Search results for "Ray"
showing 10 items of 8009 documents
Analysis of weight gain composition determined in preterm infants with Dual energy x-ray absorptiometry (DXA)
1999
Analysis of weight gain composition determined in preterm infants with Dual energy x-ray absorptiometry (DXA)
Vergleich radiologischer Verfahren zur präoperativen Beurteilung der Verankerungsfestigkeit von Wirbelsäulenimplantaten
1997
PURPOSE To compare three techniques with regards to their ability to estimate pull out strength of spinal fusion hardware. MATERIAL AND METHODS VDS-screw fixation strength in 50 human cadaveric vertebral bodies was approximated by means of pull out force measurement. Bone quality was assessed by Dual X-ray Absorptiometry (DXA). Quantitative Computed Tomography (QCT) and T2*-relaxation time. For each of these techniques, correlation with axial pull out force strength was investigated. RESULTS Highest correlation was found for cancellous bone density measured by QCT (r = 0.72; p < 0.001). Immediately followed by DXA (r = 0.70; p < 0.001), which involves all bone components. Inverted T2*-relax…
Screw‐in‐screw fixation of fragility sacrum fractures provides high stability without loosening—biomechanical evaluation of a new concept
2020
Surgical treatment of fragility sacrum fractures with percutaneous sacroiliac (SI) screw fixation is associated with high failure rates. Turn-out is detected in up to 20% of the patients. The aim of this study was to evaluate a new screw-in-screw implant prototype for fragility sacrum fracture fixation. Twenty-seven artificial hemipelvises were assigned to three groups (n = 9) for instrumentation of an SI screw, the new screw-in-screw implant prototype, ora transsacral screw. Before implantation, a vertical osteotomy was set in zone 1 after Denis. All specimens were biomechanically tested to failure in upright position. Validated setup and test protocol were used for complex axial and torsi…
Uso de la tomografía computarizada en el diagnóstico de la anquilosis de la articulación temporomandibular: Presentación de dos casos clínicos
2006
La anquilosis de la articulación temporomandibular es definida como la abolición o limitación de los movimientos de dicha articulación. Radiográficamente la anquilosis demuestra aspectos bien característicos que facilitan el diagnóstico, sin embargo, su análisis en las técnicas radiográficas convencionales, en la mayoría de las veces, no se presenta de forma clara. Con la evolución de las técnicas radiográficas, la tomografía computarizada pasó a ser un examen de gran importancia en el diagnóstico de las anquilosis temporomandibulares. En vista de ello, el presente trabajo se propone mostrar y describir imágenes tomográficas de la anquilosis de esta articulación, presentando dos casos clíni…
Improving the cementation of the tibial component in knee arthroplasty : a study of four techniques in the cadaver.
2021
Aims The main objective of this study is to analyze the penetration of bone cement in four different full cementation techniques of the tibial tray. Methods In order to determine the best tibial tray cementation technique, we applied cement to 40 cryopreserved donor tibiae by four different techniques: 1) double-layer cementation of the tibial component and tibial bone with bone restrictor; 2) metallic cementation of the tibial component without bone restrictor; 3) bone cementation of the tibia with bone restrictor; and 4) superficial bone cementation of the tibia and metallic keel cementation of the tibial component without bone restrictor. We performed CT exams of all 40 subjects, and mea…
Development of the first marmoset-specific DNA microarray (EUMAMA): a new genetic tool for large-scale expression profiling in a non-human primate
2007
Abstract Background The common marmoset monkey (Callithrix jacchus), a small non-endangered New World primate native to eastern Brazil, is becoming increasingly used as a non-human primate model in biomedical research, drug development and safety assessment. In contrast to the growing interest for the marmoset as an animal model, the molecular tools for genetic analysis are extremely limited. Results Here we report the development of the first marmoset-specific oligonucleotide microarray (EUMAMA) containing probe sets targeting 1541 different marmoset transcripts expressed in hippocampus. These 1541 transcripts represent a wide variety of different functional gene classes. Hybridisation of …
mRNA expression profiles of primary high-grade central osteosarcoma are preserved in cell lines and xenografts
2011
Abstract Background Conventional high-grade osteosarcoma is a primary malignant bone tumor, which is most prevalent in adolescence. Survival rates of osteosarcoma patients have not improved significantly in the last 25 years. Aiming to increase this survival rate, a variety of model systems are used to study osteosarcomagenesis and to test new therapeutic agents. Such model systems are typically generated from an osteosarcoma primary tumor, but undergo many changes due to culturing or interactions with a different host species, which may result in differences in gene expression between primary tumor cells, and tumor cells from the model system. We aimed to investigate whether gene expressio…
A new tool to improve pedicle screw placement accuracy in navigated spine surgery: A monocentric study
2021
Objective Navigated instrumented spine surgery is burden by a low but significant screw mispositioning risks, respectively, for the 2D imaging system from 15 to 40% and, for the 3D imaging system, ranging from 4.1 to 11.5%. The primary objective of this study was to demonstrate the efficacy of a new "screw-like" tool in order to further decrease pedicle screws mispositioning rate during vertebral navigated spine surgery. Materials and methods Between January and June 2019 an initial case series of 18 patients were enrolled. All patients underwent a pedicle screw fixation, both in thoracic (Th10-Th12) and lumbosacral (L1-S1) spine, using O-arm (Medtronic Navigation, Louisville, Colorado) and…
Impaired geometric properties of tibia in older women with hip fracture history.
2007
This study evaluated side-to-side differences in tibial mineral mass and geometry in women with previous hip fracture sustained on average 3.5 years earlier. Both tibial mineral mass and geometry were found to be reduced in the fractured leg. INTRODUCTION: The purpose of this study was to evaluate side-to-side differences in tibial mineral mass and geometry after hip fracture and to assess the determinants of such differences. METHODS: Thirty-eight 60- to 85-year-old women with a previous hip fracture and 22 same-aged control women without fractures participated in the study. Bone characteristics of the distal tibia and tibial shaft of both legs were assessed using pQCT in order to compare …
Patient Specific Instrumentation for Total Knee Arthroplasty: a Literature Review
2014
During the past decade, total knee arthroplasty (TKA) has been markedly increased. Recently, patient-specific custom cutting guides have been commercially introduced in order to achieve an accurate component alignment during TKA. In fact, these cutting blocks are specific to a patient’s knee anatomy and should help the surgeons to perform bone cuts, reducing the complexity of conventional alignment and sizing tools. Nevertheless, there are critical arguments against patient-specific cutting guides for routine use, such as poor evidence and higher costs. Additionally, there are still no mild and long-term results available that describe the clinical outcomes following patient-specific instru…