1,720,971 research outputs found
Detailed anatomy knowledge: first step to approach petroclival meningiomas through the petrous apex. Anatomy lab experience and surgical series
No full textPetroclival meningiomas are a challenge for neurosurgeons due to the complex anatomy of the region that is rich of vessels and nerves. A perfect and detailed knowledge of the anatomy is very demanding in neurosurgery, especially in skull base surgery. The authors describe the microsurgical anatomy to perform an anterior petrosectomy based on their anatomical and surgical experience and perform a literature review. The temporal bone is the most complex and fascinating bone of skull base. The apex is located in the angle between the greater wing of the sphenoid and the occipital bone. Removing the petrous apex exposes the clivus. The approach directed through the temporal bone in this anatomical area is referred to as an anterior petrosectomy. The area that must be drilled is the rhomboid fossa that is defined by the Kawase, premeatal, and postmeatal triangles. In Division of Neurosurgery - University of Turin, 130 patients, from August 2013 to September 2015, underwent surgical resection of intracranial meningiomas. In this group, we have operated 7 PCMs and 5 of these were approached performing an anterior petrosectomy with good results. In our conclusions, we feel that this surgery require an advanced knowledge of human anatomy and a specialized training in interpretation of radiological and microsurgical anatomy both in the dissection lab and in the operating room
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
Choroid Plexus Carcinoma in Adults: Literature Review and First Report of a Location into the Third Ventricle
No full textChoroid plexus carcinoma (CPC) is a rare intraventricular neoplasm originating from choroid plexus. CPC is the most aggressive choroid plexus tumor. Almost all the CPCs are detected in children, and the preferred location is the lateral ventricle. We reviewed the literature to evaluate the state of the art concerning the management of CPC in adults and report the first case described of the extremely rare localization into the third ventricle. A 38-year-old woman presented a medical history of Parinaud syndrome and occasional facial weakness. Brain magnetic resonance imaging revealed a mass lesion in the pineal region and posterior part of the third ventricle with obstructive hydrocephalus. She underwent subtotal resection through a supracerebellar infratentorial approach. After the histopathological diagnosis of CPC, the patient underwent a second surgery with gross total resection and adjuvant radiotherapy. CPC in adults, given its extreme rarity, does not have a standardized treatment. Gross total resection should be the first step of the treatment: however, according to the literature, gross total resection is achieved only in 40-75% of cases in CPC as opposed to 95% in choroid plexus papilloma, mainly due to the difficulty in managing a highly vascularized tumor in such a deep location. Chemotherapy has not an established role and adjuvant treatment is based on radiotherapy. In the case described hereby the gross total resection associated with surgical treatment of hydrocephalus and adjuvant radiotherapy has achieved a good clinical and radiological outcome
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
Role of nitric oxide and mechanisms involved into cerebral injury after subarachnoid hemorrhage: is nitric oxide a possible answer to cerebral vasospasm?
No full textCerebral vasospasm represents the most critical event that could occur after subarachnoid hemorrhage (SAH). Therapy is only partially effective because cerebral arterial constriction is not fully understood yet. One of the most important biological messenger associated to SAH is nitric oxide (NO), that is considered local regulator of cerebral blood flow. Different nitric oxide synthase (NOS) forms play a role in different biological processes, one of which is to link neuronal activity to blood flow in cerebral cortex. We performed a reassessment of the literature to summarize the role of NO as the main inflammatory pathway activated after SAH to clarify its importance for treatment of vasospasm
Glioma Surgery: Technological Advances to Achieve a Maximal Safe Resection
No full textGlioblastoma multiforme (GBM) is the most frequent primary central nervous system (CNS) tumor. Despite the best treatment and advances in therapy, prognosis remains poor. One of the mainstays of therapy in GBM is surgical excision. Several studies have confirmed that the extent of resection (EOR) positively influences overall survival (OS) in patients with high-grade gliomas (HGGs). A literature search was performed using PubMed to assess the useful neurosurgical tools to achieve the best neurosurgical performance. In order to achieve the major extent of resection, preserving neurological function, many tools are now available, especially neuronavigation, intraoperative fluorescence, intraoperative ultrasound, and neuromonitoring. In addition to the maximal excision of tumor, the neurosurgeon can use photodynamic therapy (PTD) and local drug delivery (LDD) to improve the local control and bridge conventional radio and chemotherapy. EOR improves OS in patients with HGGs. There are technological possibilities for achieving a complete resection preserving neurological function, and it is not acceptable to perform only biopsy of these lesions
Role of nitric oxide and mechanisms involved in cerebral injury after subarachnoid hemorrhage: is nitric oxide a possible answer to cerebral vasospasm?
No full text: Cerebral vasospasm represents the most critical event that could occur after subarachnoid hemorrhage (SAH). Therapy is only partially effective because cerebral arterial constriction is not fully understood yet. One of the most important biological messenger associated to SAH is nitric oxide (NO), that is considered local regulator of cerebral blood flow. Different nitric oxide synthase (NOS) forms play a role in different biological processes, one of which is to link neuronal activity to blood flow in cerebral cortex. We performed a reassessment of the literature to summarize the role of NO as the main inflammatory pathway activated after SAH to clarify its importance for treatment of vasospasm
Compartmental Cerebrospinal Fluid Events Occurring after Subarachnoid Hemorrhage: An “Heparin Oriented” Systematic Review
Full text linkSubarachnoid hemorrhage (SAH) represents a severe acute event with high morbidity and mortality due to the development of early brain injury (EBI), secondary delayed cerebral ischemia (DCI), and shunt-related hydrocephalus. Secondary events (SSE) such as neuroinflammation, vasospasm, excitotoxicity, blood-brain barrier disruption, oxidative cascade, and neuronal apoptosis are related to DCI. Despite improvement in management strategies and therapeutic protocols, surviving patients frequently present neurological deficits with neurocognitive impairment. The aim of this paper is to offer to clinicians a practical review of the actually documented pathophysiological events following subarachnoid hemorrhage. To reach our goal we performed a literature review analyzing reported studies regarding the mediators involved in the pathophysiological events following SAH occurring in the cerebrospinal fluid (CSF) (hemoglobin degradation products, platelets, complement, cytokines, chemokines, leucocytes, endothelin-1, NO-synthase, osteopontin, matricellular proteins, blood-brain barrier disruption, microglia polarization). The cascade of pathophysiological events secondary to SAH is very complex and involves several interconnected, but also distinct pathways. The identification of single therapeutical targets or specific pharmacological agents may be a limited strategy able to block only selective pathophysiological paths, but not the global evolution of SAH-related events. We report furthermore on the role of heparin in SAH management and discuss the rationale for use of intrathecal heparin as a pleiotropic therapeutical agent. The combination of the anticoagulant effect and the ability to interfere with SSE theoretically make heparin a very interesting molecule for SAH management
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