Biomechanical evaluation of a novel fenestrated pedicle screw augmented with bone cement in osteoporotic spines.

Study Design: Comparative biomechanical study was conducted in osteoporotic human cadaveric spines.

Objective: Determine the influence of the volume of polymethyl methacrylate injected through a fenestrated pedicle screw on the pullout strength and on the ability to safely remove the implant.

Summary Of Background Data: Pedicle screw fixation in the osteoporotic spine can be improved by the addition of bone cement.

Surface slide track mapping of implants for total disc arthroplasty.

Total disc arthroplasty has recently become a potential alternative to spinal arthrodesis. Until recently, there has been no standardized method for evaluating the wear of an artificial disc and myriad testing conditions have been used. The American Society for Testing and Materials (ASTM) and International Organization of Standardization (ISO) recently published guidance documents for the wear assessment of intervertebral spinal disc prostheses; however, various kinematic profiles are suggested, leading to different wear paths between the articulating surfaces of the implants.

The fundamentals of biotribology and its application to spine arthroplasty.

The biological effect of wear of articulating surfaces is a continued concern with large joint replacements and, likewise, of interest for total disc replacements. There are a number of important biotribological testing parameters that can greatly affect the outcome of a wear study in addition to the implant design and material selection. The current ASTM and ISO wear testing standards/guides for spine arthroplasty leave many choices as testing parameters.