Thesis (M.S.)--University of Missouri-Columbia, 2006. / "August 2006" The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Vita. Includes bibliographical references.

Aufgrund der Tatsache, dass die Wahl der Therapie bei Wirbelfrakturen der Klasse A3 nach Magerl et al. (1994) weiterhin kontrovers diskutiert wird, wurden in dieser Arbeit die Patientenfälle der Abteilung Orthopädie und Unfallchirurgie der Universitätsmedizin Göttingen betrachtet, die im Zeitraum von 2008 bis 2013 eine Wirbelfraktur im Bereich der Brust- und Lendenwirbelsäule erlitten. Das gesamte Kollektiv umfasst 475 Patienten, von denen 266 männlich und 209 weiblich sind. Es wurden objektive Daten wie GDW, Kyphosewinkel und Wirbelkörperhöhenminderung zu fest definierten Zeitpunkten erhoben. Anhand dieser Daten konnte der Verlauf der Stabilität und sowohl der Korrekturgewinn durch die Therapie als auch der Korrekturverlust während der Nachsorge für die jeweiligen Therapiemethoden erfasst werden. Die Therapiemethoden, die hier verglichen werden, sind die konservative Therapie, die Kyphoplastie, die dorsale und die kombiniert dorsoventrale Stabilisierung. Die in der radiologischen Verlaufskontrolle erhobenen Parameter zeigen, dass bei Frakturen der Klassen A1 und A2, die als stabil gelten, die konservative Therapie zu einem guten Ergebnis führt. Bei A3- Frakturen, bei denen in der internationalen Literatur starke Unstimmigkeit darüber besteht, ob diese Frakturen als stabil oder instabil gelten und wie solche Frakturen im allgemeinen zu behandeln sind, bringt die operative Vorgehensweise klare Vorteile. Zudem können bei kombiniert dorsoventraler Operation noch stabilere Ergebnisse erzielt werden. Für die Rotationsfrakturen stellt sich heraus, dass nach der Entfernung des eingebrachten Osteosynthesematerials ein größerer Korrekturverlust eintritt. Abschließend lässt sich sagen, dass bei isolierten Berstungsfrakturen ohne Beteiligung des Bandapparates die Indikation für die kombiniert dorsoventrale Operation häufiger und frühzeitiger gestellt werden sollte. Außerdem sollte beachtet werden, dass bei instabilen Frakturen die Verlängerung der Tragezeit des Fixateurs einen positiven Einfluss auf den Korrekturerhalt hat.

O objetivo deste estudo foi avaliar, por meio de uma análise histológica e histométrica, o processo de reparo ósseo em osteotomia mandibular e interface entre tecido ósseo e parafusos utilizando um sistema de fixação interna biodegradável de 2,0mm. Seis cães foram submetidos a uma osteotomia vertical unilateral realizada entre o 3º e o 4º pré-molares mandibulares (lado experimental), estabilizada com aplicação de duas placas de quatro furos e parafusos manufaturados com ácido poli-L-DL-lático (70:30). No lado mandibular contra-lateral (lado controle) foi realizada apenas uma demarcação óssea superficial na cortical vestibular e metade do sistema de FI (duas placas de dois furos) foi utilizado. Após 2 e 18 semanas os animais foram eutanasiados e as regiões de osteotomia e interface entre tecido ósseo e parafusos foram removidas para análise microscópica. Cada parafuso foi seccionado no seu longo eixo e a região de osteotomia foi dividida igualmente em três partes: a parte superior próxima ao processo alveolar foi denominada Terço de Tensão (TT), a parte inferior de Terço de Compressão (TC) e a parte entre TT e TC, Terço Intermediário (TI). A análise histológica mostrou no período de 2 semanas, áreas de contato ósseo direto entre a superfície do parafuso e o tecido ósseo lamelar original. No período de 18 semanas, um tecido conjuntivo não mineralizado composto por três camadas microscopicamente distintas foi observado na interface entre tecido ósseo e parafusos. Nesta área, não houve diferença estatisticamente significante no contato entre tecido ósseo e parafusos entre os lados controle e experimental em ambos os períodos analisados. Na área de osteotomia foi observada, em 18 semanas, união entre os fragmentos ósseos caracterizada por trabéculas ósseas interconectadas e alguns sistemas osteonais neofomados. Diferença estatisticamente significante de neoformação óssea foi verificada entre o TT, TI e TC (p=0,019). Em conclusão, o sistema biodegradável utilizado neste estudo permitiu a ocorrência do reparo ósseo na região de osteotomia devido ao ambiente biomecânico criado e as características teciduais adjacentes aos parafusos biodegradáveis foram altamente influenciadas pelas propriedades do ácido poli-L-DL-lático (70:30). / The aim of this study was to evaluate histologic and histometrically the bone repair in mandibular body osteotomy and bone-screw interface after using a biodegradable 2.0-mm internal fixation system. Six dogs were subjected to an unilateral osteotomy in mandibular body (experimental side), which was stabilized by applying two 4-hole plates manufactured with poly-L-DL-lactic acid (70:30). In the opposite side (control side), a superficial demarcation on the buccal cortical was performed and half of the IF system (two 2-hole plates) was applied. After 2 and 18 weeks, the dogs were euthanized and the osteotomy site and the bone-screw interface were removed for microscopic analysis. Each screw was sectioned along its long axis and the osteotomy sites were divided equally into three parts: the upper part was labelled the Tension Third (TT), the lower part Compression Third (CT), and the part between the TT and CT Intermediary Third (IT). Histologic analysis showed areas of direct contact between the screw surface and the parent lamellar bone at 2 weeks. At 18 weeks, three microscopically distinct layers at the bone-screw interface were noted. No statistically significant difference was observed in the bone-to-screw contact between the control and experimental sides for each time point. At the osteotomy sites, union between the bone fragments was observed at 18 weeks characterized by interconnected parallel-fibered bone trabeculae and some newly formed osteonal systems. Statistically significant difference of newly formed bone among TT, IT and CT (p=0.019) was observed. In conclusion, the biodegradable IF system used in this study was able to allow the bone repair at the osteotomy site due to the biomechanical environment created and the characteristics of the tissue adjacent to the biodegradable screws were highly influenced by the properties of the poly-LDL- lactic acid (70:30).

Orientador: Bruno Watanabe Minto / Banca: Cláudia Valéria Seullner Brandão / Banca: Paola Castro Moraes / Resumo: Avanços na compreensão da biologia óssea e das complicações das fraturas têm levado a modificações na abordagem da fixação interna das mesmas, sendo a osteossíntese minimamente invasiva com placa (MIPO) uma das mais recentes evoluções para o manejo biológico das fraturas. O objetivo do presente estudo foi avaliar o uso de placas bloqueadas aplicadas de forma minimante invasiva em fraturas de tíbia de cães. Foram utilizados 10 cães apresentando fraturas de tíbia, de idades e raças variadas. Os animais foram avaliados quanto a deambulação, intensidade do edema, exames radiográficos, e densitometria óptica nos períodos 0, 15, 30, 60, 90 e 120 dias de pós-operatório. Após 15 dias de pós-operatório 80% dos cães já utilizavam o membro ao caminhar e apresentavam formação de edema leve a ausente no membro operado. Após 30 dias de pós-operatório 100% dos cães já apoiavam o membro ao caminhar e não apresentavam formação de edema no membro. Todos os pacientes apresentaram sinais radiográficos e densitométricos de início de consolidação óssea após 15 dias de pós-operatório. O tratamento de fraturas de tíbia por meio da MIPO é uma alternativa eficaz, resultando em utilização precoce do membro e união clínica efetiva, e pode ser realizada sem uso de intensificadores de imagem / Abstract: Advances in the comprehension of the bone healing and complications of the treatment of the fractures have been changed some concepts. Less invasive procedures have been advocated. A minimally invasive plate osteosynthesis (MIPO) is one of the best ways to avoid over tissue damage. The aim of this study was to evaluate the use of MIPO in tibial fractures in dogs. Ten dogs presenting a tibial fracture were used. Deambulation, swelling intensity and radiographic changes were evaluated preoperatively, just after the procedure and at 15, 30, 60, 90 e 120 days postoperatively. Six of 10 (60%) dogs were able to walk at 15 days postoperatively with slight swelling and mild lameness. Two of 10 (20%) presented normal walking at the same period. At 30 days postoperatively all dogs were able to walk normally. Six of them were not lame and 9 did not present swelling. Bone healing could be followed by radiographic evaluation. All dog presented initial radiographic signs of bone healing after 15 days postoperatively. Two of 10 showed clinical union at this time. In five of 10 (50%) clinical union could be observed after 60 days. The treatment of tibial fractures by MIPO is an effective alternative resulting in early and effective clinical union and can be performed without the use of image intensifiers / Mestre

Orientador: Idelmo Rangel Garcia Júnior / Resumo: O complexo zigomático maxilar é a segunda área da face mais atingida por injúrias, superada apenas pelos ossos nasais. É elemento essencial na configuração da face, uma vez que é a principal estrutura formadora do terço médio facial. É importante na biomecânica, está situado entre o víscero e o neurocrânio, desempenha papel fundamental na absorção e escoamento das forças de mastigação através dos pilares de reforço e sustentação. Nesse contesto encontra-se o seio maxilar cujas funções destacamse: diminuição do peso do crânio; auxiliar a ressonância da voz, a produção e a armazenagem do muco, a umidificação do ar inspirado, a manutenção do aquecimento da fossa nasal, servir como acessório do olfato, definir o contorno facial, entre outras. Avaliamos, através de radiografias PA de Waters, 40 pacientes, sendo 20 pacientes traumatizados nessa região, que foram submetidos à fixação interna rígida em dois pontos e 20 pacientes hígidos, comparando a projeção da imagem do contorno do seio maxilar. Estas avaliações foram realizadas em um período pós-operatório superior a 6 meses. Após análise dos resultados, concluímos que baseado nos achados radiográficos e nos valores de áreas dos seios maxilares, a fixação interna rígida em dois pontos mostrou-se eficaz no tratamento das fraturas não cominutivas do complexo zigomáticomaxilar. / Abstract: The ZMC is the second facial area most affected by injuries, only surpassed by nasal bones fractures. It's an essential element in facial configuration because it's the middle third facial main structure. It's important biomechanical being situated between the visceral and neurocranium, develop fundamental absorving and draining of the chewing forces job, across the sustaintation and strenghten pillars. Inside this complex the maxillary sinus and its functions are: to reduce head weight, to help voice ressonance, to produce and to store mucus, to umidificate the breathen air, to maintain the nasal fossa warm, olfative accessory and to define the facial contour and others. The research was performed through PA Waters radiography; 40 patients: 20 traumatizated patients in this region, submitted to the two points IRF and 20 health patients were evaluated, comparing the image projection of the maxillary sinus and observating the stability of this kind of fixation. These evaluations were made in post-operative periods, latter 6 months. After result analysis we concluded, based radiography evidence and measurement maxillary sinus area, the two points IRF are efficient on treatment of ZMC fractures not cominutive. / Mestre

Εισαγωγή: Η θεραπεία των σύνθετων καταγμάτων του άνω πέρατος του βραχιονίου είναι αμφισβητήσιμη και παραμένει ένα θέμα διαρκούς αντιπαράθεσης στη διεθνή βιβλιογραφία. Οι ιδιομορφίες των καταγμάτων αυτών, η μικρή αξιοπιστία και αναπαραγωγικότητα των υπαρχόντων συστημάτων ταξινόμησης, η έλλειψη πολυκεντρικών προοπτικών ερευνών και ο μη καθορισμός αντικειμενικών κριτηρίων αξιολόγησης του θεραπευτικού αποτελέσματος, είναι μερικές μόνο από τις αιτίες που οδηγούν σε ασυμφωνία τους ερευνητές. Η επικρατούσα τάση στη διεθνή βιβλιογραφία σήμερα, επικεντρώνεται στις ελάχιστα παρεμβατικές τεχνικές οστεοσύνθεσης, που περιλαμβάνουν περιορισμένες αποκολλήσεις γύρω από τα κατεαγότα τμήματα, προσπάθεια διατήρησης της αιμάτωσης της κεφαλής και περιορισμό των μεταλλικών υλικών που απαιτούνται για την επίτευξη σταθερής οστεοσύνθεσης. Τα βασικά πλεονεκτήματα της μεθόδου που προτείνουμε είναι η ατραυματική προσπέλαση, η αποφυγή βίαιων χειρισμών επί του κατάγματος, η μη χρησιμοποίηση μεταλλικών υλικών οστεοσύνθεσης, η αποκατάσταση της ρήξης του μυοτενόντιου πετάλου και η χιαστί συγκράτηση των αποσπασθέντων τμημάτων της κεφαλής σε ένα ενιαίο τμήμα, δίκην ταινίας ελκυσμού (tension band effect), που επιτρέπει την σταθερή οστεοσύνθεση του κατάγματος και διευκολύνει την πρώιμη κινητοποίηση του ώμου. Υλικό-Μέθοδος: Την χρονική περίοδο 1991-2003 αντιμετωπίστηκαν χειρουργικά στην κλινική μας με τη μέθοδο της οστεοσυρραφής 214 ασθενείς. Πρόκειται για 123 γυναίκες και 91 άνδρες με πρόσφατο κάταγμα του άνω πέρατος βραχιονίου και μέσο όρο ηλικίας τα 52,7 έτη (από 18 έως 82 ετών). Συνολικά, με βάση την ταξινόμηση και τα κριτήρια του CS. Neer, αντιμετωπίστηκαν 71 κατάγματα 2-τμημάτων, 75 κατάγματα 3-τμημάτων και 64 κατάγματα 4-τμημάτων (48 ενσφηνωμένα σε βλαισότητα) καθώς και 4 περιπτώσεις με κάθετο διαχωρισμό της αρθρικής επιφανείας. Ο μέσος χρόνος παρακολούθησης ήταν 5.2 έτη και αφορούσε το 92% των ασθενών. Συνολικά 13 ασθενείς δεν προσήλθαν στον τελευταίο επανέλεγχο ενώ 4 απεβίωσαν για λόγους μη σχετιζόμενους με το κάταγμα ή την θεραπεία του, αφήνοντας 197 ασθενείς για πλήρη κλινική και ακτινολογική αξιολόγηση. Μελετήθηκαν και αξιολογήθηκαν όλα τα διεγχειρητικά ευρήματα, οι προεγχειρητικές και μετεγχειρητικές ακτινογραφίες, η επάρκεια και διατήρηση της ανάταξης, οι πρώιμες και απώτερες επιπλοκές, τα στοιχεία νοσηλείας, η επίπτωση μετεγχειρητικών φλεγμονών, η συμμόρφωση με το πρόγραμμα φυσιοθεραπείας, η ικανοποίηση του ασθενούς με τη θεραπεία και το τελικό κλινικό αποτέλεσμα, με βάσει τις παραμέτρους του Constant Score. Ακτινολογικά, η εξέλιξη της πώρωσης αξιολογήθηκε με προσθοπίσθια και διαμασχαλιαία ακτινογραφία στον 1ο, 3ο, 6ο και 12ο μήνα, καθώς και στον τελευταίο επανέλεγχο. Η παρουσία πλήρους ή τμηματικής άσηπτης νέκρωσης της κεφαλής, απορρόφησης ή παρεκτόπισης των ογκωμάτων, απώλειας της ανάταξης ή πώρωσης σε πλημμελή θέση, καθώς και οι όποιες ενδείξεις παρουσίας δευτεροπαθούς οστεοαρθρίτιδας και συνδρόμου υπακρωμιακής προστριβής κατεγράφησαν σε όλους τους ασθενείς που συμπεριελήφθησαν στη μελέτη. Σε 16 κατάγματα 4-τμημάτων εκπονήθηκε επιπλέον κλινική αγγειογραφική μελέτη για την διερεύνηση της διατήρησης της αιμάτωσης της βραχιονίου κεφαλής μετά την εφαρμογή της οστεοσυρραφής. Αποτελέσματα: Όλα τα κατάγματα πωρώθηκαν σε διάστημα 10.4 εβδομάδων κατά μέσο όρο (από 6.5 έως 14.6 εβδομάδες), εκτός από τέσσερις περιπτώσεις που παρουσίασαν ψευδάρθρωση. Η μέση τιμή του Constant score κατά τον τελευταίο επανέλεγχο ήταν 80.2 (από 35 έως 100 βαθμούς) ανεξαρτήτως τύπου κατάγματος, ενώ ως ποσοστό επί της λειτουργικότητας του υγιούς ώμου κυμάνθηκε στο 87.5%. Συνολικά 61 ασθενείς (30.9%) είχαν άριστο αποτέλεσμα, 96 (48.8%) πολύ καλό, 24 μέτριο (12.2%) και 16 πτωχό (8.1%). Η συνολική επίπτωση άσηπτης νέκρωσης της βραχιονίου κεφαλής ήταν 22/197 περιπτώσεις (11.1%), με πλήρη καθίζηση της κεφαλής σε 9 ασθενείς και μερική σε 13. Η παρουσία «λύσης» του ΜΒΟ επισημάνθηκε σε 18 ασθενείς (9.1%), έκτοπης οστεοποίησης σε 21 (10.6%), συμπτωματικής οστεοαρθρίτιδας σε 9 (4.5%) και συνδρόμου υπακρωμιακής προστριβής σε 11 (5.5%). Η συνολική επίπτωση επανεγχείρησης λόγω επιπλοκών κυμάνθηκε στο 7.1%. Η ανάλυση των αποτελεσμάτων της αγγειογραφικής μελέτης κατέδειξε διατήρηση της ενδοστικής αιματικής παροχής μετά από την εφαρμογή οστεοσυρραφής στα κατάγματα 4-τμημάτων ενσφηνωμένων σε βλαισότητα. Συμπεράσματα: Προτείνουμε την ανοικτή ανάταξη και εσωτερική οστεοσύνθεση με μη-απορροφήσιμα ράμματα σε όλα τα παρεκτοπισμένα κατάγματα του άνω πέρατος του βραχιονίου που είναι επιδεκτικά οστεοσύνθεσης (2-τμημάτων ΜΒΟ, 3-τμημάτων και 4-τμημάτων ενσφηνωμένων σε βλαισότητα). Αποφεύγοντας τις πιθανές επιπλοκές των μεταλλικών υλικών μπορούμε, με την τεχνική της οστεοσυρραφής, να επιτύχουμε ικανοποιητική ανάταξη, σταθερή οστεοσύνθεση και αποκατάσταση του μυοτενόντιου πετάλου, που επιτρέπουν την πρώιμη κινητοποίηση της άρθρωσης και την επίτευξη ενός καλού τελικού κλινικού και ακτινολογικού αποτελέσματος. Σε νεαρούς ασθενείς με παρεκτοπισμένα κατάγματα 4-τμημάτων χωρίς ενσφήνωση και σε κατάγματα-εξαρθρήματα 3- και 4- τμημάτων, μπορεί να εφαρμοστεί αρχικά η οστεοσυρραφή, με σκοπό την απώτερη βιωσιμότητα της κεφαλής, αλλά η έκβαση είναι λιγότερο προβλέψιμη και η επίπτωση των επιπλοκών σημαντική. / Background: Ideal treatment of displaced proximal humeral fractures remains controversial and a matter of continuous debate in the international literature. The particularities of those fractures, the under strength reliability and reproducibility of the existing classification systems, the lack of multicenter prospective studies and the heterology definitions about the evaluation of results are only some of the reasons that bring researchers out of step. Current trends in operative treatment of these fractures are focused in minimal invasive techniques of reconstruction, involving limited soft tissue detachments, preserving blood supply of the humeral head and eliminating of necessary hard material application for stable osteosynthesis. The main advantages of our proposed technique are the minimal approach, without forced manipulations on the fracture, the avoidance of any hard material application, the repair of coexisting rotator cuff tears and the cruciate, tension-band like manner of bone fragments retention to a uniform part that allows stable internal fixation of the fracture and early shoulder joint motion. Material-Methods: Between 1991 and 2003, 214 patients underwent transosseous suturing for displaced fractures of the proximal humerus in our Department. There were 123 women and 91 men with a mean age of 52.7 years (range, 18-82). According to Neer criteria and fracture classification we managed 71 two-part fractures, 75 three-part and 64 four-part (48 of them was of valgus impacted subtype) as well as 4 splitting head fractures. Mean follow up period was 5.2 years and concerned the 92% of the patients. Overall, 13 patients were lost from the last follow up appointment and 4 died from reasons unrelated to the fracture or its treatment, leaving a total of 197 patients for full clinical and radiological evaluation. We recorded and investigated all preoperative and postoperative radiographs, intraoperative details, kind of reduction, early and late complications, hospital stay details, the incidence of infection, the cooperation with the rehabilitation program, the patient satisfaction and the objective clinical outcome according to the parameters of Constant score. Radiologically, the union progress was evaluated with anteroposterior and auxiliary views at 1st, 3rd, 6th, and 12th month as well as at the last follow up. All radiographs were investigated for the presence of partial or total collapse of the head, lysis or tuberosity displacement, loss of reduction or malunion as well as for signs of post-traumatic osteoarthritis and subacromial impingement syndrome. In 16 patients with four-part valgus impacted fractures, a digital angiographic evaluation was performed for further investigation of humeral head supply after transosseous suturing. Results: All fractures were united until the 10.4 week (range, 6.5 to 14.6 weeks), except four that developed nonunion. The mean Constant score at the last follow up was 80.2 (from 35 to 100 points) singly from fracture type, whereas the functional score as a percentage to that of the unaffected shoulder was 87.5%. Overall, 61 patients (30.9%) were rated as excellent, 96 (48.8%) very good, 24 good (12.2%) και 16 poor (8.1%). The overall incidence of avascular necrosis was 22/197 cases (11.1%); 9 patients showed total collapse and 13 partial collapse. Greater tuberosity lysis was noted in 18 patients (9.1%), heterotopic ossification in 21 (10.6%), posttraumatic osteoarthritis in 9 (4.5%) and subacromial impingement syndrome in 11 (5.5%). The overall rate of reoperation due to complications was 7.1%. The results of angiographic investigation showed conservation of endosteal blood supply of the humeral head, after transosseous suturing. Conclusions: We suggest open reduction and internal fixation in all displaced fractures of the proximal humerus that were amenable for fixation (2-part greater tuberosity, 3-part and 4-part valgus impacted fractures). Avoiding the complications of any hard material application, we are able, with the solely use of transosseous sutures, to accomplish adequate reduction, stable osteosynthesis and repair of rotator cuff tears, allowing for early shoulder joint motion and a satisfactory clinical and radiological outcome. In young patients, with displaced four-part fractures without impaction or 3- and 4-part fractures-dislocations, the transosseous suturing can be applied initially, as a head preserving treatment, but the outcome is less predictable and the rate of complications prominent.

[Truncated abstract] Renewed interest in the fixation of fractures using plates has been stimulated by an improved understanding of the biology of fracture healing and a drive towards minimally invasive surgery. This has led to a change in the way we use plates nowadays and the way in which we build the bone-plate construct, as well as the development of new implants better suited to these techniques. As a result of this, we have now the potential to safely expand the indications for plate fixation especially in the management of fractures in osteopenic bone. This thesis provides scientific evidence allowing for better formulation of the optimum way to use the modern plating systems in the clinical setting. Biological fracture repair with conventional plates, in terms of a less rigid construct to enhance fracture healing, is becoming increasingly popular. By omitting screws the construct becomes more flexible with a risk of fixation failure. It was the aim of the first paper to investigate in an experimental model the construct strength of different conventional plate lengths and number / position of the screws, and if an oblique screw at the plate end could increase the fixation strength. Our data suggest that the plate length is the most important factor in withstanding forces in cantilever bending. Longer plates with an equal number of screws require greater peak loads to failure than short plates with more screws. Furthermore, an oblique screw at the plate end produces an increased strength of fixation in all different test setups. However, the difference is more significant in shorter plates and in constructs with no screw omission adjacent to the fracture site. ... Following cyclic loading, however, locking plates can better retain fracture reduction compared to compression plates. On the other hand, under torsional load the compression plate appears to be biomechanical superior to the locking system. In supracondylar comminuted femur fractures, combining the two principles results in less plastic deformation, and a higher load to failure compared to their single application. The last two papers examine the behaviour of locking plates in osteopenic bone. In cadaveric intra-articular calcaneal fractures, the locking plate showed a significantly lower irreversible deformation during cyclic loading and a significantly higher load to failure. In dorsal and volar fixed angle distal radius constructs in a cadaveric model, all constructs showed adequate stability with minimal deformation on fatigue testing under physiological conditions in good bone quality. In osteoporotic bone, however, dorsal fixed angle constructs are stiffer and stronger than volar constructs. The addition of a styloid plate to a volar plate does not significantly improve stability.

Η εσωτερική ακινητοποίηση καταγμάτων με πλάκες οστεοσύνθεσης χρησιμοποιείται ως μέθοδος αντιμετώπισής αυτών για πάνω από 100 χρόνια τώρα. Οι πρώτες οστεοσυνθετικές πλάκες που χρησιμοποιήθηκαν ήταν μεταλλικές. Με την πάροδο των ετών αναπτύχθηκαν πολλά καινούργια μοντέλα, με σκοπό να αντιμετωπιστούν τα προβλήματα που προέκυπταν κατά τη χρήση τους. Όσον αφορά το υλικό κατασκευής για τις πλάκες οστεοσύνθεσης, χρησιμοποιούνται κατά κύριο λόγο μέταλλα όπως ανοξείδωτος χάλυβας και κράματα τιτανίου, καθώς θα πρέπει να συμβιβάζονται απαιτήσεις όπως η αντοχή του υλικού, η δυνατότητα μεγάλης παραγωγής, το μικρό κόστος και η βιοσυμβατότητα. Εναλλακτικά των μεταλλικών υλικών και στην προσπάθεια να αποφευχθεί το φαινόμενο (stress shielding) που προκύπτει από την ασυμφωνία των μηχανικών ιδιοτήτων μεταξύ οστού και πλάκας οστεοσύνθεσης έχουν προκύψει τα σύνθετα υλικά. Αυτά ικανοποιούν τις παραπάνω προδιαγραφές και ταυτόχρονα προσφέρουν τη δυνατότητα να προκύψουν “κατά παραγγελία” μηχανικές ιδιότητες με μικρότερο βάρος σε σχέση με τα συμβατικά υλικά. Στο χώρο του σχεδιασμού των πλακών οστεοσύνθεσης κυριαρχεί η άποψη ότι η οστεοσύνθεση πρέπει να είναι πιο ελαστική με λιγότερο δύσκαμπτες πλάκες. Κινούμενο προς την κατεύθυνση αυτή, το εργαστήριο Τεχνικής Μηχανικής του Π.Π. σε συνεργασία με την Ορθοπεδική Κλινική του Π.Π.Γ.Ν.Π. σχεδίασε μια ολισθαίνουσα πλάκα, η οποία αποτελείται από δύο μέρη – αρσενικό & θηλυκό – και εφαρμόζει πάνω στην καταγματική εστία, επιτρέποντας μικροκινήσεις στην περιοχή. Αυτό έχει ως σκοπό να επιτρέψει στην καταγματική εστία να παραλαμβάνει θλιπτικά φορτία τα οποία ευνοούν τη δημιουργία δευτερογενούς πώρου, που είναι η τάχιστη και βέλτιστη διαδικασία αποκατάστασης ενός κατάγματος. Στην παρούσα εργασία, σκοπός είναι η καταγραφή των λειτουργικών προδιαγραφών της ολισθαίνουσας πλάκας από σύνθετα υλικά και η επιλογή των κατάλληλων υλικών για την ίνα και τη μήτρα. Το επόμενο βήμα είναι η βελτιστοποίηση επιλέγοντας το καταλληλότερο (lamination), χρησιμοποιώντας την θεωρία πολυστρώτων πλακών, ώστε η πλάκα που προκύπτει να πληροί τις τεθείσες προδιαγραφές. Τέλος με χρήση κώδικα πεπερασμένων στοιχείων γίνεται μοντελοποίηση και προσομοίωση ενός επουλωμένου καταγματικού οστού, μιας σταθερής και μιας ολισθαίνουσας πλάκας οστεοσύνθεσης πάνω σε καταγματικό οστό, με σκοπό τη μεταξύ τους σύγκριση όσον αφορά την ταχύτερη επούλωση του κατάγματος και την πλήρη αποκατάσταση των προκαταγματικών μηχανικών ιδιοτήτων του οστού. / -

Made available in DSpace on 2014-11-10T11:09:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-06-27Bitstream added on 2014-11-10T11:58:34Z : No. of bitstreams: 1 000790811.pdf: 1696564 bytes, checksum: 027b168593fdf7d048ba6f9ee1d8823d (MD5) / Avanços na compreensão da biologia óssea e das complicações das fraturas têm levado a modificações na abordagem da fixação interna das mesmas, sendo a osteossíntese minimamente invasiva com placa (MIPO) uma das mais recentes evoluções para o manejo biológico das fraturas. O objetivo do presente estudo foi avaliar o uso de placas bloqueadas aplicadas de forma minimante invasiva em fraturas de tíbia de cães. Foram utilizados 10 cães apresentando fraturas de tíbia, de idades e raças variadas. Os animais foram avaliados quanto a deambulação, intensidade do edema, exames radiográficos, e densitometria óptica nos períodos 0, 15, 30, 60, 90 e 120 dias de pós-operatório. Após 15 dias de pós-operatório 80% dos cães já utilizavam o membro ao caminhar e apresentavam formação de edema leve a ausente no membro operado. Após 30 dias de pós-operatório 100% dos cães já apoiavam o membro ao caminhar e não apresentavam formação de edema no membro. Todos os pacientes apresentaram sinais radiográficos e densitométricos de início de consolidação óssea após 15 dias de pós-operatório. O tratamento de fraturas de tíbia por meio da MIPO é uma alternativa eficaz, resultando em utilização precoce do membro e união clínica efetiva, e pode ser realizada sem uso de intensificadores de imagem / Advances in the comprehension of the bone healing and complications of the treatment of the fractures have been changed some concepts. Less invasive procedures have been advocated. A minimally invasive plate osteosynthesis (MIPO) is one of the best ways to avoid over tissue damage. The aim of this study was to evaluate the use of MIPO in tibial fractures in dogs. Ten dogs presenting a tibial fracture were used. Deambulation, swelling intensity and radiographic changes were evaluated preoperatively, just after the procedure and at 15, 30, 60, 90 e 120 days postoperatively. Six of 10 (60%) dogs were able to walk at 15 days postoperatively with slight swelling and mild lameness. Two of 10 (20%) presented normal walking at the same period. At 30 days postoperatively all dogs were able to walk normally. Six of them were not lame and 9 did not present swelling. Bone healing could be followed by radiographic evaluation. All dog presented initial radiographic signs of bone healing after 15 days postoperatively. Two of 10 showed clinical union at this time. In five of 10 (50%) clinical union could be observed after 60 days. The treatment of tibial fractures by MIPO is an effective alternative resulting in early and effective clinical union and can be performed without the use of image intensifiers

Made available in DSpace on 2014-06-11T19:23:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2002-08-06Bitstream added on 2014-06-13T19:50:41Z : No. of bitstreams: 1 kayatt_fe_me_araca.pdf: 1754439 bytes, checksum: e4d89ad0bd72df4dc5b0274e0a5e3695 (MD5) / O complexo zigomático maxilar é a segunda área da face mais atingida por injúrias, superada apenas pelos ossos nasais. É elemento essencial na configuração da face, uma vez que é a principal estrutura formadora do terço médio facial. É importante na biomecânica, está situado entre o víscero e o neurocrânio, desempenha papel fundamental na absorção e escoamento das forças de mastigação através dos pilares de reforço e sustentação. Nesse contesto encontra-se o seio maxilar cujas funções destacamse: diminuição do peso do crânio; auxiliar a ressonância da voz, a produção e a armazenagem do muco, a umidificação do ar inspirado, a manutenção do aquecimento da fossa nasal, servir como acessório do olfato, definir o contorno facial, entre outras. Avaliamos, através de radiografias PA de Waters, 40 pacientes, sendo 20 pacientes traumatizados nessa região, que foram submetidos à fixação interna rígida em dois pontos e 20 pacientes hígidos, comparando a projeção da imagem do contorno do seio maxilar. Estas avaliações foram realizadas em um período pós-operatório superior a 6 meses. Após análise dos resultados, concluímos que baseado nos achados radiográficos e nos valores de áreas dos seios maxilares, a fixação interna rígida em dois pontos mostrou-se eficaz no tratamento das fraturas não cominutivas do complexo zigomáticomaxilar. / The ZMC is the second facial area most affected by injuries, only surpassed by nasal bones fractures. It’s an essential element in facial configuration because it’s the middle third facial main structure. It’s important biomechanical being situated between the visceral and neurocranium, develop fundamental absorving and draining of the chewing forces job, across the sustaintation and strenghten pillars. Inside this complex the maxillary sinus and its functions are: to reduce head weight, to help voice ressonance, to produce and to store mucus, to umidificate the breathen air, to maintain the nasal fossa warm, olfative accessory and to define the facial contour and others. The research was performed through PA Waters radiography; 40 patients: 20 traumatizated patients in this region, submitted to the two points IRF and 20 health patients were evaluated, comparing the image projection of the maxillary sinus and observating the stability of this kind of fixation. These evaluations were made in post-operative periods, latter 6 months. After result analysis we concluded, based radiography evidence and measurement maxillary sinus area, the two points IRF are efficient on treatment of ZMC fractures not cominutive.