الفهرس 
PATHOGENESIS OF OSTEOPOROSISOnly 14 pages are availabe for public view
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Abstract
The spine is the most common site of osteoporotic fractures.Osteoporotic vertebral compression fractures (VCFs) are a growing public health problem with important socio-economic effects in westerncountries. The pathophysiology of osteoporotic compression fractures is different from those occurring secondary to traumatic spinal injury.
Throughout life, our skeleton loses old bone and forms new bone.Children and teenagers form new bone faster than they lose the old bone.In fact, even after they stop growing taller, young people continue to make more bone than they lose. This means their bones get denser and denser until they reach what experts call peak bone mass.
Osteoporosis is often called the ”silent” disease, because bone loss occurs without symptoms. People often do not know they have the disease until bone breaks, frequently in a minor fall that would not normally cause a fracture.
Many people confuse osteoporosis with arthritis and believe they can wait for symptoms such as swelling and joint pain to occur before seeing a doctor. It should be stressed that the mechanisms that cause arthritis are entirely different from those in osteoporosis, which usually becomes quite advanced before its symptoms appear.
A common occurrence is compression fractures of the spine. These can happen even after a seemingly normal activity, such as bending or twisting to pick up a light object. The fractures can cause severe back pain, but sometimes they go unnoticed either way, the vertebrae collapse down on themselves, and the person actually loses height.
The diagnosis of VCFs is usually made by using a combination of a complete medical history and physical examination, skeletal X-rays, bone densitometry and specialized laboratory tests.
The conservative care of a patient with osteoporotic painfulvertebral fracture focuses on two issues. The first goal is pain relief andrehabilitation, traditionally with analgesics, bed rest, and orthotic supportsuch as brace.The second goal consists of assessment and management of the underlyingosteoporosis with supplemental calcium/vitamin D in conjunction with bisphosphonates or calcitonin, or both.
Vertebral augmentation is the percutaneous administration of polymethylmethacrylate (PMMA), ana acrylic bone cement, into fractured vertebral body. Vertebral augmentation, be it vertbroplasty or kyphoplasty, is performed for pain relief and fracture stabilisation. Introduction of PMMA into fractured cancellous bone enhance the mechanical stability of that segment. Vertbroplasty was originally ”inverted” in 1984 by Galivert and Deramond to treat painful or aggressive vertebral haemangiomas.
For spine surgeons, it is unavoidable to encounter patients with osteoporotic spinal fractures who need spinal decompression and instrumentation due to neurologic deficit. The pedicle screw fixation strength is decreased significantly in osteoporotic spine. Thus, the incidence of internal fixation failure increases significantly in these elderly patients with severe osteoporosis.
Several interventions to preserve bone strength can be recommended to the general population. These include an adequate intake of calcium and vitamin D, lifelong participation in regular weight-bearing and muscle-strengthening exercise, cessation of tobacco use, identification and treatment of alcoholism, and treatment of risk factors for falling.