The Woven EndoBridge (WEB) device (Terumno Corp. parent company of Microvention) was approved by the U.S. Food and Drug Administration as the first intrasaccular device for intracranial aneurysm ...treatment in December 2018. Its use has become more common since then, but both trial results and postmarket experiences have raised questions about the efficacy in achieving complete aneurysm obliteration. Retreatment after WEB embolization has not been extensively discussed.
To discuss the incidence and retreatment of aneurysms after initial WEB embolization.
Retrospective review across 13 institutions identified all occurrences of WEB retreatment within neurovascular databases. Details regarding demographics, aneurysm characteristics, treatment considerations, clinical outcomes, and aneurysm occlusion were obtained and analyzed.
Thirty aneurysms were retreated in 30 patients in a cohort of 342 WEB-treated aneurysms. The retreatment rate was 8.8%. Endovascular methods were used for 23 cases, and 7 were treated surgically. Two aneurysms presented with rehemorrhage after initial WEB embolization. Endovascular treatments included stent-assisted coiling (12), flow diversion (7), coiling (2), PulseRider (Johnson & Johnson)-assisted coiling (1), and additional WEB placement (1). Surgical treatments included primary clipping (6) and Hunterian ligation (1). There were no major complications within the study group.
WEB retreatments were successfully performed by a variety of techniques, including stent-assisted coiling, clipping, and flow diversion as the most common. These procedures were performed safely with subsequent obliteration of most aneurysms. The potential need for retreatment of aneurysms should be considered during primary WEB treatments.
In this article, we apply philosophical and sociological theory to consider how young women skateboarders interact with and are affected by performative aspects of skateboarding cultures. Drawing on ...findings from a qualitative study of three skateparks plus other skate spaces in and around two English cities, we argue that these spaces are performative in nature and that this is frequently problematic for young woman skateboarders. We suggest that, due to their comparative rarity in these spaces, young women are put under an immediate spotlight on entry, with an expectation that they perform a competent skateboarder identity while under scrutiny from other users of the space; we examine their experiences of this. We conclude by suggesting ways that skateparks and skatespaces can be designed and used to make them more accessible to woman and girl skaters, and to other groups marginalised in skateboarding cultures.
The dural venous sinus (DVS) is a thin-walled blood channel composed of dura mater that is susceptible to injury during common neurosurgical approaches. DVS injuries are highly underreported, which ...is reflected by a lack of literature on the topic. Neurosurgeons should be familiar with appropriate techniques to successfully repair an injured DVS and prevent associated complications. This study presents a literature review on the surgical techniques for DVS repair after DVS injury during common neurosurgical approaches. The databases PubMed and Scopus were queried using the terms "cranial sinuses," "superior sagittal sinus," "transverse sinuses," "injury," and "surgery." A total of 117 articles underwent full-text review and were analyzed for surgical approach, craniotomy, lesion location, lesion characteristics, and surgical repair techniques. A literature review was performed, and a comprehensive summary is presented. Data from publications describing DVS lacerations related to pathological conditions (eg, meningioma) were excluded. A total of 9 techniques aiding with bleeding control, hemostasis, and sinus repair and reconstruction were identified, including compression, hemostatic agents, bipolar cautery, dural tenting and tack-up suturing, dural flap, direct suturing, autologous patch, venous bypass, and ligation. The advantages and drawbacks of each technique are described. Multiple options to treat DVS injuries are available to the neurosurgeon. Treatment type is based on anatomic location, complexity of the laceration, cardiovascular status, the presence of air embolism, and the dexterity and experience of the surgeon.
Abstract
BACKGROUND:
Seizures are a common symptom of supratentorial arteriovenous malformations (AVMs), and uncontrolled epilepsy can considerably reduce patient quality of life. Potential risk ...factors for epilepsy in patients with AVMs are poorly understood, and the importance of achieving freedom from seizures in their surgical treatment remains underappreciated.
OBJECTIVE:
To characterize risks factors for preoperative seizures and factors associated with postoperative freedom from seizures in patients with surgically resected supratentorial AVMs.
METHODS:
We analyzed prospectively collected patient data for 440 patients who underwent microsurgical resection of supratentorial AVMs at our institution.
RESULTS:
Among 440 patients with supratentorial AVMs, 130 (30%) experienced preoperative seizures, and 23 (18%) with seizures progressed to medically refractory epilepsy. Seizures were associated with a history of AVM hemorrhage (relative risk, 6.65; 95% confidence interval CI, 3.81-11.6), male sex (relative risk, 2.07; 95% CI, 1.26-3.39), and frontotemporal lesion location (relative risk, 1.75; 95% CI, 1.05-2.93). After resection, 96% of patients had a modified Engel class I outcome, characterized by freedom from seizures (80%) or only 1 postoperative seizure (16%; mean follow-up, 20.7 ± 2.3 months). Comparable rates of postoperative seizures were seen in patients with (7%) or without (3%) preoperative seizures. AVMs with deep artery perforators were significantly associated with postoperative seizures (hazard ratio, 4.35; 95% CI, 1.61-11.7).
CONCLUSION:
In the microsurgical treatment of supratentorial AVMs, hemorrhage, male sex, and frontotemporal location are associated with higher rates of preoperative seizures, whereas deep artery perforators are associated with postoperative seizures. Achieving freedom from seizure is an important goal that can be achieved in the surgical treatment of AVMs because epilepsy can significantly diminish patient quality of life.
Objective
We assessed types of cadaveric head and brain tissue specimen preparations that are used in a high throughput neurosurgical research laboratory to determine optimal preparation methods for ...neurosurgical anatomical research, education, and training.
Methods
Cadaveric specimens (
N
= 112) prepared using different preservation and vascular injection methods were imaged, dissected, and graded by 11 neurosurgeons using a 21-point scale. We assessed the quality of tissue and preservation in both the anterior and posterior circulations. Tissue quality was evaluated using a 9-point magnetic resonance imaging (MRI) scale.
Results
Formalin-fixed specimens yielded the highest scores for assessment (mean ± SD 17.0 ± 2.8) vs. formalin-flushed (17.0 ± 3.6) and MRI (6.9 ± 2.0). Cadaver assessment and MRI scores were positively correlated (
P
< 0.001, R
2
0.60). Analysis showed significant associations between cadaver assessment scores and specific variables: nonformalin fixation (β = −3.3), preservation within ≤72 h of death (β = 1.8), and MRI quality score (β = 0.7). Formalin-fixed specimens exhibited greater hardness than formalin-flushed and nonformalin-fixed specimens (
P
≤ 0.006). Neurosurgeons preferred formalin-flushed specimens injected with colored latex.
Conclusion
For better-quality specimens for neurosurgical education and training, formalin preservation within ≤72 h of death was preferable, as was injection with colored latex. Formalin-flushed specimens more closely resembled live brain parenchyma. Assessment scores were lower for preparation techniques performed > 72 h postmortem and for nonformalin preservation solutions. The positive correlation between cadaver assessment scores and our novel MRI score indicates that donation organizations and institutional buyers should incorporate MRI as a screening tool for the selection of high-quality specimens.
In the quest to maximize average propulsive stroke impulses over 2000-m racing, testing and training of various strength parameters have been incorporated into the physical conditioning plans of ...rowers. Thus, the purpose of this review was 2-fold: to identify strength tests that were reliable and valid correlates (predictors) of rowing performance; and, to establish the benefits gained when strength training was integrated into the physical preparation plans of rowers. The reliability of maximal strength and power tests involving leg extension (e.g. leg pressing) and arm pulling (e.g. prone bench pull) was high (intra-class correlations 0.82-0.99), revealing that elite rowers were significantly stronger than their less competitive peers. The greater strength of elite rowers was in part attributed to the correlation between strength and greater lean body mass (r = 0.57-0.63). Dynamic lower body strength tests that determined the maximal external load for a one-repetition maximum (1RM) leg press (kg), isokinetic leg extension peak force (N) or leg press peak power (W) proved to be moderately to strongly associated with 2000-m ergometer times (r = -0.54 to -0.68; p < 0.05). Repetition tests that assess muscular or strength endurance by quantifying the number of repetitions accrued at a fixed percentage of the strength maximum (e.g. 50-70% 1RM leg press) or set absolute load (e.g. 40 kg prone bench pulls) were less reliable and more time consuming when compared with briefer maximal strength tests. Only leg press repetition tests were correlated with 2000-m ergometer times (e.g. r = -0.67; p < 0.05). However, these tests differentiate training experience and muscle morphology, in that those individuals with greater training experience and/or proportions of slow twitch fibres performed more repetitions. Muscle balance ratios derived from strength data (e.g. hamstring-quadriceps ratio <45% or knee extensor-elbow flexor ratio around 4.2 ± 0.22 to 1) appeared useful in the pathological assessment of low back pain or rib injury history associated with rowing. While strength partially explained variances in 2000-m ergometer performance, concurrent endurance training may be counterproductive to strength development over the shorter term (i.e. <12 weeks). Therefore, prioritization of strength training within the sequence of training units should be considered, particularly over the non-competition phase (e.g. 2-6 sets × 4-12 repetitions, three sessions a week). Maximal strength was sustained when infrequent (e.g. one or two sessions a week) but intense (e.g. 73-79% of maximum) strength training units were scheduled; however, it was unclear whether training adaptations should emphasize maximal strength, endurance or power in order to enhance performance during the competition phase. Additionally, specific on-water strength training practices such as towing ropes had not been reported. Further research should examine the on-water benefits associated with various strength training protocols, in the context of the training phase, weight division, experience and level of rower, if limitations to the reliability and precision of performance data (e.g. 2000-m time or rank) can be controlled. In conclusion, while positive ergometer time-trial benefits of clinical and practical significance were reported with strength training, a lack of statistical significance was noted, primarily due to an absence of quality long-term controlled experimental research designs.
In vivo measurement of blood velocity fields and flow descriptors remains challenging due to image artifacts and limited resolution of current imaging methods; however, in vivo imaging data can be ...used to inform and validate patient-specific computational fluid dynamics (CFD) models. Image-based CFD can be particularly useful for planning surgical interventions in complicated cases such as fusiform aneurysms of the basilar artery, where it is crucial to alter pathological hemodynamics while preserving flow to the distal vasculature. In this study, patient-specific CFD modeling was conducted for two basilar aneurysm patients considered for surgical treatment. In addition to velocity fields, transport of contrast agent was simulated for the preoperative and postoperative conditions using two approaches. The transport of a virtual contrast passively following the flow streamlines was simulated to predict post-surgical flow regions prone to thrombus deposition. In addition, the transport of a mixture of blood with an iodine-based contrast agent was modeled to compare and verify the CFD results with X-ray angiograms. The CFD-predicted patterns of contrast flow were qualitatively compared to in vivo X-ray angiograms acquired before and after the intervention. The results suggest that the mixture modeling approach, accounting for the flow rates and properties of the contrast injection, is in better agreement with the X-ray angiography data. The virtual contrast modeling assessed the residence time based on flow patterns unaffected by the injection procedure, which makes the virtual contrast modeling approach better suited for prediction of thrombus deposition, which is not limited to the peri-procedural state.
Sporadic brain arteriovenous malformation (BAVM) is a tangled vascular lesion characterized by direct artery-to-vein connections that can cause life-threatening intracerebral hemorrhage (ICH). ...Recently, somatic mutations in KRAS have been reported in sporadic BAVM, and mutations in other mitogen-activated protein kinase (MAPK) signaling pathway genes have been identified in other vascular malformations. The objectives of this study were to systematically evaluate somatic mutations in MAPK pathway genes in patients with sporadic BAVM lesions and to evaluate the association of somatic mutations with phenotypes of sporadic BAVM severity.
The authors performed whole-exome sequencing on paired lesion and blood DNA samples from 14 patients with sporadic BAVM, and 295 genes in the MAPK signaling pathway were evaluated to identify genes with somatic mutations in multiple patients with BAVM. Digital droplet polymerase chain reaction was used to validate KRAS G12V and G12D mutations and to assay an additional 56 BAVM samples.
The authors identified a total of 24 candidate BAVM-associated somatic variants in 11 MAPK pathway genes. The previously identified KRAS G12V and G12D mutations were the only recurrent mutations. Overall, somatic KRAS G12V was present in 14.5% of BAVM lesions and G12D was present in 31.9%. The authors did not detect a significant association between the presence or allelic burden of KRAS mutation and three BAVM phenotypes: lesion size (maximum diameter), age at diagnosis, and age at ICH.
The authors confirmed the high prevalence of somatic KRAS mutations in sporadic BAVM lesions and identified several candidate somatic variants in other MAPK pathway genes. These somatic variants may contribute to understanding of the etiology of sporadic BAVM and the clinical characteristics of patients with this condition.
•A remote sensing framework maps winter cover crops, provides novel data for 2013–2019.•Efficiently maps winter-time cover and non-cover phenology and length of growing season.•Method using Random ...Forest algorithm achieves a 97.7% mean classification accuracy.•Revealed 34% increase in winter-time cover crop adoption from 2013 to 2019 in MAP delta.•The proposed method can be applied for reproducible crop identification research.
Accurately identifying and systematically mapping winter-time cover crops and their phenological characteristics offer significant benefits to agricultural producers and policymakers, as cover crops are one of several potential solutions to climate change mitigation. We present a methodological framework for identifying and mapping the presence of winter-time cover crops at the field level and aggregated to county scales from 2013 to 2019 by using the Google Earth Engine (GEE), a random forest classifier with time series data from Landsat 8, and yearly cover crop training data from the United States Department of Agriculture (USDA)-Natural Resources Conservation Service (NRCS). The methodology was tested with data from the Mississippi Alluvial Plain (MAP) region. Despite the inter-annual agronomic and climatic variations across space, results demonstrated an overall mean classification accuracy of 97.7%, with a kappa coefficient of 0.94. Results also revealed a 34% increase in model-predicted cover crop adoption in the study region from 2013 to 2019. Based on GEE, this study created, for the first time, a 30-m spatial and temporal resolution binary annual datasets and then aggregated them at the county level within the MAP study region. This multi-year novel dataset may improve our ability to anticipate and quantify the impact of summer crop production gains owing to cover crop adoption for extended periods and evaluate the adoption of cover crops on local soil ecosystems, biogeochemical cycles, and services. The methodology developed and tested broadly applies to other regions where cover crops have been promoted for climate-change mitigation and improving soil health for long-term sustainability. Agricultural producers, policymakers, and cost-share providers may use this information to develop agricultural conservation methods and land-use policies that minimize soil erosion and help mitigate climate change effects in the long run.
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