Introduction: (Experimental part). Hypothesis evaluates the quasi-static risk of transpedicular fixation failure in the spinal cadaver with anterior column defect due to the fixation extension and defines the risk of transpedicular fixation failure due to screw convergence in cyclic loading. (Clinical part). Hypothesis evaluates the risk of isolated dorsal approach to ventral lumbar spondylodiscitis due to clinic and radiopraphic results and the risk of anterior radical debridement due to using titanium implant in the site of bone infection. Methods: (Experimental part). Four anatomically preparated spinal cadavers with anterior spinal column defect transpediculary instrumented were quasi-statically tested on MTS 858,2 Mini-Bionix. Concept of cyclic loading part were based on ASTM standard F1717. (Clinical part). The group A consisting of 23 patients was treated only by dorsal transmuscular approach and the second group B consisting of 8 patients was treated by two-stage postero- anterior surgery in lumbar spondylodiscitis. Results: (Experimental part). There were progress in all assessed parametres with considerable asymmetry direction in extension to flexion and duction in spinal column loading with anterior defect during quasi-static loading. The rod deformation decrease with extent of...

Introduction: (Experimental part). Hypothesis evaluates the quasi-static risk of transpedicular fixation failure in the spinal cadaver with anterior column defect due to the fixation extension and defines the risk of transpedicular fixation failure due to screw convergence in cyclic loading. (Clinical part). Hypothesis evaluates the risk of isolated dorsal approach to ventral lumbar spondylodiscitis due to clinic and radiopraphic results and the risk of anterior radical debridement due to using titanium implant in the site of bone infection. Methods: (Experimental part). Four anatomically preparated spinal cadavers with anterior spinal column defect transpediculary instrumented were quasi-statically tested on MTS 858,2 Mini-Bionix. Concept of cyclic loading part were based on ASTM standard F1717. (Clinical part). The group A consisting of 23 patients was treated only by dorsal transmuscular approach and the second group B consisting of 8 patients was treated by two-stage postero- anterior surgery in lumbar spondylodiscitis. Results: (Experimental part). There were progress in all assessed parametres with considerable asymmetry direction in extension to flexion and duction in spinal column loading with anterior defect during quasi-static loading. The rod deformation decrease with extent of...

Im Rahmen einer experimentellen Vergleichsstudie zweier bildwandlergestützter Navigationssysteme wurde die 3D-bildwandlergestützte Navigation mit der 2D-bildwandlergestützten Navigation zur Pedikelschraubenplatzierung am Modell getestet. Neben der Präzision der Bohrungen in einem postoperativen CT wurden Bildqualität, Genauigkeit des 3D-Scans, Planbarkeit und Umsetzung der Bohrungen bewertet und verglichen. Mit der 3D- Bildwandler- Navigation wurden 38 der 40 Bohrungen exakt platziert (95%). Eine Planung wurde durch einen Softwarefehler der Alpha-Version auf dem Monitor falsch wiedergegeben. Bei einer weiteren Bohrung wurde der Bohrer verkantet, wodurch Bildschirmdarstellung und Realität voneinander abwichen. Daher kam es in einem Fall zu einer lateralen Perforation der Kortikalis im Bereich des Pedikels, im anderen zu einer kaudalen Perforation. Mit der 2D- Bildwandler- Navigation konnten alle 40 Schrauben ohne Pedikelperforation platziert werden. Zwei dieser Schrauben wurden durch die ventrale Kortikalis gebohrt. Beide Verfahren überzeugten durch hohe Präzision und Zuverlässigkeit. 3 der 4 Fehlplatzierungen waren Anwender einer Software bedingt. Eine optimierte Software und verbesserte Instrumente werden diese Fehlerquote weiter reduzieren. Voraussetzung für die 2D-bildwandlergestützten Navigation sind eine gute Bildqualität sowie normale anatomische Gegebenheiten für standardisierte Projektionen. Die neue 3D-bildwandlergestützter Navigation kombiniert die Vorteile der 2D-bildwandlergestützter Navigation und der CT- basierten Navigation mit einer Verringerung der Strahlenbelastung durch den Wegfall des präoperativen CT`s und somit der Einsatzmöglichkeit im akuten Notfall sowie nach intraoperativen Repositionsmanövern. Da kein Matching erforderlich ist, wird insbesondere bei traumatischer Verletzung oder tumorbedingter Veränderung der dorsalen Wirbelstrukturen ein großer Vorteil zur CT- basierten Navigation erwartet. Aufgrund der universellen Einsatzmöglichkeiten eines Bildwandlers wird für diese neue Technologie ein breites Indikationsspektrum angenommen. / An experimental study to compare 2D- and 3D- Computer-Assisted Fluoroscopic Navigation for pedicle screw placement. Each system was evaluated by a post-operative CT and included the comparison of the palpation of the pedicular canal, the image quality and the accuracy of planning and performance. For this purpose 40 screws have been set to 9 models of lumbar spine. Using the 3D-flouroscopy based navigation 38 from 40 (95%) drillings were placed correctly. One mistake was caused by an error of the navigation-software. The second mistake was due to a drilling mistake, the drill was not shown correctly on the monitor because the drill has been canted. Using the 2D-flouroscopy based navigation all screws could be placed correctly at the pedicle, but two times the corpus has been perforated to ventral. Both techniques are precise and reliable. 3 out of 4 mistakes were caused by incorrect handling the instrument. The other mistake happened because of a software-error. If the software and the instruments will be optimised, the amount of mistakes will be reduced in the future. In case of the 2D-flouroscopy based navigation sufficient image quality, normal anatomical structures and defined projections are required. The new 3D-flouroscopy based navigation combines the benefit of 2D-flouroscopy based navigation and CT-based navigation by reducing the radiation exposure and the preoperative planning time. Therefore, this technique is suitable for use in an emergency or intraoperative repositions. Because no matching-procedure is necessary for CT-based navigation, we expect advantages especially in therapy of traumatic injuries or changes at the dorsal structures of spine caused by tumour. Furthermore, the use of fluoroscopic based navigation extends the range of applications/the spectrum of indication for this new technology.