Ralf Westphal

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The preferred treatment of femoral (thigh bone) shaft fractures nowadays is the minimally invasive technique of intramedullary nailing. However, in addition to its advantages, this technique also has a number of disadvantages, such as the frequent occurrence of malaligned fracture reductions and high X-ray exposure, especially to the operating team. The aim(More)
We present an approach for estimating the relative transformations between fragments of a broken cylindrical structure in 3d. To solve this problem , we first measure the orientation and position of the cylinder axes for each fragment by an adapted kind of Hough Transformation. The cylinder axes are an important feature for separation of fractured areas and(More)
Manual segmentation of computed tomography (CT) datasets was performed for robot-assisted endoscope movement during functional endoscopic sinus surgery (FESS). Segmented 3D models are needed for the robots' workspace definition. A total of 50 preselected CT datasets were each segmented in 150-200 coronal slices with 24 landmarks being set. Three different(More)
Reduction in femoral shaft fractures can be difficult to achieve with minimally invasive techniques. Malalignment and high intra-operative radiation exposure can result. The hypothesis was that robot-assisted fracture reduction could improve the quality of reduction while reducing the amount of radiation exposure. A robot system was developed that allows(More)
BACKGROUND An investigation was carried out into possible increased forces, torques, and altered motions during load-bearing ankle motion after implantation of two different total ankle prostheses. We hypothesized that the parameters investigated would not differ in relation to the two implants compared. METHODS We included two different ankle prostheses(More)
8 1. Abstract 9 We presents a new CT-based approach for estimating the relative transformations between 10 fragments of fractured long bones for computer aided and semi-automatic bone alignment and 11 fracture reduction in surgery. 12 2. Materials and methods 13 First of all we segment, label and reconstruct the relevant fragments of the fractured bone in(More)
The main disadvantage of conventional functional endoscopic sinus surgery (FESS) for the surgeon is the restriction to one hand for manipulation while the other hand is holding the endoscope. In our project we develop an automatic anticipating robot assisted endoscope guidance during FESS. The robot guidance will be realized by a multisensor system which(More)
Our objectives were to detect factors that influence the accuracy of surgical navigation (magnitude of deformity, plane of deformity, position of the navigation bases) and compare the accuracy of infrared with electromagnetic navigation. Human cadaveric femora were used. A robot connected with a computer moved one of the bony fragments in a desired(More)