Made available in DSpace on 2014-06-12T16:25:36Z (GMT). No. of bitstreams: 2 arquivo2071_1.pdf: 3486855 bytes, checksum: 4eddfe224cc1f08fe1adc3eb12332c3e (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2009 / Introdução: A distração osteogênica pelo método e Iizarov foi um grande avanço no tratamento das falhas e encurtamentos ósseos. Segmentos musculoesqueléticos que anteriormente eram submetidos à amputação puderam ser salvos com esse método. Entretanto, não está isento de complicações, sendo o longo tempo necessário para que o regenerado ósseo consolide uma limitação desse método. Objetivos: Avaliar o efeito das células-tronco autógenas do estroma medular, durante a distração osteogênica pela técnica de Ilizarov, com o objetivo de reduzir o tempo de consolidação do regenerado ósseo. Material e Métodos: Foram utilizados 10 cães (20 rádios), submetidos distração osteogênica pela técnica de Ilizarov no ritmo de 1mm por dia dividido em 0,5mm a cada 12 horas. O alongamento foi realizado até o regenerado obter 20% do comprimento total do rádio. As células-tronco foram introduzidas após isolamento e cultivo prévio no regenerado ósseo, quando este apresentou comprimento de 10% do rádio total. O acompanhamento foi realizado através de radiografias simples nas incidências ântero-posterior e perfil. O tempo de consolidação total (TCT) e o índice de consolidação distração (ICD) do regenerado ósseo foram mensurados em centímetros por dia de osso alongado. Adicionalmente, o regenerado ósseo foi avaliado através de exames histológicos e histomorfométricos. Resultados: no grupo controle o TCT e ICD foram em média 117,4 (28,0) dias e 58,7 (14,0) dias, respectivamente. No grupo estudo o TCT foi de 64,3 (8,2) dias e o ICD de 32,15 (4,1) dias. Os índices histomorfomêtricos foram significativamente maiores no grupo estudo. Na avaliação histológica o tipo de consolidação óssea foi misto em 80% (ossificação intramembranosa e endocondral) em ambos os grupos; a atividade osteoblástica de moderada a alta foi maior no grupo estudo; e, quanto a ocupação pelo tecido neoformado foi mais significativa no grupo estudo. Conclusão: Os resultados sugerem que o uso de células-tronco autógenas injetadas no regenerado ósseo durante a distração osteogênica pela técnica de Ilizarov em rádios de cães, acelera a consolidação do regenerado

Ulm, Univ., Diss., 2008.

Σκοπός της διπλωματικής αυτής εργασίας είναι η μελέτη ρομποτικής διάταξης οστεογένεσης και πιο συγκεκριμένα η μελέτης της δυναμικής και ο έλεγχος αυτής. Πιο αναλυτικά, τα κεφάλαια που ακολουθούν πραγματεύονται τα ακόλουθα: θα παρουσιαστεί γενικά ο μηχανισμός της οστεογένεσης από ιατρικής πλευράς, καθώς επίσης και οι διάφορες διατάξεις με τις οποίες πραγματοποιείται η διατατική οστεογένεση. Στη συνέχεια θα παρουσιάσουμε τις κινηματικές και δυναμικές εξισώσεις της πλατφόρμας Stewart. Το τελευταίο μέρος αποτελεί και το πειραματικό μέρος της παρούσας εργασίας δηλαδή τον έλεγχο της συγκεκριμένης διάταξης μέσω του SimMechanics toolbox του πακέτου MatLab. Στο παράρτημα παρουσιάζονται τα αποτελέσματα των πειραμάτων με μορφή διαγραμμάτων. / Distraction osteogenesis and simulation of stewart platform on Simulink.

Vários implantes cirúrgicos têm sido desenvolvidos para estabilizar fraturas em seres humanos e animais. O fixador esquelético externo circular de Ilizarov é método de fixação amplamente utilizado para tratamento de fraturas complexas, desvios angulares, bem como no alongamento ósseo. O anel destaca-se como componente fundamental desse dispositivo e as cargas de compressão no mesmo plano do anel são devidas principalmente a fios ligados de um lado ao outro do implante. O estudo teve como objetivo comparar a resistência à compressão axial de anéis de Ilizarov e analisar a composição da liga metálica desses anéis. Foram testados dois diâmetros de anéis de três fabricantes nacionais para os ensaios biomecânicos de compressão axial, divididos em dois grupos com quinze corpos de prova. Os testes foram realizados em máquina universal de ensaios Kratos® modelo KE 3.000MP, dotada de célula de carga de 3000N com velocidade de ensaio de 10 milímetros por minuto. Os parâmetros força e deformação foram enviados ao computador IBM®-PC através do sistema de aquisição analógica Lynx® modelo ADS-2000, que permitiu a gravação dos parâmetros para posterior análise. Também avaliou-se a composição elementar dos anéis através do método TTPIXE (partículas induzidas pela emissão de raios X em alvos espessos) em PIXE externo. Os espectros foram acumulados em buffer-multicanal conectado a um micro-computador pessoal tipo IBM-PC®. A redução de espectros de raios-X foi realizada por meio do programa AXIL. Concluiu-se que os anéis para fixador esquelético externo circular são compostos de liga metálica de alumínio e que existe diferença entre os fabricantes nacionais no ensaio mecânico de compressão axial, sendo que o fabricante A é mais rígido que os outros fabricantes para os dois diâmetros (60 e 80 milímetros) de anel e mais resistente que os outros fabricantes para o anel de 80 milímetros. / Various surgical implants have been developed to stabilize fractures in humans and animals. Ilizarov\'s circular external skeletal fixator is a fixation method widely used for the treatment of complex fractures, angular deviation, as well as in bone lengthening. The ring stands out as a fundamental component of the device and compression loads in the same plane of the ring are due mainly to wires connected from one side to another of the implant. The study aimed to compare the resistance to axial compression on Ilizarovs rings and analyze the alloy composition of these rings. Two diameters were tested of three domestic ring manufacturers for biomechanical axial compression, divided into two groups with fifteen specimens each group. The tests were performed in a universal test machine Kratos® model 3.000MP KE, equipped with a 3000N load cell with a test speed of 10 mm per minute. The strength and deformation parameters were sent to the IBM®-PC computer through the Lynx® analog acquisition system model ADS-2000, which allowed the recording of the parameters for further analysis. Also, the rings alloy composition was evaluated using the TTPIXE method (thick-target particle induced X-ray emission) in external PIXE. The spectra were accumulated in a multi-channel buffer connected to an IBM®-PC type personal microcomputer. The reduction of X-ray spectra was performed using the AXIL program. In conclusion the rings was made from aluminum alloy, witch differs in composition among different fabricants, also the rings showed differences performance in mechanical testing of axial compression, and the manufacturer A is more rigid than the other manufacturers for the two diameters (60 and 80 mm) ring and tougher than the other manufacturers to the 80 mm ring.

Vários implantes cirúrgicos têm sido desenvolvidos para estabilizar fraturas em seres humanos e animais. O fixador esquelético externo circular de Ilizarov é método de fixação amplamente utilizado para tratamento de fraturas complexas, desvios angulares, bem como no alongamento ósseo. O anel destaca-se como componente fundamental desse dispositivo e as cargas de compressão no mesmo plano do anel são devidas principalmente a fios ligados de um lado ao outro do implante. O estudo teve como objetivo comparar a resistência à compressão axial de anéis de Ilizarov e analisar a composição da liga metálica desses anéis. Foram testados dois diâmetros de anéis de três fabricantes nacionais para os ensaios biomecânicos de compressão axial, divididos em dois grupos com quinze corpos de prova. Os testes foram realizados em máquina universal de ensaios Kratos® modelo KE 3.000MP, dotada de célula de carga de 3000N com velocidade de ensaio de 10 milímetros por minuto. Os parâmetros força e deformação foram enviados ao computador IBM®-PC através do sistema de aquisição analógica Lynx® modelo ADS-2000, que permitiu a gravação dos parâmetros para posterior análise. Também avaliou-se a composição elementar dos anéis através do método TTPIXE (partículas induzidas pela emissão de raios X em alvos espessos) em PIXE externo. Os espectros foram acumulados em buffer-multicanal conectado a um micro-computador pessoal tipo IBM-PC®. A redução de espectros de raios-X foi realizada por meio do programa AXIL. Concluiu-se que os anéis para fixador esquelético externo circular são compostos de liga metálica de alumínio e que existe diferença entre os fabricantes nacionais no ensaio mecânico de compressão axial, sendo que o fabricante A é mais rígido que os outros fabricantes para os dois diâmetros (60 e 80 milímetros) de anel e mais resistente que os outros fabricantes para o anel de 80 milímetros. / Various surgical implants have been developed to stabilize fractures in humans and animals. Ilizarov\'s circular external skeletal fixator is a fixation method widely used for the treatment of complex fractures, angular deviation, as well as in bone lengthening. The ring stands out as a fundamental component of the device and compression loads in the same plane of the ring are due mainly to wires connected from one side to another of the implant. The study aimed to compare the resistance to axial compression on Ilizarovs rings and analyze the alloy composition of these rings. Two diameters were tested of three domestic ring manufacturers for biomechanical axial compression, divided into two groups with fifteen specimens each group. The tests were performed in a universal test machine Kratos® model 3.000MP KE, equipped with a 3000N load cell with a test speed of 10 mm per minute. The strength and deformation parameters were sent to the IBM®-PC computer through the Lynx® analog acquisition system model ADS-2000, which allowed the recording of the parameters for further analysis. Also, the rings alloy composition was evaluated using the TTPIXE method (thick-target particle induced X-ray emission) in external PIXE. The spectra were accumulated in a multi-channel buffer connected to an IBM®-PC type personal microcomputer. The reduction of X-ray spectra was performed using the AXIL program. In conclusion the rings was made from aluminum alloy, witch differs in composition among different fabricants, also the rings showed differences performance in mechanical testing of axial compression, and the manufacturer A is more rigid than the other manufacturers for the two diameters (60 and 80 mm) ring and tougher than the other manufacturers to the 80 mm ring.

Limb lengthening procedures use fixation devices to extend the constantly regenerating bone and surrounding soft tissues. Automated devices have been developed that aim to provide a more gradual tissue extension, resulting in better quality of treatment for the patient. Benefits include pain reduction and probable enhanced tissue outcomes. The development of one such new smart lengthening device is described. An integrated numerical model of tissue mechanics during lengthening is presented. It represents the mechanical environment in which the devices extend. The mechanism of the automated device is also modelled using Matlab software and validation was achieved through experimental testing. Validation of the tissue model includes the design of an experimental hydraulic system with the ability to control the peak loads and relaxation over time. A simplified mechanobiological model for the longer term healing effects is proposed. Calibration of the tissue model to clinical data allows for direct comparison of the load and extension of identical tissues, one being lengthened by a traditional device, the other an automated device. This simulation can be extended to include a range of lengthening rates and frequencies of distraction alongside various patient dependent tissue properties. The models also provide the opportunity to assess the effects of iterative changes to the device parameters (such as stiffness) on its performance as well as analyse the effect that these changes have on tissue extension and loading. Use of these models to optimise the device design alongside optimisation of the extension regime can result in improved device design and consequently improved patient outcomes.

Clubfoot is one of the most common pathologies of the foot affecting 1 in 1000 newborn babies according to statistics. The first treatment approach is by using conventional procedures, such as plaster and cast, and, the literature reports a range of failures causing relapse. Patients with severe or relapsed cases or patients that are treated later in life may require unconventional procedures to provide correction. In order to increase the success rate after the correction, it is necessary to: a)perform analyses to improve the current treatments and b) investigate the tissues involved in this pathology in order to have a better understanding of clubfoot to develop future treatments. The Ilizarov fixator has been shown to be a good alternative for complex and relapsed cases. However, there are no numerical nor experimental studies to: a) improve the efficiency of the frame deployment for clubfoot, b) provide guidance on the right adjustment procedures, and c) understand the mechanical behaviour of the frame applied to clubfoot. This makes the adjustments fully dependent on the surgeon's experience instead of systematic guidelines/procedures. This results in configurations that induce stresses in the fixator that are transferred to the tissues and leading to a reduction in the success rate. Furthermore, the literature on the correction of clubfoot in babies and the role of the tissues in babies' feet during the correction is limited. Therefore, the aim of the thesis is to analyse the relationship between the adjustments of the connectors and the displacements of the fixator rods, on the one hand, and the stress-strain induced in the rods and fixator, on the other hand. This is achieved by means of a finite element analysis of the stress-strain distributions in the fixator components. The predicted stresses are used for the identification of the components that should be adjusted in the fixator to prevent them from failure. The findings and results in the thesis will enable surgeons to understand better the mechanical behaviour of the Ilizarov frame in clubfoot, and they will facilitate the establishment of a functional range of the fixator in order to improve the current procedures. Another aim is to investigate the mechanical behaviour of one of the most affected bones during the correction of clubfoot in babies, namely the talus. The literature reports a change of shape in the talus during clubfoot correction using conventional procedures. This can result in a change of the stress distribution in the foot tissues during gait in latter stages of life leading to different pathologies. This clearly shows the importance of investigating the mechanical behaviour of the talus. This is the first numerical study to investigate the right adjustment procedures of the frame for clubfoot. It is expected that the findings of this research contribute to the improvement of the current corrective procedures based on the use of the Ilizarov frame and to improve the understanding of clubfoot in babies.

Η παρούσα διατριβή αποσκοπεί στη διερεύνηση της βέλτιστης μεθόδου θεραπείας για τα ασταθή κατάγματα κάτω πέρατος κερκίδας. Προς τούτο, μετά από μια σύντομη εισαγωγή, στο γενικό της μέρος η διατριβή παρουσιάζει στοιχεία ανατομικής και κινηματικής της πηχεοκαρπικής και της κάτω κερκιδοωλενικής. Στη συνέχεια γίνεται αναφορά στα κατάγματα του κάτω πέρατος της κερκίδος, τα προβλήματα που προκύπτουν κατά τη θεραπεία τους και το ρόλο των κυκλοτερών συστημάτων εξωτερικής οστεοσύνθεσης (Ilizarov). Στο ειδικό μέρος της διατριβής παρουσιάζεται η κλινική μελέτη που έγινε στην Ορθοπαιδική Κλινική του Πανεπιστημίου Πατρών και αφορούσε σε ασθενείς με κατάγματα κάτω πέρατος κερκίδος που αντιμετωπίστηκαν με κυκλοτερές σύστημα εξωτερικής οστεοσύνθεσης. / Unstable distal radius fractures remain a challenge for the treating orthopaedic surgeon. We present a retrospective follow-up study (mean follow-up 12.5 months) of 20 patients with 21 unstable distal radius fractures that were reduced in a closed manner and stabilized with a nonbridging Ilizarov external fixator. Subsequent insertion of olive wires for interfragmentary compression was performed in cases with intra-articular fractures. According to the overall evaluation proposed by Gartland and Werley scoring system 12 wrists were classified as excellent, 6 as good, 2 as fair and 1 as poor. Grade II pin-tract infection in distal fracture fragment was detected in 3 wires from a total of 78 (3.8%) and in 4 half pins out of a total of 9 (44.4%). Pronation was the most frequently impaired movement. This was restricted in 4 patients (19%) in whom a radioulnar transfixing wire was applied. Symptoms of irritation of superficial sensory branch of the radial nerve occurred in 3 patients with an olive wire applied in a closed manner in the distal fragment. Ilizarov method yields functional results comparable to that of other methods whilst it avoids wrist immobilization, open reduction and reoperation for implant removal. The method is associated with a low rate of major complication and satisfactory functional outcome.

Η διπλωματική αυτή εργασία πραγματεύεται τη μελέτη της μεθόδου Ilizarov καθώς και το σχεδιασμό, την κατασκευή και τον έλεγχο ενός ισοδύναμου με ένα βαθμό ελευθερίας του πλαισίου Taylor στοιχείου δράσης, του οποίου η ενεργοποίηση επιτυγχάνεται με τη χρήση έξυπνων υλικών και συγκεκριμένα μεταλλικών κραμάτων με μνήμη της μορφής (SMA). Πρωτεύον μέλημά μας αποτελεί η μελέτη των γενικών χαρακτηριστικών της εξωτερικής σταθεροποίησης και η κατανόηση της μεθόδου Ilizarov με τη χρήση του πλαισίου Taylor (Κεφάλαιο 2). Ακολούθως, κάνουμε λόγο για τους ενεργοποιητές που χρησιμοποιούνται στη διάταξή μας, αναλύοντας εκτενώς τις ιδιότητες των κραμάτων με μνήμη της μορφής και πιο συγκεκριμένα των κραμάτων NiTi (Κεφάλαιο 3). Λαμβάνοντας υπόψη όλα τα προηγούμενα, είμαστε σε θέση να προχωρήσουμε στην υλοποίηση μίας κατασκευής που προσομοιώνει ένα βαθμό ελευθερίας του πλαισίου Taylor και η οποία ενεργοποιείται από τα παραπάνω έξυπνα υλικά. Πειράματα ανοικτού και κλειστού βρόχου ελέγχου της διάταξης εκτελούνται εν συνεχεία με τη βοήθεια ηλεκτρονικού υπολογιστή (Κεφάλαιο 4). Τέλος, παρουσιάζονται τα συμπεράσματα και οι προοπτικές της εν λόγω εργασίας (Κεφάλαιο 5). / The present diplomatic work consists of the study of Ilizarov method as well as the planning, the construction and the control of one out of six degrees of freedom of a Taylor platform. The activation of the experimental provision is achieved with the use of intelligent material and concretely shape memory alloys (SMA). Our first concern is the study of the general characteristics of the exterior stabilization of the bones and the comprehension of Ilizarov method using the Taylor platform (Chapter 2). Followingly, we deal with the activators that are used in our provision, analyzing extensively the attributes of shape memory alloys and more concretely the alloys NiTi (Chapter 3). Taking into consideration all the above, we are in position to advance in the concretisation of a structure that simulates one degree of freedom of the Taylor platform and is activated by the SMA. We executed control experiments using LabView in an open and closed loop in order to test the provision (Chapter 4). Finally, are presented the conclusions and the prospects of this project (Chapter 5.)

This thesis is a result of research aimed at analysis of the Taylor Spatial Frames (TSF) in Orthopaedics. The TSF is a ring external fixator, which are used to stabilise a fracture or provide stability during skeletal limb reconstruction procedures. A sound understanding of the mechanics of the fixator is essential, because mechanical stability is a key factor in bone healing. TSF is in fact an adaptation of the hexapod parallel manipulators for dynamisation of the classical ring fixators of Ilizarov type. Therefore, a general solution for Forward kinematics of parallel manipulators was provided and the solution is visualised in real-time. A three-dimensional visualisation tool for TSF, was developed, which offers improvements over the software provided by the manufacturer. Abaqus/CAE programming interfaces were used to develop two separate systems for automatic creation of FEMs of the TSF: one using beam elements and the other using 3D solid elements. The systems were used for a parametric study on axial compression of the TSF. Components of the TSF were also tested and analysed: o TSF rings were studied extensively, which lead to revealing important facts about their role in the TSF. o Fixation bolts in external fixators were studied by FE technique and the results used to relate bolt-load to the bolt-torque applied. o TSF struts were tested in compression and their load-deflection behaviour and the role of universal joints in them were described. TSF and Ilizarov fixators were tested and compared in axial compression. The results highlighted the important role of the pins and wires in deflection of the fixators.