1,720,959 research outputs found
Management of post blood patch severe rebound intracranial hypertension by the usage of an external ventricular drain
No full textSpontaneous intracranial hypotension (SIH) is a condition characterised by postural headaches due to low cerebrospinal fluid (CSF) pressure, often stemming from CSF leakage. Diagnosis poses a significant challenge, and the therapeutic approach encompasses both conservative measures and operative interventions, such as the epidural blood patch (EBP). However, EBP carries the potential risk of inducing rebound intracranial hypertension (RIH), subsequently leading to high-pressure headaches. We present a case wherein RIH following EBP was effectively managed through the implementation of an external ventricular drain (EVD) aimed at reducing CSF pressure. The patient improved significantly, underscoring the potential utility, if not necessity, of EVD in carefully selected cases, highlighting the imperative for further research to enhance the management of SIH and optimise EBP-related complications
A novel method of neurophysiological brainstem mapping in neurosurgery
Full text linkBackground: Brainstem mapping with electrical stimulation allows functional identification of neural structures during resection of deep lesions. Single pulses or train of pulses are delivered to map cranial nerves and corticospinal tracts, respectively. New method: We introduce a hybrid stimulation technique for mapping the brainstem. The stimulus consists of an electrical single pulse followed by a short train of 3-5 pulses at 500 Hz, at an interval of 60-75 ms. The responses to this stimulation pattern are recorded from appropriate cranial and limb muscles. Results: Both the single pulse and the short train elicit electromyographic responses when motor fibers or motor nuclei of the cranial nerves are stimulated. Responses to the train but not to the preceding single pulse indicate activation of the descending motor tracts, in the mesencephalon and the pons. Conversely, in the medulla, limb responses to stimulation of the corticospinal tracts are elicited by a single pulse. Identification of the extra and intra-axial courses of the trigeminal motor and sensory fibers is possible by recording responses from the masseter and the tongue muscles. Comparison with existing method(s): To date, either a pulse or a train is delivered during brainstem mapping, switching from one to the other modality according to the expected target structure. This procedure can be timeconsuming and may even lead to false negative responses to the stimulation, eventually leading to inaccurate neurosurgical procedures. Conclusions: The novel hybrid pulse-train technique enhances the advantage of brainstem mapping procedure, minimizing pitfalls and improving patient safety
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
Surgical treatment of complex craniofacial fractures
No full textOBJECTIVE: Severe craniofacial fractures may present different needs in treating intracranial lesions over facial injuries. This paper examines the results of our strategy, consisting of a single -stage combined neurosurgicalmaxillofacial treatment. - METHODS: A retrospective review was conducted of 33 consecutive patients with complex fractures of the anterior cranial fossa and facial skeleton, who required elective surgery for craniofacial reconstruction. Patients who required emergency surgery for intracranial clots or penetrating wounds were excluded. In all cases, all or almost all the anterior skull -base was injured with compound fractures of the frontal sinus, the orbital roofs, the lamina cribrosa, and the planum sphenoidale. In all cases, the prioritization of treatment was carefully discussed, and surgical timing and strategy were agreed. - RESULTS: There was 1 dead. Olfactory injuries were always found intraoperatively. There were no mucoceles, CSF-leak recurrences, cranial infections, or neurologic worsening. The functional and neurologic results were highly satisfactory. - CONCLUSIONS: The one -stage surgical treatment of complex craniofacial fractures has numerous advantages, including the possibility of reducing facial fractures without the risk of CSF leaks. It also eliminates the need for repeated procedures in fragile patients, and the need to dismantle the facial reconstruction if the skull base repair is performed later. The main issue is the surgical timing, considering that the maxillofacial surgeon usually favors early facial repair, whereas the neurosurgeon generally prefers delayed manipulation of the contused frontal lobes. A timeframe of 10 e14 days after trauma may be a good compromise for safe procedures with excellent neurologic and functional outcomes
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
The impact of pelvic balance, physical activity, and fear-avoidance on the outcome after decompression and instrumented fusion for degenerative lumbar stenosis
No full textPurpose: To evaluate the impact of pelvic balance, physical activity, and fear-avoidance in a cohort of patients undergoing decompression and instrumented fusion for degenerative lumbar stenosis. Materials and methods: This study includes consecutive patients undergoing decompression and instrumented fusion for degenerative lumbar stenosis by one main surgeon from January 2014 to January 2015. Patients were interviewed by a psychologist and underwent standing whole spine X-ray. Lumbar and pelvic parameters (PI, SS, PT, iPT, LL) were measured by an independent spinal surgeon. Physical activity was measured with the International Physical Activity Questionnaire (IPAQ). The “fear-avoidance” was measured with the Tampa Scale for Kinesiophobia (TSK). Back pain was assessed by the Graphic Rating Scale (GRS). The disability was assessed by the Roland–Morris Low Back Pain and Disability Questionnaire. Statistical interpretation of the data was performed using SPSS v19 software (SPSS Inc, Chicago, Illinois). Results: The sample included 51 patients underwent standard posterior laminectomy and instrumented fusion. Surgery has a positive global impact on the perceived low back pain. No significant (Spearman) correlations emerged among pelvic parameters and the pre- and post-surgical GSR. Patients were divided into three groups according to the IPAQ scores after the operation: “inactive” (I), “minimally inactive” (m-I), and “HEPA”. Significant differences emerged between IPAQ and Roland–Morris scores (F(2, 48) = 5.48, p = 0.007): the “inactive” (M(R-M) = 11.3) or “minimally active” (M(R-M) = 9.8) groups scored significantly higher than the “HEPA” group (M(R-M) = 4.7). Tampa scores correlated with gender (rho = −0.408, p = 0.003) and with BMI (rho = −0.369, p = 0.008). Females and obese patients reported higher levels of Tampa scores. Significant relationship was found between Tampa scores and pre-GSR (rho(pre) = 0.250, p = 0.08) and significant with post-surgical GSR (rho(post) = 0.275, p = 0.05) and with post-Roland–Morris score (rho(post) = 0.599, p < 0.01). Conclusion: The fear-avoidance and the physical inactivity are related to the highest levels of low back pain, more than pelvic imbalance. “Inactive” and “fear-avoidant” patients have also the worst outcome after surgery and the worst level of disability
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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