The stabilization effect on bone cement aggregates of pedicle bone cement anchoring technology in the treatment of Kümmell′s disease: a finite element analysis

English Keywords:Kümmell′s disease  Finite element analysis  Pedicle bone cement anchoring  Percutaneous vertebroplasty  Osteoporosis vertebral compression fracture

English Abstract:

  【Abstract】 Objectives: To use finite element analysis to evaluate the stability of bone cement clumps in the treatment of Kümmell′s disease using pedicle bone cement anchoring technology, and to provide a theoretical basis for the treatment of Kümmell′s disease. Methods: A three-dimensional finite element method was used to establish a Kümmell′s disease model of the thoracolumbar spine(T12-L2) by extracting CT thin layer scanning data from one volunteer. The anterior cortex rupture group(group A), anterior cortex rupture with pedicle bone cement anchoring group(group B), anterior cortex intact group(group C), and anterior cortex intact with pedicle bone cement anchoring group(group D) were constructed. The L2 vertebral lower endplate was fully fixed in all models, and 500N loads axial, forward, backward, and left and right bending, as well as 10N·m left and right rotation torque loads were applied to the T12 upper endplate. Statistical analysis was conducted on the maximum displacement values of the central bone cement block in the four groups of models in different motion directions, as well as the maximum displacement and stress values of the pedicle bone cement anchor rods in groups B and D. And the degree of deformation of the pedicle bone cement anchor rods was observed. Results: Comparing the maximum displacement values of bone cement blocks, group B was smaller in the load directions of flexion, extension, and left and right bending, and greater in the axial, left and right rotation than group A; Except for axial load, group D was greater than group C. Comparing the maximum stress values of bone cement pedicle anchor rods, group D was greater than group B in axial, flexion, extension, left and right bending, left and right rotation load directions; Comparing the maximum displacement values of bone anchor rods, group D was smaller than group B in flexion and extension directions, while greater in other load directions than group B. There was no significant deformation of the pedicle bone cement anchor rod in groups B and D under axial, flexion, extension, left and right bending loads, while there was significant deformation under both left and right rotation loads. Conclusions: The use of pedicle bone cement anchoring technology in the treatment of Kümmell′s disease can stabilize the central bone cement mass in the vertebral body in the event of anterior cortical bone rupture, but there is a possibility of fracture of the bone anchoring rod during left and right rotation of the human spine. However, for Kümmell′s disease with intact anterior cortex of the vertebral body, anchoring the pedicle bone cement does not increase the stability of the central bone cement mass mechanically.