Finite Element Analysis Of Prophylactic Reinforcement In Adjacent Vertebral Bodies After Kyphoplasty With Bone Cement Leakage Into The Intervertebral Discs

Objective:To explore the biomechanical changes of the adjacent vertebral bodies after PKP with bone cement leakage into the intervertebral discs using finite element analysis; to find the reasons of new fracture of the adjacent vertebral bodies. And then to explore the biomechanical changes of prophylactic reinforcement in adjacent vertebral bodies after kyphoplasty with bone cement leakage into the intervertebral discs and to seek for the remedial measures.Methods:A normal female volunteer was choosed, computed tomography (CT) date of thoracolumbar spine was got. A series of there-dimensional finite element models of the osteoporotic thoracolumbar spine (T11-L2) were constructed using MIMICS, ABAQUS and other software. Simulation of PKP treatment for L1vertebral osteoporotic compression fractures was performed to observe whether the cement leakage into the T12-L1discs has biomechanical effects on the adjacent vertebral bodies of the fractures; a further simulation of prophylactic reinforcement of2,3and4mL cement in the vertebral body T12was performed to observe the Von Mises stress of the ensemble and each of different models under different axial load (0.3Mpa、1.0Mpa、4.0Mpa)Results:1.The maximum Von Mises stress of the adjacent vertebral bodies (T12) in the group with cement leakage into the disc (T12-L1) was39%higher than that in the group without cement leakage. The stress of the inferior endplate of the adjacent vertebral bodies (T12) in the group with cement leakage into the disc (T12-L1) was209%higher than that in the group without cement leakage.2.The maximum Von Mises stress of the adjacent vertebral body (T12) decreased to some extent after the prophylactic reinforcement of different doses (2、3、4ml) of bone cement. The stress of the adjacent vertebral bodies (T12) have little change in the group of FUS-T12with2mL prophylactic reinforcement. But there was a24%decrease in the group of FUS-T12with3mL prophylactic reinforcement. The stress of the adjacent vertebral bodies (T12) in the group of FUS-T12with4mL prophylactic reinforcement keep decreasing, but at a modest rate.Conclusions:1.The relevant3D finite element models were successfully established.2.These findings indicate that kyphoplasty with bone cement leakage into the intervertebral discs may lead to secondary fractures in the adjacent vertebral bodies.3.The prophylactic reinforcement of the adjacent vertebral bodies after PKP with bone cement leakage into the intervertebral discs may reduce the occurrence of secondary fractures.