Eredeti közlemények
Objectives 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. Conclusion The 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.
The prevalence of venous diseases in Europe is 25.2%. According to studies of the University of Bonn this number can be as high as 90%. Optimistic estimates suggest this number to be 27.5% in Hungary, 21.5% in Germany. Treatment costs of varicosis and its complications are covered by 2% of the annual healthcare expenditure in Western countries. Chronic venous insufficiency (CVI, or chronic venous disease, CVD) affects 1.7% of European population, and can lead to venous ulcers. In Hungary 0.5-1% of the population suffers from venous ulcers, which is a result of primary or secondary varicosity. Although an increasing number of modern wound dressings have appeared during the last decade, the treatment of ulcerous wounds in necrotic and exudative phases requires additional methods, either conventional or surgical. Infrared light is used to discover pathologic veins. Beside sclerotherapy and surgical treatment external and internal (so called intraluminal) methods are used. Leg ulcers of venous origin in various phases can be cleaned with ultrasound devices, vacuum therapy or high pressure water. Hyperbaric oxygen treatment, keratinocytes, magnetic treatment, laser wound care and skin transplantation can be used as adjuvant. Authors present the aforementioned procedures with examples. New devices and methods help to reduce healing time and to avoid amputation in cases that are often considered hopeless. Technical advancement and modern wound dressings permit successful treatment and healing of wounds that earlier were untreatable, however monetary shortage and the current status of healthcare.
The procedure of mandible resection is basically unavoidable in case of cancer in the field of oral surgery. The reinforcement and the reconstruction of the jaw closest to its original condition is very challenging. Considering the load properties the examination of the plates used in the reconstruction is highly important. The cadaver examination procedure however is very difficult to execute, therefore the use of the Finite Element Analysis proves rather supportive. Fast recovery can be achieved by applying the implants correctly. Furthermore brakeage resulting from high loads in the plates can be avoided. The goal is to examine and understand the Non-locking screwing technique used with plate implants in different mandible resections and reconstructions, focusing on the preloaded force. Furthermore the study and comparison of different stress that arise in different cases. A toothless mandible was used for the creation of the Finite Element Analysis model. The data was provided for the model by CBCT. During the creation of the model we separated four different resection areas to which we used the plates with the Non-Locking screwing technique, also used in clinical reconstructions. For the preload of the plates we used different preloaded forces on the screws. We considered and used boundary conditions complying with the anatomical structure. The muscles required for chewing were transferred to the model and used as main loads. The bone structure is heterogenic and the bone density is based on CBCT. The preloaded forces have a major role in the stresses arising in the bone during the use of Non-locking technique. The comparison of the resection techniques can provide valuable information regarding the preloaded condition and the following chewing load condition connected to the main loads in the bone. Those measurements that are important from biomechanical point of view and would prove difficult or impossible with in vivo or in vitro load measurements to be examined can be compared with the Finite Element Analysis method.
Aim: The Zebris spine-examination system and the associated measurement control program determine the spatial coordinates of processus spinosuses. Our processing program calculates kyphosis, lordosis and scoliosis values from the measurement data similarly to Cobb method. The aim of our research is to clarify whether the angle values determined from the X-ray results of young schoolchildren suffering from scoliosis by Cobb method differ from the values calculated from the spatial coordinates of processus spinosuses. Methods: In the case of 25 children suffering from scoliosis two-way full spine X-rays in standing position on 31 occasions were taken, in accordance with the professional standards. On the basis of the photographs the thoracic kyphosis, lumbar lordosis and scoliosis values were determined with Cobb method. While the children were in standing position, ultrasound-based spine examinations was performed with a WINSPINE measuring software developed specially for the Zebris CMS-HS measuring system. From the spatial coordinates of processus spinosuses the same angle values with our self-developed Excel processing program according to the principles of Cobb method were calculated. The degree of scoliosis was evaluated in the dorsal and in the lumbar section separately. The relationship between the two measurements was indicated by the Pearson correlation. Results: From the comparison of the results of the two different measurement methods it was concluded that the correlation was strong between the values of the dorsal kyphosis and the lumbar lordosis (rkyphosis=0.80 rlordosis=0.94) while the correlation between the scoliosis values of the dorsal and lumbar sections was moderate (rthoracic scoliosis= 0.67 rlumbar scoliosis= 0.73). Conclusion: The sagittal curvatures calculated with our self-developed software from the spatial coordinates of processus spinosuses which were determined with the CMS-HS ultrasound-based motion analysing system, show a strong correlation with the values calculated from X-rays using Cobb technique. The accurate assessment of the degree of scoliosis can only be done with an X-ray. Values defined with motion analysing measurements without exposure to radiation in the terms between X-rays performed regularly as specified in the professional recommendations can give satisfactory information about the possible trend of changes.
During prosthesis implantation, the surgeon can choose from replacements of a wide variety of manufacturers and sizes. So far, no specific coefficient has been introduced that determines the suitability, or goodness of these prostheses. In this paper an apparatus is presented for the qualification of knee prostheses. This apparatus is able to measure the rotation of any prosthesis, therefore the obtained results can be compared with the measured values on human cadaver knees. The prostheses are classified by the rate of their conformity. In addition, the first experimental results are reported as well.
Scoliosis is a spinal deformity that most commonly appears in girls and makes itself apparent at puberty during the early teenage years. Living with scoliosis can be especially difficult for children, particularly when a brace is required to stop its progression. The context of clothing physiology help a clothing system of air, vapor permeable insulation and opportunities. These same characteristics are changed when brace wearing, but also help the right materials and design concepts for the development. In view of the currently available properties of fabrics during the test and we see clothing physiology using different raw materials and functional textiles, as well as the solution for improving the body's microclimate.In our research achieve an optimal physiological state of body with a corver on the brace,that improves the body's microclimate, reduce the unpleasant effects of thebrace at high temperatures, but the basic function of the medical device support.
Quite a number of medical specialties require distance and angle measurements on x-ray images. Drafting and measurement on traditional x-ray films can be done with marker pens, rulers and protractor, but this method is time consuming and often inaccurate. Authors present a computer aided drafting and measurement method for both digitized and digital x-rays. Evaluation of cervical spine x-rays is especially important for patients suffering from rheumatoid arthritis. Our computer program helps users to mark necessary points and draw lines on x-rays interactively on the computer screen, then the program calculates relevant angles and distances based on literature data. Manual drafting on traditional x-ray films is time consuming, and it is usually impossible or at least difficult to repeat. When one wants to try drafting more than once, previous lines have to be erased from the film, or a separate transparent film can be used. Reading distance and angle values requires a ruler and a protractor. The tip size of the marker pen and the precision of ruler, protractor positioning can result in measurement errors of multiple millimeters and degrees. Contrarily, computer based drafting allows arbitrary number of users arbitrary number of attempts to define necessary points on x-rays, and then predefined algorithms calculate the results. Computer aided drafting can be performed by many persons, a number of times. Accuracy can be improved by using image processing capabilities such as zooming, contrast correction, etc. Results can be superimposed on x-ray images, making follow-up easier. Compared to „traditional” drafting, the computer-aided method’s repeatability and reliability is a great advantage. It is easier to learn computer-based drafting, especially when a large number of points have to be marked and complicated measurements are involved. With an appropriate drafting and evaluation protocol, processing of x-rays provides added diagnostic value, e.g. further examinations can be ordered based on the results, scheduling of follow-ups can be optimized.
It is very important in marker-based motion capture systems that cameras can follow markers attached to anatomical points without any obstruction. Based on marker positions the computer program can reconstruct movement of the body’s biomechanical model by calculating typical distances, angles and trajectories. Analysis becomes complicated when the person wears a rigid and opaque orthotic device (e.g. a plastic corset), through which cameras can not see markers attached to the body surface. We had to find a marker attachment method, so that infrared motion capture cameras can follow movement of markers attached to certain anatomical points on scoliosis patients wearing their corsets, when analyzing the effects of corsets on posture and movement. Infrared cameras in the Gait Analysis Laboratory of Semmelweis University’s Department of Orthopedics can not „see through” polyethylene corsets. Markers have to be attached directly to the body surface, because a corset is a rigid body, therefore it moves differently, than the human body under it. Multiple considerations have to be made, when choosing markers. There is limited room between body and corset, markers can not affect wearer’s movement and can not cause discomfort. The chosen method uses magnets attached to the skin with medical tape. Size and properties of magnets were verified by simulation. Infrared cameras can follow the painted magnet counterparts on the outer surface of the corset. Magnets attached to the corset’s outer surface follow the movement of magnets taped to the body, so cameras can follow movement of anatomical points under the opaque corset, without the need of providing direct visibility by destructing corset material. Holes larger than the size of markers would be required, to avoid the shading effects of the corset resulting from body-corset and body-camera distance and angle. According to measurement results of patients with and without corsets, magnetic markers sufficiently follow the body’s movement under the corset. In the meantime with markers attached immovably to the corset’s outer surface, movement of the corset as a rigid body can be tracked, as well. The presented method allows further detailed investigation, concerning the movement altering effects of not just corsets, but other orthotics, too.
In Gerinco2 project there are a lot of examinations. To store data of examination a new database created with Internet technology. The aim of database is to screen to explore of scoliosis and follow treatment ill of children.
Lower 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.
Database of scoliosis examination stores a lot of data of patients. The exact numbers and the written opinion of doctors are useable in decision about the resolution of screening process. The moiré method and results of depth scanning are pictures. The conclusions are subjective. The paper is about a data mining based method for qualification of case to help of diagnosis.
Treatment of traumatic head injuries and various neurosurgical conditions sometimes includes a removal of a large part of the cranial bone. Later on, the formed crane window must be closed with an implant. In this paper we present a method that allows producing implants of any size and complexity, with accurate fit and relatively low manufacturing cost. The implants are finalized upon virtual verification and need short operations to built in the cranial bone. The method can be used also for changing existing implants.
More 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.
In this article we tried to introduce our renewed technology regarding the Gerincor project. Instead of the old technology the new provides much cleaner, more accurate, and more comfortable procedure for our young patients. Moreover data could be archived much easier.
Our research group aimed to develop a numerical model for the analysis of healthy and damaged human blood vessels (e.g. an aneurysm, an adverse vasodilatation) and to investigate the hyperelastic mechanical response of human brain arterial tissue. One of our tasks was to perform laboratory analysis on the specimens taken from the wall of the vessel, to calculate material model parameters for numerical models based on our measurements. Biaxial biomechanical characterization of living tissues – like the artery walls – provides important information about their in vivo behaviour. The aim of our research is to estimate stresses of the aneurysm wall and its parent artery, and to estimate the likelihood of a later aneurysm rupture, too. Laboratory measurements have been undertaken, we have taken the specimens of the vessel wall from human cerebral aneurysms and from control healthy artery carotis interna (both from surgery and cadavers), and then we investigated the biomechanical properties of samples in uniaxial and biaxial tensile tests. We attained for this by means of processing the values of the deformations and (Cauchy-)stresses arising from the wall. We verified the necessity of the parameters calculated from the laboratory measurements with finite element simulations performed on a real geometry aneurysm sack. From our study it may be concluded that there is a need for a constitutive model which describes the hyperelastic behavior of the human arterial wall. We demonstrated with numerical simulations that consideration for inhomogenity in investigations of diseased segments of blood vessels has crucial importance. We proved that damage taking place in aneurysm-sacks is many times more presumable than in healthy material parent arterial segments.
3D motion anlysis is a tool for evaluating gait and posture parameters in orthopaedic deformities. Spinal desorders are very common in paediatric orthopaedic practice. Recently used motion capture methods are not suitable for modeling the kinematics of the trunk segments. The aim of this study was to develop a kinematic model for the trunk that could be applied to measure segmental motions. In the present model the trunk was divided into three parts: the upper thorax, the lower thorax and the pelvis. 13 healthy volunteers were measured to calculate standard graphs for the segmental movements of the trunk. The distance of the C7-Th10 vertebrea, the sagittal- and frontal plane balance and the intersegmental rotation were evaluated. Results of this study present normative values of the trunk motion and highlight the flexibility of the thorax. Our trunk model provide possibility for segmental modeling the trunk in adolescence posture desorders such as scoliosis, Scheuermann’s kyphosis and also in adult spinal diseases.
Interbody devices are widely used to replace the degenerated discs of the spine. For this purpose, a novel methodology uses cement instead of conventional spacers, which is hypothesized to provide smoother transition of forces, lower risk of bone tissue damage, thus smaller subsidence, reduced risk of further pathological deformations and other complications. This new treatment approach has been compared with the conventional method experimentally by mechanical loading of human vertebral motion segments treated with either of these. The present study aimed at complementing the that work with finite element analysis and, by performing in silico mechanical testing of QCT-based case specific models incorporating the elasto-plastic behavior of bone, providing better understanding of experimental results, in particular, the differences between the two sample groups equipped with the different spacer types. This report presents the applied numerical methodology as well as the first results, which are in line with the experimental ones. Besides providing deeper insight into the experimental outcomes, these models are expected to provide a basis for virtual parameter analysis studies, which may help to optimize the surgical procedure.
According to medical research, exertion of a certain level of loading to injured lower limbs is considered as important from the point of view of their recovery. Total unloading would decelerate coalescing of bones just like their permanent overloading. In order to avoid it, patients must be trained to walk with optimal load on lower limbs. A data logger with built-in load cell is designated both to sustain this process and to store data on load values exercised to limbs during recovery as well. The report below tells how this device was developed.
In recent years the number of titanium dental implants in use has significantly increased. At the same time bacterial infection of implants has become more common. The goal of our study was to develop a titanium-dioxide layer on the surface of titanium implant materials by anodisation with a view to impeding the attachment of contagious bacteria. In our experiments Grade 2 titanium and nanograin Grade 2 titanium discs were subjected to anodisation. We investigated the effect of voltage on the surface pattern of emerging titanium-dioxide. We examined the surfaces by reflected-light microscopy. We found that the value of the applied voltage and variation in grain size affected the thickness of the formed titanium-dioxide layer. These layers may promote or support desired forms of biological activity, such as cell attachment to integrate with bone.
Objective: Laminectomy, the commonly used dorsal approach for the surgical removal of most of the pathologic lesions, situated in the spinal canal and the neuroforamen destroying the dorsal stabilizing structures of the spinal column. Retraction and detachment of the longitudinal muscles, removal of the vertebral arches (laminectomy), and injury of the joint capsules and ligaments are responsible most of short and late-time complications. Among of these complications spinal deformities, segmental instability and permanent spinal pain are most often mentioned in the literature. The main objective of the authors was to develop and evaluate the novel minimally invasive techniques suitable for exploring and treating different segmental-lateral pathologies, expanding to the neuroforamen or even paravertebraly, with preservation of the stability of the spine. One of the key issues of this article was to summarize these procedures, with evaluating the safety and efficacy in the routine spine surgery. Methods: 153 patients were operated and followed up during 2000 to 2010 in our Institute with segmental lateral spinal pathologies. For the surgical treatment we used “Over-the-top” decompression, hemi-semi laminectomy, supraforaminal burr-hole, open-tunnel and paravertebral approaches alone or combined with each-other. The above mentioned surgical techniques are mostly our developments, or modifications of previously used surgical techniques. Results: The new surgical procedures developed or modified by our team, are effective techniques for treating the spinal pathologies located in the spinal canal, neuroforamen or even the paravertebral space. The posterior stabilizing structures of the spine, as the vertebral laminae and the longitudinal musculature are mostly preserved. Leaving the longitudinal paraspinal musculature innervations intact, and with the preservation of the bone-muscle attachments and ligaments, the dynamic stability of the spine remains unchanged. Retaining the bony structures (vertebral arches) and the vertebral joints the static stability of the spinal column remain intact, the chance of developing the long-term spinal deformation is minimal. During the follow up we performed static and dynamic X-ray, MR and CT scans, completed with neurological examinations to evaluate the progression of the illness, the neurological deficit and the actual state of the spinal column. With clinical use and evaluation of the various surgical approaches we determined the main indications and contraindications of the surgical procedures, highlighting the pit-falls and limitations. Conclusion: The above mentioned minimally invasive surgical approaches are suitable for treating segmental – lateral spinal pathologies. . For the routine clinical use we organized the surgical techniques into a complete framework based on the location of the pathologic lesions.
3D finite element analysis of long term aging and sudden accidental degeneration processes is presented for physiologic compression load. A systematic modeling and simulation is applied for analyzing the separated and mutual effect of certain material moduli of the components of lumbar motion segments on the mechanical behaviour and stability of the segment during the long time and sudden degeneration processes. It was concluded that due to their smallest stiffness the younger segments with light degeneration are the most vulnerable during both the long-time age-related and the sudden overload-related degeneration.
3D 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.
3D 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.
If spine degenerations are accompanied by osteoporosis, the traditional PEEK spacers can strongly subside into the irregularly deformed endplates and vertebrae following surgical stabilization. To avoid implant subsidence, a new technique is developed where bone cement is applied as interbody device along the vertebra-implant interface. In this study, the mechanical comparison of the traditional PEEK and the new PMMA cement spacers are presented based on uniaxial compression tests. It was concluded that in osteoporotic spine the cement spacers provide better contact along the irregularly deformed endplates, and stronger vertebra-implant interface leading to enhanced stability of lumbar interbody fixation. In the case of PMMA cages, the failure deformation of segments is almost the half of that of the PEEK spacers, while the stiffness of them is more than two times larger. In strongly osteoporotic cases, a more evenly distributed cement pattern results in smaller stress concentrations and greater strength which may decrease the risk of subsidence.
The 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.
Introduction Different sports influence the balancing ability variously. The aim of this study to examine the effect of kayaking on dynamical balancing ability after sudden changes in direction. Methods The investigation included 5 race-kayakists and 5 leisure-time sportsmen. Dynamical balancing ability have analyzed by the ultrasound-based sudden perturbation test (provocation test). A rigid platform have moved from its central position and fixed by a fastening unit. The rigid platform connected to a rigid frame by 4 or 8 steel springs of identical strength. The platform swings back into its original, resting position, stimulating sudden disturbances after releasing the fastening unit. The participant must balance and re-equilibrate as the plate moves. The motions of the rigid plate were recorded by an ultrasound-based system. From this motion the Lehr’s damping ratio can be calculated and it characterizes the balancing ability of the investigated person. Results For the kayakist group, the average values of the Lehr’s damping ratio determined were significantly bigger while standing on one limb and on both limbs compared to the parameters for the control group. Discussion A high level of complex coordination is required to regain equilibrium after a sudden change in direction. Sports activities can develop this ability. This investigation demonstrate that not only the traditional methods (a sudden stoppage from running, sudden setting in motion, jumping or changing in direction) but motion in a continuously moving media (in aqueous media) can also develop the balancing ability. During kayaking the media always changes; moreover, it often surges so persistent balancing is essential. The results draw attention to the fact that dynamic balancing ability can be developed by other than traditional methods.
The knee joint is one of the most complicated joints in the human body. Fundamental knowledge about kinematics is essentially important in order to design knee prostheses which are functionally similar to the knee joint. In addition, the prosthesis should carry out similar kinematics, since only the geometrical resemblance is insufficient. As an initial step, an experimental apparatus, a test protocol and an evaluation method were developed which allows the investigation of the human knee joint kinematics. Based on the results of multiple experiments, a reference function was determined, which provides guidance on how the flexion-rotation function in the human knee joint can be described. The function also provides reference about the kinematics which should be defined in the design of prostheses, and to what extent does an arbitrary knee prosthesis follows the required kinematics. The definition of knee rotation is reported in this article.
High biocompatibility is a basic requirement in medical technology. Polymer coatings can radically improve medical device biocompatibility, especially for surfaces like stainless steel. Adhesion is an important quality in a coating, and this was our rationale for developing a polymer adhesion testing protocol. We compared two biocompatible polymers, polyurethane (PUR) and poly-(DL-lactic-co-glycolic acid) (PDLG). Polymer layers were created on surface-treated stainless steel. The properties of different layers were compared. Adhesion of the coatings was characterised by concentration of coating solution, rate of the contacted surface and surface roughness of the carriers. PUR showed better adhesion under our test conditions.
In vertebroplasty, by injecting cement into the fractured osteoporotic vertebra, the cement can leak into the surrounding soft tissues. To avoid this injurious side-effect, in kyphoplasty a suitable place is previously prepared for the cement, by an inflated and removed balloon. In this study the biomechanical evaluation of vertebroplasty and kyphoplasty is presented by comparing the strength, stiffness and deformability of post-operated vertebrae by using uniaxial compressive mechanical test. As for conclusion, mechanical properties following vertebroplasty are more sensitive to initial bone density than after kyphoplasty, however, both techniques give practically the same failure load, vertebroplasty yields larger stiffness and smaller compressive deformability.
Moiré measuring method is used widely throughout medical protocols, especially in the field of spinal diagnostics. In this article we will present an image processing method (written in National Instruments™ LabVIEW™ environment) to extract the height coordinates of a human back, by using the information provided by the moiré phenomenon formed on the surface. These data can be used to improve the accuracy of the two-dimensional deformation analysis (e.g. determination of Cobb Angle), or the relevance of three-dimensional aberrations (such as vertebral protrusions).
For in vitro mechanical testing of biomechanical objects the specimens must generally be embedded into a special material to obtain a stable position in the testing machine. However, the experimental boundary conditions may influence the results of the measurements. In this study the effect of embedding thickness on the mechanical properties of vertebrae treated by vertebroplasty and kyphoplasty and lumbar motion segments treated by interbody fusion with PEEK and PMMA cement spacers is analyzed by using compressive mechanical tests and QCT based specimen-specific finite element simulation.