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Creating aneurysm sizes in animal models that resemble human aneurysms is essential to study and test neuroendovascular devices. The commonly used rabbit surgical elastase model, however, produces saccular aneurysms that are smaller than those typically treated in humans. The goal of this study was to determine whether an increased vessel stump length and the addition of calcium chloride to the incubation solution has an effect on the resulting aneurysm size.Using a modified aneurysm creation method, 32 female New Zealand White rabbits underwent aneurysm creation procedures. Subjects were equally allocated into 4 different groups based on vessel stump length (2 cm controls vs. 3 cm) and incubation solution (elastase alone controls vs. a 1:1 mixture of elastase and calcium chloride). At 4 weeks, all animals underwent angiography to determine the resulting aneurysm size by a neurointerventionalist who was blinded to treatment group.An increase in stump length from 2 cm to 3 cm resulted in a significant increase in the height of aneurysm (P0.05). Compared with control animals, the combination of a 3-cm stump length and the addition of calcium chloride to the incubation solution resulted in a significant increase in aneurysm height, width, and volume (P0.05).Creating larger aneurysms is necessary for the rabbit model to be more clinically relevant. Our study demonstrated that the utilization of a 3-cm vessel stump as well as both calcium chloride and elastase in the incubation solution results in aneurysm sizes that more closely resemble the population of aneurysms treated in humans.

Background: Most patients with World Federation of Neurological Surgeons (WFNS) grade 5 subarachnoid hemorrhage (SAH) have poor outcomes. Accurate assessment of prognosis is important for treatment decisions and conversations with families regarding goals of care. Unjustified pessimism may lead to “self-fulfilling prophecy,” where withdrawal of life-sustaining measures (WLSM) is invariably followed by death. Methods: We performed a cohort study involving consecutive patients with WFNS grade 5 SAH to identify variables with >= 90% and >= 95% positive predictive value (PPV) for poor outcome (1-year modified Rankin Score >= 4), as well as findings predictive of WLSM. Results: Of 140 patients, 38 (27%) had favorable outcomes. Predictors with >= 95% PPV for poor outcome included unconfounded 72-hour Glasgow Coma Scale motor score = 1 pupillary light reflex (PLR) at 24 hours, and intraventricular hemorrhage (IVH) score of >= 20 (volume >= 54.6 ml). Intracerebral hemorrhage (ICH) volume >= 53 ml had PPV of 92%. Variables associated with WLSM decisions included a poor motor score (p < 0.0001) and radiographic evidence of infarction (p = 0.02). Conclusions: We identified several early predictors with high PPV for poor outcome. Of these, lack of improvement in motor score during the initial 72 hours had the greatest potential for confounding from “self-fulfilling prophecy.” Absence of PLR at 24 hours, IVH score >= 20, and ICH volume >= 53 ml predicted poor outcome without a statistically significant effect on WLSM decisions. More research is needed to validate prognostic variables in grade 5 SAH, especially among patients who do not undergo WLSM.

Aneurysm recurrence after Pipeline Embolization Device (PED) placement can be caused by oversizing of the stent as well as poor wall apposition, both of which can lead to elongation. The objective of this study was to assess whether a novel parameter for measuring device elongation based on two-dimensional imaging could be predictive for persistent aneurysm filling after treatment with the PED.A retrospective cohort analysis was initially completed on 41 aneurysms from institution A, examining demographic, aneurysmal, and device measurements. Device measurements, including the ratio of the measured length to the nominal length (ML/NL) of the PED, were taken by reviewers blinded to the primary end point, which was aneurysm occlusion status on 6 month catheter angiogram. Findings were then externally validated against 30 aneurysms (supraclinoid only) from institution B.Data from institution A showed 61% complete aneurysm occlusion at 6 months, and were lower for aneurysms in the supraclinoid region. For supraclinoid aneurysms alone, combined data from both institutions showed higher rates of nonocclusion with aneurysm neck size4 mm (P = 0.008) and a trend toward significance in aneurysms with a branch vessel (P = 0.051). The mean ML/NL ratio was significantly larger in the nonoccluded group compared with the occluded group at both institution A (ratio, 1.37 versus 1.10; P0.001) and institution B (ratio, 1.36 vs. 1.11; P = 0.002).Our data suggest that a novel parameter based on two-dimensional angiography may serve as a rapid technique to measure device elongation and predict occlusion of supraclinoid aneurysms after PED placement.

Orbital AVFs, abnormal vascular connections between orbital arteries and veins, are extremely rare. Often traumatic, few reports of spontaneous orbital fistulas have been reported so far. Treatment is warranted for deteriorating visual symptoms, but obliteration of the fistula can be challenging. We present such a case that symptomatically mirrored a carotid cavernous fistula. A novel approach was used by traversing a thrombosed superior ophthalmic vein to embolize the lesion. In addition, a complete literature review is presented.

Background Unruptured intracranial aneurysms (UIA) are increasingly being treated by endovascular coiling as opposed to open surgical clipping. Unfortunately, endovascular coiling imparts an approximate 25% recanalization rate, leading to additional procedures and increased rupture risk. While a new health technology innovation (HTI) that reduces this recanalization rate would benefit patients, few advancements have been made. We aim to determine whether cost-effectiveness has been a barrier to HTI. Methods A probabilistic Markov model was constructed from the healthcare payer perspective to compare standard endovascular treatment of UIA to standard treatment plus the addition of a HTI adjunct. Costs were measured in 2018 USD and health outcomes were measured in quality-adjusted life-years (QALY). In the base case, the HTI was a theoretical mesenchymal stem cell therapy which reduced the aneurysm recanalization rate by 50% and cost $10,000 per procedure. All other model inputs were derived from the published scientific literature. Results Based on the model results, we found that for a given HTI price (y) and relative risk reduction of aneurysm recanalization (x), the HTI was always cost-effective if the following equation was satisfied: y ≤ 20268 ∙ x, using a willingness-to-pay threshold of $50,000 per QALY. The uncertainty surrounding whether an aneurysm would recanalize was a significant driver within the model. When the uncertainty around the risk of aneurysm recanalization was eliminated, the 10-year projected additional benefit to the United States healthcare system was calculated to be $113,336,994. Conclusion Cost-effectiveness does not appear to be a barrier to innovation in reducing the recanalization rate of UIA treated by endovascular coil embolization. Our model can now be utilized by academia and industry to accentuate economically feasible HTI and by healthcare payers to calculate their maximum willingness-to-pay for a new technology. Our results also indicate that predicting a patient’s baseline risk of aneurysm recanalization is a critical area of future research.

PURPOSE Deciding about whether an unruptured intracranial aneurysm (UIA) should be treated or not is challenging because robust data on rupture risks, endovascular treatment complication rates, and treatment success rates are limited. We aimed to investigate how neurointerventionalists conceptually approach endovascular treatment decision-making in UIAs. METHODS In a web-based international multidisciplinary case-based survey among neurointerventionalists, participants provided their demographics and UIA treatment-volumes, estimated 5-year rupture rates, endovascular treatment complication and success rates and gave their endovascular treatment decision for 15 pre-specified UIA case-scenarios. Differences in estimated 5-year rupture rates, endovascular treatment complication and success rates based on physician and hospital characteristics were evaluated with the Kruskal-Wallis test. Multivariable logistic regression analysis was used to derive adjusted effect size estimates for predictors of endovascular treatment decision. RESULTS Two hundred-thirty-three neurointerventionalists from 38 countries participated in the survey (median age 47 years [IQR: 41-55], 25/233 [10.7%] females). The ranges of estimates for 5-year rupture risks, endovascular treatment complication rates, and particularly endovascular treatment success rates were wide, especially for UIAs in the posterior circulation. Estimated 5-year rupture risks, endovascular treatment complication and success rates differed significantly based on personal and institutional endovascular UIA treatment volume, and all three estimates were significantly associated with physicians' endovascular treatment decision. CONCLUSION Although several predictors of endovascular treatment decision were identified, there seems to be a high degree of uncertainty when estimating rupture risks, treatment complications, and treatment success for endovascular UIA treatment. More data on the clinical course of UIAs with and without endovascular treatment is needed.

Introduction Implantation of cerebral stents are used in several disease conditions. Although stenting procedures offer many benefits, metal stents can elicit acute/subacute thrombosis and increase the chance of stroke. The risk of in-stent thrombus formation significantly decreases after formation of an endothelial cell layer over the stent, which typically takes several weeks to occur. One potential way to reduce the formation of thrombus is through biologic modifications that hasten endothelialization. In past studies, vascular endothelial growth factor (VEGF) has been shown to facilitate the recruitment and proliferation of cells that leads to endothelialization. Methods In this study, VEGF was coated onto Solitaire stents using polylactic-co-glycolic acid (PLGA). Coated stents were deployed into the infrarenal abdominal aorta of New Zealand White rabbits for 72 hours (n=5) (72h VEGF group) and compared to uncoated stents at 72 hours (n=3) (72h Control group) and seven days (n=3) (7d Control group). Optical coherence tomography (OCT) was performed through the stented portion of the vessel, and representative images taken every five millimetres were used for analysis. Images were analyzed for neointimal area (stent area – lumen area), neointimal ratio ([stent area – lumen area]/stent area), minimal and maximal neointima thickness, stent-strut neointima coverage ratio (number of struts covered by a neointimal layer over the total number of struts), as well as thrombus area formation. The analysis was performed by a cardiologist with clinical expertise in OCT imaging, who was also blinded to group allocation. Results Post-deployment digital subtraction angiography demonstrated that VEGF-coated stents were deployed similar to uncoated stents, and without any obvious acute thrombus formation. Using two-tailed unpaired t-tests, the 72h VEGF group showed significantly higher (p Conclusion VEGF-coated stents are a promising biomodification to reduce secondary complications that may occur in the initial days following the procedure. Disclosures K. Panchendrabose: None. B. Har: 3; C; Abbot. A. Mitha: 1; C; Stryker Neurovascular. 2; C; Microvention Inc., Cerus Endovascular, Stryker Corporation. 4; C; Fluid Biotech Inc.

Background Anti-platelet therapy is an important part of the treatment regimen in patients who are receiving a cerebrovascular stent, in order to reduce the incidence of thromboembolic complications. However, there is a known variation in patient response to anti-platelet medications. Theoretically, patients with decreased responsiveness may be at increased risk of ischemic complications while those with increased responsiveness may be at a heightened risk of bleeding. The objective of this investigation was to determine if patients with an increased response to clopidogrel were at an increased risk of developing post-procedural hematomas. Methods A prospective Research Ethics Board (REB) approved study was performed on consecutive patients undergoing endovascular placement of a cerebrovascular stent at the Foothills Medical Centre in Calgary, Alberta from 2019–2020. Inclusion criteria were patients over 18 years of age, and on dual anti-platelet therapy consisting of aspirin and clopidogrel for at least 3 days prior to the procedure. Platelet function testing was performed on blood samples taken before insertion of the stent using whole blood impedance aggregometry to determine the responsiveness to aspirin and clopidogrel. As per the REB protocol, treating neurointerventionalists were blinded to the aggregometry results. The primary study endpoint was the development of hemorrhagic complications during or after the procedure. Parametric and receiver operator curve analysis was used to assess for predictors of our primary outcome. Results To determine the cut-offs for ASA and clopidogrel responsiveness, whole blood aggregometry was first performed on 25 control patients who were not on anti-platelet agents. Subsequently, 50 consecutive patients undergoing cerebrovascular stenting procedures fit our inclusion criteria. 7 (14.0%) of these patients developed a hematoma either intracranially (n=1) or at the puncture site (n=6). Age, gender, smoking status, access site, or stent location were not associated with hemorrhagic complications. Based on our controls, ASA hyper-responders could not be identified using whole blood aggregometry due to the normal response being 0–1 ohms. With these cut-offs, however, 49 (98%) of our patients were responsive to aspirin. Using whole blood aggregometry on patients receiving a cerebrovascular stent, the optimal electrical impedance value was identified as 2 ohms developed a hematoma. This association was found to be statistically significant (p=0.016). Conclusion Dual anti-platelet therapy is an important part of the treatment regimen in any patient who receives a cerebrovascular stent, but there are variations in patient response to these medications. Our study suggests that patients who have an increased response to clopidogrel may be at a higher risk of developing hemorrhagic complications. Disclosures S. Muram: None. K. Panchendrabose: None. M. Eagles: None. M. Suheel: None. A. Mitha: None.

BackgroundSimulation training has been used in the aviation industry and surgical specialties for many years, but integration into neurointerventional practice is lagging behind.ObjectiveTo investigate how neurointerventionalists perceive the usefulness and limitations of simulation tools for the treatment of unruptured intracranial aneurysms (UIAs), and to identify simulation applications that were perceived to be most valuable for endovascular UIA treatment.MethodsA web-based international multidisciplinary survey was conducted among neurointerventionalists. Participants were asked for their perceptions on the usefulness of current simulation tools and the potential impact of future simulation tools in endovascular UIA treatment. They identified simulation applications that could add most value to endovascular UIA treatment and help to specifically reduce endovascular UIA treatment complications.Results233 neurointerventionalists from 38 countries completed the survey, most of whom (157/233 (67.4%)) had access to a simulator as a trainee, but only 15.3% used it frequently. Most participants (117/233 (50.2%)) considered currently available simulation tools relatively useful for endovascular UIA treatment, with greater value for trainees than for staff. Simulation of new devices (147/233 (63.1%)) and virtual practice runs in individual patient anatomy (119/233 (51.1%)) were considered most valuable for reducing endovascular UIA treatment complications.ConclusionAlthough neurointerventionalists perceived currently available simulation tools relatively useful, they did not use them regularly during their training. A priori testing of new devices and practice runs in individual patient anatomy in a virtual environment were thought to have the greatest potential for reducing endovascular UIA treatment complications.

Background and purposeWe previously reported a single-centre study demonstrating that smoking confers a six-fold increased risk for having an unruptured intracranial aneurysm (UIA) in women aged between 30 and 60 years and this risk was higher if the patient had chronic hypertension. There are no data with greater generalisability evaluating this association. We aimed to validate our previous findings in women from a multicentre study.MethodsA multicentre case-control study on women aged between 30 and 60 years, that had magnetic resonance angiography (MRA) during the period 2016–2018. Cases were those with an incidental UIA, and these were matched to controls based on age and ethnicity. A multivariable conditional logistic regression was conducted to evaluate smoking status and hypertension differences between cases and controls.ResultsFrom 545 eligible patients, 113 aneurysm patients were matched to 113 controls. The most common reason for imaging was due to chronic headaches in 62.5% of cases and 44.3% of controls. A positive smoking history was encountered in 57.5% of cases and in 37.2% of controls. A multivariable analysis demonstrated a significant association between positive smoking history (OR 3.7, 95%CI 1.61 to 8.50), hypertension (OR 3.16, 95% CI 1.17 to 8.52) and both factors combined with a diagnosis of an incidental UIA (OR 6.9, 95% CI 2.49 to 19.24).ConclusionsWomen aged between 30 and 60 years with a positive smoking history have a four-fold increased risk for having an UIA, and a seven-fold increased risk if they have underlying chronic hypertension. These findings indicate that women aged between 30 and 60 years with a positive smoking history might benefit from a screening recommendation.

Ischemic diseases such as myocardial infarction, ischemic stroke, and critical limb ischemia are immense public health challenges. Current pharmacotherapy and surgical approaches are insufficient to completely heal ischemic diseases and are associated with a considerable risk of adverse effects. Alternatively, human mesenchymal stem cells (hMSCs) have been shown to exhibit immunomodulation, angiogenesis, and paracrine secretion of bioactive factors that can attenuate inflammation and promote tissue regeneration, making them a promising cell source for ischemic disease therapy. This review summarizes the pathogenesis of ischemic diseases, discusses the potential therapeutic effects and mechanisms of hMSCs for these diseases, and provides an overview of challenges of using hMSCs clinically for treating ischemic diseases.

IntroductionDural venous sinus stenosis (DVSS) may lead to increased intracranial pressure, sometimes requiring a stent if a high pressure gradient exists. Many neuroendovascular physicians use microcatheters to measure gradients, yet there are no studies comparing the accuracies and precisions of modern day microcatheters. We examined pressure recordings from five commonly used microcatheters in an experimental DVSS model.MethodsUsing a programmable pump, dynamic flow was established in a closed circuit mimicking the venous sinus waveform. Microcatheters with 150 cm effective lengths were connected proximally to pressure transducers. Mean recording pressures were compared with a high fidelity microcatheter (HFM) in several configurations including no stenosis, proximal to a focal stenosis, and distal to a focal stenosis in opposing orientations.ResultsAll microcatheters recorded lower pressures than the HFM. Three of the five microcatheters successfully met intracranial pressure monitoring device standards in all conditions, while one did not meet standards in any configuration. The performance of the final microcatheter was variable, with inaccuracies occurring in unrestricted flow. All microcatheters demonstrated relatively high precision, but with variable accuracies. The larger diameter microcatheters displayed the least damping and therefore the greatest accuracies. Of the three smaller microcatheters, dimensions did not predict performance, suggesting that microcatheter construction may also play a role in pressure accuracy.ConclusionThe use of microcatheters to record dural venous sinus pressures must be done with an understanding of the inherent limitations and inaccuracies, especially if clinical decisions are made from the results.

IntroductionThe advent of metal flow-diverting stents has provided neurointerventionalists with an option for treating aneurysms without requiring manipulations within the aneurysm sac. The large amount of metal in these stents, however, can lead to early and late thrombotic complications, and thus requires long-term antiplatelet agents. Bioabsorbable stents have been postulated to mitigate the risk of these complications. Here we present early data on the first self-expandable primarily bioabsorbable stent for aneurysms.MethodsBraided stents were developed using poly-L-lactic acid fibers with material surface area similar to metal flow diverters. Crush resistance force, hemolysis, and thrombogenicity were determined and compared with existing commercial devices. Stents were deployed in infra-renal rabbit aortas to determine angiographic side branch patency and to study neointima formation for a 1-month follow-up period.ResultsCrush resistance force was determined to be on the order of existing commercial devices. Hemolytic behavior was similar to existing metal devices, and thrombogenicity was lower than metal flow-diverting stents. A smooth neointimal layer was found over the absorbable stent surface and all covered side branches were patent at follow-up.ConclusionThe design of self-expanding primarily bioabsorbable flow-diverting stents is possible, and preliminary safety data is consistent with a favorable profile in terms of mechanical behavior, hemocompatibility, side branch patency, and histological effects. Additional in vitro and long-term in vivo studies are in progress and will help determine aneurysm occlusion rates and absorption characteristics of the stent.

Background Monocular vision loss, attributed to either central retinal artery occlusion ( CRAO ), branch retinal artery occlusion ( BRAO ), or ocular ischemic syndrome ( OIS ), is thought to be associated with an increased prevalence of cerebral infarcts. However, there is a paucity of data substantiating this. We aimed to investigate this relationship in a Canadian center and further understand the importance of associated internal carotid artery stenosis in potential clinical decision making. Methods and Results We performed a retrospective cohort study at a comprehensive stroke center of patients presenting initially with CRAO , BRAO , or OIS to a centralized ophthalmology center over a 5‐year period. Patients were followed for 3 years for the occurrence of a hemispheric stroke. We identified 83 affected eyes, with 31 CRAO , 35 BRAO , and 17 OIS patients. Before ocular diagnosis, 32.3%, 11.4%, and 41.2% of CRAO , BRAO , and OIS patients, respectively, experienced a symptomatic stroke. Of the remaining patients, 4.8%, 12.9%, and 40%, respectively, suffered a hemispheric stroke within 3 years of ocular diagnosis. Logistic regressions suggested that for CRAO and BRAO patients together, the degree of ipsilateral internal carotid artery stenosis is unable to predict the occurrence of a stroke ( P =0.18), whereas our model correctly predicted a stroke in 82.4% of OIS patients ( P =0.005). Conclusions CRAO , BRAO , and OIS are associated with significantly increased symptomatic stroke rates. Degree of ipsilateral internal carotid artery stenosis may not be useful in risk stratification for these patients, suggesting that they should be triaged appropriately for stroke risk‐factor management, independent of internal carotid artery stenosis.

To explore phase contrast (PC) magnetic resonance imaging of aneurysms and arteriovenous malformations (AVM). PC imaging obtains a vector field of the velocity and can yield additional hemodynamic information, including: volume flow rate (VFR) and intravascular pressure. We expect to find lower VFR distal to aneurysms and higher VFR in vessels of the AVM.Five cerebral aneurysm and three AVM patients were imaged with PC techniques and compared to VFR of a healthy cohort. VFR was calculated in vessel segments in each patient and compared statistically to the healthy cohort by computing the z-score. Intravascular pressure was calculated in the aneurysms and in the nidus of each AVM.We found that patients with aneurysm had z-0.48 in vessels distal to the aneurysm (reduced flow), while AVM patients had z6 in some vessels supplying and draining the nidus (increased flow). Pressures in aneurysms were highly variable between subjects and location, while in the nidus of the AVM patients; pressure trended higher in larger AVMs.The study findings confirm the expectation of lower distal flow in aneurysm and higher arterial and venous flow in AVM patients.

ObjectiveThe only pharmacologic prophylaxis for cerebral vasospasm after subarachnoid hemorrhage is oral nimodipine. A novel way to mitigate this risk may be to design a drug eluting stent that elutes verapamil over the time period typically associated with vasospasm. In this study, we explore different methods of coating nitinol stents with a bioabsorbable polymer and determine the release profile of various verapamil coated stents for the potential treatment of vasospasm.MethodsNitinol stents were coated with different concentrations of poly(lactic acid-co-glycolic acid) (PLGA) in chloroform solution and using three coating techniques: dip coating, spin coating, and electrospinning. Morphology of the coatings were studied with scanning electron microscopy. 12 verapamil eluting stents were then prepared using different verapamil concentrations and coatings with different numbers of layers. Drug release behaviors were studied using UV spectroscopy for 21 days.ResultsElectrospinning at 20% w/v resulted in a smooth uniform coating without significant surface irregularities, and may be the most effective technique to coat stents. Stents with a single layer of PLGA/verapamil coating showed a two phase release profile (initial burst release followed by a slow rate of release) whereas stents with a bilayer coating showed a lower level of initial release followed by a slower sustained release phase.ConclusionsDevelopment of verapamil eluting stents that elute drug over the time course typical of cerebral vasospasm, and for either immediate or prophylactic treatment, is technically feasible. Further in vitro and in vivo studies are required to determine whether this can improve the outcome of patients after subarachnoid hemorrhage.

ObjectiveTo assess the feasibility and efficacy of clinically translatable adjuvant mesenchymal stem/stromal cells (MSCs) therapy in improving the healing of coiled aneurysms in a rabbit elastase aneurysm model.MethodsBone marrow-derived MSC populations were isolated from three rabbit donors in a serum-free environment and independently characterized to confirm their identity. Elastase-induced carotid aneurysms were created in nine New Zealand white rabbits. Each animal received one of the following treatments based on previous randomization: (1) coiling alone (control group); (2) coiling with an intra-aneurysmal injection of saline (vehicle group); and (3) coiling with an intra-aneurysmal injection of 5 million allogeneic MSCs (treatment group). The animals were followed for 4 weeks post-treatment, at the end of which blinded analyses of angiograms and histology were performed.ResultsHistological results in the treatment group showed improvements over the control and vehicle groups, although the improvement over the vehicle group was not significant. Intra-aneurysmal cell therapy with 5 million allogeneic MSCs did not result in any major adverse events. Angiographic results did not show any significant difference among groups.ConclusionsThis proof-of-concept study shows that adjuvant MSC therapy for intracranial aneurysms is feasible and may enhance histological improvement of coiled aneurysms at 4 weeks post-treatment.

Mesenchymal stem cells (MSCs) are present in fat tissues throughout the body, yet little is known regarding their biological role within epidural fat. We hypothesize that debridement of epidural fat and/or subsequent loss of MSCs within this tissue, disrupts homeostasis in the vertebral environment resulting in increased inflammation, fibrosis, and decreased neovascularization leading to poorer functional outcomes post-injury/operatively. Clinically, epidural fat is commonly considered a space-filling tissue with limited functionality and therefore typically discarded during surgery. However, the presence of MSCs within epidural fat suggests that itis more biologically active than historically believed and may contribute to the regulation of homeostasis and regeneration in the dural environment. While the current literature supports our hypothesis, it will require additional experimentation to determine if epidural fat is an endogenous driver of repair and regeneration and if so, this tissue should be minimally perturbed from its original location in the spinal canal. Also see the video abstract here https://youtu.be/MIol_IWK1os.

Introduction/purpose The rabbit elastase model has become a standard in vivo representation of human intracranial aneurysms, mimicking their histology and offering a means for laboratory testing of current and novel endovascular devices. Variations of the aneurysm creation procedure in rabbits exist, such as endovascular versus surgical exposure of the right common carotid artery (RCCA), where the aneurysm is induced. One particular variation, the modified elastase technique, results in aneurysms that are generally smaller than treated human aneurysms, making the model less relevant. The purpose of this study was to determine whether larger sizes could be created by combining calcium chloride (CaCl2) with elastase in the solution used to induce aneurysms with this technique. Methods/materials Animals were assigned to one of two groups, including elastase only (control, n=7) or a combination of CaCl2 and elastase (experimental, n=9). After administration of anesthetic, the RCCA was exposed, a temporary clip was placed at the brachiocephalic bifurcation, and a silk suture was used to ligate the vessel distally. An angiocatheter was placed in the occluded portion of the vessel and, depending on group assignment, either elastase only or CaCl2/elastase was injected into the occluded segment. After 20 min of incubation, the catheter was withdrawn and a silk suture was tied just proximal to the catheter entry site (3 cm distal to the bifurcation) to permanently occlude blood flow. The clip was then removed, and blood was re-perfused into the stump of the RCCA. After 4 weeks, angiographic results were obtained from each rabbit. Statistical analysis was performed using Student’s t-test. Results Mean angiographic aneurysm heights and widths were 5.16 mm±0.96 mm (SEM) and 2.48 mm±0.50 mm, respectively, in the control group and 7.82 mm±0.58 mm and 4.19 mm±0.25 mm, in the experimental group (p-value=0.03, 0.005). Calculated mean volumes were 24.98 mm3±10.93 mm3 and 75.93 mm3±12.22 mm3 in the control and experimental groups, respectively (p-value=0.009). Conclusion In the modified elastase technique of aneurysm creation in a rabbit model, the combination of CaCl2 and elastase results in increased aneurysm size and volume, versus elastase alone. When comparing our technique to the most commonly employed variations of the rabbit model in the literature, our modification yields aneurysms that are larger and within the size range of treated human aneurysms. Disclosures B. Belanger: None. M. Avery: None. A. Mitha: None.

Background Orbital lymphaticovenous malformations (LVMs) are congenital vascular lesions that are typically infiltrative in nature. There have been reports of orbital LVMs extending intracranially through orbital fissures, but there have been no reports of intradural extension. Case Description We report the first case of orbital LVM extending intradurally through a bony defect in the medial orbital roof. A modified orbitozygomatic approach was used to successfully obliterate this lesion. Neurosurgical and ophthalmologic collaboration was used in the surgical management of this case. Conclusions This case highlights the importance of an interdisciplinary approach when managing infiltrative orbital LVMs, as both ophthalmologic and neurosurgical expertise were critical in the success of the surgery.

Background With increasing use of endovascular techniques in the treatment of ruptured and unruptured aneurysms, the issue of obliteration efficacy has become increasingly important. We have previously reported the Aneurysm Recanalization Stratification Scale, which uses accessible predictors including aneurysm-specific factors (size, rupture, and intraluminal thrombosis) and treatment-related features (treatment modality and immediate angiographic result) to predict retreatment risk after endovascular therapy. Objective To assess the external validity of the Aneurysm Recanalization Stratification Scale. Methods External validity was assessed in independent cohorts from 4 centers in the United States and Canada where endovascular and open neurovascular procedures are performed, and in a multicenter cohort of 1543 patients. Probability of retreatment stratified by risk score was derived for each center and the combined multicenter cohort. Results Despite moderate variability in retreatment rate among centers (29.5%, 9.9%, 9.6%, 26.3%, 19.7%, and 18.3%), the Aneurysm Recanalization Stratification Scale demonstrated good predictive value with C-statistics of 0.799, 0.943, 0.780, 0.695, 0.755, and 0.719 for each center and the combined cohort, respectively. Probability of retreatment stratified by risk score for the combined cohort is as follows: -2, 4.9%; -1, 5.7%; 0, 5.8%; 1, 13.1%; 2, 19.2%; 3, 34.9%; 4, 32.7%; 5, 73.2%; 6, 89.5%; and 7, 100.0%. Conclusion Surgical decision-making and patient-centered informed consent require comprehensive and accessible information on treatment efficacy. The Aneurysm Recanalization Stratification Scale is a valid prognostic index. This is the first comprehensive model that has been developed to quantitatively predict retreatment risk following endovascular therapy.

Among patients with a proximal vessel occlusion in the anterior circulation, 60 to 80% of patients die within 90 days after stroke onset or do not regain functional independence despite alteplase treatment. We evaluated rapid endovascular treatment in addition to standard care in patients with acute ischemic stroke with a small infarct core, a proximal intracranial arterial occlusion, and moderate-to-good collateral circulation. Methods We randomly assigned participants to receive standard care (control group) or standard care plus endovascular treatment with the use of available thrombectomy devices (intervention group). Patients with a proximal intracranial occlusion in the anterior circulation were included up to 12 hours after symptom onset. Patients with a large infarct core or poor collateral circulation on computed tomography (CT) and CT angiography were excluded. Workflow times were measured against predetermined targets. The primary outcome was the score on the modified Rankin scale (range, 0 [no symptoms] to 6 [death]) at 90 days. A proportional odds model was used to calculate the common odds ratio as a measure of the likelihood that the intervention would lead to lower scores on the modified Rankin scale than would control care (shift analysis). Results The trial was stopped early because of efficacy. At 22 centers worldwide, 316 participants were enrolled, of whom 238 received intravenous alteplase (120 in the intervention group and 118 in the control group). In the intervention group, the median time from study CT of the head to first reperfusion was 84 minutes. The rate of functional independence (90-day modified Rankin score of 0 to 2) was increased with the intervention (53.0%, vs. 29.3% in the control group; P

Endovascular embolization is the standard approach for management of carotid cavernous fistulas (CCFs) due to the ease of access and reduced level of risk associated with the procedure compared with open surgery. We present here a case of a CCF that eventually led to the development of brainstem venous congestion from perimedullary venous drainage. This fistula was not amenable to endovascular embolization due to lack of either ophthalmic vein or petrosal sinus drainage. Therefore, a craniotomy with direct puncture of the cavernous sinus was performed, followed by coil embolization to completely treat this fistula. This case demonstrates an uncommon progression of venous drainage to Cognard grade V, rare development of symptomatic brainstem venous congestion and a unique method to combine an open surgical approach with endovascular embolization to treat CCFs.

Introduction Intracranial aneurysms are relatively common entities, with rupture being a largely unpredictable event associated with significant morbidity and mortality. While current treatment modalities are effective at addressing mature aneurysms, disrupting aneurysm formation would potentially avoid the need for more invasive treatments. To inhibit saccular aneurysm pathogenesis would likely require blunting of the complex inflammatory cascade in the arterial wall. Mesenchymal stem cells (MSCs) are readily available cells found in adult tissues, such as bone marrow and adipose tissue, that have immunomodulatory properties and are immune evasive.1 They have been studied as potential treatments for many diseases associated with inflammation and have shown promise for clinical translation.2 While some studies have investigated MSCs as a treatment adjunct for aneurysms, none have examined their potential role in inhibiting aneurysm pathogenesis. We hypothesize that injecting MSCs IV will minimize the radiographic formation of aneurysms in a rabbit elastase-induced saccular aneurysm model by blunting the inflammatory process. Materials and methods Thirteen New Zealand White Rabbits were randomly assigned to either control (n=5) or intervention (n=8) groups. All rabbits underwent right common carotid artery saccular aneurysm creation using approximately 35 units of elastase as previously described in this accepted and effective model.(3) At both the time of surgery and 14 days post-operatively, intervention group rabbits received an IV injection of 5 × 106 MSCs in 2 mL saline, while control group rabbits received 2 mL of vehicle. On day 28, the right femoral artery was cannulated in all rabbits and digital subtraction angiography performed. Aneurysm volume was calculated and compared between groups. Results All rabbits tolerated the surgical procedures well with no peri-operative complications, and every procedure resulted in aneurysm formation. Mean volume of right common carotid saccular aneurysms in the control and intervention groups were 36.9 mm3 and 15.4 mm3, respectively. A Mann-Whitney U test was performed due to the heterogeneity of variances and found that the intervention group aneurysms were significantly smaller than control aneurysms (p=0.030). Conclusion This is the first study investigating the ability of MSCs to inhibit the formation of saccular aneurysms. We postulate that the observed effects are secondary to MSC-induced inhibition of the initial inflammatory cascade of aneurysm pathogenesis. MSCs are known to have immunomodulatory effects in many other scenarios, either by migrating to a site of inflammation or by releasing factors from afar.4 It is unclear by which mechanism the observed effect is occurring, but these findings suggest that MSCs may perhaps be utilized for inhibiting aneurysm formation. References . Kean TH, Lin P, Caplan AI, Dennis JE. MSCs: Delivery routes and engraftment, cell-targeting strategies, and immune modulation. Stem Cells Int. 2013. 2013: Article ID732742. . Kim N, Cho SG. Clinical applications of mesenchymal stem cells. Korean J Intern Med2013;28:387–402. . Hoh BL, Rabinov JD, Pryor JC, Ogilvy CS. A modified technique for using elastase to create saccular aneurysms in animals that histologically and hemodynamically resemble aneurysms in human. Acta Neurochir2004;146:705–711. . English K. Mechanisms of mesenchymal stromal cell immunomodulation. Immunol Cell Biol2013;91:19–26. Disclosures M. Avery: None. A. Sen: None. A. Mitha: None.

A 62-year-old woman presented with a subarachnoid hemorrhage secondary to a ruptured right supraclinoid internal carotid artery blister aneurysm. She was treated in an emergent fashion with two flow diverting pipeline embolization devices (PED) deployed in a telescoping fashion. CT angiography performed for unrelated reasons at 7 months showed successful treatment of the aneurysm without evidence of residual aneurysm. However, a follow-up digital subtraction angiogram performed at 9 months showed a large aneurysm in a modified position compared with the original aneurysm. This is the first case of rapid regrowth of a supraclinoid blister aneurysm after successful treatment with a PED, and demonstrates the need for close follow-up for similar aneurysms treated with this novel device.

OBJECTIVE Blunt cerebrovascular injury (BCVI) occurs in approximately 1% of the blunt trauma population and may lead to stroke and death. Early vascular imaging in asymptomatic patients at high risk of having BCVI may lead to earlier diagnosis and possible stroke prevention. The objective of this study was to determine if the implementation of a formalized asymptomatic BCVI screening protocol with CT angiography (CTA) would lead to improved BCVI detection and stroke prevention. METHODS Patients with vascular imaging studies were identified from a prospective trauma registry at a single Level 1 trauma center between 2002 and 2008. Detection of BCVI and stroke rates were compared during the 3-year periods before and after implementation of a consensus-based asymptomatic BCVI screening protocol using CTA in 2005. RESULTS A total of 5480 patients with trauma were identified. The overall BCVI detection rate remained unchanged postprotocol compared with preprotocol (0.8% [24 of 3049 patients] vs 0.9% [23 of 2431 patients]; p = 0.53). However, postprotocol there was a trend toward a decreased risk of stroke secondary to BCVI on a trauma population basis (0.23% [7 of 3049 patients] vs 0.53% [13 of 2431 patients]; p = 0.06). Overall, 75% (35 of 47) of patients with BCVI were treated with antiplatelet agents, but no patient developed new or progressive intracranial hemorrhage despite 70% of these patients having concomitant traumatic brain injury. CONCLUSIONS The results of this study suggest that a CTA screening protocol for BCVI may be of clinical benefit with possible reduction in ischemic complications. The treatment of BCVI with antiplatelet agents appears to be safe.

Object Recurrence after endovascular coiling of intracranial aneurysms is reported in up to 42% of cases and is attributed to the lack of endothelialization across the neck. In this study the authors used a novel tissue engineering approach to promote endothelialization by seeding endothelial progenitor cells (EPCs) within a fibrin polymer injected endovascularly into the aneurysm. Methods Experimental aneurysms were created in New Zealand White rabbits and were left untreated, surgically clipped, or embolized with platinum coils, fibrin biopolymer alone, or fibrin combined with autologous cultured EPCs. Results In aneurysms treated with EPCs, a confluent monolayer of endothelial cells with underlying neointima was demonstrated across the neck at 16 weeks posttreatment, which was not observed with aneurysms treated using the other methods. Conclusions This novel technique may address reasons for the limited durability of standard coil embolization and provides further avenues for the development of improved devices for the care of patients with aneurysms.

Timely recanalization during endovascular procedures for acute ischemic stroke can be challenging in cases with large clot burden, such as those encountered in the terminal internal carotid T- or L-type occlusion.A novel but simple technique to achieve fast reduction in clot burden in stroke patients with occlusion of the internal carotid artery termination is described where manual suction using a 60-ml syringe applied through an 8-F balloon guide catheter positioned in the cervical carotid vasculature with proximal flow arrest allows subsequent revascularization of the residual middle cerebral artery clot.The use of manual suction through a balloon-tipped guide catheter in internal carotid artery L- or T-type occlusion is illustrated. This resulted in a significant reduction of the clot burden and facilitated further interventions leading to full recanalization.Manual suction using a 60-ml syringe through a balloon guide catheter is a useful and feasible technique that facilitates thrombectomy of large burden cerebral clots.

Background Cerebral venous sinus thrombosis (CVT) is an uncommon cause of stroke that is usually treated medically with intravenous heparin therapy followed by long-term anticoagulation therapy. A series of patients with CVT who underwent rheolytic thrombectomy with the AngioJet as a first-line adjunctive treatment in addition to standard anticoagulation therapy is presented. Methods Prospectively maintained endovascular databases at two institutions were retrospectively reviewed. The available clinical and imaging data were compiled at each institution and combined for analysis. Results Over 18 months, 13 patients (seven women and six men; age range 17–73 years, median age 45 years) with CVT were treated with rheolytic thrombectomy. Immediate (partial or complete) recanalization of the thrombosed intracranial sinuses was achieved in all patients. At a median radiographic follow-up of 7 months there was continued patency of all recanalized sinuses. Clinical follow-up was available on nine patients: modified Rankin score of 0 in four patients, 1 in three patients and 6 in two patients. Conclusion This series demonstrates the feasibility of performing mechanical thrombectomy as a first-line treatment for acute CVT. This technique facilitates the prompt restoration of intracranial venous outflow, which may result in rapid neurological and symptomatic improvement.

Background Resection of intramedullary spinal cord cavernous malformations is associated with a significant risk of morbidity because of the high density of eloquent tissue within the spinal cord. Despite this risk, surgery remains the definitive treatment for symptomatic lesions. Objective To review the clinical aspects of surgical approaches for spinal cord cavernous malformations. Methods This article reviews the epidemiology, pathophysiology, clinical and imaging characteristics, and indications for surgical resection. Surgical issues and operative approaches by anatomical location are also detailed, drawing from evidence in the literature and from the senior author's clinical experience. Results The 3 primary approaches to spinal cord cavernous malformations-the posterior, posterolateral, and lateral approaches-are described and illustrated. Magnetic resonance imaging and intraoperative photographs of representative cases are included. Conclusion Intramedullary spinal cord cavernous malformations are complex entities, and it is our hope that this article will improve readers' understanding of their clinical characteristics, their indications for treatment, and the surgical pathways through which these lesions can be safely resected.

Object The management of intramedullary spinal cord cavernous malformations (CMs) is controversial. At Barrow Neurological Institute, the authors selectively offer surgical treatment for symptomatic spinal cord CMs. The purpose of this paper is to review the clinical outcomes in patients after resection of these lesions based on a single-center experience over a 25-year period. Methods The records of 80 patients who underwent resection of pathologically confirmed spinal cord CMs from January 1985 to May 2010 were analyzed retrospectively. Preoperative clinical status and imaging findings were evaluated as well as immediate and long-term postoperative outcomes. Results Compared with their preoperative Frankel grade, 11% of patients were worse, 83% were the same, and 6% improved immediately after surgery. At a mean follow-up interval of 5 years, 10% of patients were worse, 68% were the same, and 23% were improved compared with their preoperative status. Five percent of patients underwent reoperation for resection of a symptomatic residual or recurrent lesion. Immediate complications were encountered in 6% of patients, including CSF leakage and deep venous thrombosis. Long-term complications were encountered in 14% of patients and included kyphotic deformity, stenosis, and spinal cord tethering. A significant correlation was found between long-term outcome and anteroposterior length of the lesion (p = 0.01). Conclusions The resection of intramedullary spinal cord CMs can be achieved with good long-term outcomes and an acceptable risk of immediate or delayed complications.

Macrocephaly-cutis marmorata telangiectatica congenita is a rare overgrowth syndrome commonly associated with hydrocephalus. Although the pathophysiological characteristics of the hydrocephalus in this syndrome is not fully known, previous reports have described its treatment with ventriculoperitoneal shunt placement. The authors describe 2 cases of macrocephaly-cutis marmorata telangiectatica congenita successfully treated for progressive hydrocephalus with endoscopic third ventriculostomy. Both patients experienced clinical and radiographic stabilization following treatment, and these findings offer insight into the pathophysiology of the hydrocephalus and its ideal management.

The PS Medical Strata valve is a programmable shunt valve used in the treatment of hydrocephalus that allows for noninvasive changes in the pressure setting using a magnet. The Strata valve is sensitive to magnetic fields, and reprogramming is frequently necessary after MR imaging. A known but rare complication of the Strata valve is that the rotor can become locked, causing shunt malfunction. This complication can only occur in a first generation Strata valve.

Arteriovenous malformations are generally considered to be cured following angiographically proven complete resection. However, rare instances of AVM recurrence despite negative findings on postoperative angiography have been reported in both children and adults. In this paper, the authors present the case of a 33-year-old woman with 2 AVM recurrences. This patient represents the oldest case of recurrent AVM, and the first adult double recurrence reported in the literature. The case is presented, the radiological and surgical features are considered, and the literature on recurrent AVMs is reviewed.

Background: Indocyanine green (ICG) videoangiography is an intraoperative technique recently used in vascular neurosurgery to assess the presence or absence of blood flow during critical times of a procedure. These include, but are not limited to, detecting whether daughter branches or perforators are patent after placing a vascular clip or determining whether an aneurysm has been completely isolated from the cerebral circulation after clipping. We present a case of a less-commonly reported application of ICG videoangiography involving the selection of a vessel to act as the bypass recipient once the need is identified during the surgical treatment of a complex intracranial aneurysm. Case Description: A 51-year-old male presented with a ruptured dissecting superior cerebellar artery (SCA) aneurysm that had two branches arising from the dome. Due to the difficult morphology of this aneurysm, a superficial temporal artery to SCA bypass was planned. We used ICG videoangiography to identify the branch that had insufficient retrograde flow via collateral circulation, to which the bypass was performed, followed by the isolation of the aneurysm from the cerebral circulation using permanent surgical clips. Conclusion: Our case represents a possible use of ICG videoangiography during the operative treatment of a difficult aneurysm. Our patient suffered no infarcts postoperatively. In the correct clinical context, this method represents a possible treatment option for complex aneurysms requiring a bypass.

One in five patients undergoing endovascular coiling (the current standard of care for treating intracranial aneurysms) experience a recurrence of the aneurysm as a result of improper healing. Recurrence remains the only major drawback of the coiling treatment and has been the focus of many studies over the last two decades. Cell therapy, a novel treatment modality in which therapeutic cells are introduced to the site of the injury to promote tissue regeneration, has opened up new possibilities for treating aneurysms. The healing response that ensues aneurysm embolization includes several cellular processes that can be targeted with cell therapy to prevent the aneurysm from recurring. Ten preclinical studies involving cell therapy to treat aneurysms were published between 1999 and 2014. In this review, we summarize the results of these studies and discuss advances, shortcomings, and the future of cell therapy for intracranial aneurysms.

OBJECTIVE: A systematic approach to the consideration of various factors on outcome demands a comprehensive grading system for patients with intracranial aneurysms. We have previously identified potential patient- and lesion-specific factors that correlate strongly with outcome after treatment for intracranial aneurysms, and we have developed a comprehensive grading system based on these factors. In this study, we evaluate this grading system in a large series of aneurysm patients treated by surgery and endovascular therapy. METHODS: Between January 1998 and January 2003, ruptured and unruptured aneurysm patients were prospectively entered into a database. Based on our previous study that showed which factors correlated strongly with outcome, data were collected on patient age, aneurysm size, Hunt and Hess grade, and Fisher scale (if presenting with subarachnoid hemorrhage), and a Massachusetts General Hospital grade was then applied. The modified Glasgow Outcome Scale was used for clinical assessment at follow-up, and a binary analysis classified patients into favorable versus unfavorable outcome. Univariate and multivariate analyses for the predictor variables were performed. RESULTS: One thousand forty-nine aneurysms in 914 patients were identified. Fifty-eight percent (n = 608) of the lesions were unruptured, and 25% (n = 261) were treated endovascularly. For patients treated either surgically or endovascularly, worsening outcome was demonstrated for higher Hunt and Hess grade (surgery, P < 0.001; endovascular, P < 0.001), Fisher scale (surgery, P < 0.001; endovascular, P < 0.001) and for older patients (surgery, P < 0.001; endovascular, P = 0.004). Size of aneurysm had a significant effect on outcome after surgery (P = 0.04), but not after endovascular therapy (P = 0.3). Overall, there was a greater proportion of favorable outcomes for anterior circulation compared with posterior circulation lesions (P < 0.0001). For both the surgical and endovascular subgroups, MGH grade correlated well with clinical outcomes. CONCLUSION: The MGH grade is a comprehensive grading system that is easily applied and that allows separation of patients with aneurysms into groups with markedly different outcomes. This information can potentially be helpful in making treatment decisions and when discussing projected outcome before surgical or endovascular intervention of both unruptured and ruptured aneurysms.

Background Delayed ipsilateral intraparenchymal haemorrhage is a recently recognised complication after endovascular flow diversion for intracranial aneurysms. Although the mechanism of this phenomenon is not understood, one proposed explanation (the windkessel hypothesis) is that removal of aneurysmal compliance increases distal pulse pressure. Methods We present a case of delayed haemorrhage after placement of a Pipeline stent, discuss the proposed mechanisms, and describe a novel electrical analogue model that was used to evaluate the likely haemodynamic effect of stent placement. Results Model-based analysis suggests that stenting is not likely to produce a significant change in distal pulse pressure. Moreover, basic fluid dynamics principles suggest that a local reduction in disturbed flow in the region of the aneurysm could produce only a minor increase in distal pressure (a few mmHg), which is unlikely to be the main cause of the observed haemorrhage. Conclusion The windkessel hypothesis is unlikely to explain the occurrence of delayed ipsilateral intraparenchymal haemorrhage after flow diversion; however, other mechanisms involving altered haemodynamics distal to the treated aneurysm may play a role. Further studies involving the assessment of haemodynamic changes after flow diversion would be useful to understand, and eventually mitigate, this currently unpredictable risk.

In acute ischemic stroke, good outcome following successful recanalization is time dependent. In patients undergoing endovascular therapy at our institution, recanalization times with the Solitaire stent were retrospectively evaluated to assess for the presence of a learning curve in achieving rapid recanalization.We reviewed patients who presented to our stroke center and achieved successful recanalization with the Solitaire stent exclusively. Time intervals were calculated (CT to angiography arrival, angiography arrival to groin puncture, groin puncture to first deployment, and deployment to recanalization) from time stamped images and angiography records. Patients were divided into three sequential groups, with overall CT to recanalization time and subdivided time intervals compared.83 patients were treated with the Solitaire stent from May 2009 to February 2012. Recanalization (Thrombolyis in Cerebral Infarction score 2A) occurred in 75 (90.4%) patients. CT to recanalization demonstrated significant improvement over time, which was greatest between the first 25 and the most recent 25 cases (161-94 min; p0.01). The maximal contribution to this was from improvements in first stent deployment to recanalization time (p=0.001 between the first and third groups), with modest contributions from moving patients from CT to the angiography suite faster (p=0.02 between the first and third groups) and from groin puncture to first stent deployment (p=0.02 between the first and third groups).There is a learning curve involved in the efficient use of the Solitaire stent in endovascular acute stroke therapy. Along with improvements in patient transfer to angiography and improved efficiency with intracranial access, mastering this device contributed significantly towards reducing recanalization times.

Objective To present a case of a cavernous malformation presenting with a subdural hematoma. Methods A 27-year-old woman was admitted with progressively worsening headache, vomiting, weakness, and word-finding difficulties 1 week after she was discharged from an outside hospital, where she was managed conservatively for a presumed traumatic subdural hematoma. Computed tomography revealed an enlarging subacute left hemispheric subdural hematoma for which she underwent drill craniostomy. Postprocedural magnetic resonance imaging showed a posterior left temporal lobe mass consistent with a cavernous malformation juxtaposed with the subdural hematoma. Craniotomy for resection of the lesion was performed. She had an uncomplicated postoperative course and experienced a good recovery. Results The signs and symptoms, diagnostic imaging, and intraoperative findings suggest that the subdural hematoma was caused by extralesional hemorrhage of the cavernous malformation, which is a rare finding associated with these malformations. Conclusions The clinical course, radiologic, and intraoperative findings suggest that the subdural hemorrhage was caused by extralesional hemorrhage of the cavernous malformation.

Brainstem cavernous malformations (CMs) are low-flow vascular lesions in eloquent locations. Their presentation is often marked with symptomatic hemorrhages that appear to occur more frequently than hemorrhage from supratentorial cavernomas. Brainstem CMs can be removed using 1 of the 5 standard skull-base approaches: retrosigmoid, suboccipital (with or without telovelar approach), supracerebellar infratentorial, orbitozygomatic, and far lateral. Patients being referred to a tertiary institution often have lesions that are aggressive with respect to bleeding rates. Nonetheless, the indications for surgery, in the authors' opinion, are the same for all lesions: those that are symptomatic, those that cause mass effect, or those that abut a pial surface. Patients often have relapsing and remitting courses of symptoms, with each hemorrhage causing a progressive and stepwise decline. Many patients experience new postoperative deficits, most of which are transient and resolve fully. Despite the risks associated with operating in this highly eloquent tissue, most patients have had favorable outcomes in the authors' experience. Surgical treatment of brainstem CMs protects patients from the potentially devastating effects of rehemorrhage, and the authors believe that the benefits of intervention outweigh the risks in patients with the appropriate indications.

Use of the Kerrison rongeur for bone removal in spinal surgery is associated with dural tears and cerebrospinal fluid (CSF) leaks. We report a modification of the Kerrison rongeur footplate designed to reduce the risk of dural tears. A novel footplate was designed by incorporating the following parameters: (1) tapering the footplate to deflect soft tissue downward during positioning of the rongeur underneath the bone, and (2) making the footplate longer and wider than the cutting element to prevent soft tissue from entering into the cutting surface. Stereolithography models of the modified footplate were made and tested in a cadaver. A stainless steel modified footplate was then incorporated into an existing Kerrison rongeur as a working prototype, and tested in 20 laminectomy cases to clinically validate its design. The modified footplate prevented soft tissue from entering the cutting surface of the Kerrison rongeur in the manner intended by its design. No dural tears or CSF leaks were encountered in any instance. Potential soft tissue compression caused by an increase in footplate dimensions was not a significant issue in the rongeur size tested. This modification, however, might not be practical in rongeurs larger than 3 mm. The risk of dural tears and cerebrospinal fluid leaks in spinal surgery may be reduced by this footplate modification of the Kerrison rongeur. Soft tissue compression may limit the incorporation of this modification to rongeurs of 3 mm or smaller. The promising results warrant further tests with a wider range of sizes., Center for Integration of Medicine and Innovative Technology (U.S. Army Medical Research Acquisition Activity Cooperative Agreement No. DAMD17-02-2-0006)

Object Imaging of intracranial aneurysms using conventional multidetector CT (MDCT) is limited because of nonvisualization of features such as perforating vessels, pulsatile blebs, and neck remnants after clip placement or coil embolization. In this study, a model of intracranial saccular aneurysms in rabbits was used to assess the ultra-high resolution and dynamic scanning capabilities of a prototype flat-panel volumetric CT (fpVCT) scanner in demonstrating these features. Methods Ten New Zealand white rabbits underwent imaging before and after clipping or coil embolization of surgically created aneurysms in the proximal right carotid artery. Imaging was performed using a prototype fpVCT scanner, a 64-slice MDCT scanner, and traditional catheter angiography. In addition to the slice data and 3D views, 4D dynamic views, a capability unique to fpVCT, were also created and reviewed. The images were subjectively compared on 1) 4 image quality metrics (spatial resolution, noise, motion artifacts, and aneurysm surface features); 2) 4 posttreatment features reflecting the metal artifact profile of the various imaging modalities (visualization of clip or coil placement, perianeurysmal clip/coil anatomy, neck remnant, and white-collar sign); and 3) 2 dynamic features (blood flow pattern and aneurysm pulsation). Results Flat-panel volumetric CT provided better image resolution than MDCT and was comparable to traditional catheter angiography. The surface features of aneurysms were demonstrated with much higher resolution, detail, and clarity by fpVCT compared with MDCT and angiography. Flat-panel volumetric CT was inferior to both MDCT and angiography in terms of image noise and motion artifacts. In fpVCT images, the metallic artifacts from clips and coils were significantly fewer than those in MDCT images. As a result, clinically important information about posttreatment aneurysm neck remnants could be derived from fpVCT images but not from MDCT images. Time-resolved dynamic sequences were judged slightly inferior to conventional angiography but superior to static MDCT images. Conclusions The spatial resolution, surface anatomy visualization, metal artifact profile, and 4D dynamic images from fpVCT are superior to those from MDCT. Flat-panel volumetric CT demonstrates aneurysm surface features to better advantage than angiography and is comparable to angiography in metal artifact profile. Even though the temporal resolution of fpVCT is not quite as good as that of angiography, fpVCT images yield clinically important anatomical information about aneurysm surface features and posttreatment neck remnants not attainable with either angiography or MDCT images.

Intracranial dural arteriovenous fistulas (dAVFs) are commonly encountered in centers specializing in cerebrovascular diseases. Knowing the precise site of fistulous communication with the venous structures is essential in targeting the appropriate surgical or endovascular therapy once a decision to treat has been made. Such sites can usually be located with digital subtraction angiography alone. The authors describe a case in which localization was best performed using cone-beam volume CT in the angiography suite after selective microcatheterization of the feeding vessel and injection of a contrast agent in a dAVF related to the petrous temporal bone. Imaging studies showed the lesion was related to the inferior aspect of the tentorium, warranting a suboccipital surgical approach to treat the fistula.

✓ To the authors' knowledge, only 1 case of communicating hydrocephalus after endovascular coiling of unruptured brain aneurysms has been reported previously. Here, they report on 2 such cases of delayed communicating hydrocephalus after treatment with hydrogel-coated coils and offer the first histopathological evidence of foreign material, presumably related to the coils, as the cause of hydrocephalus.

Object Digital subtraction (DS) angiography is the current gold standard of assessing intracranial aneurysms after coil placement. Magnetic resonance (MR) angiography offers a noninvasive, low-risk alternative, but its accuracy in delineating coil-treated aneurysms remains uncertain. The objective of this study, therefore, is to compare a high-resolution MR angiography protocol relative to DS angiography for the evaluation of coil-treated aneurysms. Methods In 2003, the authors initiated a prospective protocol of following up patients with coil-treated brain aneurysms using both 1.5-tesla gadolinium-enhanced MR angiography and biplanar DS angiography. Using acquired images, the subject aneurysm was independently scored for degree of remnant identified (complete obliteration, residual neck, or residual aneurysm) and the surgeon's ability to visualize the parent vessel (excellent, fair, or poor). Results Thirty-seven patients with 42 coil-treated aneurysms were enrolled for a total of 44 paired MR angiography–DS angiography tests (median 9 days between tests). An excellent correlation was found between DS and MR angiography for assessing any residual aneurysm, but not for visualizing the parent vessel (κ = 0.86 for residual aneurysm and 0.10 for parent vessel visualization). Paramagnetic artifact from the coil mass was minimal, and in some cases MR angiography identified contrast permeation into the coil mass not revealed by DS angiography. An intravascular microstent typically impeded proper visualization of the parent vessel on MR angiography. Conclusions Magnetic resonance angiography is a noninvasive and safe means of follow-up review for patients with coil-treated brain aneurysms. Compared with DS angiography, MR angiography accurately delineates residual aneurysm necks and parent vessel patency (in the absence of a stent), and offers superior visualization of contrast filling within the coil mass. Use of MR angiography may obviate the need for routine diagnostic DS angiography in select patients.

Background: Penetrating nail-gun injuries to the head are rare, however, the incidence has been gradually rising over the last decade. While there is a large volume of case reports in the literature, there are only a few incidences of cerebrovascular injury. We present a case of a patient with a nail-gun injury to the brain, which compromised the cerebral vasculature. In this article, we present the case, incidence, pathology, and a brief literature review of penetrating nail-gun injuries to highlight the principles of management pertaining to penetration of cerebrovascular structures. Case Description: A 26-year-old male presented with a penetrating nail-gun injury to his head. There were no neurological deficits. Initial imaging revealed that the nail had penetrated the cranium and suggested the vasculature to be intact. However, due to the proximity of the nail to the circle of Willis the operative approach was tailored in anticipation of a vascular injury. Intraoperatively removal of the foreign body demonstrated a laceration to the M1 branch of the middle cerebral artery (MCA), which was successfully repaired. Conclusion: To our knowledge, this is the first reported case of a vascular arterial injury to the MCA from a nail-gun injury. It is imperative to have a high clinical suspicion for cerebrovascular compromise in penetrating nail-gun injuries even when conventional imaging suggests otherwise.