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Abstract To compare between the growing rod internal fixation system of sliding pedicle screw and the universal spine system(USS) by the limit loading test in order to provide the basis for further improvement and clinical application of the system in the future .[Methods] A total of 12 spine specimens of fresh porcine(3 thoracic vertebra functional units ) were randomly divided into the sliding group (attachment screws in the 3rd vertebra and sliding pedicle screws in 1st vertebra) and fixation group (attachment screws in 1st and 3rd vertebra) .The limit loading of antexion and rotation state of USS and the growing rod internal fix-ation system of sliding pedicle screw was tested .All data were analyzed by SPSS 18 .0 software .[Results]At antexion state ,screw loosening occurred in the sliding group at about 400N ,while screw loosening occurred in the fixation group at about 1800N ,and there was significant difference between two groups ( P <0 .05) .At rotation state ,screw loosening occurred in the sliding group at about 5 degrees ,while screw loosening oc-curred in fixation group at about 10 degrees ,and there was significant difference between two groups ( P <0 .05) .[Conclusion] The limit loading of the growing rod internal fixation system of sliding pedicle screw is smaller than that of USS .It indicates that the growing rod internal fixation system of sliding pedicle screw has some deficiencies which need to be further optimized in order to increase the strength of the fixation .
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2014, Vol. 31 
