Total disc arthroplasty/replacement

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... 

Future research efforts in IVD arthroplasty should focus on either partial or full disc functional restoration. This may include NP implants and/or reinforcement or total disc replacement. PVA-C, as a hydrogel, has many interesting properties, such as its long-term biocompatibility and nontoxicity. It is also strongly hydrophilic and viscoelastic with nonlinear stress-strain characteristics similar to the IVD. It has a very low coefficient of friction and has good wear resistance [23]. However, its strength is still too low to serve as a practical functional replacement of the annulus fibrosus. PVA-BC may further increase the strength of the PVA-C to make it a viable candidate material for IVD fabrication. 

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]. 

Total disc replacement is a new, promising field of spine implant technology that has the potential to revolutionize the treatment of degenerative disc disease. Today, conventional UHMWPE is incorporated in both cervical and lumbar disc arthroplasty. It is clear from both in vitro and clinical data that disc replacements can successfully preserve the motion of treated spinal level. Aside from patient satisfaction and the speed of recovery, there are modest clinical benefits with disc replacement that manifest in the short term as compared with fusion. Furthermore, unlike fusion procedures, disc replacements may also need to be revised due to poor implantation technique or failure of the device. On the other hand, over the long term, the primary benefit of disc replacement is expected to be the reduced incidence of adjacent segment degeneration, which will hopefully offset the new, and as yet, poorly quantified risks associated with the technology. It will be many years, probably over a decade, before sufficient... 

Cunningham BW, Dmitriev AE, Hu N, McAfee PC. General principles of total disc replacement arthroplasty seventeen cases in a nonhuman primate model. Spine 2003 October 15 28(20) S118-24. 

Wright T, Cottrell J. Retrieval analysis of ProDisc total disc replacements. 7th annual meeting of the Spine Arthroplasty Society. BerUn, Germany 2007 May 1-4. P124. 

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