36 results on '"Jettkant B"'
Search Results
2. Langzeitergebnisse nach operativer Rekonstruktion von Strecksehnenrupturen am Kniegelenk mittels EMG- und Bewegungsanalyse
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Rosteius, T, Jettkant, B, Rausch, V, Brinkemper, A, Lotzien, S, Geßmann, J, Schildhauer, TA, and Königshausen, M
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ddc: 610 ,Ganganalyse ,Medicine and health ,Langzeitergebnisse ,EMG Analyse ,Strecksehnenrupturen - Abstract
Fragestellung: Patella- und Quadrizepssehnenrupturen sind schwerwiegende Verletzungen mit einem langwierigen Heilungs- und Rehabilitationsverlauf. Langzeitdaten sind jedoch in der Literatur nur wenige zu finden. Ziel der Studie war es daher, Langzeitergebnisse mittels 3D Bewegungs- und EMG Analyse zu [zum vollständigen Text gelangen Sie über die oben angegebene URL]
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- 2021
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3. 3D-Ganganalyse und frühfunktionelle Ergebnisse nach augmentierter Primärnaht von Schenck III und IV Kniegelenksluxationen
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Rosteius, T, Jettkant, B, Rausch, V, Lotzien, S, Königshausen, M, Schildhauer, TA, Seybold, D, Geßmann, J, Rosteius, T, Jettkant, B, Rausch, V, Lotzien, S, Königshausen, M, Schildhauer, TA, Seybold, D, and Geßmann, J
- Published
- 2021
4. Die Arretierung des Taylor Spatial Frame. Eine Analyse der Auswirkungen additiver starrer Längsstreben auf die Biomechanik des Ringfixateurs
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Lotzien, S, Jettkant, B, Rausch, V, Rosteius, T, Schildhauer, TA, Geßmann, J, Lotzien, S, Jettkant, B, Rausch, V, Rosteius, T, Schildhauer, TA, and Geßmann, J
- Published
- 2019
5. Biomechanischer Vergleich verschiedener Osteosyntheseverfahren von Frakturen des Processus coronoideus ulnae
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Rausch, V, Jettkant, B, Lotzien, S, Mempel, E, Rosteius, T, Schildhauer, TA, Geßmann, J, Königshausen, M, Rausch, V, Jettkant, B, Lotzien, S, Mempel, E, Rosteius, T, Schildhauer, TA, Geßmann, J, and Königshausen, M
- Published
- 2019
6. BIO-RSA vs. Glenoidrekonstruktion mit Knochenspan und inverser Prothese beim anterior-globalen Glenoiddefekt im biomechanischen Vergleich. Was ist stabiler für die unmittelbare Nachbehandlung?
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Königshausen, M, Sverdlova, N, Mersmann, C, Ehlert, C, Jettkant, B, Dermietzel, R, Schildhauer, TA, and Seybold, D
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ddc: 610 ,610 Medical sciences ,Medicine - Abstract
Fragestellung: Bezüglich der erlaubten physiologischen Kräfte in der physiotherapeutischen Nachbehandlung stellt sich die Frage, ob große anterior-globale Glenoiddefekte mittels Knochenspan oder nach planem Fräsen mittels "BIO-RSA" (bony increased offset - reversed shoulder[zum vollständigen Text gelangen Sie über die oben angegebene URL], Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2015)
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- 2015
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7. Auswirkung der Draht-Schrauben-Verbindung auf die Fixationssteifigkeit des Ilizarov- Ringfixateurs
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Geßmann, J, Jettkant, B, Schildhauer, TA, and Seybold, D
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ddc: 610 ,610 Medical sciences ,Medicine - Abstract
Fragestellung: Die Fixationssteifigkeit des Ilizarov-Ringfixateurs wird bedeutend durch die Spannung der transfixierenden Drähte bestimmt. Ein Hauptgrund für eine Drahtlockerung ist neben der Materialermüdung das Drahtrutschen an den Schrauben-Ringverbindungen. Diese wird durch die Ha[for full text, please go to the a.m. URL], Deutscher Kongress für Orthopädie und Unfallchirurgie; 75. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie, 97. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie, 52. Tagung des Berufsverbandes der Fachärzte für Orthopädie
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- 2011
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8. Ein biomechanischer Vergleich unterschiedlicher Schraubenosteosynthesen bei medialen Schenkelhalsfrakturen
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Roetman, B., Fülling, Y., Jettkant, B., and Muhr, G.
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ddc: 610 ,610 Medical sciences ,Medicine - Abstract
Fragestellung: Die Schraubenosteosynthese als hüftkopferhaltendes Verfahren bei medialen Schenkelhalsfrakturen ist bei jungen Patienten ein Standardverfahren. Diese Arbeit vergleicht die biomechanische Stabilität dreier verschiedener Schraubenanordnungen. Untersucht wurden der Versatz entlang[for full text, please go to the a.m. URL], Deutscher Kongress für Orthopädie und Unfallchirurgie; 74. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie, 96. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie, 51. Tagung des Berufsverbandes der Fachärzte für Orthopädie
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- 2010
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9. Optimaler Versorgungszeitpunkt thorakaler/lumbaler Wirbelsäulenverletzungen beim mehrfach verletzten Patienten - eine prospektive Studie
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Frangen, T.M., Konieczny, M., Schinkel, C., Jettkant, B., and Muhr, G.
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ddc: 610 ,610 Medical sciences ,Medicine - Abstract
Fragestellung: Es ist kein klinischer oder laborchemischer Parameter bekannt, aus welchem man den optimalen Versorgungszeitpunkt von Verletzungen der thorakolumbalen Wirbelsäule beim Mehrfachverletzten ableiten könnte. Die Mehrzahl der bislang publizierten Analysen bei Patienten mit den genannten[for full text, please go to the a.m. URL], Deutscher Kongress für Orthopädie und Unfallchirurgie; 74. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie, 96. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie, 51. Tagung des Berufsverbandes der Fachärzte für Orthopädie
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- 2010
10. Knochenspanaugmentation am schrägen vs. eckig präparierten anterioren Glenoiddefekt in der inversen Revisionsendoprothetik. Eine biomechanische Analyse am Kunst- und Humanknochen
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Königshausen, M, Sverdlova, N, Mersmann, C, Ehlert, C, Jettkant, B, Dermietzel, R, Schildhauer, TA, Seybold, D, Königshausen, M, Sverdlova, N, Mersmann, C, Ehlert, C, Jettkant, B, Dermietzel, R, Schildhauer, TA, and Seybold, D
- Published
- 2014
11. Einfluss der direkten und indirekten Krafteinleitung auf die Fixation langer Röhrenknochen mit dem Ilizarov-Ringfixateur: eine experimentelle, biomechanische Arbeit
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Geßmann, J, Baecker, H, Jettkant, B, Muhr, G, and Seybold, D
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ddc: 610 ,610 Medical sciences ,Medicine - Abstract
Fragestellung: Die Ringfixateurbehandlung hat in der rekonstruktiven Knochenchirurgie und Deformitätenkorrektur bei schlechten Weichteilverhältnissen in den letzten Jahren immer mehr an Bedeutung gewonnen. Der Patientenkomfort bei der Unterschenkelmontage mit Ruckfuß/Vorfußtransfixation[for full text, please go to the a.m. URL], Deutscher Kongress für Orthopädie und Unfallchirurgie; 73. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie, 95. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie, 50. Tagung des Berufsverbandes der Fachärzte für Orthopädie
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- 2009
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12. Die intrinsische Stabilität der hexapod basierten Ringfixateure: ein biomechanischer Vergleich des Hexapod und Taylor Spatial Frame Fixateur
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Seybold, D, Geßmann, J, Jettkant, B, Baecker, H, Citak, M, and Muhr, G
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ddc: 610 ,610 Medical sciences ,Medicine - Abstract
Fragestellung: Zur Korrektur von Achsfehlstellungen in der rekonstruktiven Skelettchirurgie stehen zwei hexapod basierte Ringfixateure zur Verfügung. Diese Ringfixateure ermöglichen eine simultane Korrektur von mehrdimensionalen Fehlstellungen der unteren und oberen Extremität. Die intrinsische[for full text, please go to the a.m. URL], Deutscher Kongress für Orthopädie und Unfallchirurgie; 73. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie, 95. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie, 50. Tagung des Berufsverbandes der Fachärzte für Orthopädie
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- 2009
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13. Nachweis einer drahtlosen Diagnostik von Prothesenschaftlockerungen in vitro mit Hilfe von Beschleunigungssensoren
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Clasbrummel, B, Jettkant, B, and Muhr, G
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ddc: 610 - Published
- 2003
14. Der knöcherne Glenoidaufbau in der Revisionsendoprothetik der Schulter- Biomechanische Überlegungen
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Seybold, D, Königshausen, M, Geßmann, J, Jettkant, B, Schildhauer, TA, Seybold, D, Königshausen, M, Geßmann, J, Jettkant, B, and Schildhauer, TA
- Published
- 2013
15. Die primäre glenoidale Fixationsstabilität bei knöchernen Glenoidaufbauten in der Revisionsschulterendoprothetik. Eine biomechanische Studie
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Seybold, D, Königshausen, M, Geßmann, J, Jettkant, B, Schildhauer, TA, Seybold, D, Königshausen, M, Geßmann, J, Jettkant, B, and Schildhauer, TA
- Published
- 2012
16. Optimaler Versorgungszeitpunkt thorakaler/lumbaler Wirbelsäulenverletzungen beim mehrfach verletzten Patienten - eine prospektive Studie
- Author
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Frangen, TM, Konieczny, M, Schinkel, C, Jettkant, B, Muhr, G, Frangen, TM, Konieczny, M, Schinkel, C, Jettkant, B, and Muhr, G
- Published
- 2010
17. Ein biomechanischer Vergleich unterschiedlicher Schraubenosteosynthesen bei medialen Schenkelhalsfrakturen
- Author
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Roetman, B, Fülling, Y, Jettkant, B, Muhr, G, Roetman, B, Fülling, Y, Jettkant, B, and Muhr, G
- Published
- 2010
18. Use of a Calibration Gas Generator for Irritation Threshold Assessment and As Supplement of Dynamic Dilution Olfactometry
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Monse, C., primary, Broding, H. C., additional, Hoffmeyer, F., additional, Jettkant, B., additional, Berresheim, H., additional, Bruning, T., additional, Bunger, J., additional, and Sucker, K., additional
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- 2010
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19. The influence of a weight-bearing platform on the mechanical behavior of two Ilizarov ring fixators: tensioned wires vs. half-pins
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Gessmann Jan, Citak Mustafa, Jettkant Birger, Schildhauer Thomas A, and Seybold Dominik
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Orthopedic surgery ,RD701-811 ,Diseases of the musculoskeletal system ,RC925-935 - Abstract
Abstract Background A weight-bearing platform applied at the distal end of an Ilizarov external frame allows patients with hindfoot transfixations, foot deformities or plantar skin lesions to bear weight. This leads to an indirect loading of the fracture or osteotomy site. However, the effect on the fracture/osteotomy site's motion or compressive loads is unknown. The aim of this study was to analyze the mechanical effects of a weight-bearing platform on the traditional all-wire, four-ring frame in comparison to a two-ring frame consisting of half-pins. Methods Two frame configurations, with either anatomically positioned wires or half-pins, were analyzed with and without a weight-bearing platform applied underneath the distal ring. Composite tibiae with a mid-diaphyseal osteotomy of 3.5 mm were used in all the experiments. An axial load was applied with the use of a universal test machine (UTS®). Interfragmentary movements, the relative movements of bone fragments and movements between rings were recorded using displacement transducers. Compressive loads at the osteotomy site were recorded with loading cells. Results Indirect loading with a weight-bearing platform altered the force transmission through the osteotomy. Indirect loading of the tibiae decreased the extent of the axial micro-motion by 50% under the applied weight load when compared to direct weight loading (p < 0.05). The half pin frame was 25% stiffer than the wire frame under both direct and indirect loading of the tibiae (p < 0.05). Compressive loads under indirect loading were reduced by 67% in the wire frame and by 57% in the half-pin frames compared to direct loading of the bones (p < 0.05). While axial loading in the wire frames resulted in plain axial movements at the site of the osteotomy, it was coupled with translational movements and angular displacements in the half pin mountings. This effect was more apparent in the case of indirect loading. Conclusions A weight-bearing platform has substantial influence on the biomechanical performance of an Ilizarov external fixator. Half-pins induce greater stiffness to the Ilizarov external fixator and allow the usage of only one ring per bone segment, but shear stresses at the osteotomy under axial loading should be considered. The results allow an estimation of the size and direction of interfragmentary movements based on the extent of weight bearing.
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- 2011
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20. Effects on gait kinematics, pedobarography, functional and subjective results after isolated chopart injury.
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Cibura C, Lülsdorff R, Rosteius T, Brinkemper A, Bernstorff M, Jettkant B, Godolias P, Ramczykowski T, Königshausen M, Schildhauer TA, and Kruppa C
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- Humans, Male, Adult, Biomechanical Phenomena, Female, Middle Aged, Young Adult, Electromyography, Range of Motion, Articular, Ankle Injuries physiopathology, Gait Analysis methods, Ankle Joint physiopathology, Gait physiology
- Abstract
Background: This study analysed changes in gait and pedobarography and subjective and functional outcomes after isolated Chopart joint injury., Methods: The results of 14 patients were reviewed. Kinematic 3D gait analysis, comparative bilateral electromyography (EMG) and pedobarography were performed., Results: On the injured side, the 3D gait analysis showed a significantly increased internal rotation and decreased external rotation of the hip and significantly decreased adduction and decreased range of motion (ROM) for the ankle. On the healthy side, the pedobarography revealed a significantly increased mean force in the forefoot, an increased peak maximum force and an increased maximum pressure in the metatarsal. When standing, significantly more weight was placed on the healthy side. The EMG measurements showed no significant differences between the healthy and injured legs., Conclusions: After isolated Chopart injuries, significant changes in gait and pedobarography can be seen over the long term., (© 2024. The Author(s).)
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- 2024
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21. Influence of face masks on the subjective impairment at different physical workloads.
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van Kampen V, Marek EM, Sucker K, Jettkant B, Kendzia B, Strauß B, Ulbrich M, Deckert A, Berresheim H, Eisenhawer C, Hoffmeyer F, Weidhaas S, Behrens T, Brüning T, and Bünger J
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- Adult, Aged, Female, Humans, Male, Middle Aged, Young Adult, Dyspnea, Physical Examination, Physical Exertion, Masks adverse effects, Workload
- Abstract
To quantify the subjective and cognitive impairment caused by wearing face masks at work, 20 men and 20 women (median age 47 years, range 19-65) were tested under different ergometer workloads while wearing surgical mask, community mask, FFP2 respirator or no mask in a randomized and partially double-blinded design. Masks were worn also at the workplace for four hours. Subjective impairment was recorded by questionnaires. Cognitive performance was tested before and after the workplace examination. Subjective feeling of heat, humidity, and difficult breathing increased with rising physical exertion and wearing time for all three mask types, most notably for FFP2. Even when blinded, participants with FFP2 reported difficult breathing already at rest. During physical exertion, individuals with low tolerance to discomfort reported significantly stronger impairment (OR 1.14, 95% CI 1.02-1.27). Regarding light work, older subjects (OR 0.95, 95% CI 0.92-0.98) and women (OR 0.84, 95% CI 0.72-0.99) showed significantly lower and atopic subjects stronger impairment (OR 1.16, 95% CI 1.06-1.27). No significant influence of mask wearing was detected on cognitive performance. Wearing a mask had no effect on cognitive performance, but led to discomfort which increased with physical exertion and wearing time. Individuals who tolerate discomfort poorly felt more impaired by wearing a mask during physical exertion., (© 2023. The Author(s).)
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- 2023
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22. Effects of wearing different face masks on cardiopulmonary performance at rest and exercise in a partially double-blinded randomized cross-over study.
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Marek EM, van Kampen V, Jettkant B, Kendzia B, Strauß B, Sucker K, Ulbrich M, Deckert A, Berresheim H, Eisenhawer C, Hoffmeyer F, Weidhaas S, Behrens T, Brüning T, and Bünger J
- Subjects
- Humans, SARS-CoV-2, Masks, Cross-Over Studies, Respiration, COVID-19 prevention & control
- Abstract
The use of face masks became mandatory during SARS-CoV-2 pandemic. Wearing masks may lead to complaints about laboured breathing and stress. The influence of different masks on cardiopulmonary performance was investigated in a partially double-blinded randomized cross-over design. Forty subjects (19-65 years) underwent body plethysmography, ergometry, cardiopulmonary exercise test and a 4-h wearing period without a mask, with a surgical mask (SM), a community mask (CM), and an FFP2 respirator (FFP2). Cardiopulmonary, physical, capnometric, and blood gas related parameters were recorded. Breathing resistance and work of breathing were significantly increased while wearing a mask. During exercise the increase in minute ventilation tended to be lower and breathing time was significantly longer with mask than without mask. Wearing a mask caused significant minimal decreases in blood oxygen pressure, oxygen saturation, an initial increase in blood and inspiratory carbon dioxide pressure, and a higher perceived physical exertion and temperature and humidity behind the mask under very heavy exercise. All effects were stronger when wearing an FFP2. Wearing face masks at rest and under exercise, changed breathing patterns in the sense of physiological compensation without representing a health risk. Wearing a mask for 4-h during light work had no effect on blood gases., (© 2023. The Author(s).)
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- 2023
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23. Publisher Correction: Mortality rates of severe COVID-19-related respiratory failure with and without extracorporeal membrane oxygenation in the Middle Ruhr Region of Germany.
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Aweimer A, Petschulat L, Jettkant B, Köditz R, Finkeldei J, Dietrich JW, Breuer T, Draese C, Frey UH, Rahmel T, Adamzik M, Buchwald D, Useini D, Brechmann T, Hosbach I, Bünger J, Ewers A, El-Battrawy I, and Mügge A
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- 2023
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24. Mortality rates of severe COVID-19-related respiratory failure with and without extracorporeal membrane oxygenation in the Middle Ruhr Region of Germany.
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Aweimer A, Petschulat L, Jettkant B, Köditz R, Finkeldei J, Dietrich JW, Breuer T, Draese C, Frey UH, Rahmel T, Adamzik M, Buchwald D, Useini D, Brechmann T, Hosbach I, Bünger J, Ewers A, El-Battrawy I, and Mügge A
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- Humans, Male, Aged, Female, Treatment Outcome, Retrospective Studies, Bilirubin, COVID-19 therapy, Extracorporeal Membrane Oxygenation, Respiratory Insufficiency therapy
- Abstract
The use of extracorporeal membrane oxygenation (ECMO) is discussed to improve patients' outcome in severe COVID-19 with respiratory failure, but data on ECMO remains controversial. The aim of the study was to determine the characteristics of patients under invasive mechanical ventilation (IMV) with or without veno-venous ECMO support and to evaluate outcome parameters. Ventilated patients with COVID-19 with and without additional ECMO support were analyzed in a retrospective multicenter study regarding clinical characteristics, respiratory and laboratory parameters in day-to-day follow-up. Recruitment of patients was conducted during the first three COVID-19 waves at four German university hospitals of the Ruhr University Bochum, located in the Middle Ruhr Region. From March 1, 2020 to August 31, 2021, the charts of 149 patients who were ventilated for COVID-19 infection, were included (63.8% male, median age 67 years). Fifty patients (33.6%) received additional ECMO support. On average, ECMO therapy was initiated 15.6 ± 9.4 days after symptom onset, 10.6 ± 7.1 days after hospital admission, and 4.8 ± 6.4 days after the start of IMV. Male sex and higher SOFA and RESP scores were observed significantly more often in the high-volume ECMO center. Pre-medication with antidepressants was more often detected in survivors (22.0% vs. 6.5%; p = 0.006). ECMO patients were 14 years younger and presented a lower rate of concomitant cardiovascular diseases (18.0% vs. 47.5%; p = 0.0004). Additionally, cytokine-adsorption (46.0% vs. 13.1%; p < 0.0001) and renal replacement therapy (76.0% vs. 43.4%; p = 0.0001) were carried out more frequently; in ECMO patients thrombocytes were transfused 12-fold more often related to more than fourfold higher bleeding complications. Undulating C-reactive protein (CRP) and massive increase in bilirubin levels (at terminal stage) could be observed in deceased ECMO patients. In-hospital mortality was high (Overall: 72.5%, ECMO: 80.0%, ns). Regardless of ECMO therapy half of the study population deceased within 30 days after hospital admission. Despite being younger and with less comorbidities ECMO therapy did not improve survival in severely ill COVID-19 patients. Undulating CRP levels, a massive increase of bilirubin level and a high use of cytokine-adsorption were associated with worse outcomes. In conclusion, ECMO support might be helpful in selected severe cases of COVID-19., (© 2023. The Author(s).)
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- 2023
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25. No inflammatory effects after acute inhalation of barium sulfate particles in human volunteers.
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Monsé C, Westphal G, Raulf M, Jettkant B, van Kampen V, Kendzia B, Schürmeyer L, Seifert CE, Marek EM, Wiegand F, Rosenkranz N, Wegener C, Merget R, Brüning T, and Bünger J
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- Animals, Barium Sulfate toxicity, Healthy Volunteers, Humans, Inhalation Exposure adverse effects, Particle Size, Nanoparticles, Zinc Oxide toxicity
- Abstract
Background: Most threshold limit values are based on animal experiments. Often, the question remains whether these data reflect the situation in humans. As part of a series of investigations in our exposure lab, this study investigates whether the results on the inflammatory effects of particles that have been demonstrated in animal models can be confirmed in acute inhalation studies in humans. Such studies have not been conducted so far for barium sulfate particles (BaSO
4 ), a substance with very low solubility and without known substance-specific toxicity. Previous inhalation studies with zinc oxide (ZnO), which has a substance-specific toxicity, have shown local and systemic inflammatory respones. The design of these human ZnO inhalation studies was adopted for BaSO4 to compare the effects of particles with known inflammatory activity and supposedly inert particles. For further comparison, in vitro investigations on inflammatory processes were carried out., Methods: Sixteen healthy volunteers were exposed to filtered air and BaSO4 particles (4.0 mg/m3 ) for two hours including one hour of ergometric cycling at moderate workload. Effect parameters were clinical signs, body temperature, and inflammatory markers in blood and induced sputum. In addition, particle-induced in vitro-chemotaxis of BaSO4 was investigated with regard to mode of action and differences between in vivo and in vitro effects., Results: No local or systemic clinical signs were observed after acute BaSO4 inhalation and, in contrast to our previous human exposure studies with ZnO, no elevated values of biomarkers of inflammation were measured after the challenge. The in vitro chemotaxis induced by BaSO4 particles was minimal and 15-fold lower compared to ZnO., Conclusion: The results of this study indicate that BaSO4 as a representative of granular biopersistent particles without specific toxicity does not induce inflammatory effects in humans after acute inhalation. Moreover, the in vitro data fit in with these in vivo results. Despite the careful and complex investigations, limitations must be admitted because the number of local effect parameters were limited and chronic toxicity could not be studied., (© 2022. The Author(s).)- Published
- 2022
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26. Maggot Extract Interrupts Bacterial Biofilm Formation and Maturation in Combination with Antibiotics by Reducing the Expression of Virulence Genes.
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Becerikli M, Wallner C, Dadras M, Wagner JM, Dittfeld S, Jettkant B, Gestmann F, Mehlhorn H, Mehlhorn-Diehl T, Lehnhardt M, and Behr B
- Abstract
Biofilms are aggregates of bacteria encased in an extracellular polymer matrix that acts as a diffusion barrier protecting the microbial community. Bacterial communication occurs by small signaling molecules called quorum sensing (QS) factors, which are involved in the activation of virulence genes and formation of biofilms. Larvae of the green bottle blowfly Lucilia sericata remove necrotic tissue by mechanical action (debridement) and proteolytic digestion. We produced a freeze-dried storable powder from larval extract and investigated its therapeutic effect on biofilms. Larval extract in concentrations of 6 and 12 mg/mL in combination with 0.5% antibiotics (≙50 U/mL penicillin and 50 μg/mL streptomycin) diminished free-floating (planktonic) Pseudomonas aeruginosa maintenance, while it showed no effect on S taphylococcus aureus and was not toxic to dermal cells. We established an ex vivo human dermal wound model. Larval extract in concentrations of 24 and 75 mg/mL in the presence of antibiotics (0.5%) significantly destroyed the biofilm stability of both P. aeruginosa and S. aureus biofilms. Furthermore, SEM analyses revealed crack and gap formations on P. aeruginosa. biofilm surface and decreased expression of P. aeruginosa biofilm maturation and virulence genes ( lasR , rhlR and rhlA ) was observed after treatment by larval extract in combination with antibiotics.
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- 2022
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27. Improved Physiological Gait in Acute and Chronic SCI Patients After Training With Wearable Cyborg Hybrid Assistive Limb.
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Brinkemper A, Aach M, Grasmücke D, Jettkant B, Rosteius T, Dudda M, Yilmaz E, and Schildhauer TA
- Abstract
In recent years robotic devices became part of rehabilitation offers for patients suffering from Spinal Cord Injury (SCI) and other diseases. Most scientific publications about such devices focus on functional outcome. The aim of this study was to verify whether an improvement in physiological gait can be demonstrated in addition to the functional parameters after treatment with neurological controlled HAL® Robot Suit. Fifteen subjects with acute (<12 months since injury, n = 5) or chronic (>12 months since injury, n = 10) incomplete paraplegia (AIS B, n = 0/AIS C, n = 2/AIS D, n = 8) or complete paraplegia (AIS A, n = 5) with zones of partial preservation participated. Subjects underwent a body weight supported treadmill training for five times a week over 12 weeks using HAL®. At baseline and at the end of the study a gait analysis was performed and additional functional parameters such as 10-Meter-Walk-Test, Timed-Up-and-Go-Test, 6-Minutes-Walk-Test, and WISCI II score were collected. Results were evaluated for whole group and individually for acute and chronic subgroups. All functional parameters improved. Differences were also found in physiological parameters such as phases of gait cycle and accompanied by significant improvement in all spatiotemporal and gait phase parameters. The presented study shows signs that an improvement in physiological gait can be achieved in addition to improved functional parameters in patients with SCI after completing 12-week training with HAL®. Trial Registration: DRKS, DRKS00020805. Registered 12 February 2020-Retrospectively registered, https://www.drks.de/DRKS00020805., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Brinkemper, Aach, Grasmücke, Jettkant, Rosteius, Dudda, Yilmaz and Schildhauer.)
- Published
- 2021
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28. Clinical and Radiological Outcomes After Surgical Treatment of Lower Limb Fractures in Patients With Spinal Cord Injury.
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Ung L, Ohlmeier M, Jettkant B, Grasmücke D, Aach M, Meindl R, Nicolas V, Schildhauer TA, and Citak M
- Abstract
Study Design: Retrospective observational study., Objectives: To analyze the clinical and radiological outcomes of lower limb fractures following surgical treatment in patients with chronic spinal cord injury (SCI)., Methods: Between January 2003 and December 2015, 102 chronic SCI patients with a lower limb fracture were surgically treated at our hospital. A total of 58 patients met the inclusion criteria and were recruited for final analysis. Patients with 2-stage procedure or incomplete clinical records with lost-to-follow-up were excluded from the study. Patients were divided into 2 groups (group 1= internal fixation; group 2 = external fixation). Primary outcome measures were to identify the number of nonunions via Kaplan-Meier analysis and the time to bone consolidation. The diagnosis of a pseudarthrosis was made after more than 180 days of consolidation time. Considering the Kaplan-Meier analysis, pseudarthrosis was interpreted as treatment failure. Secondary outcome measure was to evaluate the complication rate with special focus on heterotopic ossification., Results: A total of 58 chronic SCI patients with closed bone fractures were included in this study. Fifty-two fractures (88%) were simple and 7 (12%) were complex (type C) fractures according to AO classification. The majority of patients (34 cases, 59%) developed femur fractures followed by 24 tibial fractures (41%). Seventeen patients received an external (29%) and 41 an internal fixation (71%). Bone consolidation was reported in 31 patients (53%) with a mean time interval of bone consolidation after 97 days (range from 45 to 160 days; SD = 30). The reported nonunion (pseudarthrosis) rate was 47%. Comparing the internal group (n = 15 patients) versus the external group (n = 14), we could not find any significant difference ( P = .939) concerning the bone consolidation time. The Kaplan-Meier analysis showed a 75% cumulative survivorship at 120 days (internal group) versus 111 days (external group). Most common postoperative complications occurred in the internal fixation group with Wound infections being predominantly observed (10%), followed by heterotopic ossifications (8%)., Conclusions: Our results show that surgical treatment of lower limb fractures in chronic SCI patients is a challenging treatment with a high pseudarthrosis rate in both groups. The complication rate seems to be lower in the patients treated with external fixation. As a clinical recommendation, longer implants should be used for a stable osteosynthesis since SCI patients seem to have a higher load on the osteosynthesis material due to missing sensomotoric feedback.
- Published
- 2020
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29. Heart rate variability and cardiac repolarization after exposure to zinc oxide nanoparticles in healthy adults.
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Aweimer A, Jettkant B, Monsé C, Hagemeyer O, van Kampen V, Kendzia B, Gering V, Marek EM, Bünger J, Mügge A, Brüning T, and Merget R
- Abstract
Background: Exposure to airborne zinc oxide (ZnO) particles occurs in many industrial processes, especially in galvanizing and welding. Systemic inflammation after experimental inhalation of ZnO particles has been demonstrated previously, but little is known about the impact on the cardiovascular system, particularly on the autonomic cardiac system and the risk of arrhythmias. In this study we investigated the short-term effects of ZnO nanoparticles on heart rate variability (HRV) and repolarization in healthy adults in a concentration-dependent manner at rest and during exercise in a controlled experimental set-up., Methods: Sixteen healthy subjects were exposed to filtered air and ZnO particles (0.5, 1.0 and 2.0 mg/m
3 ) for 4 h, including 2 h of cycling at low workloads. Parameters were assessed before, during, immediately after, and about 24 h after each exposure. For each subject, a total number of 46 10-min-sections from electrocardiographic records were analyzed. Various parameters of HRV and QT interval were measured., Results: Overall, no statistically significant effects of controlled ZnO inhalation on HRV parameters and QT interval were observed. Additionally, a concentration-response was absent., Conclusion: Inhalation of ZnO nanoparticles up to 2.0 mg/m3 for 4 h does not affect HRV and cardiac repolarization in healthy adults at the chosen time points. This study supports the view that cardiac endpoints are insensitive for the assessment of adverse effects after short-term inhalation of ZnO nanoparticles., Competing Interests: Competing interestsThe authors declare that they have no competing interests., (© The Author(s) 2020.)- Published
- 2020
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30. Airway inflammation after inhalation of nano-sized zinc oxide particles in human volunteers.
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Monsé C, Raulf M, Hagemeyer O, van Kampen V, Kendzia B, Gering V, Marek EM, Jettkant B, Bünger J, Merget R, and Brüning T
- Subjects
- Administration, Inhalation, Adult, Female, Healthy Volunteers, Humans, Male, Nanoparticles administration & dosage, Particle Size, Sputum chemistry, Young Adult, Zinc Oxide administration & dosage, Cough chemically induced, Nanoparticles adverse effects, Pharyngitis chemically induced, Zinc Oxide adverse effects
- Abstract
Background: Workers in the zinc production and processing of galvanized sheet steel are exposed to a complex mixture of particles and gases, including zinc oxide (ZnO) that can affect human health. We aimed to study the effects of short-term controlled exposure to nano-sized ZnO on airway inflammatory markers in healthy volunteers., Methods: Sixteen subjects (8 females, 8 men; age 19-42, non-smokers) were exposed to filtered air and ZnO nanoparticles (0.5, 1.0 and 2.0 mg/m
3 ) for 4 h, including 2 h of cycling with a low workload. Induced sputum samples were collected during a medical baseline and a final examination and also about 24 h after each exposure. A number of inflammatory cellular and soluble markers were analyzed., Results: Frequency and intensity of symptoms of airway irritation (throat irritation and cough) were increased in some subjects 24 h after ZnO exposures when compared to filtered air. The group comparison between filtered air and ZnO exposures showed statistically significant increases of neutrophils and interleukin-8 (IL-8), interleukin-6 (IL-6), matrix metalloproteinase (MMP-9) and tissue inhibitors of metalloproteinases (TIMP-1) in sputum starting at the lowest ZnO concentration of 0.5 mg/m3 . However, a concentration-response relationship was absent. Effects were reversible. Strong correlations were found between neutrophil numbers and concentrations of total protein, IL-8, MMP-9, and TIMP-1., Conclusions: Controlled exposures of healthy subjects to ZnO nanoparticles induce reversible airway inflammation which was observed at a concentration of 0.5 mg/m3 and higher. The lack of a concentration-response relationship warrants further studies.- Published
- 2019
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31. P2000 - A high-nitrogen austenitic steel for application in bone surgery.
- Author
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Becerikli M, Jaurich H, Wallner C, Wagner JM, Dadras M, Jettkant B, Pöhl F, Seifert M, Jung O, Mitevski B, Karkar A, Lehnhardt M, Fischer A, Kauther MD, and Behr B
- Subjects
- Alkaline Phosphatase metabolism, Alloys chemistry, Alloys pharmacology, Animals, Bone Diseases surgery, Bone Diseases therapy, Bone Substitutes pharmacology, Bone Substitutes therapeutic use, Cell Line, Cell Proliferation drug effects, Core Binding Factor alpha Subunits metabolism, Corrosion, Hardness, Mice, Osteoblasts cytology, Osteoblasts drug effects, Osteoblasts metabolism, Prostheses and Implants, Stainless Steel pharmacology, Surface Properties, Bone Substitutes chemistry, Nitrogen chemistry, Stainless Steel chemistry
- Abstract
Optimal treatment of bone fractures with minimal complications requires implant alloys that combine high strength with high ductility. Today, TiAl6V4 titanium and 316L steel are the most applied alloys in bone surgery, whereas both share advantages and disadvantages. The nickel-free, high-nitrogen austenitic steel X13CrMnMoN18-14-3 (1.4452, brand name: P2000) exhibits high strength in combination with superior ductility. In order to compare suitable alloys for bone implants, we investigated titanium, 316L steel, CoCrMo and P2000 for their biocompatibility and hemocompatibility (according to DIN ISO 10993-5 and 10993-4), cell metabolism, mineralization of osteoblasts, electrochemical and mechanical properties. P2000 exhibited good biocompatibility of fibroblasts and osteoblasts without impairment in vitality or changing of cell morphology. Furthermore, investigation of the osteoblasts function by ALP activity and protein levels of the key transcription factor RUNX2 revealed 2x increased ALP activity and more than 4x increased RUNX2 protein levels for P2000 compared to titanium or 316 steel, respectively. Additionally, analyses of osteoblast biomineralization by Alizarin Red S staining exhibited more than 6x increased significant mineralization of osteoblasts grown on P2000 as compared to titanium. Further, P2000 showed no hemolytic effect and no significant influence on hemocompatibility. Nanoindentation hardness tests of Titanium and 316L specimens exposed an indentation hardness (HIT) of about 4 GPa, whereas CoCrMo and P2000 revealed HIT of 7.5 and 5.6 GPa, respectively. Moreover, an improved corrosion resistance of P2000 compared to 316L steel was observed. In summary, we could demonstrate that the nickel-free high-nitrogen steel P2000 appears to be a promising alternative candidate for applications in bone surgery. As to nearly all aspects like biocompatibility and hemocompatibility, cell metabolism, mineralization of osteoblasts and mechanical properties, P2000 was similar to or revealed advantages against titanium, 316L or CoCrMo., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2019
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32. Concentration-dependent systemic response after inhalation of nano-sized zinc oxide particles in human volunteers.
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Monsé C, Hagemeyer O, Raulf M, Jettkant B, van Kampen V, Kendzia B, Gering V, Kappert G, Weiss T, Ulrich N, Marek EM, Bünger J, Brüning T, and Merget R
- Subjects
- Acute-Phase Reaction blood, Adult, Female, Healthy Volunteers, Humans, Inhalation Exposure adverse effects, Male, Nanoparticles administration & dosage, Particle Size, Surveys and Questionnaires, Young Adult, Zinc Oxide administration & dosage, Acute-Phase Reaction chemically induced, Inhalation Exposure analysis, Nanoparticles toxicity, Zinc Oxide toxicity
- Abstract
Background: Inhalation of high concentrations of zinc oxide particles (ZnO) may cause metal fume fever. In an earlier human inhalation study, no effects were observed after exposure to ZnO concentrations of 0.5 mg/m
3 . Further data from experimental studies with pure ZnO in the concentration range between 0.5 and 2.5 mg/m3 are not available. It was the aim of this experimental study to establish the concentration-response relationship of pure nano-sized ZnO particles., Methods: Sixteen healthy subjects were exposed to filtered air and ZnO particles (0.5, 1.0 and 2.0 mg/m3 ) for 4 h on 4 different days, including 2 h of cycling with a low workload. The effects were assessed before, immediately after, and about 24 h after each exposure. Effect parameters were symptoms, body temperature, inflammatory markers and clotting factors in blood, and lung function., Results: Concentration-dependent increases in symptoms, body temperature, acute phase proteins and neutrophils in blood were detected after ZnO inhalation. Significant effects were detected with ZnO concentrations of 1.0 mg/m3 or higher, with the most sensitive parameters being inflammatory markers in blood., Conclusion: A concentration-response relationship with nano-sized ZnO particles in a low concentration range was demonstrated. Systemic inflammatory effects of inhaled nano-sized ZnO particles were observed at concentrations well below the occpational exposure limit for ZnO in many countries. It is recommended to reassess the exposure limit for ZnO at workplaces.- Published
- 2018
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33. The Influence of Humidity on Assessing Irritation Threshold of Ammonia.
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Monsé C, Sucker K, Hoffmeyer F, Jettkant B, Berresheim H, Bünger J, and Brüning T
- Subjects
- Administration, Inhalation, Adult, Ammonia administration & dosage, Ammonia chemistry, Dose-Response Relationship, Drug, Female, Humans, Male, Middle Aged, Threshold Limit Values, Ammonia toxicity, Humidity, Sensory Thresholds drug effects, Sensory Thresholds physiology, Smell drug effects, Smell physiology
- Abstract
A large number of occupational exposure limit values (OELs) are based on avoiding of sensory irritation of the eyes and the upper respiratory tract. In order to investigate the chemosensory effect range of a chemical, odor and sensory irritation thresholds (lateralization thresholds, LTs) can be assessed. Humidity affects olfactory function and thus influences odor thresholds; however, a similar effect has not been shown for sensory irritation thresholds. The purpose of the present study was to explore whether LTs for ammonia vapor vary depending on the water vapor content of the inspired stimulus. Eight healthy nonsmoking volunteers were simultaneously exposed to ammonia vapor through one nostril and clean air through the other and were asked to determine which nostril received the chemical. Within experimental runs, ascending ammonia concentrations (60-350 ppm) that were either dry or humidified were administered at fixed time intervals. Geometric mean LTs obtained at wet (181 ppm) or dry (172 ppm) conditions did not differ significantly (P = 0.19) and were within the range of those reported by previous studies. These results suggest that humidity is not a critical factor in determining sensory irritation thresholds for ammonia, and future studies will examine if these findings are transferable to sensory irritation thresholds for other chemicals.
- Published
- 2016
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34. Improved wire stiffness with modified connection bolts in Ilizarov external frames: a biomechanical study.
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Gessmann J, Jettkant B, Königshausen M, Schildhauer TA, and Seybold D
- Subjects
- Elastic Modulus, Equipment Failure Analysis, Prosthesis Design, Stress, Mechanical, Tensile Strength, Bone Screws, Bone Wires, Ilizarov Technique instrumentation
- Abstract
Frame stability in Ilizarov external fixators is mainly dependent on the tension of the transosseous wires, which are clamped to the ring by connection bolts. It was the purpose of this biomechanical study to investigate the holding capacity of a modified bolt design featuring a ruffled wire-bolt interface (TrueLok™) and its influence on wire stiffness in comparison with that of classic bolts featuring a smooth, unruffled wire-bolt interface. Six different ring and bolt configurations were tested using a simplified model consisting of a single ring and wire. The holding capacity at two different tightening torques (10 and 14 Nm) of classic cannulated bolts (CB) and slotted bolts (SB) was determined on Ilizarov and Taylor Spatial Frame (TSF™) rings, whereas the modified TrueLok™ CBs and SBs were used with the TrueLok™ rings. The wire stiffness was calculated via a regression analysis of the load-displacement graphs. The modified TrueLok™ bolts demonstrated significantly better slippage resistance than the classic bolts in all configurations and wire stiffness was significantly higher in the TrueLok™ frame set-ups. After maximum loading, all of the wires showed plastic deformation, including constant wire deflection and dent marks at the clamped wire ends. In conclusion, the decrease in wire stiffness can be explained mainly as a result of wire slippage, but plastic deformation and material yielding also contribute. The relatively simple modification made by roughening the wire-bolt interface results in improved holding capacity and wire stiffness. A frame that contains these modified TrueLok™ bolts should provide improved mechanical stiffness.
- Published
- 2012
35. Direct and indirect loading of the Ilizarov external fixator: the effect on the interfragmentary movements and compressive loads.
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Gessmann J, Baecker H, Jettkant B, Muhr G, and Seybold D
- Abstract
The amount of weight bearing and the force transmission to the frame have an important influence on the results of treatment with an Ilizarov external fixator. The frame provides beneficial interfragmentary movements and compressive loads at the fracture site through elastic wires. Mobilisation can be achieved by applying a weight-bearing platform at the distal end of the fixator. The effect on the interfragmentary movements and the compressive loads in indirect and direct loading were analysed in this study using a composite tibia bone model. Displacement transducers were attached to measure the interfragmentary movements and to detect relative movements of the bone fragments and movements between the rings. The compressive loads in the osteotomy were measured with loading cells in the defect zone. The weight-bearing platform had a substantial effect on the biomechanical behaviour of the frame. It led to an indirect force transmission through the fixator with respect to the osteotomy, resulting in lower compressive loads, lower interfragmentary movements and higher mechanical stress on the frame.
- Published
- 2011
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36. Burn model for in vivo investigations of microcirculatory changes.
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Goertz O, Vogelpohl J, Jettkant B, Daigeler A, Steinau HU, Steinstraesser L, and Langer S
- Abstract
Objective: The treatment of burns remains a challenge due to the associated high morbidity and mortality. Besides the administration of physiologic saline, local disinfection, and symptomatic medications, no causal therapy is known to reduce the tissue damage and accelerate wound healing. The aim of the study was to develop a reliable burn model that allows for reproducible quantitative in vivo analysis of the microcirculation, angiogenesis, and leukocyte endothelium interaction after burn injury., Methods: Experiments were carried out on male hairless mice (n = 9). Full-thickness burns were inflicted with a hot air jet without any contact to the tissue (117 +/- 2.1 degrees C for 1 second; burn area: 1.3 mm(2)). Intravital fluorescent microscopy, in combination with FITC-dextran as plasma marker, was used to assess microcirculatory standard parameters; leukocytes were stained with rhodamine 6G. Values were obtained before, immediately after, as well as at days 1, 3, 7, and 14 postburn., Results: The nonperfused area decreased during the observed period and perfusion was almost completely due to angiogenesis at day 14. No posttraumatic expansion of the nonperfused area after 24 hours could be observed. Leukocyte endothelium interaction showed its maximum 24 hours postburn. The formation of edema occurred immediately postburn and decreased during the following observation time., Conclusion: The developed burn model allows a reproducible assessment with significant results of the microcirculation, angiogenesis, and leukocyte endothelium interaction without causing mechanical damage to the tissue; therefore, this model qualifies for the further investigations of interventional drugs to decrease the effects of burn injury.
- Published
- 2009
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