3/31/2023 0 Comments Compression fracture![]() ![]() due to menopause), may explain why fractures occur in the anterior vertebral body and why flexion movements often precipitate it. This combined with a reduced ability for the endplate to adapt (e.g. The elderly may spend less time in flexion leading to a reduced mechanical stimulus for hypertrophic adaptation. However in the flexed position the anterior vertebral body is severely loaded in the degenerative disc. With intervertebral height reduction, more of the compressive load is taken up by the posterior column, and the anterior column is "stress-shielded" in the neutral and extended positions. Furthermore, the endplate is weaker anteriorly than posteriorly. There is also relative loss of the horizontal compared to the vertebral trabeculae, which reduces resistance to tension. It is thought that with osteoporosis there is relative loss of thickness of the anterior trabeculae compared to the posterior trabeculae. Īnterior wedge fractures are where there is collapse of the cortex of the vertebral body plus collapse of the underlying trabecular bone leading to a wedge shape. Osteoporotic vertebra display different patterns of failure: anterior wedge fractures, biconcave fractures, and crush fractures (figure 2). They also lead to height loss and kyphosis. They can result in significant back pain and loss of function however those that occur slowly over time are often asymptomatic. They often occur at the midthoracic region (T7-8) and at the thoracolumbar junction (T12-L1). Vertebral compression fractures are the most common type of osteoporotic fracture. ![]() ![]() Osteoporotic fractures are fragility or low-trauma fractures. Types of osteoporotic vertebral body compression fractures and respective Genant classifications Osteoporotic and Elderly Vertebraįigure 2. Īt the microscopic level, it is thought that compressive fatigue damage is a common event throughout life because microfractures and healing trabeculae are found in most cadavers. They are less likely to occur with intervertebral disc degeneration. They are more common in the thoracic spine but resemble the transverse fracture type in figure 1. The adjacent intervertebral discs are also damaged with this injury and disc material is forced into the vertebral bodies. Bone can retropulse into the spinal canal causing neurological signs and symptoms. They are characterised by an increased interpedicular distance. MRI is more accurate and this modality can also show Modic changes which are reactions to the endplate fracture.īurst fractures are comminuted vertebral body fractures where the anterior and posterior walls of the vertebral body are disrupted. Endplate fractures are not always seen on plain films. In adolescents, endplate failure may occur differently with fracture of the posterior edge that runs from the endplate down to the cartilage growth plate. This defect can become calcified in what is called a Schmorl's node. In some instances there can be intrusion of disc material into the trabecular bone called intraosseous herniation. Various types of macroscopic endplate fracture have been found to occur in the lumbar spine (figure 1). Types of vertebral compression fractures in the non-osteoporotic lumbar spine. Failure occurs with the endplate bulging into the vertebra due to pressure from the nucleus pulposus. Please note that the superior endplate of the vertebral body is the same thing as the inferior endplate of the intervertebral disc. The superior endplate of the vertebral body is thinner and weaker than the inferior endplate and has less trabecular support from the pedicles in the parasagittal plane. It is thought that the endplate needs to be thin to allow nutrient diffusion into the intervertebral disc. ![]() Initial damage from compressive forces usually occurs in the endplate or in the trabeculae that support the endplate. The endplate is the weakest part of the vertebral body of the lumbar spine. With severe reduction of disc height, up to 90% of the compressive force is resisted by the posterior column. It can also lead to the inferior articular process tip to impinge on the caudal lamina. Narrowing of the intervertebral discs leads to an increase of force taken up by the posterior column. The compressive force is resisted mainly by the anterior column (vertebral bodies and discs), plus a variable amount of around ~15% from the posterior column (zygapophysial joints). The compressive force on the thoracolumbar spine is the force that acts along the long axis of the spine as arises from tension in the paraspinal muscles and gravity. This article is still missing information. ![]()
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