1,721,000 research outputs found
The Decision-Making Process in Traumatic Lesions of the Craniovertebral Junction: An Evidence-Based Approach? Part II.
No full textThis paper is Part II of a two-part report. Part I of the report covered atlanto-occipital dislocation or dissociation, and isolated condylar fractures. This part of the report covers isolated and combination fractures of the atlas and axis
Schwalbe's Triangular Fossa: Normal and Pathologic Anatomy on Frozen Cadavers. Anatomo-Magnetic Resonance Imaging Comparison and Surgical Implications in Colloid Cyst Surgery
No full textBackground: The fornix is a region of greatest neurosurgical interest in regards to its complex anatomy and surgical approaches to this area. The objective of this study was to evaluate the morphology of the triangular recess (TR) and its role in the growth pattern of the colloid cysts (CC) within the third ventricle and in the choice of the surgical approach for their removal. Furthermore, to compare the results of the dissections with measurements performed on a magnetic resonance imaging scan. Methods: In the anatomic study, 20 cadaveric specimens were dissected and analyzed. In the radiologic study, a magnetic resonance imaging scan was performed in 20 healthy volunteers. In the clinical study, a retrospective analysis of all the patients affected with CCs microsurgically removed at our institute between 2010 and 2018 was conducted. Results: In the anatomic study, the width, height, and the area of the TR were respectively 0.31 cm, 0.33cm, and 0.051 cm2. In the radiologic study, 3 different typologies of TR were identified: open recess in ventriculomegaly (7 patients); open recess in physiologic ventricular system (3 patients); closed or blind recess (10 patients). Three different growth patterns of CCs were identified: type 1) CCs localized at the foramen of Monro growing behind the fornix and below the third ventricular roof; type 2) CCs growing rostrally between the column of fornix; and type 3) CCs growing above the plane of the third ventricular roof. Conclusions: The anatomy of the TR influences the growth pattern of CC within the ventricular cavity and determines the surgical strategy for their removal
Complex aneurysm: The unpredictable pathological entity
No full textBackground. Surgical treatment of complex aneurysms often requires the execution of a revascularization procedure. Even if avoiding the concomitant trapping of the aneurysm during the bypass procedure (waiting for the subsequent endovascular or spontaneous closure) permits one to verify the graft’s patency and patient’s adaptation to increased flow, the hemodynamic changes induced by the bypass may cause the aneurysmal rupture. Whether or not to perform the concomitant trapping of the aneurysm still remains a dilemma. Here we illustrate our management protocol through the critical analysis of some illustrative cases of our series. Materials and methods. Between 1990 and 2016, 48 of 157 patients affected by complex aneurysms underwent a revascularization procedure. In 19 cases (1990–1997) only a bypass procedure was performed. Spontaneous or endovascular closure was obtained within the first postoperative week once the graft patency had been verified (staged revascularization strategy). In the remaining 29 cases. The total amount of cases is 48. 19 cases staged revascularization strategy. 29 cases single stage revascularization strategy. Results. In the staged revascularization era, one patient died because of the rupture of the aneurysm before its closure. In the single-stage era no further cases of rebleeding were observed. Neurologic status of this group was unvaried or improved. Conclusions. Given the unpredictable response of complex aneurysms to the hemodynamic changes induced by the revascularization, in our opinion it is always preferable to perform complete or at least incomplete trapping of the aneurysm during the bypass procedure
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
Cervical Spondylotic Myelopathy: When and Why the Cervical Corpectomy?
No full textBackground: Cervical spondylotic myelopathy (CSM) is a degenerative disease that represents the most common spinal cord disorder in adults. The best treatment option has remained controversial. We performed a prospective study to evaluate the clinical, radiographic, and neurophysiologic outcomes for anterior cervical corpectomy in the treatment of CSM. Methods: From January 2011 to January 2017, 60 patients with CSM were prospectively enrolled in the present study. The patients were divided according to the modified Japanese Orthopaedic Association scale (mJOA) score into 2 groups: group A, patients with mild to moderate CSM (mJOA score ≥13); and group B, patients with severe myelopathy (mJOA score <13). Data were collected for each participating subject, including demographic information, symptoms, medical history, radiologic and neurophysiologic features, and functional impairment. Results: Of the 60 patients, 35 were men (58.3%) and 25 were women (41.7%). Their average age was 57.48 ± 10.60 years. The mean symptom duration was 25.33 ± 16.00 months; range, 3–57 months). Of the 60 patients, 22 had undergone single-level corpectomy and 36 multilevel corpectomy. A significant improvement in the motor evoked potentials was observed in both groups. Conclusions: Single- and multilevel corpectomy are valid and safe options in the treatment of CSM. In the present prospective study, a statistically significant improvement in the mJOA score and neurophysiologic parameters was observed for both moderate and severe forms of CSM
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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