Amaç: Bu çalışmada her türlü kırığın bilgisayarlı simülas-yonuna uygun olan ve güvenilir sonuçlar veren gerçekçi bir model yaratıldı. Hastalar ve yöntemler: İleri numune elde edebilmek için plastik bir pelvis modeli kullanıldı. Veriler sağlıklı bir pelvisin bilgisayarlı tomografi taramasından elde edildi. Üç boyutlu plastik pelvis taraması ile geometrik olarak kesin bir model oluşturuldu. Bilgisayarlı tomografi taramalarından elde edilen verilere göre kemikli kısımların materyal özellikleri modifiye edildi. Pelvis farklı segmentlere ayrıldı ve materyal özelliklerinin doğru olması için her segmentte kortikal ve kansellöz kemik maddesinin oranı tayin edildi. Pelvis modelinin doğrulanmasında, tip C pelvis hasarının simülasyonu yapıldı ve sakrum kırığı ve semfizyoliz plaklar ile stabilize edildi. Bu veriler daha önceki kadavra deneylerinden elde edilen veriler ile karşılaştırıldı. Bulgular: Yeni model üzerinde yapılan simülasyona göre, sakrum kırığının fragmanları arasındaki kayma değerleri, kadavra deneylerinde bildirilen değerlere yakındı ve artan gerilme tolere edilebilir aralıkta kaldı. Sonuç: Yeni sonlu eleman pelvis modelimiz, eski modele göre, pelvisi daha doğru yansıtmaktadır. Modelin doğ-rulaması başarılı olduğundan, güvenilir sonuçlar ile bu yöntem her türlü kırığın bilgisayarlı simülasyonu için uygundur.Anahtar sözcükler: Sonlu eleman analizi; kırık tespiti; pelvis kemiği. Objectives:In this study, we aimed to create a realistic model which is suitable for computerized simulation of any kind of fractures and provides reliable results. Patients and methods: We used a plastic pelvic model to construct advanced specimens. The data were retrieved from the computed tomography scans of a healthy pelvis. A geometrically exact model by the means of three-dimensional scanning of the plastic pelvis was obtained. The material properties of the bony parts based on the data retrieved from the computed tomography scans were modified. The pelvis was divided into distinct segments and the proportion of the cortical and cancellous bone substance in each segment were determined to make the material properties accurate. In the validation of the pelvic model, a type C pelvic injury was simulated and the fracture of the sacrum and the symphyseolysis were stabilized with plates. These data were compared with those of previously performed cadaver experiments. Results: Based on the simulation performed on the new model, the shift values between the fragments of the broken sacrum approximated the reported values of our cadaver experiments and also arising strains remained in the tolerable interval. Conclusion: Our new finite element pelvic model represents the pelvis more accurately than the former one. As the validation of the model was successful, it is suitable for computerized simulation of any kind of fractures offering reliable results.
Based on our results, we recommend osteosynthesis in the case of Garden type III femoral neck fractures and, in turn, arthroplasty with respect to the high rate of early redisplacement in the case of Garden type IV fractures, especially in the case of subcapital fractures. For patients confined to a bed and in poor general condition (ASA score IV), the first choice treatment option is the minimally invasive percutaneous osteosynthesis.
Different bones have different blood supplies, which may influence bone healing. Therefore, elucidation of the mechanisms involved in the regulation of bone marrow blood flow in different bones is of high clinical importance. To assess the micro circulation of bone marrow of the femur and tibia simultaneously, flow velocities were continuously measured by a two-channel laser-Doppler flowmeter. The probes were introduced into the femoral and tibial diaphysis, respectively, in the anesthetized rabbit. Changes in micro circulation of the bone marrow were elicited by intra-arterial bolus injections of vasoactive substances: epinephrine (E), calcitonine-gene related peptide (CGRP), substance P (SP), sodium nitroprusside (SNP), E and Ebrantil. Systemic arterial blood pressure was recorded with an electro-manometer. Micro vascular resistance (MVR) and 50% recovery time (50RT) to baseline flow level were calculated from the measured data. Flow velocity in the femur was significantly higher. Epinephrine considerably reduced micro vascular blood flow, which could be significantly warded off by Ebrantil. CGRP and SP did not change MVR. Application of SNP resulted in reduction of flow velocity, but it also decreased MVR. No statistically significant differences were found between reactions of the micro circulation in the two marrows. These results suggest that there are no significant differences between the blood flow response patterns of these two bone marrow sites, thus the regulation patterns of the micro circulation of the two bones are also similar.
Complications of open tibial fractures have been found to be very frequent after application of monotherapies (external fixator, plate, intramedullary nailing). The use of combined therapy has improved our results. We treated 658 patients for open tibial fractures over a course of 15 years. Plating was the method of treatment in the initial phase, and then external fixators and unreamed tibial nails (UTN) were used as a monotherapy. In the last ten years the option of a combined therapy was at our disposal, namely, changing the method of treatment. Monotherapy was performed in 352 cases, and 270 patients were treated in a combined manner. The rate of septic complications could be reduced with the combined therapy from 15.5% to 6.6%, the rate of bone healing disorders from 31.6% to 8.7%, and that of amputations from 4.9% to 0.7%. Elaboration of therapeutic tactics and their consistent application increases the healing potential of open tibial fractures. During this 15 year period, our therapeutic concepts have changed, whereby gradual, combined therapy models were initiated, increasing the advantages and decreasing the disadvantages of the different methods.Résumé Les complications après fractures ouvertes du tibia sont très fréquentes quel que soit le traitement: fixateur externe, plaque, enclouage centro-médullaire. Les traitements combinés permettent d'améliorer les résultats. Nous avons traité 658 patients présentant une fracture ouverte du tibia sur une période de 15 ans. Ces patients ont d'abord été traités, au début de notre expérience, par ostéosynthèse par plaque et, plus tard, par fixateur externe ou par clou centromédullaire sans alésage. Dans les 10 dernières années, nous avons préféré combiner les traitements. Un traitement unique a été réalisé chez 352 patients et des traitements combinés chez 270. le taux de complications septiques a diminué du fait des traitements combinés de 15,5 à 6,6%, les problèmes de complications osseuses ont diminué de 31,6 à 8,7% de même en ce qui concerne les amputations qui ont également diminué de 4,9 à 0,7%. l'indication thérapeutique est un élément important du traitement notamment pour obtenir une bonne guérison dans les fractures ouvertes du tibia. Sur une période de 15 ans notre concept thérapeutique a changé en passant de traitements uniques à des traitements combinés. Ceux-ci permettent d'améliorer les avantages de chaque méthode et de diminuer leurs inconvénients.
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