| Objective:To investigate the morphological feasibility of transarticular placement of the lumbar pedicle screw.Methods:The CT data of 40 patients(20 males and 20 females)who met the inclusion criteria in the First Bethune Hospital of Jilin University were selected and imported into the Mimics Medical software for three-dimensional model reconstruction of the lumbar spine and sacrum.Select the screw with the largest diameter that can safely pass through the facet and pedicle of the lumbar facet joint to simulate the screw trajectory during screw placement,and measure the parameters of the screw trajectory on a three-dimensional model,including the maximum width of the screw trajectory,the maximum height of the screw trajectory,the length of the screw trajectory,the camber angle of the screw trajectory,and the tail angle of the screw trajectory.Then,determine the optimal screw for different segments of the lumbar spine based on the screw trajectory parameters,The optimal screw placement is simulated in the reconstructed three-dimensional model,and the ratio of the joint surface to be exposed is calculated to guide clinical practice.Results:(1)The width,height,and length of the screw trajectory:(1)The width of the screw trajectory in the male and female groups gradually increased at the L1-S1segment;The change was 4.92 ± 0.61mm～8.29 ± 1.02 mm in the male group and4.10 ± 0.73mm～7.40 ± 0.95 mm in the female group.There was a significant difference between the male and female groups in L4 and L5(P<0.05)The screw trajectory height in the male group was 8.02 ± 1.33mm～9.66 ± 1.04 mm,while that in the female group was 7.09 ± 1.09mm～8.17 ± 1.17 mm.There was a significant difference between the male and female groups in L1,L2,L4,and S1(P<0.05)The screw trajectory length in the male group was 34.15 ± 2.05 mm to35.13 ± 2.80 mm,while in the female group was 30.27 ± 1.86 mm to 42.82 ±4.82 mm.There was a significant difference between the male and female groups in L1,L5,and S1(P<0.05).(2)The camber and caudal angle of screw trajectory:(1)The camber angle in the male group was 2.92 ± 4.52 ° to 10.00 ± 2.87 °,while the camber angle in the female group was 0.61 ± 1.74 ° to 6.56 ± 3.74 °.There was a significant difference between the male and female groups in L3 and L5(P<0.05)The caudal inclination of the male group was 14.12 ± 6.54 ° to 25.40 ± 3.78 °,while that of the female group was 16.65 ± 6.51 ° to 28.21 ± 1.98 °.There was no significant difference between the male and female groups(P>0.05).(3)The optimal screw entry area and related parameters:(1)The screw entry points for both male and female groups are located in the lower quadrant of the articular surface.(2)The reference screw diameters for males in L2-S1 were 5.0mm,5.5mm,6.0mm,7.0mm,and 7.0mm,respectively;The lengths are 40 mm,45mm,35 mm,35mm,and 30 mm respectively;The camber angles were 8.49 ± 1.73 °,10.00 ± 2.87 °,8.58 ± 2.69 °,4.82 ± 3.20 °,2.92 ± 4.52 °,respectively;The tail angles are 25.40 ± 3.78 °,24.52 ± 4.56 °,17.90 ±4.26 °,14.12 ± 6.54 °,and 23.23 ± 7.87 °,respectively.The reference screw diameters for females in L4-S1 are 5.5mm,6.5mm,and 7.0mm,respectively;The length is: 35 mm,30mm,30mm;The camber angles are 5.29 ± 3.91 °,0.61± 1.74 °,and 1.16 ± 2.29 °,respectively;The tail inclination angles are 18.63± 3.04 °,16.65 ± 6.51 °,and 28.21 ± 1.98 °,respectively.(4)The ratio of upper articular surface to be exposed during screw insertion was between 46%-52% for males and 41%-53% for females,while there was no significant difference between the male and female groups(P>0.05).Conclusion:(1)Transarticular pedicle screw placement in the lumbar spine is feasible at the L2 S1 level in males and L4 S1 level in females.Select a screw diameter of 5-7mm;The screw length is about 30-45 mm for males and 30-35 mm for females;The camber angle of the screw is about 3-10 ° for males and 1-5 ° for females;There was no significant difference in the inclination angle of the screw tail between men and women,about 14-28 °.(2)The screw insertion points of both male and female groups were located in the lower quadrant of the articular surface.The ratio of joint surfaces that need to be exposed to simulate the optimal screw placement is approximately... |
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