Soft Tissue Prostheses

Soft Tissue Prostheses.—Tissue compatibility is a far less complex problem than is that of blood compatibility. In the former case physical form appears to be a 

Experience over a three year period with polytetrafluoroethylene (Proplast) is reported together with early results on chlorinated polyethylene which is claimed to have advantages over other available materials. The sunlight stability of facial prostheses presents an obvious problem and the behaviour of polyurethanes in this respect has been examined. Experimental reconstructive prostheses have involved for example silicone rubber in the repair of nasal septal perforation and ear reconstruction and polytetrafluoroethylene in frontal sinus reconstruction. Breast reconstruction and augmentation with silicone rubber and polyurethanes, tissue reaction to polyurethane coated implants, and the use of polyethylene in this type of surgery have been discussed. A useful review on silicone fluids (which are for example iiyected to improve scars ) has appeared. 

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Hydrogels have many potential uses in biomedicine, ranging from materials for the construction of soft-tissue prostheses or... 

Nunez J and Schmitt P J, Shaped woven tubular soft tissue prostheses and methods of manufacturing , US Patent 5,904,714,1 September 1998. Sidebottom J B, Bifurcated textile fibers and method of weaving the same US Patent 2,845,959,5 August 1958. 

Soft-tissue Prosthesis. Several useful reviews adequately cover the present status and recent advances in materials for oral, maxillofacial, plastic, and reconstructive surgery. ... 

Soft tissue Mammary prosthesis 1-7 Staphylococcus aureus... 

Ultrasound as a method to measure UHMWPE wear in TKA. The figure shows a posterior stabilized TKR (A) and an ultrasound of the same prosthesis taken in a water bath without soft tissues (B). The red inset represents the ultrasound region shown in (B). The UHMWPE tibial insert is visible between the green arrows. The large white arrow indicates the direction from which the ultrasound probe was applied. The images were provided courtesy of John Martell, University of Chicago. 

Hemipelvectomy Prostheses. The prosthesis for an individual witfi a hemipelvectomy is similar to that of the hip disarticulation prosthesis. However, the residuum of an individual with a hemipelvectomy no longer contains the ischial tuberosity. The socket must therefore provide distal support solely through the soft tissues. To minimize soft tissue pressures, the socket may extend more proximally using the iliac crest, distal ribs, and gluteal muscles for support. Suspension may be augmented by shoulder straps. This prosthesis is typically endoskeletal so as to minimize the weight of the prosthesis. 

The prosthetist also evaluates prosthetic fit, or the comfort (pressure distribution), stability, suspension, aligiunent, and function of the prosthesis. The fitting of a prosthesis is an empirical process. The prosthetist has no quantitative information regarding the load distribution of the soft tissues and... 

Two primary limitations of these modeling efforts involve the representation of tissue properties across the entire limb and the interface condition between the residual limb and prosthesis. The ability of current finite-element models to estimate prosthetic interface stresses, while performing reasonably well in some cases, has not been highly accurate. Nevertheless, the methodology has potential. Advances in finite-element software enabling nonlinear elastomeric formulations of bulk soft tissue, contact analysis, and dynamic analysis may help address some of the current model limitations. Corresponding advances in pressure-transducer technology will help validate the computer models and facilitate interpretation of the analyses. 

In 1978, two years after the recognition of pseudo tumors of bone induced by the degradation products of total hip arthroplasty, Arden and Bywaters [20] (Table 5.1) reported a case of a 56-year-old patient who developed a high-grade fibrosarcoma of soft tissue 2.5 years after receiving a metal-on-metal McKee-Farrar hip prosthesis. The tumor apparently did not have a direct association with the underlying bone or any components of the total hip arthroplasty. No formal analysis of the tumor for debris... 

Along with PP, PTFE, and polyesters, PE is used for sutures, soft tissue augmentation, vascular prosthesis, implants, and so on. 

External velour polyester vascular prosthesis (Bionit II) warp-knitted from texturized multifilament yarns with soft, open structure to encourage tissue ingrowth. 

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