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The prosthetic socket is the key part connecting the prosthesis and the stump. It needs to be functional, safe, and comfortable at the same time. However, the volume fluctuation of the stump causes the incompatibility between the stump and the socket. This paper designs an adaptive prosthetic socket with rope-driven to fit stump volume fluctuation. The designed adaptive prosthetic socket with constant force characteristic using superelastic shape memory alloy may solve the problem of uneven pressure on the stump due to stump volume fluctuation and adapt stump volume. To obtain a good constant force range, the constant force characteristic of the socket is optimized and validated by finite element analysis. The experimental results show that the constant force mechanism using the C-shaped shape memory alloy sheets can obtain good constant force characteristics, and the socket can apply a constant force to the stump to solve the problem of uneven pressure distribution between the stump and the socket. [ABSTRACT FROM AUTHOR]

Fecal incontinence caused by sphincter dysfunction is an unresolved problem which has a serious effect on patients, both physically and psychologically. For patients with severe symptoms, treatment with an artificial anal sphincter could be a potential option to restore continence. Acticon Neosphincter still has safety and efficacy problems, which is the only device certified by the US Food and Drug Administration. The biomechanical compatibility is the key problem of artificial anal sphincter in the clinical application. This paper describes an artificial anal sphincter with superelastic shape memory alloys and its mechanical properties assessment in artificial intestine models. The new design was developed as a low invasive and constant force or pressure prosthesis with a simple structure to solve the problem of severe fecal incontinence in patients. [ABSTRACT FROM AUTHOR]

Clamping devices with constant force or pressure are desired in medical device, such as hemostatic forceps and the artificial sphincter, to prevent soft tissues from injures due to overloading. It is easily obtained by stretching an SMA wire. However, studies with SMA bending round bar have seldom been reported before. This paper studied constant force characteristic of C-shaped round bar with shape memory alloys. Optimization designs of the components were carried out with computational simulation. Numerical results show that the phenomenon of constant force strongly depends on contour curve shape and geometric dimensions of the C-shaped round bar of SMA component. [ABSTRACT FROM AUTHOR]

Fecal incontinence caused by sphincter dysfunction is a difficult medical problem which has not been fully resolved. An artificial anal sphincter (AAS) is considered an eventual choice as prosthesis to maintain anal continence. Currently, Acticon Neosphincter, the only device certified by the US Food and Drug Administration can not maintain the long-term effectiveness. The crucial problem of this study was to keeping long-term biomechanical compatibility between the AAS and the surrounding tissue. This paper presented a design of an AAS with constant force or pressure using superelastic shape memory alloy (SMA) to solve the problem. A C-shaped superelastic SMA sheet was optimized to obtain constant force or pressure by combing finite element analysis with ANSYS and genetic algorithm in MATLAB. The result of optimization was validated by performing an experiment. The optimized model was embedding into the device to realize clamping the soft tissue with constant force, which was confirmed by experiments. [ABSTRACT FROM AUTHOR]

Patients with fecal incontinence suffer both physically and psychosocially. Puborectalis helps with continence, and dysfunction of this muscle may cause fecal incontinence. Though some medical treatments have been introduced, little work has been done on functional assist device to puborectalis. This paper presents a design of a functional assist device to human puborectalis with Ti-Ni shape memory alloy as the actuating part, and evaluates its deformation and mechanical properties. The effectiveness of this device was confirmed by preliminary experiments conducted at body temperature. [ABSTRACT FROM AUTHOR]

Control of clamping pressure on blood vessel is a commonly concerned issue in minimally invasive surgeries. While complicated sensing-feedback-control systems are developed for clamping in robotic surgeries, a simple mechanism for the pressure control is desired. In this paper, we propose a new structure of endoscopic forceps to solve the problem of nonlinear relation between the clamping pressure and grasping force. A shape memory alloy (SMA) wire embedded endoscopic clamp is proposed to control the clamping pressure within a safe range. A typical configuration of the clamp is designed based on the discussion on the detailed geometric dimension of SMA wires and blood vessels. [ABSTRACT FROM AUTHOR]