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The chapter discusses the advantages and limitations of arterial prostheses (or vascular grafts) in terms of their biocompatibility, biofunctionality and biostability. 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.

The biocompatibility, biofunctionality and biostability of a prosthesis, its degradation and the host response are determined through an implant retrieval study. This chapter focuses on various aspects of analyzing retrieved biotextile implants. Sample preparation techniques, analytical test methods and different test standards are reviewed. Some precautions and the limitations of implant retrieval studies are also discussed.

The chapter describes the pathology of aneurysms and explains the technique of endovascular aortic repair. The development of stent grafts is reviewed and a number of different types are described and evaluated. The use of branched stent grafts and in situ fenestration techniques for patients with more challenging anatomies is discussed.

Trends in ruptured anterior cruciate ligament (ACL) management have included primary repair, allograft, augmentation and prosthetic devices, autograft and, recently, tissue engineering and xenograft, but the primary goals remain restoring knee function, stability and normal kinematics to allow patients to return to a preinjury level of activity as early as possible. Autografts, either with hamstring or bone–patellar tendon–bone, remain the treatment of choice in ACL reconstructive surgery, with allograft attracting renewed interest in recent years. The chapter discusses the low popularity of ACL prosthesis and considers alternative solutions from the emerging field of tissue engineering.

A review of the strength and endurance of current vascular prostheses. Data is referenced to demonstrate that endurance is a property separate from strength. Current proposed test methods are described. It is proposed that endurance is to be demonstrated by bench testing, animal studies, and carefully controlled clinical studies. Strength characteristics are then used to control the production of the product.

Poly (?-hydroxyalkanoates) (PHAs) are bacterial polyesters with chemical and physical properties that make them suitable for medical applications. They are obtained by fermentation techniques, are biodegradable and may be metabolized into normal constituents of the body. A PHA produced by Pseudomonas oleovorans has generated a random copolymer called poly (?-hydroxyoctanoate) (PHO) having elastomeric properties and displaying lower crystallinity and less rigidity than poly (?-hydroxybutyrate) (PHB). As part of an extensive study, we compared the effects of two methods of sterilization on the physical and structural characteristics of PHO, studied the mechanism and degradation rate of PHO in vitro over a 24-month period in physiological media and finally, investigated the biocompatibility and degradation rate of PHO in vivo as a new sealant for the polyester arterial prosthesis. Results have shown that the physical and structural properties of PHO were well-preserved after ethylene oxide sterilization, whereas gamma radiation caused random chain scission and physical cross-linking. In vitro incubation studies demonstrated that the degradation rate of PHO films in water or isoosmotic PBS is a very slow hydrolytic process exceeding two years. In vivo, PHO showed good biocompatibility in terms of tissue enzymatic activity and cellular reactions. Degradation was slow and exhibited similar rate as that observed in vitro. As a sealant in a polyester arterial prosthesis, PHO contributed to the impermeabilization of the graft wall and to the development of an internal collagenous capsule with a confluent endothelium secreting prostacyclin.

Despite earlier claims of biological stability, there is growing evidence from case histories, in vitro testing, and implant retrieval programs that poly(ethylene terephthalate) fibers experience some degradation when implanted in humans as arterial prostheses.

Paul Ricoeur (1913-2005) has been heralded as one of the most notable philosophers of the twentieth century. Like a stone skipping across the philosophical pond, he would write a major work in one field, then move on to another. As a consequence, he is among the most inter-disciplinarian of philosophers whose work not only explores such areas as existentialism, phenomenology, hermeneutics, structuralism, psychoanalysis, metaphor, narrative, and political ethics; it also bridges the gulf between Continental and Anglo-American philosophy. Despite this diversity,one can identify continuous threads running through Ricoeur's work that make him a major representative of hermeneutical philosophy, developing it much further in a critical direction. One of the areas to which he contributed greatly, almost in passing, was the philosophy of religion, where he made notable contributions in the areas of symbol, metaphor and epistemology. Ricoeur's work has been appropriated in theology, but often in an indirect way. This book will help the reader grasp the breadth of a complex philosopher, indicating the increasing relevance and appropriation of Ricoeur's work in theology.