Diagnosis, Classification and General Treatment Options for Hyperkyphosis
The physiological sagittal shape of the spine consists of kyphosis of thoracic spine and lordosis of cervical and lumbar spine. Normal range of thoracic kyphosis and lumbar lordosis are 20–45° and 40–60°, respectively (Bernhardt M, Bridwell K. Spine 14:717–721, 1989). The sum of these curvatures aims to keep the spine in sagittal balance, a condition with lowest energy consumption during standing position. The sagittal balance is characterized by the plump line, which is drawn vertically from the center of the C7 vertebral body down to the sacrum. In normal condition, the plump line bisects the sacral endplate. A variety of conditions may lead to increasing segmental (angular) or regional (arcuar) kyphosis. Compensatory mechanisms exist to counteract the shift of the trunk to the forward as hyperlordosis of cervical and lumbar spine, reclination of pelvis and flexion of knees. Exhaustion of these compensatory mechanism result in the shift of the plump line anterior to the femoral head axis and sagittal imbalance of the spine. Table 26.1 illustrates etiologic conditions that result in kyphotic deformities.
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