TY - JOUR A1 - Albanna, Walid A1 - Conzen, Catharina A1 - Weiss, Miriam A1 - Clusmann, Hans A1 - Fuest, Matthias A1 - Mueller, Marguerite A1 - Brockmann, Marc Alexander A1 - Vilser, Walthard A1 - Schmidt-Trucksäss, Arno A1 - Hoellig, Anke A1 - Seiz, Marcel A1 - Thomé, Claudius A1 - Kotliar, Konstantin A1 - Schubert, Gerrit Alexander T1 - Retinal Vessel Analysis (RVA) in the context of subarachnoid hemorrhage: A proof of concept study JF - PLoS ONE N2 - Background Timely detection of impending delayed cerebral ischemia after subarachnoid hemorrhage (SAH) is essential to improve outcome, but poses a diagnostic challenge. Retinal vessels as an embryological part of the intracranial vasculature are easily accessible for analysis and may hold the key to a new and non-invasive monitoring technique. This investigation aims to determine the feasibility of standardized retinal vessel analysis (RVA) in the context of SAH. Methods In a prospective pilot study, we performed RVA in six patients awake and cooperative with SAH in the acute phase (day 2–14) and eight patients at the time of follow-up (mean 4.6±1.7months after SAH), and included 33 age-matched healthy controls. Data was acquired using a manoeuvrable Dynamic Vessel Analyzer (Imedos Systems UG, Jena) for examination of retinal vessel dimension and neurovascular coupling. Results Image quality was satisfactory in the majority of cases (93.3%). In the acute phase after SAH, retinal arteries were significantly dilated when compared to the control group (124.2±4.3MU vs 110.9±11.4MU, p<0.01), a difference that persisted to a lesser extent in the later stage of the disease (122.7±17.2MU, p<0.05). Testing for neurovascular coupling showed a trend towards impaired primary vasodilation and secondary vasoconstriction (p = 0.08, p = 0.09 resp.) initially and partial recovery at the time of follow-up, indicating a relative improvement in a time-dependent fashion. Conclusion RVA is technically feasible in patients with SAH and can detect fluctuations in vessel diameter and autoregulation even in less severely affected patients. Preliminary data suggests potential for RVA as a new and non-invasive tool for advanced SAH monitoring, but clinical relevance and prognostic value will have to be determined in a larger cohort. Y1 - 2016 U6 - https://doi.org/10.1371/journal.pone.0158781 SN - 1932-6203 VL - 11 IS - 7 PB - PLOS CY - San Francisco ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Lanzl, I. M. T1 - Mit Statistik gemeistert: perfekte Augentropfen und idealer Screeningtest : Möglichkeiten und Grenzen statistischer Methoden beim Glaukom JF - Der Ophthalmologe: Zeitschrift Der Deutschen Ophthalmologischen Gesellschaft N2 - Hintergrund Die Anwendung und das Verständnis von Statistik sind sehr wichtig für die biomedizinische Forschung und für die klinische Praxis. Dies gilt insbesondere auch zur Abschätzung der Möglichkeiten unterschiedlichster Diagnostik- und Therapieoptionen beim Glaukom. Die scheinbare Komplexität der Statistik, die zum Teil dem „gesunden Menschenverstand“ zu widersprechen scheint, zusammen mit der nur vorsichtigen Akzeptanz der Statistik bei vielen Medizinern können zu bewussten und unbewussten Manipulationen bei der Datendarstellung und -interpretation führen. Ziel der Arbeit Ziel ist die verständliche Darstellung einiger typischer Fehler in der medizinisch-statistischen Datenbehandlung. Material und Methoden Anhand hypothetischer Beispiele aus der Glaukomdiagnostik erfolgen die Darstellung der Wirkung eines hypotensiven Medikamentes sowie die Beurteilung der Ergebnisse eines diagnostischen Tests. Es werden die typischsten statistischen Einsatzbereiche und Irrtumsquellen ausführlich und verständlich analysiert Ergebnisse Mechanismen von Datenmanipulation und falscher Dateninterpretation werden aufgeklärt. Typische Irrtumsquellen bei der statistischen Auswertung und Datendarstellung werden dabei erläutert. Schlussfolgerungen Die erläuterten praktischen Beispiele zeigen die Notwendigkeit, die Grundlagen der Statistik zu verstehen und korrekt anwenden zu können. Fehlendes Grundlagenwissen und Halbwissen der medizinischen Statistik können zu folgenschweren Missverständnissen und falschen Entscheidungen in der medizinischen Forschung, aber auch in der klinischen Praxis führen. Y1 - 2016 U6 - https://doi.org/10.1007/s00347-016-0312-y SN - 0941-293X SN - 1433-0423 N1 - Englischer Titel: Mastered with statistics: perfect eye drops and ideal screening test : possibilities and limits of statistical methods for glaucoma IS - 113 SP - 838 EP - 843 PB - Springer CY - Berlin ER - TY - CHAP A1 - Tran, Ngoc Trinh A1 - Tran, Thanh Ngoc A1 - Matthies, H. G. A1 - Stavroulakis, G. E. A1 - Staat, Manfred ED - Papadrakakis, M. T1 - Shakedown analysis of plate bending analysis under stochastic uncertainty by chance constrained programming T2 - ECCOMAS Congress 2016, VII European Congress on Computational Methods in Applied Sciences and Engineering. Crete Island, Greece, 5–10 June 2016 Y1 - 2016 ER - TY - JOUR A1 - Wegmann, Kilian A1 - Hackl, Michael A1 - Staat, Manfred A1 - Mayer, Katharina A1 - Müller, Lars-Peter T1 - Double plate osteosynthesis of proximal ulna fractures: biomechanical and clinical results JF - Knee surgery, sports traumatology, arthroscopy N2 - While plate fixation of proximal ulna fractures might lead to superior clinical results compared to tension band wiring, regular plates represent an established risk factor for wound complications. The olecranon double plates (Medartis, Basel, CH) might decrease complications related to the osteosynthesis because of their low profile and better anatomical fit. This study aimed to evaluate the biomechanical performance and clinical results of the olecranon double plates. Y1 - 2016 U6 - https://doi.org/10.1007/s00167-016-4079-0 SN - 0942-2056 VL - Volume 24 IS - Supplement 1 SP - 58 EP - 59 PB - Springer CY - Berlin ER - TY - JOUR A1 - Hackl, Michael A1 - Leschinger, T. A1 - Staat, Manfred A1 - Müller, Lars-Peter A1 - Wegmann, Kilian T1 - Reconstruction of the interosseous membrane in the Essex Lopresti lesion — a biomechanical evaluation JF - Knee surgery, sports traumatology, arthroscopy N2 - Surgical reconstruction of the interosseous membrane (IOM) could restore longitudinal forearm stability to avoid persisting disability due to capituloradial and ulnocarpal impingement in Essex Lopresti lesions. This biomechanical study aimed to assess longitudinal forearm stability of intact specimens, after sectioning of the IOM and after reconstruction with a TightRope construct using either a single or double bundle technique. Y1 - 2016 U6 - https://doi.org/10.1007/s00167-016-4080-7 SN - 0942-2056 VL - Volume 24 IS - Supplement 1 SP - 130 EP - 131 PB - Springer CY - Berlin ER - TY - JOUR A1 - Hackl, Michael A1 - Kahmann, Stephanie Lucina A1 - Wegmann, Kilian A1 - Ries, Christian A1 - Staat, Manfred A1 - Müller, Lars-Peter T1 - Shortening osteotomy of the proximal radius — a treatment option for isolated osteoarthritis of the lateral column of the elbow joint? JF - Knee surgery, sports traumatology, arthroscopy N2 - Treatment of posttraumatic osteoarthritis of the radial column of the elbow joint remains a challenging yet common issue. While partial joint replacement leads to high revision rates, radial head excision has shown to severely increase joint instability. Shortening osteotomy of the radius could be an option to decrease the contact pressure of the radiohumeral joint and thereby pain levels without causing valgus instability. Hence, the aim of this biomechanical study was to evaluate the effects of radial shortening on axial load distribution and valgus stability of the elbow joint. Y1 - 2016 U6 - https://doi.org/10.1007/s00167-016-4080-7 SN - 0942-2056 VL - Volume 24 IS - Supplement 1 SP - 128 EP - 129 PB - Springer CY - Berlin ER - TY - JOUR A1 - Hackl, Michael A1 - Müller, Lars-Peter A1 - Staat, Manfred A1 - Kahmann, Stephanie Lucina A1 - Wegmann, Kilian T1 - Proximal phalangeal neck fractures of the hand — a biomechanical comparison of three fixation techniques JF - Knee surgery, sports traumatology, arthroscopy N2 - Plate osteosynthesis of displaced proximal phalangeal neck fractures of the hand allows early mobilization due to a stable internal fixation. Nevertheless, joint stiffness—because of soft tissue irritation—represents a common complication leading to high complication rates. Del Pinal et al. recently reported promising clinical results for a new, minimally invasive fixation technique with a cannulated headless intramedullary compression screw. Hence, the aim of this study was to compare plate fixation of proximal phalangeal neck fractures to less two less invasive techniques: Crossed k-wire fixation and intramedullary screw fixation. We hypothesized that these fixation techniques provide inferior stability when compared to plate osteosynthesis. Y1 - 2016 U6 - https://doi.org/10.1007/s00167-016-4080-7 SN - 0942-2056 VL - Volume 24 IS - Supplement 1 SP - 148 EP - 149 PB - Springer CY - Berlin ER - TY - BOOK A1 - Iomdina, E. N. A1 - Bauer, S. M. A1 - Kotliar, Konstantin T1 - БИОМЕХАНИКА ГЛАЗА: ТЕОРЕТИЧЕСКИЕ АСПЕКТЫ И КЛИНИЧЕСКИЕ ПРИЛОЖЕНИЯ T2 - Eye biomechanics : theoretical aspects and clinical applications Y1 - 2015 SN - 978-5-903025-57-2 PB - Real Time CY - Moscow ER - TY - CHAP A1 - Kahmann, Stephanie A1 - Hackl, Michael A1 - Wegmann, Kilian A1 - Müller, Lars-Peter A1 - Staat, Manfred ED - Erni, Daniel T1 - Impact of a proximal radial shortening osteotomy on the distribution of forces and the stability of the elbow T2 - 1st YRA MedTech Symposium 2016 : April 8th / 2016 / University of Duisburg-Essen N2 - The human arm consists of the humerus (upper arm), the medial ulna and the lateral radius (forearm). The joint between the humerus and the ulna is called humeroulnar joint and the joint between the humerus and the radius is called humeroradial joint. Lateral and medial collateral ligaments stabilize the elbow. Statistically, 2.5 out of 10,000 people suffer from radial head fractures [1]. In these fractures the cartilage is often affected. Caused by the injured cartilage, degenerative diseases like posttraumatic arthrosis may occur. The resulting pain and reduced range of motion have an impact on the patient’s quality of life. Until now, there has not been a treatment which allows typical loads in daily life activities and offers good long-term results. A new surgical approach was developed with the motivation to reduce the progress of the posttraumatic arthrosis. Here, the radius is shortened by 3 mm in the proximal part [2]. By this means, the load of the radius is intended to be reduced due to a load shift to the ulna. Since the radius is the most important stabilizer of the elbow it has to be confirmed that the stability is not affected. In the first test (Fig. 1 left), pressure distributions within the humeroulnar and humeroradial joints a native and a shortened radius were measured using resistive pressure sensors (I5076 and I5027, Tekscan, USA). The humerus was loaded axially in a tension testing machine (Z010, Zwick Roell, Germany) in 50 N steps up to 400 N. From the humerus the load is transmitted through both the radius and the ulna into the hand which is fixed on the ground. In the second test (Fig. 1 right), the joint stability was investigated using a digital image correlation system to measure the displacement of the ulna. Here, the humerus is fixed with a desired flexion angle and the unconstrained forearm lies on the ground. A rope connects the load actuator with a hook fixed in the ulna. A guide roller is used so that the rope pulls the ulna horizontally when a tensile load is applied. This creates a moment about the elbow joint with a maximum value of 7.5 Nm. Measurements were performed with varying flexion angles (0°, 30°, 60°, 90°, 120°). For both tests and each measurement, seven specimens were used. Student ́s t-test was employed to determine whether the mean values of the measurements in native specimen and operated specimens differ significantly. Y1 - 2016 U6 - https://doi.org/10.17185/duepublico/40821 SP - 7 EP - 8 PB - Universität Duisburg-Essen CY - Duisburg ER - TY - CHAP A1 - Jung, Alexander A1 - Staat, Manfred ED - Erni, Daniel T1 - Computing olympic gold: Ski jumping as an example T2 - 1st YRA MedTech Symposium 2016 : April 8th / 2016 / University of Duisburg-Essen Y1 - 2016 SN - 978-3-940402-06-6 U6 - https://doi.org/10.17185/duepublico/40821 SP - 54 EP - 55 PB - Universität Duisburg-Essen CY - Duisburg ER -