Vertebroplasty: Patient and treatment variations studied through parametric computational models

Abstract

BackgroundVertebroplasty is increasingly used in the treatment of vertebral compression fractures. However there are concerns that this intervention may lead to further fractures in the adjacent vertebral segments. This study was designed to parametrically assess the influence of both treatment factors (cement volume and number of augmentations), and patient factors (bone and disc quality) on the biomechanical effects of vertebroplasty.MethodsSpecimen-specific finite element models of two experimentally-tested human three-vertebral-segments were developed from CT-scan data. Cement augmentation at one and two levels was represented in the respective models and good agreement in the predicted stiffness was found compared to the corresponding experimental specimens. Parametric variations of key variables associated with the procedure were then studied.FindingsThe segmental stiffness increased with disc degeneration, with increasing bone quality and to a lesser extent with increasing cement volume. Cement modulus did not have a great influence on the overall segmental stiffness and on the change in the elemental stress in the adjoining vertebrae. However, following augmentation, the stress distribution in the adjacent vertebra changed, indicating possible load redistribution effects of vertebroplasty.InterpretationThis study demonstrates the importance of patient factors in the outcomes of vertebroplasty and suggests that these may be one reason for the variation in clinical results.

Biomechanical effects of cement distribution in the fractured area on osteoporotic vertebral compression fractures: a three-dimensional finite element analysis

“…This FE model was developed on the data collected from a spinal CT scan of a healthy volunteer's thoracolumbar region and biomechanical material properties reflecting the pathologic characteristics of vertebral osteoporosis. A validated three-vertebra segment (T11-T12-L1) was constructed, but not individual vertebra (T12), because a three-vertebra segment model with intervertebral discs and facet joints might not only highly simulate the motion and load transfer of the thoracolumbar junction of the spine when compression fracture was simulated in the middle vertebra but also avoid loading positions and boundary conditions being directly connected to the target vertebra of T12, which may have an influence on biomechanical behavior of T12 [32]. The validation test proved that the constructed three-dimensional FE model could accurately simulate physiological activity at the thoracolumbar region and, therefore, could be a valuable tool for later research.…”

Numerical investigation of the effect of bone cement porosity on osteoporotic femoral augmentation

“…This figure shows the relative frequency distribution of the optimum volumes from the 1452 examined combinations. In total, 8 classes were used of width equal to 2 and ranging from [6,8) up to and including [20,22]. For porosity levels up to 4%, almost 50% of the combinations of frontal and transverse angles would require a volume of bone cement within the class of (8,10].…”

“…[16][17][18] Given the volume of the published computational studies, it is clear that results from numerical simulations depend on a variety of factors such as the bone morphology, the degree of osteoporosis, the imposed boundary conditions, and the material properties of the augmented bone. 19,20 The bone geometry, the degree of osteoporosis, and the respective material properties are often obtained from a computed tomography scan. [16][17][18]21 Similarly, the most commonly used boundary conditions in the experimental and computational study of femoroplasty replicate a lateral fall on the greater trochanter.…”

Optimizing Cement Distribution in the Fractured Area for Osteoporotic Vertebral Compression Fractures Through Biomechanical Effects Analysis Based on a Three Dimentional Lumbar Finite Element Modeling

“…This nite element model was developed on the data collected from a spinal CT scan of a healthy lumbar spine and biomechanical material properties re ecting the pathological characteristics of vertebral osteoporosis. A validated ve-vertebra segment was constructed, but not individual vertebra, because a ve-vertebra segment model with intervertebral discs and facet joints might not only highly simulated the motion and load transfer of lumbar spine when OVCF was simulated in the middle vertebra, but also avoid loading positions and boundary conditions being directly connected to the target vertebra of L3, which may have an in uence on biomechanical behaviors of L3 [29]. The validation test proved that the constructed three-dimensional nite element model could accurately simulate physiological activity and load transfer at the lumbar spine and, therefore, could be a valuable tool for later research.…”