Applications to Soft Tissue

Many, but not all, of the images of internal structures that are provided by the MRI technique are also available by using X-ray technology. However, the latter method, albeit currently less expensive, is less applicable to soft tissue structures such as the brain and internal organs. X-rays are also a high-energy form of radiation that can damage tissue MRI does not suffer... 

Wang and coworkers first reported the use of these monomers as a novel elastomeric material for potential application in soft tissue engineering in 2002. The molar ratio of glycerol to sebacic acid they used was 1 1. The equimolar amounts of the two monomers were synthesized by polycondensation at 120°C for three days. The reaction scheme is shown in Scheme 8.1. To obtain the elastomers, they first synthesized a prepolymer and then poured an anhydrous 1,3-dioxolane solution of the prepolymer into a mold for curing and shaping under a high vacuum. 

Calcium phosphate with an apatitic structure occurs naturally in the human body and can be described as a calcium deficient carbonate-hydroxylapatite. The chemical similarity of hydroxylapatite to the bone mineral suggests an intrinsic biocompatibility. Implantation of solid blocks of hydroxylapatite has revealed direct bonding to soft tissue (Jansen et al. 1985, Aoki et al. 1987), muscle tissue (Negami 1988) and bone tissue. This aspect of being able to create an artificial material, that provokes excellent tissue response, has provided the impetus for development of hydroxylapatite and other apatites for applications in the body. 

A risk factor is defined as an attribute or exposure that increases the probability of a disease or disorder (Putz-Anderson, 1988). Biomechanical risk factors for musculoskeletal disorders include repetitive and sustained exertions, awkward postures, and application of high mechanical forces. Vibration and cold environments may also accelerate the development of musculoskeletal disorders. Typical tools that can be used to identify the potential for development of musculoskeletal disorders include conducting work-methods analyses and checklists designed to itemize undesirable work site conditions or worker activities that contribute to injury. Since most of manual work requires the active use of the arms and hands, the structures of the upper extremities are particularly vulnerable to soft tissue injury. WUEDs are typically associated with repetitive manual tasks with forceful exertions, such as those performed at assembly lines, or when using hand tools, computer keyboards and other devices, or operating machinery. These tasks impose repeated stresses to the upper body, that is, the muscles, tendons, ligaments, nerve tissues, and neurovascular structures. There are three basic types of WRDs to the upper extremity tendon disorder (such as tendonitis), nerve disorder (such as carpal tunnel syndrome), and neurovascular disorder (such as thoracic outlet syndrome or vibration-Raynaud s syndrome). The main biomechanical risk factors of musculoskeletal disorders are presented in Table 22. 

Ebenstein, D. M. and Pruitt, L. A. 2004. Nanoindentation of soft hydrated materials for application to vascular tissues, / Biomed Mater Res 69A, 222-232. 

Prevention of adhesions is included within the application of soft tissue restoration as the purpose is indeed to restore a soft tissue site to the normal state that preceded the operation or other trauma. The several examples discussed below include abdominal, eye, and spinal soft tissue sites. 

Some of these pol miers and copolymers do not possess the mechanical properties that are required for certain applications. For example, as implants for soft tissue poly(lactide)s, poly(glycolide)s, PCL, poly(dioxanone) and their copolymers may require increased flexibiUty and a modulus of elasticity that is closer to soft tissue. 

Jacobsen K (1974) Area intercondylaris tibiae osseous surface stracture and its relation to soft tissue stractures and applications to radiography. J Anat 117 605-618... 

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