related TBIs and 13 % of the pediatric sports-related TBIs were moderate or severe in nature. Patients presenting with headache and neck pain should prompt further investigation for cervical spine and vascular injuries. CT angiography is becoming the modality of choice to screen for blunt cerebrovascular injuries. The treatment of these injuries remains controversial. High-quality evidence in sports-related TBI is lacking. Further research is required to help guide management of this increasingly prevalent condition. The role of prevention and education should also not be underestimated.

Management of infectious intracranial aneurysms in the pediatric population.

INTRODUCTION: Infectious intracranial aneurysms (IIAs) account for approximately 15 % of all pediatric intracranial aneurysms. Histologically, they are pseudoaneurysms that develop in response to an inflammatory reaction within the adventitia and muscularis layers, ultimately resulting in disruption of both the internal elastic membrane and the intima. The majority of pediatric IIAs are located within the anterior circulation, and they can be multiple in 15-25 % of cases. BACKGROUND: The most common presentation for an IIA is intracerebral and/or subarachnoid hemorrhage. In children with a known diagnosis of infective endocarditis who develop new neurological manifestations, it is imperative to exclude the existence of an IIA. The natural history of untreated infectious aneurysms is ominous; they demonstrate a high incidence of spontaneous rupture. High clinical suspicion, prompt diagnosis, and adequate treatment are of paramount importance to prevent devastating neurological consequences. DISCUSSION: The prompt initiation of intravenous broad-spectrum antibiotics represents the mainstay of treatment. Three questions should guide the management of pediatric patients with IIAs: (a) aneurysm rupture status, (b) the presence of intraparenchymal hemorrhage or elevated intracranial pressure, and (c) relationship of the parent vessel to eloquent brain tissue. Those three questions should orient the treating physician into either antibiotic therapy alone or in combination with microsurgical or endovascular interventions. This review discusses important aspects of the epidemiology, the diagnosis, and the management of IIAs in the pediatric population.

Natural history of brain arteriovenous malformations: a systematic review.

OBJECT: The authors aimed to systematically review the literature to clarify the natural history of brain arteriovenous malformations (BAVMs). METHODS: The authors searched PubMed for one or more of the following terms: natural history, brain arteriovenous malformations, cerebral arteriovenous malformations, and risk of rupture. They included studies that reported annual rates of hemorrhage and that included either 100 patients or 5 years of treatment-free follow-up. RESULTS: The incidence of BAVMs is 1.12-1.42 cases per 100,000 person-years; 38%-68% of new cases are first-ever hemorrhage. The overall annual rates of hemorrhage for patients with untreated BAVMs range from 2.10% to 4.12%. Consistently implicated in subsequent hemorrhage are initial hemorrhagic presentation, exclusively deep venous drainage, and deep and infrantentorial brain location. The risk for rupture seems to be increased by large nidus size and concurrent arterial aneurysms, although these factors have not been studied as thoroughly. Venous stenosis has not been implicated in increased risk for rupture. CONCLUSIONS: For patients with BAVMs, although the overall risk for hemorrhage seems to be 2.10%-4.12% per year, calculating an accurate risk profile for decision making involves clinical attention and accounting for specific features of the malformation.

Management of intracranial aneurysms associated with arteriovenous malformations.

Intracranial or brain arteriovenous malformations (BAVMs) are some of the most interesting and challenging lesions treated by the cerebrovascular neurosurgeon. It is generally believed that the combination of BAVMs and intracranial aneurysms (IAs) is associated with higher hemorrhage rates at presentation and higher rehemorrhage rates and thus with a more aggressive course and natural history. There is wide variation in the literature on the prevalence of BAVM-associated aneurysms (range 2.7%-58%), with 10%-20% being most often cited in the largest case series. The risk of intracranial hemorrhage in patients with unruptured BAVMs and coexisting IAs has been reported to be 7% annually, compared with 2%-4% annually for those with BAVM alone. Several different classification systems have been applied in an attempt to better understand the natural history of this combination of lesions and implications for treatment. Independent of the classification used, it is clear that a few subtypes of aneurysms have a direct hemodynamic correlation with the BAVM itself. This is exemplified by the fact that the presence of a distal flow-related or an intranidal aneurysm appears to be associated with an increased hemorrhage risk, when compared with an aneurysm located on a vessel with no direct supply to the BAVM nidus. Debate still exists regarding the etiology of the association between those two vascular lesions, the subsequent implications for patients' risk of hemorrhagic stroke, and finally the determination of which patients warrant treatment and when. The ultimate goals of the treatment of a BAVM associated with an IA are to prevent hemorrhage, avoid stepwise neurological deterioration, and eliminate the mortality risk associated with recurrent hemorrhagic events. The treatment is only justifiable if the risks associated with an intervention are lower than or equivalent to the long-term risks of disability or mortality caused by the lesion itself. When faced with this difficult decision, a few questions need to be answered by the treating neu-rosurgeon: What is the mode of presentation? What is the symptomatic lesion? Which one of the lesions bled? What is the relationship between the BAVM and IA? Is it possible to safely treat both BAVM and IA? The objective of this review is to discuss the demographics, natural history, classification, and strategies for management of BAVMs associated with IAs.

Remote magnetic navigation enables precision telesurgery.

Medical devices actuated by external magnetic fields can create opportunities for clinical adoption of precision telesurgery.

A Transcriptomic Comparative Study of Cranial Vasculature.

In genetic studies of cerebrovascular diseases, the optimal vessels to use as controls remain unclear. Our goal is to compare the transcriptomic profiles among 3 different types of control vessels: superficial temporal artery (STA), middle cerebral arteries (MCA), and arteries from the circle of Willis obtained from autopsies (AU). We examined the transcriptomic profiles of STA, MCA, and AU using RNAseq. We also investigated the effects of using these control groups on the results of the comparisons between aneurysms and the control arteries. Our study showed that when comparing pathological cerebral arteries to control groups, all control groups presented similar responses in the activation of immunological processes, the regulation of intracellular signaling pathways, and extracellular matrix productions, despite their intrinsic biological differences. When compared to STA, AU exhibited upregulation of stress and apoptosis genes, whereas MCA showed upregulation of genes associated with tRNA/rRNA processing. Moreover, our results suggest that the matched case-control study design, which involves control STA samples collected from the same subjects of matched aneurysm samples in our study, can improve the identification of non-inherited disease-associated genes. Given the challenges associated with obtaining fresh intracranial arteries from healthy individuals, our study suggests that using MCA, AU, or paired STA samples as controls are feasible strategies for future large-scale studies investigating cerebral vasculopathies. However, the intrinsic differences of each type of control should be taken into consideration when interpreting the results. With the limitations of each control type, it may be most optimal to use multiple tissues as controls.

Magnetization spoiling in radial FLASH contrast-enhanced MR digital subtraction angiography.

PURPOSE: To increase the in-plane spatial resolution and image update rates of 2D magnetic resonance (MR) digital subtraction angiography (DSA) pulse sequences to 0.57 × 0.57 mm and 6 frames/sec, respectively, for intracranial vascular disease applications by developing a radial FLASH protocol and to characterize a new artifact, not previously described in the literature, which arises in the presence of such pulse sequences. MATERIALS AND METHODS: The pulse sequence was optimized and artifacts were characterized using simulation and phantom studies. With Institutional Review Board (IRB) approval, the pulse sequence was used to acquire time-resolved images from healthy human volunteers and patients with x-ray DSA-confirmed intracranial vascular disease. RESULTS: Artifacts were shown to derive from inhomogeneous spoiling due to the nature of radial waveforms. Gradient spoiling strategies were proposed to eliminate the observed artifact by balancing gradient moments across TR intervals. The resulting radial 2D MR DSA sequence (2.6 sec temporal footprint, 6 frames/sec with sliding window factor 16, 0.57 × 0.57 mm in-plane) demonstrated small vessel detail and corroborated x-ray DSA findings in intracranial vascular imaging studies. CONCLUSION: Appropriate gradient spoiling in radial 2D MR DSA pulse sequences improves intracranial vascular depiction by eliminating circular banding artifacts. The proposed pulse sequence may provide a useful addition to clinically applied 2D MR DSA scans.

Early platelet transfusion improves platelet activity and may improve outcomes after intracerebral hemorrhage.

BACKGROUND: In patients with acute intracerebral hemorrhage (ICH), reduced platelet activity on admission predicts hemorrhage growth and poor outcomes. We tested the hypotheses that platelet transfusion improves measured platelet activity. Further, we hypothesized that earlier treatment in patients at high risk for hemorrhage growth and poor outcome would reduce follow-up hemorrhage size and poor clinical outcomes. METHODS: We prospectively identified consecutive patients with ICH who had reduced platelet activity on admission and received a platelet transfusion. We defined high-risk patients as per a previous publication, reduced platelet activity, or known anti-platelet therapy (APT) and the diagnostic CT within 12 h of symptom onset. Platelet activity was measured with the VerifyNow-ASA (Accumetrics, CA), ICH volumes on CT with computerized quantitative techniques, and functional outcomes with the modified Rankin Scale (mRS) at 3 months. RESULTS: Forty-five patients received a platelet transfusion with an increase in platelet activity from 472 ± 50 (consistent with an aspirin effect) to 561 ± 92 aspirin reaction units (consistent with no aspirin effect, P < 0.001). For high-risk patients, platelet transfusion within 12 h of symptom onset, as opposed to >12 h, was associated with smaller follow-up hemorrhage size (8.4 [3-17.4] vs. 13.8 [12.3-62.5] ml, P = 0.04) and increased odds of independence (mRS < 4) at 3 months (11 of 20 vs. 0 of 7, P = 0.01). There were similar results for patients with known APT. CONCLUSIONS: In patients at high risk for hemorrhage growth and poor outcome, early platelet transfusion improved platelet activity assay results and was associated with smaller final hemorrhage size and more independence at 3 months.

Management of brainstem cavernous malformations.

OPINION STATEMENT: The risk of hemorrhage from brainstem cavernous malformations (BSCMs) ranges between 2.33 % and 4.1 % per patient-year across natural history studies and between 2.68 % and 6.8 % per patient-year across surgical series. The recurrent hemorrhage rate from BSCMs ranges between 5 % and 60 % per patient-year. Asymptomatic BSCMs tend to have a benign course, whereas symptomatic lesions often have a more aggressive course and carry an increasing risk of hemorrhage with subsequent bleeds. Hemorrhagic presentation, female gender, family history, and associating venous anomalies have been correlated with an increased risk of hemorrhage from BSCMs. MRI is the diagnostic imaging method of choice for the detection of CMs. Preoperative T1-weighted MRI can help assess the proximity of the lesion to the pial or ependymal surface of the brainstem and is thus essential to operative planning. Fluid attenuated inversion recovery (FLAIR) sequences can detect inflammatory activity and perilesional gliosis and may therefore correlate with an increased biological activity in the CM. This might help predict the aggressiveness of these lesions and their clinical activity. Due to the potential risks of surgery, conservative management with close follow-up should be the primary treatment option for patients with BSCMs. At least two clinically significant hemorrhagic episodes and an anatomical pial representation of the lesion are required before considering surgical intervention as an option because of the potential irreversible neurological damage to the patient. Life-threatening bleeds and rapidly progressive neurological deterioration are also potential indications for surgery. Complete removal of BSCMs when feasible is crucial to the prevention of future hemorrhage from BSCMs. An intraoperative ultrasound and a post-operative MRI can be used to rule out any unnoticed residual lesion. Minimizing the risk of surgery can be achieved by undergoing a case-based selection of the optimal surgical approach that allows for easy access to the lesion with minimal manipulation of normal neural tissues. Preserving any associated venous anomaly during surgery is crucial in order to avoid any undesirable hemorrhagic infarction. Advanced imaging techniques, such as diffusion tensor imaging integrated with intra-operative neuronavigation MRI, can be used to determine the anatomical relation between BSCM and the surrounding eloquent structures. Radiosurgery is not considered an effective treatment option for BSCMs. It is reserved only for extremely biologically aggressive lesions that cannot be accessed surgically.

Somatic Variants in SVIL in Cerebral Aneurysms.

Background and Objectives: While somatic mutations have been well-studied in cancer, their roles in other complex traits are much less understood. Our goal is to identify somatic variants that may contribute to the formation of saccular cerebral aneurysms. Methods: We performed whole-exome sequencing on aneurysm tissues and paired peripheral blood. RNA sequencing and the CRISPR/Cas9 system were then used to perform functional validation of our results. Results: Somatic variants involved in supervillin (SVIL) or its regulation were found in 17% of aneurysm tissues. In the presence of a mutation in the SVIL gene, the expression level of SVIL was downregulated in the aneurysm tissue compared with normal control vessels. Downstream signaling pathways that were induced by knockdown of SVIL via the CRISPR/Cas9 system in vascular smooth muscle cells (vSMCs) were determined by evaluating changes in gene expression and protein kinase phosphorylation. We found that SVIL regulated the phenotypic modulation of vSMCs to the synthetic phenotype via Krüppel-like factor 4 and platelet-derived growth factor and affected cell migration of vSMCs via the RhoA/ROCK pathway. Discussion: We propose that somatic variants form a novel mechanism for the development of cerebral aneurysms. Specifically, somatic variants in SVIL result in the phenotypic modulation of vSMCs, which increases the susceptibility to aneurysm formation. This finding suggests a new avenue for the therapeutic intervention and prevention of cerebral aneurysms.

Neurosurgery residency and fellowship education in the United States: 2 decades of system development by the One Neurosurgery Summit organizations.

The purpose of this report is to chronicle a 2-decade period of educational innovation and improvement, as well as governance reform, across the specialty of neurological surgery. Neurological surgery educational and professional governance systems have evolved substantially over the past 2 decades with the goal of improving training outcomes, patient safety, and the quality of US neurosurgical care. Innovations during this period have included the following: creating a consensus national curriculum; standardizing the length and structure of neurosurgical training; introducing educational outcomes milestones and required case minimums; establishing national skills, safety, and professionalism courses; systematically accrediting subspecialty fellowships; expanding professional development for educators; promoting training in research; and coordinating policy and strategy through the cooperation of national stakeholder organizations. A series of education summits held between 2007 and 2009 restructured some aspects of neurosurgical residency training. Since 2010, ongoing meetings of the One Neurosurgery Summit have provided strategic coordination for specialty definition, neurosurgical education, public policy, and governance. The Summit now includes leadership representatives from the Society of Neurological Surgeons, the American Association of Neurological Surgeons, the Congress of Neurological Surgeons, the American Board of Neurological Surgery, the Review Committee for Neurological Surgery of the Accreditation Council for Graduate Medical Education, the American Academy of Neurological Surgery, and the AANS/CNS Joint Washington Committee. Together, these organizations have increased the effectiveness and efficiency of the specialty of neurosurgery in advancing educational best practices, aligning policymaking, and coordinating strategic planning in order to meet the highest standards of professionalism and promote public health.

Idiopathic pontine Streptococcus salivarius abscess in an immunocompetent patient: management lessons through case illustration and literature review.

A 55-y-old woman with no previous medical history presented with a 3-day history of progressive headache, nausea, emesis, right-sided facial numbness, and right-sided extremity weakness. Serial magnetic resonance imaging demonstrated rapid enlargement of a left-sided ring-enhancing dorsal pontine lesion with an exophytic portion, raising concern for an abscess. A stereotactically guided left-sided retrosigmoid craniotomy for abscess incision and decompression was performed given the rapid progression of her neurological deficits. Streptococcus salivarius was isolated from the intra-operative samples. After an extensive evaluation, no source for the S. salivarius was identified. Solitary brainstem abscesses are uncommon intracranial infections with high morbidity and mortality. Patients can present with non-specific symptoms and often have no previous medical history. Since 1974, 40 patients with solitary brainstem abscess have survived to hospital discharge. We outline management strategies for solitary brainstem abscess based on a literature review of survivors.

Decompressive hemicraniectomy after malignant middle cerebral artery infarction: rationale and controversies.

Malignant middle cerebral artery stroke carries a very poor prognosis. Significant retrospective data support the hypothesis that decompressive hemicraniectomy decreases mortality rates due to this disease entity. Recently, 3 randomized controlled studies have been published and shed light on these issues and enhance the quality of evidence revolving around this procedure. In this review, the rationale, risks, benefits, and unanswered questions related to hemicraniectomy for acute ischemic stroke are reviewed with an emphasis on how 3 randomized trials have influenced knowledge on this life-saving yet controversial procedure. Further randomized studies are needed to clarify lingering questions regarding age indications and impact on quality of life.

Moyamoya disease: functional and neurocognitive outcomes in the pediatric and adult populations.

OBJECT: Moyamoya disease is an occlusive cerebrovascular disorder commonly resulting in neurocognitive impairment. The cognitive outcome parameters commonly affected are intelligence, memory, executive function, and quality of life. In this paper, the authors review the existing literature on cognitive and clinical outcomes in adult and pediatric moyamoya populations separately. METHODS: A systematic review of the cognitive and clinical outcome literature was performed using the PubMed/MEDLINE database. Outcomes data were contrasted between adult and pediatric populations. RESULTS: Intelligence is the main cognitive outcome parameter affected in pediatric patients with moyamoya disease, whereas adults most commonly suffer from executive function impairment. Memory has not been studied sufficiently in pediatric patients, and its dysfunction in the adult population remains controversial. Quality of life has not been studied appropriately in either population. Surgical revascularization is the only beneficial treatment option, and a combination of direct and indirect bypass techniques has shown benefit, but the impact on the above-mentioned parameters has not been sufficiently elucidated. CONCLUSIONS: Moyamoya disease affects the cognition and daily function in pediatric patients to a greater extent than in adult patients. Due to the rarity of the disease, there is a distinct lack of high-level evidence regarding cognitive and clinical outcomes.

Moyamoya disease: a review of histopathology, biochemistry, and genetics.

OBJECT: Moyamoya disease (MMD) is a rare cerebrovascular disorder involving stenosis of the major vessels of the circle of Willis and proximal portions of its principal branches. Despite concerted investigation, the pathophysiology of the disorder has not been fully elucidated. Currently, the major proteins believed to play an active role in the pathogenesis include vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF), transforming growth factor-ß1 (TGFß1), and granulocyte colony-stimulating factor (G-CSF). In terms of the genetics, recent literature suggests a low penetrance autosomal dominant or polygenic mode of transmission involving chromosomes 3, 6, 8, 12, and 17 for familial MMD. This review summarizes the current knowledge on the histopathology, pathophysiology and genetics of MMD. METHODS: A PubMed/Medline systematic study of the literature was performed, from which 45 articles regarding MMD pathophysiology were identified and analyzed. CONCLUSIONS: Moyamoya disease is characterized by the intimal thickening and media attenuation of the proximal vessels of the circle of Willis as well as the development of an aberrant distal vascular network. The primary proteins that are currently implicated in the pathophysiology of MMD include VEGF, bFGF, HGF, TGFß1, and G-CSF. Furthermore, the current literature on familial MMD has pointed to a low penetrance autosomal dominant or polygenic mode of transmittance at loci on chromosomes 3, 6, 8, 12, and 17.

Aspirin use or reduced platelet activity predicts craniotomy after intracerebral hemorrhage.

BACKGROUND: Craniotomy is potentially life-saving in selected patients with intracerebral hemorrhage (ICH). Aside from specific scenarios (cerebellar hemorrhage with hydrocephalus, midline shift from an accessible lesion, etc.) the indications for surgical decompression are controversial. Based on the earlier work that aspirin and reduced platelet activity are associated with larger hemorrhage size and hemorrhage growth, we tested the hypothesis that aspirin or reduced platelet activity would be associated with increased odds of craniotomy, likely through hemorrhage growth. METHODS: We prospectively identified patients with spontaneous ICH and routinely measured platelet activity on admission. Patients were prospectively tracked, and outcomes were obtained with the modified Rankin Scale (mRS). RESULTS: There were 187 patients in the sample. Craniotomy (N = 32, 17%) was associated with a higher initial ICH volume (37.9 [20-63] vs. 12 [5-24] ml, P < 0.001) and location (P = 0.005). In multivariate logistic regression, after controlling for ICH volume and location, any known aspirin use (OR 3.4, 95% CI 1.1-10.4, P = 0.03), platelet activity ≤550 aspirin reaction units (OR 3.1, 95% CI 1.05-9.3, P = 0.04), or an elevated PFA-EPI closure time (OR 3.2, 95% CI 1.02-10.3, P = 0.04) were associated with increased odds of craniotomy. Craniotomy was not associated with mRS at 14 days, 28 days, or 3 months. CONCLUSIONS: After correction for ICH volume and location, aspirin use or reduced platelet activity was associated with similar increased odds for craniotomy.

Microvascular Decompression Technique for Trigeminal Neuralgia Using a Vascular Clip.

Microvascular decompression (MVD) surgery is a well-established, effective treatment option for trigeminal neuralgia1 and hemifacial spasm.2 In 1967, Janetta et al3 introduced the concept of MVD surgery and pioneered the Janetta technique in which Teflon felt implants are placed between the trigeminal nerve and offending vessel. Though many cases are successfully managed with Teflon interposition, alternative techniques have been developed with the objective to alleviate vascular compression symptoms indefinitely, including transposition using biological glue,4 vascular clips,5,6 and a variety of "sling" techniques.7 In Video 1, we demonstrate a fenestrated clip transposition technique in the treatment of trigeminal neuralgia. We present the case of a 72-year-old female who presented with classic trigeminal neuralgia pain along the V2 and V3 distributions. Magnetic resonance imaging revealed evident compression of the trigeminal nerve by the superior cerebellar artery (SCA). A retrosigmoid craniotomy was performed, and the vascular loop of the SCA was visualized compressing the root entry zone with significant indentation of the trigeminal nerve. Wide arachnoid dissection along the SCA was carried out in order to mobilize the SCA away from the nerve. A small slit was created in the undersurface of the tentorium, and then the SCA loop was transposed to the tentorium using a fenestrated aneurysm clip. The postoperative course was uneventful, and the patient had complete resolution of her facial pain at 6-month follow-up. This method is likely an effective and durable method of decompression for trigeminal neuralgia.

Normalization of Peri-Arteriovenous Malformation Hemodynamics Prior to Direct Microsurgery: 2-Dimensional Operative Video.

Arteriovenous malformations (AVMs) are highly complex vascular lesions characterized by abnormal connections between arteries and an intervening nidus. Definitive and safe treatment of AVMs may require the combination of multiple treatment modalities to address the various complex features of the AVM.1 Endovascular embolization can be used as an adjuvant to surgery in order to control deep feeders, reduce flow, and address high-risk features such as aneurysms. In addition, by progressively reducing the AVM flow, staged embolization can lead to normalization of peri-AVM hemodynamics and therefore may decrease the risk of postresection hemorrhage.2,3 In this operative video, we present a case of a 41-yr-old female who presented with progressively worsening left-sided hemiparesis. Magnetic resonance imaging (MRI) and angiography revealed a complex right fronto-parietal AVM with significant associated edema, likely due to the vascular steal phenomenon. The area of edema, which included the motor cortex, was thought to be at high risk for postoperative hemorrhage from normal perfusion pressure breakthrough. We therefore decided to proceed with staged presurgical embolization to gradually normalize the perilesional hemodynamics, and therefore possibly reduce the risk of postoperative morbidity. The patient underwent 3 embolization sessions at 6-wk intervals. An MRI after the last embolization showed near-complete resolution of the fluid-attenuated inversion-recovery (FLAIR) signal around the AVM. Microsurgical resection was performed on the day after the last embolization. The patient tolerated the procedure well and was discharged at her neurological baseline with mild contralateral hemiparesis, which has continued to improve at follow-up. Postoperative angiography showed complete resection of the AVM. The patient consented to the procedure as shown in this operative video and gave informed written consent for use of her images in publication.