| Summary: | 博士 === 長庚大學 === 機械工程學系 === 99 === The key of success for corrective osteotomy of deformed elbow is to evaluate the carrying angle precisely, but assessment according to gross appearance or X-ray images is greatly influenced by the rotation and flexion angle of the elbow joint; besides, the latter method can only measure the coronal deformity, and is not able to detect the rotational angle, leading to inadequate assessment and unsatisfactory result. Furthermore, correct positioning of surgical site and instrument is another important factor; however, there is still lack of proper pre-operative position planning or intra-operative position guiding devices, which may lead to unexpected results. This study dose not only propose the kinematic analysis and a method of quantitative measurement for deformed elbow joint, but also brings up solutions for four different types of orthopedic surgeries (correction for elbow malunion, osteotomy for hip deformity, intramedullary nailing for long bone fracture, and fracture reduction for lower limb). Through the integration of mechanical design, rapid prototyping, auditory biofeedback, and automation technique, series of pre-operative position planning and intra-operative guiding assist devices are developed, and at the same time, clinical verification are carried out.
The study composes of two parts; in the first part, the mathematical model of elbow kinematics has been derived as the basic theory for calculating the angle of deformity. By combining the RANSAC (random sample consensus) and recursive least square methods, the plane of ulna motion and rotation axis of elbow joint are obtained, which are then used to determine the extend of deformity on both the coronal and transverse plane. In order to verify the clinical applicability of the proposed method, fresh frozen cadavers have also been used to simulate various types of elbow deformities, and the results are within 5o from the expected value. The second part of this study is to develop pre-operative position planning devices and intra-operative position guiding systems for some common orthopedic procedures, including pre-operative planning and simulation tools for elbow correction and hip osteotomy respectively, auditory biofeedback intramedullary nail navigation system for long bone fracture, and automation controlling system in lower limb fracture reduction. As a result, separate cases on pediatric humerus supracondyle and on proximal femur osteotomy planning have been completed. The accuracy of localizing the distal locking screws during intramedullary nailing is within 5mm, and the functional assessment of the automatic controlled fracture table reveals of a statistically significant results.
This research has completed a mathematical model for the kinematics for deformed elbow joint, and also developed a practical method of assessing the elbow deformity three dimensionally. By aiming at four different orthopedic surgeries, this research has also developed an osteotomy positioning device, a surgical simulation tool, an auditory navigation system, and an automatic controlled fracture table. These devices and systems developed can also be extended to other applications, such as craniofacial or spinal reconstructive surgeries.
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