Technology and health care : official journal of the European Society for Engineering and Medicine
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Technol Health Care · Jan 2008
Randomized Controlled TrialThe effect of tourniquet release timing on perioperative blood loss in simultaneous bilateral cemented total knee arthroplasty: a prospective randomized study.
Today the use of pneumatic tourniquet is commonly accepted in total knee arthroplasty (TKA) to reduce perioperative blood loss. There are a few prospective randomised and nonrandomised studies that compare the effect of tourniquet release timing in cementless or cemented unilateral TKA. However, many of these studies show an inadequate reporting and methodology. ⋯ Other studies report an increase the blood loss in early tourniquet release and an increase the risk of early postoperative complications in deflation of tourniquet after wound closure. In this study we found no significant difference in perioperative blood loss and no increase of postoperative complications. Therefore, we recommend a tourniquet release after wound closure to reduce the duration of TKA procedure and to avoid possible risks of extended anaesthesia.
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Technol Health Care · Jan 2008
Interference of neodymium magnets with cardiac pacemakers and implantable cardioverter-defibrillators: an in vitro study.
Permanent magnets may interfere with the function of cardiac pacemakers and implantable cardioverter-defibrillators (ICDs). Neodymium-iron-boron (NdFeB) magnets have become widely available in recent years and are incorporated in various articles of daily life. We conducted an in-vitro study to evaluate the ability of NdFeB magnets for home and office use to cause interference with cardiac pacemakers and ICDs. ⋯ The pacemaker behavior was influenced at distances from 1 cm to 24 cm. NdFeB magnets for home and office use may cause interference with cardiac pacemakers and ICDs at distances up to 24 centimeters. Patient education and product declarations should include information about the risk associated with these magnets.
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Technol Health Care · Jan 2008
A new bending stiffness measurement device to monitor the influence of different intramedullar implants during healing period.
To manage fractures in long bones, intramedullar implants, plates or external fixators are often used. In many cases, the implants are removed after bone consolidation. X-ray images are normally used to monitor bone formation and to determine the point of return to full load bearing and removal of the implants. ⋯ Both the test-specimen and bones of the in vivo study were compared with data in a materials testing system (MTS) in four-point bending. The device was found to have a high precision and significant in vitro and in vivo correlation with the MTS. The results suggest that this measurement device has the ability to monitor the healing process of bone and to analyse the influence of degradable implants on the mechanical behaviour of bone or bone metabolism effecting pharmaceutics.
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Technol Health Care · Jan 2008
Response of a viscoelastic layer (mucus) to turbulent airflow in a rigid tube.
Basic interaction mechanism between the air flow and viscoelastic mucus layer lining a rigid tube is computationally studied. Linear wave instability theory is applied to the coupled air-mucus system to explore the stability of the interface. Primary velocity profile is taken to be the mean profile of turbulent flow and turbulent fluctuations are neglected. ⋯ Model also predicts that the waves initiate at lower flow velocities for the turbulent case compared to the published laminar case. Turbulent onset flow speed is only 34% Flow is considered to be turbulent during forced expiration and coughing in central and upper airways. Model predicts that this flow behavior tends to favor wave initiation at lower flow rates and may facilitate cough clearance.
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Technol Health Care · Jan 2006
Clinical TrialFirst clinical and biomechanical results of the Trochanteric Fixation Nail (TFN).
Conventional osteosynthesis of proximal femur fractures is still affected by serious complication rates between 4-18%, even though advanced implant modifications and surgical techniques are common practice. In terms of increasing age and co-morbidity of patients this complication ratio is expected to increase even further in the immediate future. One major reason for implant failure is the decreasing stability potential of the implant due to a loss in mechanical properties of cancellous bone. ⋯ All investigations were performed on human femoral heads. The bone mineral densities of the specimens were detected by QCT-scans. Prior to cadaveric testing the experimental set-up was validated (n = 8) by the use of synthetic foam blocks (Sawbone).