Design Of Cortical Bone Channel Screws And Its Biomechanical Properties

OBJECTIVE: A new type of total cortical bone screw was developed to compare the cortical force of the cortical bone channel and the pedicle channel.The biomechanical properties of the cortical bone screw and the traditional pedicle screw were studied.METHODS:Eighteen adult cadaveric lumbar vertebrae specimens were used to determine the osteoporotic vertebral body by bone mineral density(BMD).L1-L5 vertebral bodies were selected as experimental specimens,and the vertebral bodies were excluded.They were randomly divided into 6 groups,each group 8 One vertebral body,the remaining vertebral bodies were used as spare,and the left and right sides of the vertebral body were used as the experimental group and the control group: Group A and Group B: the same specification cortical bone screw(?4.5mm,L30mm)was implanted into the cortical bone channel and the traditional pedicle Channel;group C and group D:cortical bone screws and single-thread pedicle screws of the same specification(?4.5mm,L30 mm)were implanted into the cortical bone channels of the same vertebral body respectively;groups E and F: the same specification(Cortical bone screws and double-threaded pedicle screws of ?4.5 mm,L30 mm were implanted into the cortical bone channels of the same vertebral body,respectively.Among them,the A,C,and E groups were the largest pull-out experiments,and the B,D,and F groups were subjected to the cycle-resistant biomechanical experiments.Results: 1.The maximum extraction force of cortical bone screws(?4.5mm,L30mm)applied to cortical bone and pedicle channel was 476.38 N and 222.65 N respectively.After t test,t=8.664,P<0.01.Statistically significant;the cyclic anti-buckling test load of cortical bone and pedicle channel was tested by t test,t=6.509,P<0.01,statistically significant;period: t=3.761,P<0.01,statistically significant.2.In the cortical bone channel,the maximum extraction force of the new cortical bone screw with uniform specification(?4.5mm,L30mm)is greater than that of the single thread pedicle screw,t=4.798,P<0.01,which is statistically significant.The cyclic anti-buckling load of cortical screw and single-thread pedicle screw showed: t=4.337,P<0.01,statistically significant;period: t=3.337,P<0.05,statistically significant.3.In the cortical bone channel,the maximum extraction force of the new cortical bone screw with uniform specification(?4.5mm,L30mm)is greater than that of the double-threaded pedicle screw,t=5.421,P<0.01,which is statistically significant.The cyclic anti-buckling load of cortical screw and single-thread pedicle screw showed: t=3.185,P<0.01,statistically significant;period: t=3.582,P<0.05,statistically significant.Conclusion: 1.The cortical bone channel has better grip on the screw than the traditional pedicle channel.2.The cortical bone channel should use a full cortical bone screw,which can improve the biomechanical properties of the screw.