Sutures mechanical properties

The first synthetic polyglycoHc acid suture was introduced in 1970 with great success (21). This is because synthetic polymers are preferable to natural polymers since greater control over uniformity and mechanical properties are obtainable. The foreign body response to synthetic polymer absorption generally is quite predictable whereas catgut absorption is variable and usually produces a more intense inflammatory reaction (22). This greater tissue compatibihty is cmcial when the implant must serve as an inert, mechanical device prior to bioresorption. 

Table 5.12 Representative Mechanical Properties of Some Commercial Sutures...

Artificial Soft Biologies. In addition to sutures, polymers are used for a number of biomedical applications, as illustrated in Figure 5.128. Polymers used for hard structural applications such as dentures and bones are presented in this figure, but will be described in the next section. In this section, we will concentrate on polymers for soft biological material applications and will limit the description to mechanical properties as much as possible. 

Mechanical Properties Stress-strain, Elasticity, DuctiUty Fatigue, Fracture, Creep Viscoelasticity, Elastomers Laminates Sutures, Bone, Teeth... 

Polyglycolide was one of the first synthetic polymers used as a degradable surgical suture [122]. Fig. 8 shows the glycolide monomer and polymer structures. This aliphatic polyester is biodegradable and exhibits negligible toxicity when implanted in tissue. It is also possible to fabricate a strong fiber of this polyester with satisfactory mechanical properties. 

Early reports of the biomedical use of poly(lactic acid) date back to the 1960s [3, 175]. Since then, PLA has gained widespread application in the medical field, for use in sutures [8], drug delivery devices [15, 17, 24, 59-90], prosthetics, scaffolds, vascular grafts, and bone screws, pins and plates for temporary internal fracture fixation [10-13]. Good mechanical properties and the fact that it de-... 

Biodegradable materials were initially used in medical applications such as sutures, prostheses, controlled drug-release systems, and vascular grafts. These applications are enabled by their biocompatibility, their ability to be absorbed by the body, and because of their mechanical properties appropriate for such applications [6]. 

Optical properties, optimum mechanical properties and suturability, and permeability to glucose and albumin were evaluated... 

This chapter contains three case studies. The first one on climbing rope illustrates the technology of fibre production and rope construction to meet specific mechanical property targets. There are some similarities between rope and the much smaller scale braided sutures used in surgery. Further sport case studies, on polymer foam protective gear and materials in running shoes, are mentioned in the Further Reading section. 

The degradation time of PLLA is much slower than that of PDLLA, requiring more than 2 years to be completely absorbed. Copolymers of L-lactide and DL-lactide have been prepared to disrupt the crystallinity of L-lactide and accelerate the degradation process. The final crystallinity and mechanical properties of the polymer depend on the stereochemistry of the polymer backbone. PLA has a number of biomedical applications, such as sutures, stents, dialysis media, and drug delivery devices. " °... 

The physical properties of a biomateiial include mechanical properties, such as stiffness, strength, and durability, together with other properties, such as oxygen permeability. The properties need to be suitable for the intended lifetime of the implant, which can range from the few weeks required for resorbable sutures to the lifetime of the patient receiving a hip replacement. 

Poly(propylene) is one of the biocompatible, biostable polymer used widely in clinical applications ranging from sutures to load-bearing implants (Figure 18.1b). Poly(propylene) has fiber-forming characteristics and has been used in the treatment of ventral incisional hernia [22,23]. Poly(propylene) has excellent stiffness and strength when compared to polyethylene [24]. Superior mechanical performance in fatigue and temperature resistance offers sufficient mechanical property even at body temperature and able to bear millions... 

The high chemical stabiUly and favourable mechanical properties of PP lead to its important use in medicine. It was applied for lining the valves of artificial hearts and for ball joint prostheses in the early 1970s. PP shows a moderate response of the tissues of the living body. It is commercially available in the form of suture threads [54]. 

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