Hungarian Society of Biomechanics: E-Journals / Magyar Biomechanikai Társaság
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Integration of data resulting from various types of lumbar spine examinations
Get PDFLower back region and lumbar spine in particular can be measured and evaluated with a number of methods and from a number of viewpoints. Measurement method depends essentially on the objective. Tests can be static or dynamic, can target detection of pathological conditions or just evaluate persons with no specific complaints, can be performed once or repeatedly (as follow-up series).Authors present the development of a complex system that records and stores examination data of various types and formats (image, video, numeric, text, etc.).Moiré-based virtual imaging method and a mechano-optical handheld scanning device, developed at the Department of Mechatronics, Optics and Engineering Informatics, Budapest University of Technology and Economics (BME MOGI) are used for static examinations. Dynamic tests can be performed with the system (developed also at BME MOGI) that gives 3D information with the help of depth sensors. Conventional examination results, such as static pressure maps obtained with a podoscope, x-ray images, and results of manual measurements (distances, angles, muscle ductility) provide useful information one by one. Measurement protocols help systematic data collection.Integrating measurement results from previously mentioned methods, and utilizing 3D visualization, data storage and processing, increases the amount of information compared to individual pieces of data, and previously unknown connections can be revealed.The integrated data acquisition and processing system helps organization and systematic processing of data stored in various (file) formats, type (text, image, numerical, etc.) and information content. DOI: 10.17489/biohun/2013/1/1
Finite element parameter-analysis of age-related degenerations of components of lumbar spine segments in compression
Get PDF3D finite element parameter analysis of the degeneration-sensitivity of the material properties of the components of lumbar spinal motion segments is presented for physiologic compression load. The aim was to determine that material behaviour which dominantly determines the mechanical behaviour of the aging spine. Systematic numerical simulation was executed by using a finite element model validated by experimental results for both tension and compression. It was concluded that to keep the hydrostatic compression state of nucleus is the most important factor to maintain the stability of lumbar segments in the first period of aging process. DOI: 10.17489/biohun/2013/1/2
Finite element analysis of weightbath hydrotraction treatment in the case of osteoporosis
Get PDF3D finite element analysis of the first elastic period of the weightbath hydrotraction treatment is presented to analyze the effect of osteoporosis during the traction procedure. A systematic parameter analysis of the material moduli of the aging spinal motion segment with osteoporotic bone was investigated. It was concluded that the osteoporosis in itself can not be a contraindicating factor of weightbath hydrotraction treatment. However, if applying extra weigts, beside the quality of bone and the grade of osteoporosis, the age of patients, their body structure and body weight must be carefully considered as well. DOI: 10.17489/biohun/2013/1/2
Numerical simulation of blood flow in large vessels during thrombus formation
Get PDFThe thrombus formation in vessels is a very complex cascade process that is, amongst many other factors, dependent on the local blood flow characteristics. With the progressing formation, the geometry, and with it the flow pattern changes continuously. In addition to this, the adhesion, activation, and aggregation of the thrombocytes are heavily influenced by certain properties of the flow, most importantly by the emerging local shear forces. In the current work, the formation of a thrombus has been simulated using a simplified model of blood coagulation inside an artificial vessel section. While the employed blood coagulation model has heavily reduced the number of degrees of freedom compared to the real in-vivo bio-chemical processes, it is still capable of successfully reproducing several vital properties of a thrombus qualitatively. DOI: 10.17489/biohun/2013/1/2
Biomechanical investigation of alternative treatment of late joint destruction of lateral condyles fractures of the tibia
Get PDFPrimer traumatológiai ellátás során a sérült ízületi felszín kiemelése után olyan támasztóleme -zes szintézis kialakításának kísérleti biomechanikai vizsgálatát kívánjuk bemutatni, amely többnyirestabil és defi nitív ellátást biztosít a törés ellátására. Végső soron ez az osteosynthesis terhelhetőízületi felszínt biztosít, azonban az esetek egy nem elhanyagolható részében az ízületifelszínen necrosist, fájdalmas térdízületet találunk. Az általunk ajánlott eljárás során azt vizsgáljuk,hogy a lemezes rögzítést nem felváltva, hanem kiegészítve egy unicondylaris protézissel,olyan terhelhető ízületet tudunk kialakítani, amely megoldja a hosszú távon rossz eredményeketmutató, főleg lateralis condylusok töréseinek ellátását. Ha a kísérleti biomechanikai vizsgálatokalátámasztják az eddigi klinikai tapasztalatokat, kiegészíthetjük a tibiacondylusok ellátásánakalgoritmusát. DOI: 10.17489/biohun/2013/2/04Injuries of the proximal leg are frequently associated with fractures involving the joint surfaces of the lateral or medial tibia condyles.Primary treatment of these types of fractures consists of reconstruction of the joint surface and plate osteosythesis with a so called buttress plate.However, postoperative radiographs usually show a good surgical outcome, but these injuries heal often, or – according to some authors – always with destruction of the joint surface.Clinical appearance, i. e. the functional outcome and the patients’ complaints do not always correlate to the radiographs, thus no further corrections are required in case of satisfactory functional outcome and absence of complaints. However, pain upon weight bearing and the treatment of considerable unicompartmental posttraumatic osteoarthritis of the knee joint pose a real problem.According to the current protocol, implant removal and joint surface replacement with prosthesis is the solution. If the medial compartment is involved, total knee replacement or – if adequate – implantation of a medial unicondylar prosthesis is performed. According to the experiences gained so far, implantation of a unicondylar prosthesis was not advisable in case of injured lateral compartment, because it would be subject to adverse biome chanical effects, resulting in relaxation due to osteonecrosis and impaired stability of the cortical bone caused by the fracture. This creates a disadvantageous situation requiring repeated surgery very soon, furthermore, frequently implantation of a revision prosthesis. But if we remove only the proximal few screws and implant a unicondylar prothesis in a minimally invasive manner, the buttress plate left in place reinforces the lateral cortex, and the unicondylar prosthesis makes up a solid biomechanical unit with the screws supported by the bone cement. Application of this method makes plate removal unnecessary. The aim of our experiments is to demonstrate the effi ciency of the above method by the means of biomechanical measurements.Validation has been carried out with photostress analysis of experimental mechanics, in the Cooperation Research Centre of Biomechanics for Budapest University of Technology and Economics
Tomographic reconstruction of micro-vascular network in cerebral cortical samples
Get PDFObjectives The purpose of the research is the automatic processing and analysis of high-amount (nearly 1500) and high-resolution synchrotron based tomography images of mammalian cerebral cortical tissues. The objective was to acquire quantitative data allowing future blood flow modeling based on the structure of cerebral vessel network. . The brain samples were processed with histological method compatible with synchrotron x-ray microtomography. The method developed performs automated extraction of the relevant parameters of the vessel network on a standard personal computer using previously set parameters. Method The method implemented on the image series performs automatic segmentation by using determined intensity values. The procedure finds the boundary of the vessels and provides quantitative measures of the segments, and it also creates the topology of the vessel network. Results Our method produces topologically correct network of continuous, branching micro blood vessels of the sample studied. We present multiple options for the visualization of the detected vessels. The data structure also contains the statistics of each detected cross-section, in addition with the numerical quality statistics of the continuous vessel branches (e. g. vessel length or mean diameter). The algorithm resulted in highly accurate fitting at micrometer geometric resolution. ConclusionThe reconstructed vessel network is the geometrically accurate description of the blood vessels in the tissue. The data acquired could be the base of a blood vessel surface reconstruction, and by adding physiological information it could be used for simulations in normal and pathological conditions (e. g. arteriosclerosis). The precise vascular geometry and the distance distribution provides information about the barely understood neurovascular coupling, which is the basis of such modern diagnostic and research tools as the fMRI. After analyzing samples from multiple species or brain regions the difference could be determined objectively. DOI: 10.17489/biohun/2013/1/0
Processing of digital moiré images in Salus Ortopédtechnika Kft.
Get PDFMore and more children and youngsters are affected by spinal deformities these days. These diseases can be well cured if they are detected and filtered out in time. We wanted to set up an objective and safe method with which we can diagnose wide spectrum of school-aged youngsters without harmful side-effects. Creating moiré images was one way to solve this problem, that is the reason why we started to test this method in filtering and following the condition of our young patients. Patients measured by us were going through a general examination method where their phisical status was examined by physiotherapists, and relief images were taken of their back.The initial aim to make the moiré image use an objective method to filter and follow the patient’s condition in case of weed curvature of the spine could not be totally fulfilled. The reason is that the evaluation of the images is still a subjective method done by our vision. A possible solution could be to find an objective evaluation method where we can process, evaluate and compare the images with the same conditions. The programming and use of a proper image processing algorithm could be a great help for us. DOI: 10.17489/biohun/2013/1/1
Digitális moiré képek vizsgálata gerincferdüléses betegek nyomon követésére
Get PDFA gerincferdüléses gyermekek konzervatív kezelésének eszköze a korzett, mely egy kemény PE „páncél”, ami a gerinc helyes állását nyomófelületeken átadott nyomóerő közvetítésével éri el. A Salus Ortopédtechnika Kft.-nél a korzettet viselőgyermekek állapotváltozásának diagnosztizálására évek óta használnak moiré berendezést. A rendszerhez kapcsolódó mérési módszer általános használatbavételéhez elengedhetetlen a hitelesítés. A hitelesítés a moiré rendszerrel meghatározott Cobb fokok és az általánosan elfogadott, kétirányú, álló helyzetben készített röntgenfelvételeken meghatározható Cobb fokok összehasonlításával történhet. 19 páciens – 9 és 17 év közötti scoliosissal és Scheuermann-betegséggel kezelt gyermek – 49 moiré felvétele alapján készült a kiértékelés. Az eredmények alapján látható, hogy a módszer a gerincferdülés követésére jól alkalmazható, de röntgenfelvételeken meghatározott szögértékekhez képest a moiré felvételeken meghatározott értékek jelentősen (akár 10–15°-kal) kisebbek lehetnek, különösen a felsőháti és az ágyéki görbületek esetén, ahol statisztikai úton is szignifikáns eltérés igazolódott a két módszer eredményei között. Ez okot adhat arra, hogy elgondolkodjunk az értékelési algoritmus alaposabb elemzésén és pontosításán, melyet a későbbiekben tervezünk elvégezni. DOI: 10.17489/biohun/2014/1/0