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EN
The paper presents a dynamic spatial mathematical model in which a head, seven cervical vertebrae, a group of 19 couples of neck muscles, 6 intervertebral discs, ligaments and facet joints are taken into consideration. The created model enables simulation of dynamical forces inside anatomical parts of human neck. The behaviour of the modelled body exposed to action of a~force corresponding to the real enforcement, which occurs at a head-on collision during the road accident was simulated, and the model was verified on the basis of the data obtained from published experiments.
PL
W pracy przedstawiono analizę obciążeń kręgosłupa szyjnego kierowcy podczas zderzenia bocznego i dachowania samochodu. Przeprowadzona analiza pozwoliła na wyznaczenie parametrów ruchu (przemieszczeń, prędkości, przyspieszeń) użytkownika pojazdu oraz sił działających na jego struktury anatomiczne. Wyniki symulacji zostały zweryfikowane na podstawie dostępnych danych literaturowych i posłużyły do określenia miejsc najbardziej podatnych na urazy podczas omówionych typów kolizji.
EN
The driver’s cervical spine loading analysis during side impact and rollover car accidents in this paper were presented. Performed researches allow to determine motion and loads occurring between driver’s anatomic parts. Obtained results show displacement, velocity and acceleration of modelled occupant segments and have been compared and validated with published data. Due to forces estimation we could predict occupant’s injuries during car crashes.
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Content available SOME NON-OPERATIVE WAYS OF CERVICAL SPINE TREATMENT
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EN
Though cervical spine disorders occur less frequently than lumbar spine problems, their course and final results may have severe implications for patients. Despite significant development in operative treatment of cervical spine; patients, if possible, choose conservative methods basing mainly on pharmacotherapy and rehabilitation (physiotherapy). A case report of non-operative treatment with use of selected techniques of manual therapy and physiotherapy is described. Achieved improvement allowed postponing the surgery, but we cannot exclude the necessity of operation in the future.
EN
Described in the paper is the model of cervical spine formulated using finite element method. This FE model was developed to biomechanical analysis ofthe stability ofthe cervical spine after anterior stabilisation. The present results demonstrates behaviour of three-dimensional model of cervical spine under various physiological loads. The investigations can be used to understanding the biomechanics of the cervical spine stabilised with fixation system.
PL
Praca dotyczy oceny wpływu stabilizatora na zachowanie się segmentów sasiadujących. Wyniki badań wykazały zmiany stanu obciążenia w układach po stabilizacji. Stabilizacja powodowała wzrost sił w stawach w przyległych implantacji segmentach ruchowych. Wyniki mogą posłużyć do celów optymalizacji doboru parametrów leczenia dysfunkcji kręgosłupa szyjnego poprzez stosowanie stabilizacji z przedniego dostępu operacyjnego.
EN
Creation of a virtual 3D model is usually connected with giving it characteristic geometrical and material constructional features. More frequently these features are defined as separate geometrical objects (bored holes, stiffeners and trusses, threads etc). Usage of geometrical objects to 3D model shape creation, is a necessary condition to realizing automatical control process of the model correctness. The second condition of this process realization is a possibility to record producer or customer requirements (for example as a set of rules). The third of these conditions is a possibility of confronting producer/customer requirements (written as - for example a rule knowledge base) with created model shape. In this paper the author will present an example of application of engineering knowledge base to geometric verification of an element of milling machine solid model.
EN
Background: Masticatory dysfunctions are a common problem in society today. Disorders such as clenching, bruxism can lead to a loosening of teeth in the jaw, abrasion of the tooth crowns, inflammatory changes, and ultimately degenerative changes in the temporo-mandibular joints.Aim: The aim of this study was to assess the relationship between masseter and temporalis anterior muscles activity and body posture.Material and Methods: In 20 subjects (20-35 years) the sEMG of the masseter and temporalis anterior muscles was measured twice during functional clenching: in casual posture and in posture with the head in retraction. The study was conducted using sEMG Tele-Myo (Noraxon). Results: The bioelectrical activity of the evaluated muscles was significantly higher in the casual posture than in retraction (p<0.05). Temporomandibular disorders appear not only due to facial muscle activity abnormalities, but also due to incorrect body posture, especially a head forward posture. The measurement was performed twice in a sitting position: in casual posture and in a posture with the head in retraction. Mean masseter activity during teeth clenching was statistically significant in retraction compared to the habitual position (p<0.05), both for the left and right side. There was also statistically significant activity in the temporalis muscles in retraction compared to the habitual position.Conclusion: The observed decreased activities in both the masseters and temporalis muscles suggest that masticatory system dysfunctions may not only be the result of dysfunction in the craniofacial region but also may be posture dependent.
EN
The main objective of this study is to design three-dimensional geometrical and mechanical finite element model of the intervertebral disc between L2-L3 vertebras in the lumbar and C5-C6 cervical spinal segment. The model was directed toward understanding the work and the role of the intervertebral disc that performs in the human spinal segment body. The three-dimensional finite element motion segment was developed and its response to different loads was performed. The model accounted for the solid component of the nucleus pulposus while anulus fibrosus was modeled as a matrix of homogeneous ground substance reinforced by anulus fibers. End plates similarly to the nucleus pulposus were simulated using volumic elements. Simultaneously the vertebral bodies have been modeled as a complex construction of a cancellous core covered by a cortical shell of the orthotropic material properties. Isotropic material has been used to model posterior elements. To simulate ligament like behavior, tension only elements have been used. Numerical studies of the lumbar segment have been consequently compared with the experimental investigation performed on the porcine model by authors and other in vitro experiments on human lumbar spine accomplished by other scientists. In cervical spinal segment numerically two surgical techniques (Cloward and Robinson-Smith) have been tested. Two types of loads have been applied to three models - to an intact C5-C6 spinal segment and then to the vertebras after performing those two surgical techniques. All numerical analysis have been undertaken using ANSYS 5.4 commercial application.
EN
Aim. The aim of the study was to review the literature on the prevalence of cervical spine injuries divided between the level of the injury and the causes of fractures. Material and methods. A review of Polish and foreign literature was performed. The following databases were searched: PubMed, Medline, Science Direct, Termedia, and Polish Medical Bibliography. Literature analysis. In Poland the incidence of spinal injuries, including damage to the cord, is estimated at the level of 25–35 persons per one million of the population, half of these being cervical spine injuries. More than one in three of all spinal injuries affect the atlantoaxial and occipital area. It is estimated that axis fractures occur in up to 40% of the cases involving cervical spine injury. Odontoid fractures constitute 10–15% of all cervical spine fractures. Hangman fractures account for 20% of vertebral fractures. Cervical spine injuries more frequently occur in males than in females, and the relevant rates for males are from 1.5 to 2.7 times higher. The most common causes of cervical spine injuries include road traffic accidents, accounting for 33 to 75% of the cases, falls from heights (15–44%) and sports injuries (4–18%). Cervical spine injuries are most often diagnosed in subjects over thirty years of age. Such injuries most commonly are related to the second, fifth and sixth cervical vertebrae. On the other hand damage to the first and second cervical vertebrae is often observed in the same patients who are found with injury to lower cervical vertebrae (approx. 9% of the cases). In the group of advanced age subjects the most frequent cervical spine injuries are axial fractures and they are diagnosed in 15% of adult patients with cervical spine fractures.
EN
This study develops a three-dimensional FE model of the C4-C6 unit of the cervical spine, with nonlinear material properties of the joints and stabilized with an anterior fixation system, after a simulated injury. The model of the 3 vertebrae, the fixation plate and bone screws included non-linear definition of the ligaments and discs. Appropriate material properties from the literature were used. The motion characteristics of the spine segment, as well as the stiffness and strength of the stabilized unit, were compared with available experimental data. Cleary the fixation system replicates the intact spinal segment in static compression tests under a standard head's weight but improvements are necessary to design a more biomechanically relevant fixation system. The FE method proved to be essential for this kind of biomechanical analysis, and the model will be used in further investigations.
10
Content available remote Biomechanical model of the human cervical spine
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EN
The paper describes the biomechanical model simulating dynamic phenomena in the human cervical spine caused by assumed acceleration and external impact on head and trunk, especially in car accident. The model assumption, generals equations describing dynamic equilibrium of spine members and detailed analysis of important elements are presented. The method of solving obtained set of equations is described.
11
Content available remote Experimental investigation of the axis dens fracture
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EN
Vertebra C2 causes numerous difficulties in post-traumatic stabilization because of a special character of injury resulting from its untypical structure due to its function. Understanding of the mechanism of C2 vertebra injury has a crucial importance for the treatment process and also for the development of new stabilization techniques in C2 vertebra dens (odontoid process) breakage. A series of endurance tests has been carried out to determine the value of force which breaks a vertebra dens and the character of a resulting breakage. The tests were carried out with the use of a material testing machinę for nine section preparations. Cause and effect-type conncctions have been established between the results obtained and individual features of the vertebrae tested. The recognition of the value of injuring force makes predicting the occurrence of C2 vertebra injury resulting from a simulated bending mechanism possible.
EN
Cervical spine fractures pose an increasing burden to society despite accounting for merely 3- 5% of all traumatic injury cases [10,14]. C2 fractures comprise 7,8% of all spinal fracture cases [8] and represent a predominant type within cervical spine fractures. Odontoid fractures form a notable subset of C2 fractures, with Anderson and D'Alonzo type II [1] being the most common odontoid fractures (OFII). Granted their clinical significance and relatively frequent occurrence, controversies continue about whether conservative or surgical treatments are preferable, particularly concerning the geriatric population [23,20,17,6,11,7].
EN
The method developed and used by the authors to measure intradiscal pressure is presented. We constructed 'needle* indicators lilted with miniature pressure transducers. Our analysis assessed the impact of stabilisation on pressure in intervcrtcbral discs adjacent to the stabilisation area under compression and bending loads. The research was carried out on the post-mortem specimens of the cervical spine. The results showed that during axial compression there is a small increase in pressure following the introduction of bone graft when compared to the intact spine. On the other hand, bending has a major influence on the resultant pressure, depending on spinal level and the type of bending (flexion/extension). We have also concluded that, regardless of the type of load, in the discs above (the planned and then implemented) stabilisation area, the pressure is lower than in discs located below.
PL
W pracy opisano model kręgosłupa szyjnego sformułowanego przy użyciu metody elementów skończonych. Model ten opracowano do biomechanicznej analizy stabilności odcinka szyjnego po stabilizacji. Prezentowane wyniki pokazują zachowanie się trójwymiarowego modelu pod wpływem różnych fizjologicznych obciążeń. Badania te posłużyły do określenia stabilności kręgosłupa szyjnego zespolonego przednią stabilizacją.
EN
Described in the paper is the model of cervical spine formulated using finite element method. This FE model was developed to biomechanical analysis of the stability of the cendcal spine after anterior stabilisation. The present results demonstrates behaviour of three-dimensional model of cendcal spine under various physiological loads. The investigations was used to ąualifying the stability of the cendcal spine stabilised with fkation system.
EN
Treatment process needs improving the methods of joining interdisciplinary knowledge of doctors and engineers. It is the proper way to successful effects treatment of skeletal failures. This article presented modelling researches concerning analysis of internal forces inside cervical spine after stabilization. Created models were loaded by forces emanated weight of head.
16
Content available remote Modelling of dynamic interactions in cervical spine during car collision
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EN
The paper presents a dynamic spatial mathematical model in which a head, two cervical vertebrae, a group of neck muscles, an intervertebral disc, ligaments and intervertebral joints are taken into consideration. The behaviour of modelled body exposed to action of a force corresponding to the real enforcement, which occurred at a head-on collision during the road accident, was simulated, and the model was verified on the basis of data obtained from published experiments.
PL
W pracy przedstawiono metodologię wyznaczania sił mięśniowych w kręgosłupie szyjnym człowieka opierającą się na modelowaniu wspomaganym nowoczesnymi metodami diagnostyki medycznej. Celem badań było określenia sił głównych mięśni szyi oraz analiza ich wpływu na oddziaływania w połączeniu głowa kręgosłup w warunkach fizjologicznych i urazowych. Do celów badawczych wykorzystano wyniki badań diagnostycznych: EMG, MRI rutynowo przeprowadzanych przez neurologów na pacjentach z problemami w obszarze odcinka szyjnego kręgosłupa. Badania doświadczalne pozwoliły określić wzajemne relacje wśród najbardziej istotnych dla ruchu głowy mięśni szyi, które to informacje zostały wykorzystane dla identyfikacji sił mięśniowych w procesie modelowania. W pracy sformułowano przestrzenny dynamiczny model odcinka szyjnego kręgosłupa człowieka z wykorzystaniem metod optymalizacji.
EN
The paper presents modelling research supported by modern medical diagnostic methods: electromyography EMG and magnetic resonance MRI. The aim of the research was determination of forces of main cervical muscles and analysis of their influence on cervical spine during physiological and accident situations. Identification of forces was carried out with use of 3-dimensional dynamical model of cervical spine, taking under consideration group of main neck muscles. The model was created.
EN
This article presents modelling researches concerning analysis of strain and stress of physiological human cervical spine and the segment C4-C5 after stabilization. Created models were loaded by gravity and physiological forces.
EN
The paper present tree dimensional model of human cervical spine, stabilized by two different anterior fixation systems. The results of investigations showed the changes of load state on whole system after implantation. The stabilization caused the increase of forces, acting in facet joints and in intervertebral discs, adjoining the segments stabilized by implants. These results may facilitate optimization of the treatment of dysfunction of cervical spine with anterior stabilization.
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