TY - JOUR A1 - Lenz, Maximilian A1 - Kahmann, Stephanie Lucina A1 - Behbahani, Mehdi A1 - Pennig, Lenhard A1 - Hackl, Michael A1 - Leschinger, Tim A1 - Müller, Lars Peter A1 - Wegmann, Kilian T1 - Influence of rotator cuff preload on fracture configuration in proximal humerus fractures: a proof of concept for fracture simulation JF - Archives of Orthopaedic and Trauma Surgery N2 - Introduction In regard of surgical training, the reproducible simulation of life-like proximal humerus fractures in human cadaveric specimens is desirable. The aim of the present study was to develop a technique that allows simulation of realistic proximal humerus fractures and to analyse the influence of rotator cuff preload on the generated lesions in regards of fracture configuration. Materials and methods Ten cadaveric specimens (6 left, 4 right) were fractured using a custom-made drop-test bench, in two groups. Five specimens were fractured without rotator cuff preload, while the other five were fractured with the tendons of the rotator cuff preloaded with 2 kg each. The humeral shaft and the shortened scapula were potted. The humerus was positioned at 90° of abduction and 10° of internal rotation to simulate a fall on the elevated arm. In two specimens of each group, the emergence of the fractures was documented with high-speed video imaging. Pre-fracture radiographs were taken to evaluate the deltoid-tuberosity index as a measure of bone density. Post-fracture X-rays and CT scans were performed to define the exact fracture configurations. Neer’s classification was used to analyse the fractures. Results In all ten cadaveric specimens life-like proximal humerus fractures were achieved. Two III-part and three IV-part fractures resulted in each group. The preloading of the rotator cuff muscles had no further influence on the fracture configuration. High-speed videos of the fracture simulation revealed identical fracture mechanisms for both groups. We observed a two-step fracture mechanism, with initial impaction of the head segment against the glenoid followed by fracturing of the head and the tuberosities and then with further impaction of the shaft against the acromion, which lead to separation of the tuberosities. Conclusion A high energetic axial impulse can reliably induce realistic proximal humerus fractures in cadaveric specimens. The preload of the rotator cuff muscles had no influence on initial fracture configuration. Therefore, fracture simulation in the proximal humerus is less elaborate. Using the presented technique, pre-fractured specimens are available for real-life surgical education. KW - Proximal humerus fracture KW - Biomechanical simulation KW - Fracture configuration KW - Fracture simulation KW - Rotator cuff Y1 - 2022 U6 - https://doi.org/10.1007/s00402-022-04471-9 SN - 1434-3916 PB - Springer CY - Berlin, Heidelberg ER - TY - JOUR A1 - Chloé, Radermacher A1 - Malyaran, Hanna A1 - Craveiro, Rogerio Bastos A1 - Peglow, Sarah A1 - Behbahani, Mehdi A1 - Pufe, Thomas A1 - Wolf, Michael A1 - Neuss, Sabine T1 - Mechanical loading on cementoblasts: a mini review JF - Osteologie N2 - Orthodontic treatments are concomitant with mechanical forces and thereby cause teeth movements. The applied forces are transmitted to the tooth root and the periodontal ligaments which is compressed on one side and tensed up on the other side. Indeed, strong forces can lead to tooth root resorption and the crown-to-tooth ratio is reduced with the potential for significant clinical impact. The cementum, which covers the tooth root, is a thin mineralized tissue of the periodontium that connects the periodontal ligament with the tooth and is build up by cementoblasts. The impact of tension and compression on these cells is investigated in several in vivo and in vitro studies demonstrating differences in protein expression and signaling pathways. In summary, osteogenic marker changes indicate that cyclic tensile forces support whereas static tension inhibits cementogenesis. Furthermore, cementogenesis experiences the same protein expression changes in static conditions as static tension, but cyclic compression leads to the exact opposite of cyclic tension. Consistent with marker expression changes, the singaling pathways of Wnt/ß-catenin and RANKL/OPG show that tissue compression leads to cementum degradation and tension forces to cementogenesis. However, the cementum, and in particular its cementoblasts, remain a research area which should be explored in more detail to understand the underlying mechanism of bone resorption and remodeling after orthodontic treatments. KW - Cementoblast KW - Compression KW - Tension KW - Mechanotransduction KW - Forces Y1 - 2022 U6 - https://doi.org/10.1055/a-1826-0777 SN - 1019-1291 VL - 31 IS - 2 SP - 111 EP - 118 PB - Thieme CY - Stuttgart ER - TY - CHAP A1 - Schmitz, Annika A1 - Apandi, Shah Eiman Amzar Shah A1 - Spillner, Jan A1 - Hima, Flutura A1 - Behbahani, Mehdi ED - Digel, Ilya ED - Staat, Manfred ED - Trzewik, Jürgen ED - Sielemann, Stefanie ED - Erni, Daniel ED - Zylka, Waldemar T1 - Effect of different cannula positions in the pulmonary artery on blood flow and gas exchange using computational fluid dynamics analysis T2 - YRA MedTech Symposium (2024) N2 - Pulmonary arterial cannulation is a common and effective method for percutaneous mechanical circulatory support for concurrent right heart and respiratory failure [1]. However, limited data exists to what effect the positioning of the cannula has on the oxygen perfusion throughout the pulmonary artery (PA). This study aims to evaluate, using computational fluid dynamics (CFD), the effect of different cannula positions in the PA with respect to the oxygenation of the different branching vessels in order for an optimal cannula position to be determined. The four chosen different positions (see Fig. 1) of the cannulas are, in the lower part of the main pulmonary artery (MPA), in the MPA at the junction between the right pulmonary artery (RPA) and the left pulmonary artery (LPA), in the RPA at the first branch of the RPA and in the LPA at the first branch of the LPA. Y1 - 2024 SN - 978-3-940402-65-3 U6 - https://doi.org/10.17185/duepublico/81475 N1 - 4th YRA MedTech Symposium, February 1, 2024. FH Aachen, Campus Jülich SP - 29 EP - 30 PB - Universität Duisburg-Essen CY - Duisburg ER - TY - JOUR A1 - Thiebes, Anja Lena A1 - Klein, Sarah A1 - Zingsheim, Jonas A1 - Möller, Georg H. A1 - Gürzing, Stefanie A1 - Reddemann, Manuel A. A1 - Behbahani, Mehdi A1 - Cornelissen, Christian G. T1 - Effervescent atomizer as novel cell spray technology to decrease the gas-to-liquid ratio JF - pharmaceutics N2 - Cell spraying has become a feasible application method for cell therapy and tissue engineering approaches. Different devices have been used with varying success. Often, twin-fluid atomizers are used, which require a high gas velocity for optimal aerosolization characteristics. To decrease the amount and velocity of required air, a custom-made atomizer was designed based on the effervescent principle. Different designs were evaluated regarding spray characteristics and their influence on human adipose-derived mesenchymal stromal cells. The arithmetic mean diameters of the droplets were 15.4–33.5 µm with decreasing diameters for increasing gas-to-liquid ratios. The survival rate was >90% of the control for the lowest gas-to-liquid ratio. For higher ratios, cell survival decreased to approximately 50%. Further experiments were performed with the design, which had shown the highest survival rates. After seven days, no significant differences in metabolic activity were observed. The apoptosis rates were not influenced by aerosolization, while high gas-to-liquid ratios caused increased necrosis levels. Tri-lineage differentiation potential into adipocytes, chondrocytes, and osteoblasts was not negatively influenced by aerosolization. Thus, the effervescent aerosolization principle was proven suitable for cell applications requiring reduced amounts of supplied air. This is the first time an effervescent atomizer was used for cell processing. KW - tri-lineage differentiation KW - survival KW - twin-fluid atomizer KW - adipose-derived stromal cells (ASCs) KW - cell atomization KW - cell aerosolization Y1 - 2022 U6 - https://doi.org/10.3390/pharmaceutics14112421 N1 - This article belongs to the Special Issue "Stromal, Stem, Signaling Cells: The Multiple Roles and Applications of Mesenchymal Cells" VL - 14 IS - 11 PB - MDPI CY - Basel ER - TY - JOUR A1 - Brockhaus, Moritz K. A1 - Behbahani, Mehdi A1 - Muris, Farina A1 - Jansen, Sebastian V. A1 - Schmitz-Rode, Thomas A1 - Steinseifer, Ulrich A1 - Clauser, Johanna C. T1 - In vitro thrombogenicity testing of pulsatile mechanical circulatory support systems: Design and proof-of-concept JF - Artificial Organs N2 - Thrombogenic complications are a main issue in mechanical circulatory support (MCS). There is no validated in vitro method available to quantitatively assess the thrombogenic performance of pulsatile MCS devices under realistic hemodynamic conditions. The aim of this study is to propose a method to evaluate the thrombogenic potential of new designs without the use of complex in-vivo trials. This study presents a novel in vitro method for reproducible thrombogenicity testing of pulsatile MCS systems using low molecular weight heparinized porcine blood. Blood parameters are continuously measured with full blood thromboelastometry (ROTEM; EXTEM, FIBTEM and a custom-made analysis HEPNATEM). Thrombus formation is optically observed after four hours of testing. The results of three experiments are presented each with two parallel loops. The area of thrombus formation inside the MCS device was reproducible. The implantation of a filter inside the loop catches embolizing thrombi without a measurable increase of platelet activation, allowing conclusions of the place of origin of thrombi inside the device. EXTEM and FIBTEM parameters such as clotting velocity (α) and maximum clot firmness (MCF) show a total decrease by around 6% with a characteristic kink after 180 minutes. HEPNATEM α and MCF rise within the first 180 minutes indicate a continuously increasing activation level of coagulation. After 180 minutes, the consumption of clotting factors prevails, resulting in a decrease of α and MCF. With the designed mock loop and the presented protocol we are able to identify thrombogenic hot spots inside a pulsatile pump and characterize their thrombogenic potential. Y1 - 2021 U6 - https://doi.org/10.1111/aor.14046 SN - 1525-1594 VL - 45 IS - 12 SP - 1513 EP - 1521 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Jansen, S. V. A1 - Behbahani, Mehdi A1 - Laumen, M. A1 - Kaufmann, T. A1 - Hormes, M. A1 - Behr, M. A1 - Schmitz-Rode, T. A1 - Steinseifer, U. T1 - Investigation of Steady Flow Through a Realistic Model of the Thoracic Human Aorta Using 3D Stereo PIV and CFD-Simulation JF - ASAIO Journal Y1 - 2010 U6 - https://doi.org/10.1097/01.mat.0000369377.65122.a3 N1 - American Society of Artificial Organs (ASAIO), Baltimore, USA, May 27-29, 2010 VL - 56 IS - 2 SP - 98 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - JOUR A1 - Behbahani, Mehdi A1 - Nam, J. A1 - Waluga, C. A1 - Behr, M. A1 - Pasquali, M. A1 - Mottaghy, K. T1 - Modeling and Numerical Analysis of Platelet Activation, Adhesion and Aggregation in Artificial Organs Y1 - 2010 U6 - https://doi.org/10.1097/01.mat.0000369377.65122.a3 N1 - Posterpresentation American Society of Artificial Organs (ASAIO), Baltimore, USA, May 27-29, 2010 VL - 56 IS - 2 SP - 85 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - JOUR A1 - Behbahani, Mehdi A1 - Probst, M. A1 - Mai, A. A1 - Tran, L. A1 - Vonderstein, K. A1 - Keschenau, P. A1 - Linde, T. A1 - Steinseifer, U. A1 - Behr, M. A1 - Mottaghy, K. T1 - The influence of high shear on thrombosis and hemolysis in artificial organs JF - The International Journal of Artificial Organs Y1 - 2010 SN - 0391-3988 VL - 33 IS - 7 SP - 426 EP - 426 PB - Sage CY - Thousand Oaks ER - TY - JOUR A1 - Schoenrock, Britt A1 - Muckelt, Paul E. A1 - Hastermann, Maria A1 - Albracht, Kirsten A1 - MacGregor, Robert A1 - Martin, David A1 - Gunga, Hans-Christian A1 - Salanova, Michele A1 - Stokes, Maria J. A1 - Warner, Martin B. A1 - Blottner, Dieter T1 - Muscle stiffness indicating mission crew health in space JF - Scientific Reports N2 - Muscle function is compromised by gravitational unloading in space affecting overall musculoskeletal health. Astronauts perform daily exercise programmes to mitigate these effects but knowing which muscles to target would optimise effectiveness. Accurate inflight assessment to inform exercise programmes is critical due to lack of technologies suitable for spaceflight. Changes in mechanical properties indicate muscle health status and can be measured rapidly and non-invasively using novel technology. A hand-held MyotonPRO device enabled monitoring of muscle health for the first time in spaceflight (> 180 days). Greater/maintained stiffness indicated countermeasures were effective. Tissue stiffness was preserved in the majority of muscles (neck, shoulder, back, thigh) but Tibialis Anterior (foot lever muscle) stiffness decreased inflight vs. preflight (p < 0.0001; mean difference 149 N/m) in all 12 crewmembers. The calf muscles showed opposing effects, Gastrocnemius increasing in stiffness Soleus decreasing. Selective stiffness decrements indicate lack of preservation despite daily inflight countermeasures. This calls for more targeted exercises for lower leg muscles with vital roles as ankle joint stabilizers and in gait. Muscle stiffness is a digital biomarker for risk monitoring during future planetary explorations (Moon, Mars), for healthcare management in challenging environments or clinical disorders in people on Earth, to enable effective tailored exercise programmes. KW - Ageing KW - Anatomy KW - Muscle KW - Musculoskeletal system KW - Physiology Y1 - 2024 U6 - https://doi.org/10.1038/s41598-024-54759-6 SN - 2045-2322 N1 - Corresponding author: Dieter Blottner VL - 14 IS - Article number: 4196 PB - Springer Nature CY - London ER - TY - JOUR A1 - Seynnes, O. R. A1 - Bojsen-Moller, J. A1 - Albracht, Kirsten A1 - Arndt, A. A1 - Cronin, N. J. A1 - Finni, T. A1 - Magnusson, S. P. T1 - Ultrasound-based testing of tendon mechanical properties: a critical evaluation JF - Journal of Applied Physiology Y1 - 2015 U6 - https://doi.org/10.1152/japplphysiol.00849.2014 SN - 8750-7587 VL - 118 IS - 2 SP - 133 EP - 141 ER -