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Scoliosis is defined as the lateral and rotational deformity of the thoracolumbar spine. The progressive deformity causes the vertebral bodies to rotate toward the convex side pushing the ribs posteriorly and narrowing the thoracic cage. Consequently, the spinous process will deviate to the concave side and force the ribs laterally. This distortion in the thorax results in restriction of lung volumes and function.


Scoliosis may be classified under the subcategories idiopathic, congenital, neuromuscular, traumatic, neoplastic, and other syndromes (Table 148-1). Of these, idiopathic scoliosis is the most common form of all the spinal deformities accounting for approximately 70% of all diagnosis, usually genetic and classified by onset of age. Adolescent scoliosis is the more common of the three idiopathic scoliosis subcategories and occurs commonly in girls. The greatest curvature progression observed in girls includes younger age (<11 years), premenarche and immature bone growth compared to older age, postmenarchal, and mature bone development. Neuromuscular scoliosis deteriorate faster because of the lack of motor integrity and poor muscle development. Ultimately, this will lead to rapid deterioration of the curve and respiratory function compromise. Congenital scoliosis occurs at birth and is often very severe, necessitating aggressive treatment. Although the specific etiology of scoliosis is unknown, influential factors include problems with collagen, growth, brainstem function, and hormones.

TABLE 148-1Classification of Scoliosis


The severity of scoliosis has a profound effect on the signs and symptoms observed in this population. The Cobb angle is the most commonly accepted modality for assessing severity. It is determined by locating the most tilted vertebra above the curve and drawing a parallel line from its superior surface followed by locating the most tilted vertebra below the curve and drawing a parallel line from its inferior surface. The angle at which the two lines intersect is the Cobb angle (Figure 148-1). Cobb angles less than 20° spontaneously improve in greater than 50% of cases, greater than 40° usually warrant surgical intervention, and those above 65° are typically accompanied by pulmonary dysfunction (Table 148-2).

FIGURE 148-1

Scoliosis curve measurement using the Cobb angle. (Data from Murray JF and Nadel JA. Textbook of Respiratory Medicine. Philadelphia: WB Saunders; 1988.)

TABLE 148-2The Degree of Curvature and Its Clinical Symptoms

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