Prostheses Design

The flow velocity, shear stress and pressure fields in the immediate vicinity of a given heart valve prosthesis design are directly related to the fluid dynamic characteristics of the prosthesis. Therefore, detailed in vitro fluid dynamic studies should help predict potential problems and complications that may arise in vivo with different designs of prosthetic heart valves. 

Describe the necessary ingredients for biofeedback. How can these be used in prosthesis design and use ... 

M. Herold, H.B. Lo, H. Reul, et al.. The Helmholtz-Institute tri-leaflet-polyurethane-heart valve prosthesis design, manufacturing and first in-vitro and in-vivo results, in H. Planck, I. Syre, M. Dauner, G. Egbers (Eds.), Polyurethanes in Biomedical Engineering, vol. II, Elsevier Science, Amsterdam, 1987, pp. 231-256. 

T. Mackay, D. Wheatley, G. Bernacca, A. Fisher, C. Hindle, New polyurethane heart valve prosthesis design, manufacture and evaluation, Biomaterials 17 (19) (1996) 1857-1863. 

Study Prosthesis design Fixation Mean follow-up (years) Incidence of osteolysis in study population Osteolysis diagnosis Incidence of revisions for osteolysis... 

The reverse total shoulder prosthesis design concept is one in which the humeral head is replaced with a concave polyethylene bearing surface and the glenoid face is augmented by a convex articular metal component. As the name implies, this reverses the normal anatomic geometries of the humeral head and glenoid face. An example of this prosthesis concept is shown in Figure 9.12. 

The concept is, however, very much in its infancy and its place in the future of shoulder repair has yet to be determined. Encore Medical Corp. (Austin, TX) is currently conducting an investigational device exemption (IDE) study of its new Reverse Shoulder Prosthesis system (Figure 9.12). The first implantation in North America of another reverse prosthesis design (the Delta prosthesis [DePuy, Warsaw, IN]) was reported to have been conducted on February 27, 2003, hy Dr. Anthony Miniaci in Toronto, Canada (Canada Newswire 2003). The potential benefits of the concept are that it can allow better function than standard prostheses without relying on rotator cuff function and that it can decrease bending moment forces at the prosthesis-glenoid interface. If these benefits are clinically realized, then it could become an important addition to standard prostheses, especially in difficult arthroplasty cases. 

Composed of ultra-high-molecular-weight polyethylene fibers. Spectra cable is another option that is available to body-powered prosthesis designers and users. Spectra cable is now widely used at almost all major upper-limb fitting... 

Kenworthy s hand had the fingers fixed with only the thumb being able to move. While flat-surface operation is important, it is perhaps not the most important feature of prosthesis design. This hand was designed primarily for use in bilateral arm systems in which one hand was a conventional pincer-type hand and the oAer was of Kenworthy s design. The 90 degrees of the Kenworthy hand was chosen so that at least one hand of the bilateral arm system could have flat-surface operation. 

Clarke, I.C. (1982) Wear-screening and joint simulation studies vs. materials selection and prosthesis design. CRC Crit. Rev. in Biomed. Eng., 8, 29-91. 

Mittlmeier, T. and Walter, A. (1987) The influence of prosthesis design on wear and loosening phenomena. CRC Critical Reviews in Biocompatibility. 3, 319-419. 

Expose the weaknesses of the prosthesis design that have not been elucidated during in vitro tests, leading to the discontinuation of the product or change in material selection, design, processing or fabrication ... 

Abstract The chapter discusses the advantages and limitations of arterial prostheses (or vascular grafts) in terms of their biocompatibility, biofunctionahty and biostabUity. Criteria for biomaterials selection and prosthesis design that have enabled patients to recover more rapidly without any device-related complications are reviewed, and developments are considered that may lead to future improvements in healing and clinical outcomes for the next generation of vascular prostheses. 

C. R. Gentle, The role of simulation studies in cardiac valve prosthesis design, Eng1 in Med., 7 101 (1978). 

This combination of materials has had a profound effect upon the development of surgery for the treatment of Joint disease and prostheses are readily available, not just for the hip joint but also for the knee, ankle, shoulder and other joints. It is the good biological acceptability of UHMWPE coupled with its mechanical properties that has led to this widespread acceptance. In particular, the tribological characteristics appear to be the most satisfactory for use in a metal-polymer combination. Prosthesis designs utilising alumina ceramic also incorporate an acetabular component of UHMWPE in consequence of the low rate of wear observed. 

Lower-limb-powered prostheses are another example of mobility robotic aids. In the past 30 years, the rapid advances in prosthetic technology resulted in a number of devices that improve the functional mobility and quality of life in individuals with lower-limb amputations [94]. Focusing on above-knee amputation, knee prosthesis design varies from the very simple single-axis knee to high-tech microprocessor-controlled prosthetic knees, such as the C-Leg from Ottobock [95]. One of the most important advancements in the... 

Sonoda H, Takamizawa K, Nakayama Y, Yasui H, Matsuda T. Small-diameter compliant arterial graft prosthesis design concept of coaxial double tubular graft and its fabrication. J Biomed Mater Res 2001 55 266-76. 

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