1,721,003 research outputs found
How SARS-CoV-2 is forcing us to reconsider and reorganize our daily neurosurgical practice
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Aggressive primary scalp lymphoma mimicking an acute epidural hematoma: Case report and review of the literature
No full textBackground: Cutaneous Central Follicular Lymphoma (CCFL) is a type B cutaneous lymphoma with a usually indolent course. Scalp localization of CCFL is extremely rare, we report a new case mimicking an epidural hematoma, and showing a rapid progression with aggressive infiltration of skin, calvaria, dura and brain parenchyma. Case report: A 58-year-old patient with an unlabeled polymalformative syndrome was admitted to the Emergency department following a head injury secondary to a self-resolving tonic-clonic epileptic seizure. The initial CT-scan was interpreted as a minor subcutaneous and epidural hematoma initially deemed for conservative management. Within 4 days, the patient showed a progressive neurological deterioration culminating into a stuporous status which prompted a constrast-enhanced brain MRI. The scan revealed a multilayered solid lesion, extending from the subgaleal compartment to the subdural space, threatening the integrity of overlying skin and causing infiltration of the brain parenchyma. Following emergency neurosurgical excision a definitive histology diagnosis of central follicular lymphoma was made. A focused chemotherapy with high-dose Methotrexate with R-CHOP protocol led to disease control until the latest follow up at 2 years. Conclusion: To our knowledge, this case represents the first CCFL invading the brain parenchyma and the second extending to the dura. Although such tumor is usually indolent the aggressive behavior herein reported extend the differential diagnosis to high-grade meningiomas, sarcomas, and metastases. Prognostication and appropriate adjuvant treatment require prompt surgical excision and histological confirmation
Petrous internal carotid artery aneurysm: A cause of chronic otitis
Full text linkBackground: Aneurysm of the petrous segment of the internal carotid artery (pICA) is a rare pathology presenting with extracranial and especially oto-rhinological symptoms that can be misleading and delay diagnosis. Methods: We report the case of a giant pICA aneurysm compressing the Eustachian tube (ET), presenting with hearing loss due to chronic serous otitis. A PRISMA review of the literature was performed to find similar cases. In addition, relevant anatomical sources were screened. Results: Five reports about 7 cases of middle-ear effusion caused by pICA aneurysm compressing the ET were identified. Median age at diagnosis was 18.5 years. After endovascular treatment, overall outcome was favorable, with no mortality, although outcome was sometimes impaired by neurological comorbidities and unclear prognosis of hearing-loss recovery. Discussion: These reports, though rare, offer relevant insights into the poorly known regional anatomy of the pICA, in the borderland between neurosurgery and ENT. Within the petrous bone, the osseous separation between the ET and the pICA is narrow, when not dehiscent. This leads to a risk of any pathological process in either the pICA or the ET impinging on the other. Conclusion: Giant pICA aneurysm is a rare cause of hearing loss, due to compression of the ET, leading to chronic serous otitis. This co-dependency between pICA and ET should be kept in mind, as it underlines the necessity of multidisciplinary management and could facilitate earlier diagnosis and therapeutic management when facing atypical clinical situations
Letter: Risks for Oculomotor Nerve Palsy and Time to Recovery After Surgical Clipping of Posterior Communicating Artery Aneurysms: A Multicenter Retrospective Cohort Study
No full textIn response to Syrmos et al. letter: Proposal of a decisional algorithm for abdominal pseudocysts in patients with ventriculoperitoneal shunt
No full textIs physical activity a trigger factor for subarachnoid hemorrhage?
Full text linkIntroduction: Subarachnoid hemorrhage (SAH) is a serious pathology, associated with 43% mortality and significant disability. In the absence of relevant guidelines, some teams advocate that patients harboring an unruptured intracranial aneurysm (ICA) abstain from all sports activity, as a prophylactic precaution. The aim of the present study was to evaluate the impact of physical activity as a risk factor for SAH, through a review of the literature. Method: A systematic literature review was performed for the period 2000 to 2020 in accordance with the PRISMA guidelines. Prospective and retrospective articles reporting more than 50 patients whose physical activity was associated with onset of SAH were included. The main end-point was prevalence of SAH occurring after physical activity. For comparison purposes, the prevalences of other circumstances were calculated to establish a range of frequency. Results: Physical activity appeared to be quite rarely associated with onset of SAH, with a prevalence of 3%, compared to 30% at rest, 7.3% in association with defecation and 4.5% in association with sexual activity. Age under 60 years, male gender (M/F ratio 1.38) and smoking (67.1%) were associated with onset of SAH during physical activity. Conclusion: Physical activity appears to be a rare trigger factor for SAH. These results are in contrast to the idea that physical activity should, as a precaution, be avoided in patients with unruptured ICA. There is at present no scientific evidence of an association with aneurysmal SAH.Introduction. – L’hémorragie sous-arachnoïdienne (HSA) est une maladie grave responsable de 43 % de
mortalité et d’un handicap important. Devant l’absence de recommandation, le principe de précaution a conduit certains soignants à déconseiller la pratique sportive chez les patients présentant un
anévrisme intracrânien. L’objectif de ce travail était d’évaluer la responsabilité de l’activité physique
comme circonstance de la survenue d’une HSA en se basant sur une revue de la littérature.
Méthode. – Une revue systématique de la littérature selon les critères PRISMA a été réalisée de 2000 à
2020. Des articles prospectifs ou rétrospectifs de plus de 50 patients dont l’activité physique était une
circonstance d’hémorragie sous-arachnoïdienne ont été inclus. Le critère de jugement principal était la
prévalence de l’HSA survenant après une activité physique. À des fins de comparaison, les prévalences
des autres circonstances ont été calculées pour établir un rang de fréquence.
Résultats. – L’activité physique semble être une circonstance rare dans la survenue de l’HSA avec une
prévalence de 3 % par rapport au repos (30 %), à la défécation (7,3 %) ou aux rapports sexuels (4,5 %). Les
patients de moins de 60 ans (67 %), les hommes (ratio H/F de 1,38) et les fumeurs (67,1 %) semblaient
plus susceptibles d’être victimes d’une HSA lors de la pratique d’une activité physique.
Conclusion. – L’activité physique semble être une circonstance rare d’HSA. Ces résultats vont à l’encontre
du principe de précaution chez les patients atteints d’un anévrisme intracrânien non rompu, car il n’existe
actuellement aucune preuve scientifique d’association de l’activité physique avec l’HSA anévrismale.
© 2021 Elsevier Masson SAS. Tous droits reserves
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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