Spine
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A retrieval analysis of wear modes and fixation of lumbar total disc replacements (TDRs). Explanted Prodisc-L TDRs were prospectively collected during a 7-year period (2005-2011) and analyzed. ⋯ Metallic end plate burnishing was evident in a large percentage of clinically failed Prodisc-L TDR devices, most commonly posteriorly, consistent with impingement in extension. Long-term follow-up studies will evaluate the effects of the observed backside wear, third-body wear, and end plate impingement on clinical outcomes.
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A human cadaveric biomechanical analysis. ⋯ Our results suggest that the caudad half of the pedicle is denser and withstands higher forces compared with the cephalad aspect. In turn, the incidence of intraoperative screw loosening and/or pedicle fracture may be reduced if the compressive forces (cantilever bending during deformity correction) placed upon the construct are applied against the caudad portion of the pedicle.
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A biomechanical comparison of 2 commonly used posterior surgical procedures for spinal cord decompression in the cervical spine: laminoplasty (open door) and laminectomy. ⋯ Both 2-level and multilevel laminoplasty preserved the C2-T1 range of motion. Laminectomy resulted in a significant increase in C2-T1 motion due to the loss of the posterior structures.