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440 results on '"Bergmann, Georg"'

1. Knieendoprothetik: Biomechanik des Kniegelenks

Author

Duda, Georg N., Moewis, Philippe, Hommel, Hagen, Heller, Markus O., Taylor, William R., Bergmann, Georg, Trepczynski, Adam, Matziolis, Georg, Section editor, Pfitzner, Tilman, Section editor, Reichel, Heiko, Section editor, Wirtz, Dieter, Section editor, Wirtz, Dieter Christian, editor, Reichel, Heiko, editor, Matziolis, Georg, editor, and Pfitzner, Tilman, editor

Published
2023
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34. Implantable 9-channel telemetry system for in vivo load measurements with orthopedic implants

Author

Graichen, Friedmar, Arnold, Rudiger, Rohlmann, Antonius, and Bergmann, Georg

Subjects
Telemetry -- Usage, Orthopedic implants -- Research, Circuit design -- Research, Circuit designer, Integrated circuit design, Biological sciences, Business, Computers, Health care industry
Abstract

Knowledge of the loads to which orthopedic implants are subjected is a fundamental prerequisite for their optimal biomechanical design, long-term success, and improved rehabilitation outcomes. In vivo load measurements are more accurate than those obtained using mathematical musculoskeletal models. An inductively powered integrated circuit inside the implant measures six load components as well as the temperature and supplied voltage. This low-power circuit includes a 9-channel multiplexer, a programmable memory, a pulse interval modulator, and a radio-frequency transmitter. Together with a few passive components, the integrated circuit is mounted on a ceramic substrate with thick-film hybrid technology. The sensor signals are multiplexed, modulated, and transmitted to an external device. The microcontroller of the external device regulates the alternating magnetic field produced by a power oscillator and synchronizes the pulse interval modulated data stream. A personal computer displays forces, moments, and temperatures in real time. The new telemetry transmitter has, thus far, been used for in vivo load measurements in three patients with shoulder endoprostheses. Eight instrumented vertebral body replacements are ready for implantation, and an instrumented tibial tray is being submitted to laboratory tests. Index Terms--Biomedical telemetry, implantable orthopedic device, integrated circuit design, knee, prosthesis, shoulder, spine, tibial tray.

Published
2007

46. Der reibungsinduzierte Temperaturanstieg im künstlichen Hüftgelenk beim Gehen

Author

Damm, Philipp, Bender, Alwina, Dymke, Jörn, Bergmann, Georg, and Duda, Georg N.

Subjects
in vivo, Hüfte, ddc: 610, Implantat, Temperatur, 610 Medical sciences, Medicine
Abstract

Fragestellung: Die Reibung zwischen Kopf und Pfanne ist ein primärer Faktor für die Lebensdauer des Gelenkersatzes und dessen Gleitflächen. Bei bis zu 40% aller Revisionen muss infolge des Abriebs die Pfanne bzw. das Inlay ausgetauscht werden (Report of the Can. Inst. Of Health Inf.,[zum vollständigen Text gelangen Sie über die oben angegebene URL], Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2019)

Published
2019

48. Loads on an internal spinal fixation device during physical therapy. (Technical Report)

Author

Rohlmann, Antonius, Graichen, Friedmar, and Bergmann, Georg

Subjects
Prosthesis -- Physiological aspects -- Research, Implants, Artificial -- Physiological aspects -- Research, Spinal fusion -- Care and treatment -- Physiological aspects -- Research, Stress (Physiology) -- Research -- Physiological aspects, Health
Abstract

Background and Purpose. Modified internal spinal fixation devices allow the measurement of the forces and moments acting on the implants. The aim of this study was to measure the loads on internal fixation devices for selected body positions and movements during physical therapy. Subjects and Methods. Loads on an internal spinal fixation device were measured in 10 patients with degenerative instability or compression fractures using a telemeterized implant. Results. Relatively low implant loads were found in the recumbent body positions. Most exercises performed in a lying position caused implant loads less than that measured for standing and are therefore not likely to increase the risk of screw breakage. Fixation device loads were lower for sitting relaxed than for standing. The highest implant loads (128% of the value for standing) were measured during walking. Standing up, sitting down, and lateral bending and axial rotation of the upper body while standing led to fixation device loads between 111% and 120% related to the value for standing. Even higher fixation device loads were measured for ventral flexion and extension of the upper body while standing. Kneeling on hands and knees, and flexing and extending the back in this position, caused implant loads that were lower than for standing. Discussion and Conclusion. Standing up, sitting down, and lateral bending and axial rotation of the upper body while standing may slightly increase the risk of pedicle screw breakage, whereas ventral flexion and extension of the upper body while standing may increase this risk considerably if the region bridged by the implant is distracted (the distance between upper and lower screws was increased) during surgery. However, walking is the exercise that plays the major role concerning pedicle screw breakage because it causes the highest bending moments of all exercises studied and it loads the fixation devices most frequently. [Rohlmann A, Graichen F, Bergmann G. Loads on an internal spinal fixation device during physical therapy. Phys Ther. 2002;82:44-52.] Key Words: Biomechanics, Internal spinal fixation device, Load measurement, Physical therapy, Spine., Spines that are unstable (eg, due to fracture or degenerative disorder) are often stabilized by an internal spinal fixation device. The 2 longitudinal rods of the paired implanted fixation devices [...]

Published
2002

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