1,720,957 research outputs found
Large multicystic spinal lesion in a young African migrant: a problem of differential diagnosis
No full textWe describe a rare case of large, fully cystic spinal schwannoma in a young adult from The Gambia. The initial clinical suspicion was spinal cystic echinococcosis. He came to our attention reporting progressive walking impairment and neurological symptoms in the lower limbs. An expansive lesion extending from L2 to S1 was shown by imaging (ie, CT scan and MRI). Differential diagnoses included aneurysmal bone cyst and spinal tuberculosis and abscess; the initial suggested diagnosis of spinal cystic echinococcosis was discarded based on contrast enhancement results. The final diagnosis of cystic schwannoma was obtained by histopathology of the excised mass. Cystic spinal lesions are rare and their differential diagnosis is challenging. Awareness of autochthonous and tropical infectious diseases is important, especially in countries experiencing consistent migration flow; however, it must be kept in mind that migrants may also present with 'non-tropical' pathologies
The use of Grauer classification in the management of type II odontoid fracture in elderly: prognostic factors and outcome analysis in a single centre patient series
No full textObjective: To evaluate the results of Type II odontoid fractures management in the elderly, according to the Grauer classification. Methods: Consecutive patients with type II odontoid fracture, age > 65 years and follow-up longer than 3 months were included. Fracture management was proposed according to Grauer classification. Peri-surgical risk factors, NDI, VAS and rate of fusion were evaluated according to the treatment modality and compared between conservative and surgical groups. Results: Thirty-four patients were considered eligible for the study; 2 patients showed a Type IIa fracture, 30 patients a type IIb, and 2 patients a type IIc. Type IIa patients underwent conservative treatment that resulted in failure. A conservative management was adopted in 9 cases with type IIb due to patient preference or anaesthesiologic reasons with a treatment success at 6 months of 11%. Trans-odontoid stabilization was adopted in 21 type IIb cases with an evidence of bony or fibrous union at 6 months of 95% and a median NDI of 20%. A posterior approach was reserved for 2 type IIc fracture patients and in 6 cases as rescue surgery (bony union at 6 months of 100%; median NDI 37%). Higher Lakshmanan grade, gap and displacement of the fracture were found as significant risk factor for fracture non-union (p < 0.05). Conclusions: The surgical group presented better clinical and radiological outcome and the anterior approach proved to achieve the best results in type IIb fractures. The presence of osteoporosis and fracture spatial features should be duly considered in the decision-making process
Spinal hemangioblastomas: analysis of surgical outcome and prognostic factors
No full textThe prognostic factors for surgically removed spinal hemangioblastomas, the impact of VHL disease on outcome, and the role of intraoperative neuromonitoring are still not completely clear. The aim of this study was to review our experience with spinal hemangioblastomas in order to assess potential predictors of neurological outcome after surgery. All cases of spinal hemangioblastomas removed at two Italian academic institutions from 1985 to 2020 were reviewed. Data about clinical presentation and symptom duration, diagnosis of VHL, surgical approach, use of IONM, duration of hospital stay, follow-up, and modified McCormick grade before and after surgery were extracted. Sixty-one patients (31 F, 30 M) underwent 69 surgeries to remove 74 spinal hemangioblastomas (37 cervical, 32 thoracic, 5 lumbar). Improvement was found in 32.3% of cases, neurological condition remained stable in 51.6% of cases, and deteriorated in 16.1% of patients. A worsening trend in VHL patients and an improvement trend in non-VHL patients were detected, despite the lack of statistical significance. Laminotomy and use of IONM were found to be associated with better outcome, although no association was found between surgery without IONM and worse outcome. In most cases, patients affected by spinal hemangioblastomas can expect a good long-term outcome. In our experience, laminotomy seems to be associated with better outcome compared to laminectomy. While its absence is not associated with worse outcome, IONM seems to be associated with a better neurological outcome. Our study suggests that the more impaired the preoperative neurological condition, the worse the outcome
Utility of preoperative electrodiagnosis together with peripheral nerve high-resolution ultrasound: a complex case report of Neurofibromatosis type I
No full textOur case report underscores the importance of electroneuromyography (ENMG) combined with peripheral nerve high-resolution ultrasound (HRUS) in the evaluation of neurofibromatosis type 1 (NF1). A 49-year-old woman affected by NF1 came to our attention because of new-onset left arm weakness and atrophy. Debulking of a cervicothoracic C7-T1 neurofibroma had been performed 8 years earlier. On current admission, magnetic resonance imaging disclosed increased lesion volume that was thought to cause the neurologic deficits by compressing the C8 root. Findings from intraoperative neurophysiologic monitoring during repeat debulking suggested that C8 root integrity had been compromised during the first operation and that the new-onset symptoms probably stemmed from peripheral nervous system damage distal to the cervical roots. Postoperative ENMG showed chronic denervation signs in the muscles innervated by C7-C8-T1 roots, moderate carpal tunnel syndrome (CTS), and ulnar nerve conduction block at the elbow. HRUS confirmed the CTS and revealed multiple neurofibromas involving the distal tract of the radial, ulnar, and median nerves. Surgical debulking was considered unnecessary in this case. ENMG combined with nerve and plexus HRUS evaluation may help identify the cause of neurologic deficits and choose the best surgical option in such complex clinical conditions as NF1
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
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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