1,720,970 research outputs found
Petrous bone cholesteatoma: classification, management and review of the literature.
No full textOBJECTIVE:
To discuss the classification of petrous bone cholesteatoma (PBC) and add a subclassification; to review the existing literature and to propose the ideal surgical management of PBC based upon the experience of the largest series published in the literature until now.
STUDY DESIGN:
Retrospective analysis.
SETTING:
Quaternary referral neuro-otologic private practice.
MATERIALS AND METHODS:
The data of 129 patients who underwent surgery for PBC between 1979 and 2008 were analyzed with respect to the classification, type of the approach used, facial nerve lesion and its management, recurrences and outcome.
RESULTS:
Out of the 129 PBC cases 64 were supralabyrinthine, 9 infralabyrinthine, 7 infralabyrinthine-apical, 48 massive and 1 apical. The facial nerve was involved in 95% of the cases. Hearing could not be preserved in 82% of the cases due to the extent of the lesions and the surgical approaches used. The internal carotid artery, jugular bulb and the lower cranial nerves were infrequently involved, but demanded careful identification and meticulous care to avoid complications. Obliteration of the cavities provided a safe solution for protection of the exposed dura and the vital neurovascular structures. Recurrences were observed in 5 cases.
CONCLUSION:
The classification of PBC is fundamental to choose the appropriate surgical approach; the facial nerve is involved in almost all the cases, radical removal takes priority over hearing preservation and cavity obliteration is important to protect the vital neurovascular structures which may be exposed
Management of complex cases of petrous bone cholesteatoma.
No full textOBJECTIVES:
In a retrospective analysis of a quaternary referral neuro-otologic private practice, we identify complex cases of petrous bone cholesteatoma (i.e., cases with encasement of vital structures such as the internal carotid artery, jugular bulb, and sigmoid sinus, with further extension to the clivus, sphenoid sinus, or rhinopharynx), review surgical approaches and techniques of management of vital structures, and propose the ideal surgical management.
METHODS:
We performed a retrospective case study of 130 cases of petrous bone cholesteatoma submitted to surgery between 1979 and 2009 to identify the complex cases and their classification, approach used, outcomes, and recurrences.
RESULTS:
Of 130 cases. 13 were complex. Facial palsy was the presenting feature in 11 cases, 7 of which presented with grade VI palsy. A long duration of facial palsy (more than 3 years) was seen in 5 cases. Clival involvement was seen in 6 cases; 1 case extended to the sphenoid sinus, and 1 to the rhinopharynx. The internal carotid artery was encased in 11 cases in the vertical and the horizontal parts. The jugular bulb was involved in 7 cases. Modified transcochlear approaches or infratemporal fossa approaches were used in all cases. There were no recurrences.
CONCLUSIONS:
Classification is fundamental to choosing the right surgical approach. Transotic and modified transcochlear approaches hold the key to treating complex cases. Infratemporal fossa approach type B has to be used for extension into the clivus, sphenoid sinus, or rhinopharynx. Internal carotid artery, jugular bulb, and sigmoid sinus involvement should be identified before operation
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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