Publications (2)2.08 Total impact
Article: Augmentation of pedicle screw fixation strength using an injectable calcium sulfate cement: an in vivo study.[show abstract] [hide abstract]
ABSTRACT: An in vivo landrace model of cement augmentation of pedicle screw was established, and axial pull-out tests and histological analysis were performed. To investigate the long-term in vivo biomechanical performance of pedicle screws augmented with calcium sulfate cement. Little information is available on the long-term biomechanical performance of pedicle screws augmented with calcium sulfate cement in vivo. Ten pedicle screws were implanted into the lumbar vertebrae of 15 adult females landraces weighing 105 to 115 kg. The pedicle screws were augmented with Polymethyl methacrylate (PMMA), augmented with the calcium sulfate cement, or not augmented. The landraces were randomized into 3 study periods of day 1, 6 weeks, and 12 weeks. At the end of the assigned study periods, the animals were killed and axial pull-out tests and histological analyses were conducted on the isolated specimen vertebrae. No significant difference was found among the 1-day, 6-week,and 12-week control group (P > 0.18), no significant difference was found among the 1-day, 6-week and 12-week PMMA group (P > 0.59), and no significant difference was found among the 1-day, 6-week and 12-week calcium sulfate group (P > 0.27). The maximum POS of the PMMA groups was significantly greater than that of the calcium sulfate groups (P < 0.002), the maximum POS of the calcium sulfate groups was significantly greater than that of the control groups (P < 0.004). Histologically progressive absorption of the calcium sulfate was evident. The bone walls around the screws in the 12-week calcium sulfate group were statistically significantly thicker than that of the 12-week control group and that of the 12-week PMMA group. Results of this study demonstrate that the injectable calcium sulfate cement can significantly improve the immediate POS of pedicle screw fixation, and this effect can be maintained even if the calcium sulfate cement has been absorbed completely, which may result from that the calcium sulfate cement resorption paralleled bone ingrowth.Spine 11/2008; 33(23):2503-9. · 2.08 Impact Factor
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ABSTRACT: To study the manufacture of pelvic mirror physical model using rapid prototyping and the accuracy of the models. The pelvic CT images were acquired by spiral CT thin slice scanning, and the slicing data of pelvis were created from these CT images by computer image-processing. Then the pelvic mirror physical model was manufactured using rapid prototyping. The model of a cadaver pelvis and the pelvic model of an experimental dog were manufactured respectively using the method above, and the accuracy of the models were examined. The model of the cadaver pelvis manufactured with this method was very similar to the cadaver pelvis. So was the pelvic model of the experimental dog. The manufacture of pelvic mirror physical model using rapid prototyping was feasible, and the models were quite accurate.Beijing da xue xue bao. Yi xue ban = Journal of Peking University. Health sciences 03/2003; 35(1):82-4.