In recent years, novel surgical planning methods based on computer visualization using preoperative CT images have been developed. Although they enable surgeons to perform accurate operations with surgical navigation systems and robots, they cause low reproducibility of placement and much manual manipulation on 3D planning systems, because of increase of dimensions of parameter space to be searched (e.g. depth direction) compared with the conventional 2D planning. Therefore, we objectified the expertise on planning of experienced surgeons and developed the automated planning system for a femoral stem in total hip replacement. In this paper, an automated preoperative planning procedure for acetabular cup, which is a hemisphere implant placed in the pelvic bone, is described. The algorithm is based on multiple criteria for evaluating stability of the cup and suitability with the host bone, which include host bone thickness, cup teardrop line displacement, cup center-edge angle, and cup bone coverage ratio. We define the optimal state of cup placement as a solution, which maximizes cup bone coverage ratio and fulfills the restrictions of other criteria. The solution is searched within the limited 3D zone determined by anatomical feature data. We applied the proposed algorithm to 18 cases and compared computer planning with expert surgeon's planning and apprentice surgeon's. The average differences between computer planning and expert surgeon's planning were 3.94 mm in position and 1.44 mm in size. 16 out of 18 computer planning were judged as acceptable or almost passable by both of the surgeons and only two cases were judged as a failure. We also tested variation of cup-teardrop line displacement threshold and confirmed that it is possible to customize the automated planning according to the surgeon's tendency. These results showed a potential usefulness of automated planning.
The number of osteoporosis patients is increasing every year in Japan. Bone mineral density (BMD), which is the helpful feature quantity in diagnosing osteoporosis, is generally measured in the central part of the vertebral body. It's possible to measure BMD at each location in X-ray CT images having a high spatial resolution. If bone mineral density of the vertebral body is not homogeneous, grasp of the lower BMD location inside the vertebral body may be helpful to clinical diagnosis. In this paper, using X-ray CT images of 80 subjects (40 male and 40 female subjects), BMDs of trabecular bones from the 12th thoracic vertebra to the 1th sacral vertebra (S1) were measured at each location. The present study showed that anterior and central locations of thoracolumbar and lumbar vertebra, and posterior, inferior, and central locations of S1 had lower BMD values. Therefore, at the thoracolumbar and lumbar vertebra, if the BMDs of anterior or central locations are selectively measured, prediction of fracture risk at vertebral bodies could be improved.
Improvement of the quality of medical care is strongly required. Decreasing malpractice in medical treatment is quite important theme. Especially in the developing countries, numbers of people have been in the danger of accidental injection or sharing of needle, due to the poor design of conventional syringes. Proposing a new design of the syringe must be very important for better quality of medical care in such developing countries. By applying design methodology, the authors have experienced aware some breakthrough and achieved a novel design of the new syringe, that was safer than conventional syringes, and could be manufactured in lower costs than conventional ones. In concrete, the authors conceived of the idea of a novel syringe whose main material is paper sheet. The authors actualized safety mechanism by folding paper base, packaging design for prevention of reuse and a graphic design for easy-to-understand usage. In this paper, the author presents the design of this novel syringe, as well as the design process of the syringe.
Diagnostic standard of osteoporosis in the Japanese Society for Bone and Mineral Research has proposed to diagnose osteoporosis by visual interpretation of bone contraction degree on lateral lumber plain X-ray and measurement of bone density using Dual Energy X-ray Absorptiometry (DXA) method. However doctor's experience and knowledge might affect those results. Therefore, a method that osteoporosis can be diagnosed objectively is required. In this paper, the method for graduation of osteoporosis is proposed. Using public domain software, ImageJ, we evaluate bone contraction degree by spatial frequency analysis of region of interest (ROI) (64×64 matrix) on the lateral view of third lumbar vertebrae of digital radiographs. Digital radiographs of 48 patients are examined with normalized integral value calculated by power spectrum values of the 2 Dimension Fast Fourier Transform (2DFFT), and accuracies are found by cluster analysis using the obtained values of 48 patients. Next, these radiographs are diagnosed of osteoporosis by doctors (specialists+non-specialists), and we find accuracies by doctors. Both accuracies were 89.6% (computer) and 73.6% (doctors). As the result of the analysis on these values, it is found that objective evaluation of osteoporosis can be performed by analysis of computer using the proposed method.