Artificial disc replacement

Van Ooij A., RC. Oner, and A.J. Verbout. 2003. CompUcations of artificial disc replacement A report of 27 patients with the SB Charite disc. Spine 28SuppI S369-383. 

Zeegers W.S., L.M. Bohnen, M. Laaper, and M.J. Verhaegen. 1999. Artificial disc replacement with the modular tjqje SB Charite III 2-year results in 50 prospectively studied patients. Eur Spine J 8 210-217. 

Thorpe PLPJ, Licina P. Osteolysis and complications associated with artificial disc replacement. 2004 annual meeting of the spine society of Australia. Coolum, Australia 2004. p. Poster 21. 

McAfee PC, Geisler FH, Saiedy SS, Moore SV, Regan JJ, Guyer RD, et al. Revisability of the CHARITE artificial disc replacement analysis of 688 patients enrolled in the U.S. IDE study of the CHARITE artificial disc. Spine 2006 May 15 31(ll) 1217-26. 

It is important to distinguish between mechanical behavior and clinical performance. Although one may conceptualize different regimes of UHMWPE mechanical behavior based on their oxidation index, the association between oxidation, mechanical behavior, and clinical performance is not straightforward. The clinical significance of in vivo oxidation in the hip and knee is further explored in the following sections. Additional details about in vivo oxidation in artificial disc replacements can be found in Chapter 12. 

Link H.D., and A. Keller. 2003. Biomechanics of total disc replacement. In The artificial disc. K. Biittner-Janz, S. Hochschuler, and P. McAfee, Eds. Berlin Springer Verlag. 

Despite the current controversies surrounding the CHARITE, it is nonetheless the icon for contemporary total disc arthroplasty. Other artificial disc designs are currently in chnical use in Europe and may become available in the United States within the coming decade. However, these newer designs build upon the design philosophy established by the CHARITE, which adapted the successful bearing concepts from hip and knee replacements for total... 

In this section, we summarize the design features and available literature for contemporary cervical metal-on-UHMWPE artificial discs. Many cervical disc replacements have been proposed over the years, but today five contemporary designs have been documented in the peer-reviewed literature and are currently in chnical trials in the United States ProDisc-C, PCM, Mobi-C, and Discover (Table 12.5). As detailed in the table, these designs differ from each other in several respects, including the philosophy as well as the constraint in the bearing (Table 12.5). 

Based on the clinical experience of UHMWPE in total hip and knee replacements, the prodnction of wear debris from artificial discs, as well as from other motionpreserving spine implants, is a clinical concern. Wear debris indnced osteolysis has been implicated as a potential mechanism for late onset pain following the faUme of stainless steel and titanium instrumented fusions [65]. Osteolysis has also been observed around certain total disc replacement designs, such as the Acroflex artificial disc [66], and case smdies of osteolysis around CHARITE disc replacements have also been reported [67-69]. According to recent conference presentations, the UHMWPE particle load around long-term implanted artificial discs may be comparable to total hip arthroplasty [70], and the periprosthetic particle concentration appears to be correlated with a local inflammatory response [71]. Although the occurrence of osteolysis with metal-on- X)lyethylene total disc replacements has thus far been relatively rare, the long-term wear behavior of artificial discs remains of clinical importance [69]. 

Blumenthal S, McAfee PC, Guyer RD, Hochschuler SH, Geisler FH, Holt RT, et al. A prospective, randomized, multicenter Food and Drug Administration investigational device exemptions study of lumbar total disc replacement with the CHARITE artificial... 

Delamarter RB, Fribourg DM, Kanim LE, Bae H. ProDisc artificial total lumbar disc replacement introduction and early results from the United States clinical trial. Spine 2003 October 15 28(20) S167-75. 

Biocompatibility and Mechanical Properties. Currently, their are no suitable artificial materials for the prosthetic replacement of articular cartilage. The biocompatibility is considered the primary criterion in the selection of such a material. In a recent study, Furst and co-workers(10) compared the biocompatibility of the polyurethane to the well known medical grade silicone polymer. The tissue reactions to small polymer discs, inserted in an articulating space—the suprapatellar bursa of rabbits, was examined. The foreign body reaction of the tissue at the implantation site was evaluated at intervals of 7 days,... 

Replacement of diseased heart valves with prosthetic ball valves— The special flaps of tissue which serve eis valves for the heart may become damaged or diseased, and require replacement Most surgeons now use prosthetic valves eis replacement parts rather than human or animal tissues because the artificial devices are better tolerated by the body. Hence, the type of valve which is implanted in the heart is likely to be a wear-resistant ball or disc that moves back and forth in a small wire cage in response to the ebb and flow of blood from the heart. 

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