1,087 research outputs found

    A cervical ligamentum flavum cyst in an 82-year-old woman presenting with spinal cord compression: a case report and review of the literature

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    <p>Abstract</p> <p>Introduction</p> <p>We report on a very rare case of a cervical ligamentum flavum cyst, which presented with progressive myelopathy and radiculopathy. The cyst was radically extirpated and our patient showed significant recovery. A review of the relevant literature yielded seven cases.</p> <p>Case presentation</p> <p>An 82-year-old Greek woman presented with progressive bilateral weakness of her upper extremities and causalgia, cervical pain, episodes of upper extremity numbness and significant walking difficulties. Her neurological examination showed diffusely decreased motor strength in both her upper and lower extremities. Magnetic resonance imaging of her cervical spine demonstrated a large, well-demarcated cystic lesion on the dorsal aspect of her spinal cord at the C3 to C4 level, significantly compressing the spinal cord at this level, in close proximity to the yellow ligament and the C3 left lamina. The largest diameter of this lesion was 1.4 cm, and there was no lesion enhancement after the intravenous administration of a paramagnetic contrast. The lesion was surgically removed after a bilateral C3 laminectomy. The thick cystic wall was yellow and fibro-elastic in consistency, while its content was gelatinous and yellow-brownish. A postoperative cervical-spine magnetic resonance image was obtained before her discharge, demonstrating decompression of her spinal cord and dural expansion. Her six-month follow-up evaluation revealed complete resolution of her walking difficulties, improvement in the muscle strength of her arms (4+/5 in all the affected muscle groups), no causalgia and a significant decrease in her preoperative upper extremity numbness.</p> <p>Conclusion</p> <p>Cervical ligamentum flavum cysts are rare benign lesions, which should be included in the list of differential diagnosis of spinal cystic lesions. They can be differentiated from other intracanalicular lesions by their hypointense appearance on T<sub>1</sub>-weighted and hyperintense appearance on T<sub>2</sub>-weighted magnetic resonance images, with contrast enhancement of the cystic wall. Surgical extirpation of the cyst is required for symptom alleviation and decompression of the spinal cord. The outcome of these cysts is excellent with no risk of recurrence.</p

    Consensus-based recommendations for diagnosis and surgical management of cranioplasty and post-traumatic hydrocephalus from a European panel

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    Introduction: Planning cranioplasty (CPL) in patients with suspected or proven post-traumatic hydrocephalus (PTH) poses a significant management challenge due to a lack of clear guidance. Research question: This project aims to create a European document to improve adherence and adapt to local protocols based on available resources and national health systems. Methods: After a thorough non-systematic review, a steering committee (SC) formed a European expert panel (EP) for a two-round questionnaire using the Delphi method. The questionnaire employed a 9-point Likert scale to assess the appropriateness of statements inherent to two sections: “Diagnostic criteria for PTH” and “Surgical strategies for PTH and cranial reconstruction.” Results: The panel reached a consensus on 29 statements. In the “Diagnostic criteria for PTH” section, five statements were deemed “appropriate” (consensus 74.2−90.3 %), two were labeled “inappropriate,” and seven were marked as “uncertain.” In the “Surgical strategies for PTH and cranial reconstruction” section, four statements were considered “appropriate” (consensus 74.2−90.4 %), six were “inappropriate,” and five were “uncertain.” Discussion and conclusion: Planning a cranioplasty alongside hydrocephalus remains a significant challenge in neurosurgery. Our consensus conference suggests that, in patients with cranial decompression and suspected hydrocephalus, the most suitable diagnostic approach involves a combination of evolving clinical conditions and neuroradiological imaging. The recommended management sequence prioritizes cranial reconstruction, with the option of a ventriculoperitoneal shunt when needed, preferably with a programmable valve. We strongly recommend to adopt local protocols based on expert consensus, such as this, to guide patient care

    Performance of the ATLAS forward proton Time-of-Flight detector in Run 2

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    We present performance studies of the Time-of-Flight (ToF) subdetector of the ATLAS Forward Proton (AFP) detector at the LHC. Efficiencies and resolutions are measured using high-statistics data samples collected at low and moderate pile-up in 2017, the first year when the detectors were installed on both sides of the interaction region. While low efficiencies are observed, of the order of a few percent, the resolutions of the two ToF detectors measured individually are 21 ps and 28 ps, yielding an expected resolution of the longitudinal position of the interaction, z vtx, in the central ATLAS detector of 5.3 ± 0.6 mm. This is in agreement with the observed width of the distribution of the difference between z vtx, measured independently by the central ATLAS tracker and by the ToF detector, of 6.0 ± 2.0 mm

    Measurement of substructure-dependent jet suppression in Pb+Pb collisions at 5.02 TeV with the ATLAS detector

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    The ATLAS detector at the Large Hadron Collider has been used to measure jet substructure modification and suppression in Pb+Pb collisions at a nucleon–nucleon center-of-mass energy √sNN = 5.02 TeV in comparison with proton–proton (pp) collisions at √s = 5.02 TeV. The Pb+Pb data, collected in 2018, have an integrated luminosity of 1.72 nb−1, while the ppdata, collected in 2017, have an integrated luminosity of 260 pb−1. Jets used in this analysis are clustered using the anti-kt algorithm with a radius parameter R = 0.4. The jet constituents, defined by both tracking and calorimeter information, are used to determine the angular scale rg of the first hard splitting inside the jet by reclustering them using the Cambridge–Aachen algorithm and employing the soft-drop grooming technique. The nuclear modification factor, RAA, used to characterize jet suppression in Pb+Pb collisions, is presented differentially in rg, jet transverse momentum, and in intervals of collision centrality. The RAA value is observed to depend significantly on jet rg. Jets produced with the largest measured rg are found to be twice as suppressed as those with the smallest rg in central Pb+Pb collisions. The RAA values do not exhibit a strong variation with jet pT in any of the rg intervals. The rg and pT dependence of jet RAA is qualitatively consistent with a picture of jet quenching arising from coherence and provides the most direct evidence in support of this approach

    Cavernous Malformations of the Central Nervous System: An International Consensus Statement

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    Introduction: Cavernous malformations (CM) of the central nervous system constitute rare vascular lesions. They are usually asymptomatic, which has allowed their management to become quite debatable. Even when they become symptomatic their optimal mode and timing of treatment remains controversial. Research question: A consensus may navigate neurosurgeons through the decision-making process of selecting the optimal treatment for asymptomatic and symptomatic CMs. Material and methods: A 17-item questionnaire was developed to address controversial issues in relation to aspects of the treatment, surgical planning, optimal surgical strategy for specific age groups, the role of stereotactic radiosurgery, as well as a follow-up pattern. Consequently, a three-stage Delphi process was ran through 19 invited experts with the goal of reaching a consensus. The agreement rate for reaching a consensus was set at 70%. Results: A consensus for surgical intervention was reached on the importance of the patient’s age, symptomatology, and hemorrhagic recurrence; and the CM’s location and size. The employment of advanced MRI techniques is considered of value for surgical planning. Observation for asymptomatic eloquent or deep-seated CMs represents the commonest practice among our panel. Surgical resection is considered when a deep-seated CM becomes symptomatic or after a second bleeding episode. Asymptomatic, image-proven hemorrhages constituted no indication for surgical resection for our panelists. Consensus was also reached on not resecting any developmental venous anomalies, and on resecting the associated hemosiderin rim only in epilepsy cases. Discussion and conclusion: Our Delphi consensus provides an expert common practice for specific controversial issues of CM patient management

    Anomaly detection search for new resonances decaying into a Higgs boson and a generic new particle X in hadronic final states using Formula Presented pp collisions with the ATLAS detector

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    A search is presented for a heavy resonance Formula Presented decaying into a Standard Model Higgs boson Formula Presented and a new particle Formula Presented in a fully hadronic final state. The full Large Hadron Collider run 2 dataset of proton-proton collisions at Formula Presented collected by the ATLAS detector from 2015 to 2018 is used and corresponds to an integrated luminosity of Formula Presented. The search targets the high Formula Presented-mass region, where the Formula Presented and Formula Presented have a significant Lorentz boost in the laboratory frame. A novel application of anomaly detection is used to define a general signal region, where events are selected solely because of their incompatibility with a learned background-only model. It is constructed using a jet-level tagger for signal-model-independent selection of the boosted Formula Presented particle, representing the first application of fully unsupervised machine learning to an ATLAS analysis. Two additional signal regions are implemented to target a benchmark Formula Presented decay into two quarks, covering topologies where the Formula Presented is reconstructed as either a single large-radius jet or two small-radius jets. The analysis selects Higgs boson decays into Formula Presented, and a dedicated neural-network-based tagger provides sensitivity to the boosted heavy-flavor topology. No significant excess of data over the expected background is observed, and the results are presented as upper limits on the production cross section Formula Presented) for signals with Formula Presented between 1.5 and 6 TeV and Formula Presented between 65 and 3000 GeV. A search is presented for a heavy resonance Y decaying into a Standard Model Higgs boson H and a new particle X in a fully hadronic final state. The full Large Hadron Collider run 2 dataset of proton-proton collisions at √ s = 13     TeV collected by the ATLAS detector from 2015 to 2018 is used and corresponds to an integrated luminosity of 139     fb − 1 . The search targets the high Y -mass region, where the H and X have a significant Lorentz boost in the laboratory frame. A novel application of anomaly detection is used to define a general signal region, where events are selected solely because of their incompatibility with a learned background-only model. It is constructed using a jet-level tagger for signal-model-independent selection of the boosted X particle, representing the first application of fully unsupervised machine learning to an ATLAS analysis. Two additional signal regions are implemented to target a benchmark X decay into two quarks, covering topologies where the X is reconstructed as either a single large-radius jet or two small-radius jets. The analysis selects Higgs boson decays into b ¯ b , and a dedicated neural-network-based tagger provides sensitivity to the boosted heavy-flavor topology. No significant excess of data over the expected background is observed, and the results are presented as upper limits on the production cross section σ ( p p → Y → X H → q ¯ q b ¯ b ) for signals with m Y between 1.5 and 6 TeV and m X between 65 and 3000 GeV

    Expertise in surgical neuro-oncology. Results of a survey by the EANS neuro-oncology section

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    Introduction: Technical advances and the increasing role of interdisciplinary decision-making may warrant formal definitions of expertise in surgical neuro-oncology. Research question: The EANS Neuro-oncology Section felt that a survey detailing the European neurosurgical perspective on the concept of expertise in surgical neuro-oncology might be helpful. Material and methods: The EANS Neuro-oncology Section panel developed an online survey asking questions regarding criteria for expertise in neuro-oncological surgery and sent it to all individual EANS members. Results: Our questionnaire was completed by 251 respondents (consultants: 80.1%) from 42 countries. 67.7% would accept a lifetime caseload of &gt;200 cases and 86.7% an annual caseload of &gt;50 as evidence of neuro-oncological surgical expertise. A majority felt that surgeons who do not treat children (56.2%), do not have experience with spinal fusion (78.1%) or peripheral nerve tumors (71.7%) may still be considered experts. Majorities believed that expertise requires the use of skull-base approaches (85.8%), intraoperative monitoring (83.4%), awake craniotomies (77.3%), and neuro-endoscopy (75.5%) as well as continuing education of at least 1/year (100.0%), a research background (80.0%) and teaching activities (78.7%), and formal interdisciplinary collaborations (e.g., tumor board: 93.0%). Academic vs. non-academic affiliation, career position, years of neurosurgical experience, country of practice, and primary clinical interest had a minor influence on the respondents’ opinions. Discussion and conclusion: Opinions among neurosurgeons regarding the characteristics and features of expertise in neuro-oncology vary surprisingly little. Large majorities favoring certain thresholds and qualitative criteria suggest a consensus definition might be possible

    Measurement of vector boson production cross sections and their ratios using pp collisions at s=13.6 TeV with the ATLAS detector

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