Biomechanics of Circumferential Cervical Fixation Using Posterior Facet Cages: A Cadaveric Study.

OBJECTIVE: Anterior cervical discectomy and fusion (ACDF) is a common procedure for the treatment of cervical disease. Circumferential procedures are options for multilevel pathology. Potential complications of multilevel anterior procedures are dysphagia and pseudarthrosis, whereas potential complications of posterior surgery include development of cervical kyphosis and postoperative chronic neck pain. The addition of posterior cervical cages (PCCs) to multilevel ACDF is a minimally invasive option to perform circumferential fusion. This study evaluated the biomechanical performance of 3-level circumferential fusion with PCCs as supplemental fixation to anteriorly placed allografts, with and without anterior plate fixation. METHODS: Nondestructive flexibility tests (1.5 Nm) performed on 6 cervical C2-7 cadaveric specimens intact and after discectomy (C3-6) in 3 instrumented conditions: allograft with anterior plate (G+P), PCC with allograft and plate (PCC+G+P), and PCC with allograft alone (PCC+G). Range of motion (ROM) data were analyzed using 1-way repeated-measures analysis of variance. RESULTS: All instrumented conditions resulted in significantly reduced ROM at the 3 instrumented levels (C3-6) compared to intact spinal segments in flexion, extension, lateral bending, and axial rotation (p \u3c 0.001). No significant difference in ROM was found between G+P and PCC+G+P conditions or between G+P and PCC+G conditions, indicating similar stability between these conditions in all directions of motion. CONCLUSION: All instrumented conditions resulted in considerable reduction in ROM. The added reduction in ROM through the addition of PCCs did not reach statistical significance. Circumferential fusion with anterior allograft, without plate and with PCCs, has comparable stability to ACDF with allograft and plate

Hemorragia digestiva alta decorrente de varize duodenal isolada: um relato de caso e revisão de literatura: Upper gastrointestinal bleeding from isolated duodenal variceal varices: a case report and literature review

Introdução: A hemorragia digestiva é um problema comum encontrado no pronto-socorro. Destacando a relevância desse tema na prática médica, chama atenção uma apresentação atípica de hemorragia digestiva alta: a ruptura de varizes duodenais. O desenvolvimento das varizes duodenais é bastante raro, representando apenas 0,4% de todas as varizes. A maioria dos casos é descoberta acidentalmente, e não é uma causa comum de sangramento por varizes. Objetivos: Este trabalho tem como objetivo o esclarecimento sobre a hemorragia digestiva por varizes duodenais na síndrome de hipertensão portal por esquistossomose visando proporcionar conhecimento sobre suas diferentes apresentações. Métodos: Realizou-se um estudo descritivo do tipo relato de caso. O caso selecionado foi coletado no Hospital Maria Lucinda, localizado em Recife-PE. Para a revisão bibliográfica, foram pesquisados artigos nos bancos de dados PubMed e Science Direct. Resultados: O sangramento de varizes duodenais é uma das complicações da hipertensão portal que está associada à alta morbidade e mortalidade. Apesar dos avanços na terapia, a taxa de letalidade permaneceu alta e a taxa de mortalidade de um único episódio de sangramento por varizes é em torno de 20% no esquistossomótico. Conclusão: A ruptura de variz duodenal é uma causa rara de sangramento gastrointestinal e ocorre, em sua maioria, por cirrose hepática com consequente hipertensão portal. Por se tratar de uma entidade de difícil diagnóstico, ainda não há diretrizes relacionadas ao manejo e as opções terapêuticas incluem abordagem multidisciplinar

Tumor neuroendócrino de intestino delgado: relato de caso / Small bowel neuroendocrine tumor: case report

Os tumores neuroendócrinos (TNEs) são um grupo diverso de neoplasias que surgem de células epiteliais com diferenciação neuroendócrina predominante.¹ Eles representam uma neoplasia rara, de crescimento lento, com algumas características comuns a todas as formas e outras atribuíveis ao órgão de origem.³ Os tumores do intestino delgado correspondem a 1-2% de todas as malignidades gastrointestinais, e os TNEs são apenas um dos subtipos dessas neoplasias raras.4 Os pacientes podem apresentar episódios de dor abdominal em cólica, característica de semi-oclusão intestinal, ou com obstrução completa que requer cirurgia de emergência.¹Apresentamos neste artigo um relato de caso de uma paciente com diagnóstico de tumor neuroendócrino de íleo, o qual apresentou-se inicialmente como um quadro de obstrução intestinal. Para execução do estudo foram extraídos os dados retrospectivos da paciente em questão, presentes no prontuário médico eletrônico do Hospital Otávio de Freitas. Para revisão da literatura foram selecionados artigos científicos nas plataformas online PubMed e Scielo usando os buscadores Tumores Neuroendócrinos, Tumores Neuroendócrinos de Intestino Delgado, e Obstrução Intestinal. Foram selecionados, então, 6 artigos publicados entre os anos de 2016-2020

A search for ultra-high-energy photons at the Pierre Auger Observatory exploiting air-shower universality

The Pierre Auger Observatory is the most sensitive detector to primary photons with energies above ∼0.2 EeV. It measures extensive air showers using a hybrid technique that combines a fluorescence detector (FD) with a ground array of particle detectors (SD). The signatures of a photon-induced air shower are a larger atmospheric depth at the shower maximum (X$_{max}$) and a steeper lateral distribution function, along with a lower number of muons with respect to the bulk of hadron-induced background. Using observables measured by the FD and SD, three photon searches in different energy bands are performed. In particular, between threshold energies of 1-10 EeV, a new analysis technique has been developed by combining the FD-based measurement of X$_{max}$ with the SD signal through a parameter related to its muon content, derived from the universality of the air showers. This technique has led to a better photon/hadron separation and, consequently, to a higher search sensitivity, resulting in a tighter upper limit than before. The outcome of this new analysis is presented here, along with previous results in the energy ranges below 1 EeV and above 10 EeV. From the data collected by the Pierre Auger Observatory in about 15 years of operation, the most stringent constraints on the fraction of photons in the cosmic flux are set over almost three decades in energy

Study on multi-ELVES in the Pierre Auger Observatory

Since 2013, the four sites of the Fluorescence Detector (FD) of the Pierre Auger Observatory record ELVES with a dedicated trigger. These UV light emissions are correlated to distant lightning strikes. The length of recorded traces has been increased from 100 μs (2013), to 300 μs (2014-16), to 900 μs (2017-present), to progressively extend the observation of the light emission towards the vertical of the causative lightning and beyond. A large fraction of the observed events shows double ELVES within the time window, and, in some cases, even more complex structures are observed. The nature of the multi-ELVES is not completely understood but may be related to the different types of lightning in which they are originated. For example, it is known that Narrow Bipolar Events can produce double ELVES, and Energetic In-cloud Pulses, occurring between the main negative and upper positive charge layer of clouds, can induce double and even quadruple ELVES in the ionosphere. This report shows the seasonal and daily dependence of the time gap, amplitude ratio, and correlation between the pulse widths of the peaks in a sample of 1000+ multi-ELVES events recorded during the period 2014-20. The events have been compared with data from other satellite and ground-based sensing devices to study the correlation of their properties with lightning observables such as altitude and polarity