比嘉 昌

BACKGROUND: Correction of coronal plane deformity by osteotomies around the knee is theoretically three-dimensional (3D) and can be associated with changes in other planes. It has been shown that 3D rotational changes are induced by biplanar high tibial osteotomy; however, relevant information in biplanar lateral closed-wedge distal femoral osteotomy (LCW-DFO) has not been reported in literatures. This study aimed to investigate rotational changes in axial and sagittal planes in LCW-DFO using computer-aided design (CAD) simulations. METHODS: LCW-DFO is composed of three cuts: one ascending cut and two transverse cuts. In the simulations, the following geometrical parameters were adopted as factors potentially influencing 3D changes occurring in the osteotomy. The ascending cut angle measured as the angle between the edge of the ascending cut and the edge of the transverse cut in the lateral view, and the ascending cut obliquity measured as the angle corresponding to anterior/posterior inclination of the ascending cut with reference to the posterior condylar tangent line in the axial view. In the analysis, the effects of these bony cut angles on associated rotational changes in the axial and sagittal planes (internal/external rotation and flexion/extension) were calculated. Variation of wedge size ranged from 2 to 8 mm. RESULTS: The degree of the ascending cut obliquity substantially correlated with associated change in the sagittal plane (extension/flexion) while inducing only minimal change in rotation in the axial plane (internal/external rotation). When the osteotomy was made without ascending cut obliquity, the change in knee extension/flexion was minimal for the conditions analyzed while coupled internal rotation of the distal bony segment was induced. CONCLUSIONS: In biplanar LCW-DFO, the ascending cut angle substantially influenced the amount of internal rotation of the distal bony segment with little effect on flexion/extension angles. By contrast, ascending cut obliquity in the axial plane yields an effect on flexion/extension angles and little effect on internal rotation of the distal bony segment.

PURPOSE: Instability and fractures may result from tensioning errors during reverse total shoulder arthroplasty (RTSA). To help understand tension, we measured intraoperative glenohumeral contact forces (GHCF) during RTSA. METHODS: Twenty-six patients underwent RTSA, and a strain gauge was attached to a baseplate, along with a trial glenosphere. GHCF were measured in passive neutral, flexion, abduction, scaption, and external rotation (ER). Five patients were excluded due to wire issues. The average age was 70 (range, 54-84), the average height was 169.5 cm (range, 154.9-182.9), and the average weight was 82.7 kg (range, 45.4-129.3). There were 11 females and 10 males, and thirteen 42 mm and 8 38 mm glenospheres. RESULTS: The mean GHCF values were 135 N at neutral, 123 N at ER, 165 N in flexion, 110 N in scaption, and 205 N in abduction. The mean force at terminal abduction is significantly greater than at terminal ER and scaption (p < 0.05). CONCLUSIONS: These findings could help reduce inappropriate tensioning.

Recently, a study to evaluate the optical properties of wearing CL has begun to improve the quality of vision. The soft contact lens (SCL) consists of an optics region, intermediate region and bevel, which improves the wearing feeling mainly. Because soft contact lens is composed of a soft material, it is deformed along the cornea when it is worn on the eye. In the present report, the shape of the commercial SCL is measured firstly by the light-section method. Then, the shape change of wearing SCL is calculated using a finite element method. At the end, influence on the lens diopter of the shape change of the SCL was investigated by CODE V. As a result, the focal length shortened by a shape change of SCL, and in the case of a lens of -6 Diopter, the lens changed than the diopter unit (0.25D) of production.

Recently, a study to evaluate the optical properties of wearing contact lens has begun to improve the quality of vision (QOV). Because soft contact lens (SCL) is composed of a soft material, it deforms along the cornea when it is worn on the eye. Therefore, it is necessary for the study of QOV to develop a method to measure SCL shape of the soft material. In this study, the shape of SCL in a saline was measured by laser slit light. As a result, the measurements became almost same as value of standard of SCL. Front curve and shape of the bevel region which are non-publication were also measured.

<p>ソフトコンタクトレンズ（SCL）は軟質材料であるので，眼の装用時に角膜に沿って形状が変化する。本研究では，SCLの光学領域，中間領域，ベベル領域の形状が異なる3種類のSCLの装用における形状変化について評価した。はじめに，有限要素法により装用時のSCLの形状変化を解析した。次に，この形状変化がSCLの度数に及ぼす影響を光線追跡によって求めた。得られた主な知見は，1）SCLの形状は，装用によって度数の製造単位である0.25D以上に変化する。2）中間領域の僅かな隙間に涙液を保持するSCL形状では，光学領域が上方向に変位して度数変化が小さい。3）ベベル領域ではB.C.側に引張応力，F.C.側に圧縮応力が作用して曲げ変形が起きる。</p>

When the relationship between the dimensions of face form and those of spectacle frames is poor, it may cause problems such as slipping frames and sore areas on the nose and behind the ears. This paper reports the results of mechanically modeling the contact conditions in the vicinity of the nose. We created a CAD model of a human head by considering the skin thickness distribution. We then performed finite element method (FEM) analysis about the contact region between the pad and the skin. As a result, the nose pad is pressed down in the nose while slanting toward the lower part of the nose gently. Furthermore, the pad is fixed by a slight upsurge by the reaction of the imposition of the skin.

著者版日本人の脱臼性および亜脱性股関節症患者73関節に対して大腿骨全長5mm間隔でCT撮影を施行し、パーソナルコン ピューター上にて皮質骨の外形、内形の輪郭を抽出した。3次元CADであるPro ENGINEER(Parametric Technology)にて大腿骨の各種計測を行った。症例の中には大腿骨頸部前捻が強く、骨髄腔がかなり狭い例が含まれており、ステムを細くストレート にし、オフセットを確保した製品が必要であることが明らかになった。3次元有限要素法によりデザインの妥当性を検討し、ステムサイズ(1〜7号)を決定し た。この製品はハイブリッド型THA4-U Hip Systemとして、ナカシマメディカルより販売されている。当科および関連病院にて、約550関節の初回THA手術が終了しているが、ほぼテンプレート を用いた術前計画通り手術が行われ、短期成績は良好である。

Most spectacle frames are now made of titanium alloy. Recently, however, frames made of gum metal have become available. Gum metal is a new material having a low Young's modulus, high strength and high elastic deformation. The effectiveness of these spectacle frames, however, has not yet been mechanically evaluated. In this study, by using the recently proposed optical 3D shape measurement method, the deformation behavior of full-rim and rimless spectacle frames, made of gum metal and available on the market, were compared with that of conventional titanium frames. In addition, CAD models of these frames were created and their mechanical characteristics were evaluated in detail by the finite element method. Consequently, the gum metal frames were found more comfortable to wear than titanium ones. However, the rimless type of gum metal frames allowed more load to reach the front than did the titanium frames, causing lens damage due to stress concentration at the screws.

As the result of developments in computer technology in recent years, the calculation, simulation and analysis of the stress environment for the artificial hip prosthesis and the femur have been made possible. In order to perform an exact calculation, three-dimensional modeling with the hip prosthesis and femur is required. The modeling of a femur is done by reconstructing the femoral outline data from CT images using three-dimensional CAD. The outline extraction work is performed by the experience and subjectivity of the operator, and the reliability of the data and working efficiency is low. In this paper, algorithms that extract the femur outline from CT images automatically are proposed. A Snake-based outline extraction algorithm is used. Although this method is capable of extracting the cortical bone outline of femoral diaphysis with sufficient accuracy, there was high incorrect detection at the trochanter. The shape of the trochanter is complicated, and it is difficult to process using a simple algorithm. Therefore, we proposed a method of visually expressing the possibility that a certain pixel in an image is high or low. This method is capable of detecting portions of images with high differentiations in value (contrast changes rapidly). It can also detect outlines at the diaphysis and trochanter. The problems of this technique are that the pixels judged as possibly being a part of the outline appear in the portion that is not a true outline, and that the pixels judged as possibly being on the outline may not be continuous. When each method was used independently, neither was capable of performing a positive outline extraction. However, an outline sampling sufficiently high certainty was achieved when using the two methods simultaneously.

In artificial internal organs, smaller is better. And an important issue is bio affinity. From these points of view, Regenerative medicine and Nano technology are very useful technology. In Tohoku University, various artificial internal organ research including Artificial esophagus, Artificial Myocardium, and Artificial sphincter based on 21 COE program. Ideal artificial organs may be embodied in future.

The number of stem designs for total hip arthroplasty is increasing, and occasionally design changes have yielded unexpected clinical results. At present, we are not able to clearly identify which parameter of the stem is most important, and the optimum value of many parameters. The goals of this study were to identify which parameter is most important, to understand the effect of design change, and to find the optimum stem shape. For this purpose, we used adaptive p-method together with three-dimensional computer-aided design software program for the design sensitivity analysis (DSA) and shape optimization of the stem. The results suggested that increasing the lateral and medial width of the distal cross-section together with decreasing the medial-lateral width and the medial radius of the distal cross-section from the default value would lead to a decrease in the largest maximum principal stress of the distal cement. The medial width of middle cross-section, however, was not so simple. The result of DSA suggested that decreasing this parameter from the default value decreased the stress in the distal cement, but the optimum shape was obtained by increasing this parameter. The method used in this study will assist our engineers and surgeons in the process of modifying and optimizing the stem design.

Where is a place to be assisted for the patients with congestive heart failure? It is contraction of myocardium. We do not need to exchange the whole hearts. We started the ARTIFICIAL MYOCARDIUM development project. In the first step, pneumatic drive type artificial myocardium was developed. Next, development of an implantable type device was started. The animal experiment which studies the direct ventricle supporting effect by this motor was conducted. Although cardiac assistance of the right ventricle was enough as a result of repeating an animal experiment, the left ventricle supporting effect was inadequate. By such reason, we planned the development of an electrohydraulic driving system with grass fiber belt for fixation. The drive system with which it equipped between ribs controls silicon oil in our plan. Energy is supplied by transcutaneous energy transmission system from the outside of the body. As the results, this device is easily attached to the ventricle and the left ventricle and the right ventricle were able to be assisted as a result of the animal experiment. The cardiac output increased and blood pressure rose in the time series data during artificial myocardium support. Since this device is not a pump, it does not have a valve and does not have the risk of a thrombus, either. Therefore, it is also possible to implant in prevention to a slight heart failure patient. It is expected that it becomes an important artificial organ with a big market.

This article proposes a novel concept of hemostatic forceps for less invasive surgical operation. Hemostatic forceps has more than 400-year's history but remain an instrument with a potential of over-pressure induced lesion. The proposed hemostatic forceps allows a possibility to limit the clamping pressure within a safe range. This is to be realized by employing the constant stress property of superelastic shape memory alloys to limit the pressure applied on biological tissues. It is expected that the development of safe hemostatic forcepses based on this concept would reduce medical accidents.

Severe dysfunction of muscle tissues can be treated by transplantation but the success rate is still not high enough. One possibility instead is to replace the dysfunctional muscle with artificial muscles. This article introduces a unique approach using shape memory alloys (SMAs) to replace the anal sphincter muscle for solving the problem of fecal incontinence. The use of SMAs that exhibit a two-way shape memory effect allows the device to function like a sphincter muscle and facilitates simple design. In this article, we will give a brief introduction to the functional material-SMA-together with its medical applications, and will follow this with a description of the recent progress in research and development of an SMA-based artificial sphincter. The possibility of its commercialization will also be discussed.

When cemented hip replacement implants are developed using a finite element method (FEM), the validation of the inplants comparing with experimental tests and clinical survival data should be required. As the first step, the optimum shape of the femoral component of total hip arthroplasty (THA) was designed to minimize the stress peak in the cement mantle that is the primal cause for fixation failure. In the next step, the strain in the cement mantle surrounding the cemented femoral components of THA was measured using strain gauges embedded within the cement mantle adjacent to the developed femoral stem to validate the optimization results of FEM. As a result of this study, optimum shape of femoral component was developed and the FEM results were validated by strain gauge experiments.

The present paper introduces an optimum design of the hip prosthesis and a method for shape optimization which minimizes the stress concentration within the cement mantle. A gradient projection method of numerical optimization and a p-version three-dimensional FEM of stress analysis were employed. A generic three-dimensional FEM model of the proximal femur containing a cemented fomoral stem of a total hip arthroplasty was developed. The three types of analysis was then performed in this study. First, stastic stress analysis measuring the stress in the bone cement was performed. The generic model was then valified parametrically by changing the each parameters individually that compose the stem geometry measureing the stress occuring within the cement mantle concurrently. As it is called design sensitivity analysis was performed. Finally, optimal stem shape was desigend using shape optimization. The design objective was to minimize the largest maximum principal stress in the cement. The results of shape optimization showed considerable reduction in stress concentration within the cement mantle compared to the starting design that were used. Moreover, the optimal stem shape obtained in this study showed unique geometry differ from the standard trend that has been believed to be better. The results of this study has shown to be attractive for evaluating stem design and develop the optimal new stem shape.