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Retrieval analysis of motion preserving spinal devices and periprosthetic tissues

Steven M. Kurtz, PhD,1,2 Marla Steinbeck, PhD,1 Allyson Ianuzzi, PhD,1 André van Ooij, MD,3 Ilona M. Punt,3 Jorge Isaza, MD,4 E.R.S. Ross, MD5
1Implant Research Center, School of Biomedical Engineering, Science, and Health Systems and Department of Materials Engineering, Drexel University, Philadelphia, PA 2Exponent, Inc. 3Departments of Orthopaedic Surgery, Maastricht University Medical Center, AZ Maastricht, 6202 AZ Maastricht, the Netherlands 4Our Lady of the Lake Medical Center, Baton Rouge, LA 5Hope Hospital, Safford, UK

Abstract 

This article reviews certain practical aspects of retrieval analysis for motion preserving spinal implants and periprosthetic tissues as an essential component of the overall revision strategy for these implants. At our institution, we established an international repository for motion-preserving spine implants in 2004. Our repository is currently open to all spine surgeons, and is intended to be inclusive of all cervical and lumbar implant designs such as artificial discs and posterior dynamic stabilization devices. Although a wide range of alternative materials is being investigated for nonfusion spine implants, many of the examples in this review are drawn from our existing repository of metal-on-polyethylene, metal-on-metal lumbar total disc replacements (TDRs), and polyurethane-based dynamic motion preservation devices. These devices are already approved or nearing approval for use in the United States, and hence are the most clinically relevant at the present time. This article summarizes the current literature on the retrieval analysis of these implants and concludes with recommendations for the development of new test methods that are based on the current state of knowledge of in vivo wear and damage mechanisms. Furthermore, the relevance and need to evaluate the surrounding tissue to obtain a complete understanding of the biological reaction to implant component corrosion and wear is reviewed.

keywords: 
Dynamic motion preservation, Artificial discs, Retrieval analysis, Explant analysis, Polyurethane, Ultra-high molecular weight polyethylene, PU, UHMWPE, Mechanical testing, Chemical analysis, Histology, Wear particles wear debris
Volume 3 Issue 4
doi: 
10.1016/j.esas.2009.11.003