Osteoporosis: If the normal continuous formation and breakdown of the bone derails in such a fashion that the cancellous bone loses its density and stability to a greater degree than normal for that age, fractures may occur spontaneously or after minor trauma. Such a degree of demoralization of bone is termed osteoporosis. Bone density is the highest around 35 years of age. After that it declines steadily; estrogen-depleted postmenopausal women are at a greater risk than men. The consequences of osteoporosis—pathological fractures and vertebral height loss due to progressive collapse—lead to the typical loss of body height and stature (the famous/infamous "little old lady"). Another major complication is, of course, the femoral neck fracture. Standard radiographs of the thoracic and lumbar spine show the osteoporosis best. The density of the vertebral bodies is decreased; the vertebral end plates therefore appear enhanced. If the vertebral end plates fracture, the typical "fish vertebra" sign of the vertebral body results (Fig. 8.24a, b). Serial measurements of the attenuation of an x-ray beam sent through the lumbar spine and femoral neck can establish the actual bone mineral density and estimate the risk of fracture (dual-energy x-ray absorptiometry, DXA; see Fig. 8.26). This helps stratify patients into groups of those in whom treatment may be beneficial and those who do not need any specific therapy. Bone mineral density measurement can also be used to monitor the effect of therapy. A specific interventional procedure
Fig. 8.24a All vertebral bodies are decreased in density—their internal trabecular structure is very coarse. Lower and upper end plates are fractured, resulting in the typical fish vertebra configuration. b This is a real vertebral body of a fish (Whitsunday Islands, summer of 2004). c During a vertebroplasty, a cannula is
Fig. 8.24a All vertebral bodies are decreased in density—their internal trabecular structure is very coarse. Lower and upper end plates are fractured, resulting in the typical fish vertebra configuration. b This is a real vertebral body of a fish (Whitsunday Islands, summer of 2004). c During a vertebroplasty, a cannula is has been developed recently for this problem: percutaneous injection of methylmethacrylate (a kind of super-glue) into the vertebral body stabilizes the affected vertebra and also treats the pain (Fig. 8.24c).
Metastases, multiple myeloma: Metastases and vertebral destructions due to multiple myeloma can become symptomatic with back pain, loss of vertebral body height, nerve root compression syndromes, and paraplegia. Owing to the large bone mass, destructions in the vertebral bodies are easily overlooked. It is therefore important to inspect the pedicles and the spinous processes with great care where smaller destructions are more evident (Fig. 8.25). The soft tissue component and abnormal bone marrow signal in vertebral bodies are best documented by MRI.
• Diagnosis: Paul and Ajay are quite relieved that in Mrs. Vord's case osteoporosis is their final and certain diagnosis. To verify the diagnosis and monitor any medical therapy, they suggest a bone densitometry either by quantitative CTor DXA (Fig. 8.26). These methods are also used for the early diagnosis of osteoporosis. If the pain becomes too severe or does not respond to conservative treatment, they suggest a vertebroplasty. Mrs. Vord takes a deep breath when learning the results of the study. She will try to manage without vertebroplasty for now. "Should I get a completely new set of clubs?" she asks. "My grandpa has an adjustable one. That might help!" says Ajay.
advanced into the vertebral body through the pedicle and a stabilizing methylmethacrylate compound is injected. Careful placement is key: high temperatures are reached as the material hardens, which is why nerve roots and of course the spinal cord should be separated from the material by intact bone.
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