Affiliations: Engineering Center for Orthopaedic Research Excellence, Departments of Bioengineering and Orthopaedic Surgery, The University of Toledo, Toledo, OH, USA | Interventional Spine, Irvine, CA, USA | R.J. Lee Group Inc., Monroeville, PA, USA | OrthoKinetic Technologies, LLC and OrthoKinetic Testing Technologies, LLC, Southport, NC, USA
Note: [] Address for correspondence: Vijay K. Goel, PhD, Endowed Chair and McMaster-Gardner Professor of Orthopaedic Bioengineering, Engineering Center for Orthopaedic Research Excellence, Departments of Bioengineering and Orthopaedic Surgery, 5046 NI, MS 303, Colleges of Engineering and Medicine, The University of Toledo, Toledo, OH 43606, USA. Tel.: +1 419 530 8035; Fax: +1 419 530 8076; E-mail: [email protected].
Abstract: Dynamic stabilization systems are emerging as an alternative to fusion instrumentation. However, cyclic loading and micro-motion at various interfaces may produce wear debris leading to adverse tissue reactions such as osteolysis. Ten million cycles of wear test was performed for PercuDyn™ in axial rotation and the wear profile and the wear rate was mapped. A validation study was undertaken to assess the efficiency of wear debris collection which accounted for experimental errors. The mean wear debris measured at the end of 10 million cycles was 4.01 mg, based on the worst-case recovery rate of 68.2%. Approximately 40% of the particulates were less than 5 μm; 92% less than 10 μm. About 43% of particulates were spherical in shape, 27% particulates were ellipsoidal and the remaining particles were of irregular shapes. The PercuDyn™ exhibited an average polymeric wear rate of 0.4 mg/million cycles; substantially less than the literature derived studies for other motion preservation devices like the Bryan disc and Charité disc. Wear debris size and shape were also similar to these devices.
Keywords: Wear debris, wear mechanism, osteolysis, SEM
