Biomedizinische Technik. Biomedical engineering
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Clinical Trial
Adaptive on-line classification for EEG-based brain computer interfaces with AAR parameters and band power estimates.
We present the result of on-line feedback Brain Computer Interface experiments using adaptive and non-adaptive feature extraction methods with an on-line adaptive classifier based on Quadratic Discriminant Analysis. Experiments were performed with 12 naïve subjects, feedback was provided from the first moment and no training sessions were needed. ⋯ The study was done using single trial analysis of each of the sessions and the value of the Error Rate and the Mutual Information of the classification were used to discuss the results. Finally, it was shown that even subjects starting with a low performance were able to control the system in a few hours: and contrary to previous results no differences between AAR and BP estimates were found.
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The method of retransfusion of drainage blood as known from the literature was investigated in a prospectiv study regarding effectivness and rate of side effects. 200 patients who underwent total hip and knee arthroplasty were investigated concerning hemoglobin, hematocrit, amount and quality of the retransfused drainage blood, the amount of autologous and homologous transfusions as well as complications and costs. 100 of these patients were selected as the control group. The amount of the retransfused drainage blood after hip arthroplasty amounted an average of 387 +/- 194 ml and after knee arthroplasty 595 +/- 250 ml. The retransfused blood had an average hemoglobin of 5,2 +/- 0,9mmol/l with a hematocrit of 0,24 0,05. ⋯ Substantial complications were not observed, so that this method seems to be save enough for clinical usage. The method is easy to handle and usable without special technical devices. The autologous retransfusion of drainage blood can contribute to lower costs in patients treatement.
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Clinical Trial Controlled Clinical Trial
[Prospective screw misplacement analysis after conventional and navigated pedicle screw implantation].
[corrected] The aim of this prospective study was (1) to evaluate the accuracy of pedicle screw placement using Computer - Assisted Orthopedic - Surgery (CAOS) in comparison to conventionelly image intensifier controlled pedicle screw instrumentation, (2) to compare our results with data from literature and (3) report our experiences with this technique. ⋯ Computer assisted surgery reduces significantly the misplacement rate of pedicle screws and remains for experienced spine surgeons an important support in the operative treatment of complex spinal deformities in future. Additionally it can be expected that Computer-Navigation will also spread out in the field of minimal-invasive spinal surgery, e.g. the kyphoplasty. The use of this technique supports beside the medical-technical knowledge an improved three-dimensional orientation in the education of spine surgeons.
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Heliox is a mixture of Oxygen and Helium. The low density of Helium allows this mixture to flow in a laminar pattern where oxygen, nitrogen or air flow would be turbulent. Therefore the force necessary to move a volume of gas (e.g. ⋯ Heliox showed effects on hemodynamic as well as respiratory and subjective variables. These effects can be interpreted as a reduction of the extent of pressure variations in the intrapleural space leading to less impact on hemodynamic variables while breathing Heliox vs. room air in a resistive loading experiment. In the future the combined measurement of hemodynmic variables as well as non-invasive assessment of respiration might shed new light on cardio-respiratory interaction and effects of Heliox during airway obstruction.
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Animals are becoming more and more common as in vivo models for the human spine. Especially the sheep cervical spine is stated to be of good comparability and usefulness in the evaluation of in vivo radiological, biomechanical and histological behaviour of new bone replacement materials, implants and cages for cervical spine interbody fusion. In preceding biomechanical in vitro examinations human cervical spine specimens were tested after fusion with either a cubical stand-alone interbody fusion cage manufactured from a new porous TiO2/glass composite (Ecopore) or polymethylmethacrylate (PMMA) after discectomy. ⋯ The decrease of the ROM correlated with the radiological-morphological degree of fusion. Our evaluation of the new porous TiO2/glass composite as interbody fusion cage has shown satisfactory radiological results as well as distinct biomechanical stability and fusion of the segments after 4 months in comparison to PMMA. After histological analysis of the bone-biomaterial-interface, further examinations of this biomaterial previous to an application as alternative to other customary cages in humans are necessary.