[An anatomical study of lumbar unilateral transverse process-pedicle percutaneous vertebral augmentation]

To measure the anatomical parameters related to lumbar unilateral transverse process-pedicle percutaneous vertebral augmentation, and to assess the feasibility and safety of the approach.

A total of 300 lumbar vertebral bodies of 60 patients were randomly selected, and vertebral augmentation were simulated 600 times on X-ray and CT image with unilateral conventional transpedicle approach (control group) and unilateral transverse process-pedicle approach (experimental group). The distance between the entry point and the midline of the vertebral body, the puncture inner inclination angle, the safe range of the puncture inner inclination angle, and the puncture success rate were measured and compared between the left and right with the same approach, and between the two approaches.

The distance between the entry point and the midline gradually increased from L ₁ to L ₅ on both sides in the 2 groups. In the control group, the right sides distance of L ₁ and L ₂ was much longer than the left sides, and the right sides distance of L ₁, L ₂, and L ₅ was much longer than the left sides in the experimental group ( P<0.05); the distance of the experimental group between the entry point and the midline was much longer than the control group regardless of the sides from L ₁ to L ₅ ( P<0.05). In the experimental group, the right maximum inner inclination angle from L ₁ to L ₅, the right middle inner inclination angle from L ₁ to L ₅, and the right minimum inner inclination angle from L ₁, L ₂, L ₄, L ₅ were significantly larger than the left side ( P<0.05). The maximum inner inclination angle and the middle inner inclination angle presented increased tendency, the tendency of minimum inner inclination angle was ambiguous, however, the all inner inclination angles were much larger than those in control group among the different lumbar levels( P<0.05). There was no significant difference of the safe range of the puncture inner inclination angle between 2 sides in 2 groups at L ₁ to L ₅ ( P<0.05); the safe range angle in experimental group at L ₅ was significantly smaller than that in control group ( P<0.05). The difference in total puncture success rate of all lumbar levels was significant between the experimental group and the control group ( χ²=172.252, P=0.000); the puncture success rates of the experimental group were higher than those in the control group form L ₁ to L ₄ ( P<0.05), but no significant difference was found in the puncture success rate between 2 groups at L ₅ ( P>0.05).

Compared with the unilateral conventional transpedicle approach, the entry point of the unilateral transverse process-pedicle approach is localized outside, the puncture inclination angle is wider, and the puncture success rate is higher. It shows that the unilateral transverse process-pedicle approach is safer and more reliable than the unilateral conventional transpedicle approach.