BACKGROUND:Because the vertebrae of children aged 1 to 3 years are not fully mature,there is no specific pedicle screw for children.At present,the existing pedicle screw with the smallest diameter is for adult cervical lateral mass or pedicle screw fixation.OBJECTIVE:To compare the biomechanical changes of adult cervical pedicle screw used in cervical pedicle fixation of adult pigs and lumbar pedicle fixation of young pigs.METHODS:C3-6 segments for six fresh adult pigs and lumbar spinal specimens from six 8-week-old young pigs were selected to prepare 54 single vertebrae with 108 pedicles.Adult cervical pedicle screw was placed into the prepared pedicles,and the maximum axial pull-out strength was detected using biomechanical methods.RESULTS AND CONCLUSION:The maximum axial pull-out strength of the cervical specimen was lower than that of the lumbar specimen,but there was no significant difference(P > 0.05).The mean pull-out strength of L1 was significantly lower than that of L3(P < 0.05).The mean pull-out strength of C5 was significantly higher than that of C3(P < 0.05).There was a significant difference between the bone marrow density of the cervical and lumbar specimens(P < 0.01).From this study,we got the preliminary experimental foundation about applying adult cervical pedicle screw to the lumbar spine of young children from the viewpoint of axial pull-out strength.
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