Three-dimensional Finite Element Analysis Of Thoracolumbar Spine Bending Compression Injuries

Objective To investigate biomechanical background of thoracolumbarsegment bending compression injuries, providing the theories foundationand sciences gist for proper clinical diagnosis and treatments.Methods A mechanical model of human normal thoracolumbar segmentspine(T₁₁～L₂)was developed using three dimensional finite element method.The different kinds of destructive loads of the bending compression andthe side bending compression were exerted respectively on the surface ofthe model T₁₁ vertebral body, and the stress distribution was analyzed.Results 1,Being exerted the destructive load of the bending compression,which formed 85°with the arrow shape surface level axis, the stressesof T₁₂ and L₁'s anterior pillars were highest, the stresses of T₁₂ and L₁'scentral and posterior pillars were lower. The manifestations were theanterior pillar's bone fracture, completeness of the central andposterior pillars. Being exerted the destructive loads of the bendingcompression, which formed 80°,75°the two different kinds with the arrowshape surface level axis, the stresses of T₁₂ and L₁'s anterior andposterior pillars were higher, the stresses of T₁₂ and L₁'s central pillarswere lower. The manifestations were the anterior and posterior pillars'bone fracture, completeness of the central pillars. Being exerted thedestructive load of the bending compression, which formed 60°with thearrow shape surface level axis, the stresses of T₁₂'s anterior andposterior pillars were higher, the stress of T₁₂'s central pillar waslower. The manifestations were the anterior and posterior pillars'bonefracture, completeness of the central pillar. And the stress of L1?ˉsposterior pillar was highest, the stresses of L1?ˉs anterior and centralpillar were higher. The manifestation was three pillars?ˉbone fracture.Being exerted the destructive load of the bending compression, whichformed 30o with the arrow shape surface level axis, the stresses of T12and L1?ˉs posterior pillars were highest, the stresses of T12 and L1?ˉsanterior and central pillars were higher. The manifestation was threepillars?ˉbone fracture. Being exerted the above-mentioned differentkinds destructive loads of the bending compressionï¿¡?the stresses of theT12L1 intervertebral disc fibre wreath foreparts were much higher than thestresses of their posterior parts. 2?ï¿ Being exerted the destructive loads of the side bending compression,which formed 85o?ï¿ 80o the two different kinds with the coronary shapesurface level axis, the stresses on the bending parts of L1?ˉs anteriorand central pillars were higher, the stress on the bending part of L1?ˉsposterior pillar was low. The manifestations were the anterior and centralpillars?ˉbone fracture, completeness of the posterior pillar on thebending parts. Being exerted the destructive loads of the side bendingcompression, which formed 75o?ï¿ 60o?ï¿ 30o the three different kinds withthe coronary shape surface level axis, the stresses on the bending partsof L1?ˉs anterior ?ï¿ central and posterior pillars were higher. Themanifestation was three pillars?ˉbone fracture on the bending parts.Being exerted the destructive loads of the side bending compression, whichformed 85o?ï¿ 80o?ï¿ 75o?ï¿ 60o?ï¿ 30o the five different kinds with the coronaryshape surface level axis, the stresses on the bending parts of T12?ˉsanterior?ï¿ central and posterior pillars were higher. The manifestationwas three pillars?ˉbone fracture on the bending parts. Being exerted theabove-mentioned different kinds destructive loads of the side bendingcompressionï¿¡?the stresses on the bending parts of the T12L1 intervertebraldisc fibre wreath were much higher than the stresses of their other parts.Conclusion (1)Being exerted the destructive load of the bendingcompression on the surface of the T11 vertebral body, which formed 85o withthe arrow shape surface level axis, T12 and L1 manifest thoracolumbarsegment bending compression Fergusonï¿ ?type injuries.(2)Being exerted thedestructive loads of the bending compression on the surface of the T11vertebral body, which formed 80o?ï¿ 75o the two different kinds with thearrow shape surface level axis, L1 manifest thoracolumbar segment bendingcompression Ferguson II type injuries. Being exerted the destructiveloads of the bending compression on the surface of the T11 vertebral body,which formed 80o?ï¿ 75o?ï¿ 60o the three different kinds with the arrow shapesurface level axis, T12 manifest thoracolumbar segment bending compressionFerguson II type injuries.(3)Being exerted the destructive loads of thebending compression on the surface of the T11 vertebral body, which formed60o?ï¿ 30o the two different kinds with the arrow shape surface level axis,L1 manifest thoracolumbar segment bending compression Ferguson III typeinjuries. Being exerted the destructive load of the bending compressionon the surface of the T11 vertebral body, which formed 30o with the arrowshape surface level axis, T12 manifests thoracolumbar segment bendingcompression Ferguson III type injuries.(4)That Ferguson ranks thethoracolumbar segment side bending compression injury as an independenttype and classifies its types agree with the biomechanical mechanism ofits injuries.