Scoliosis - Introduction

Highlights	Symptoms	Surgery
Introduction	Diagnosis	Treatment for Adult Scoliosis
Causes	Treatment	Resources
Risk Factors	Managing Scoliosis	References
Prognosis	Braces

Introduction

Scoliosis is the abnormal curvature of the spine. While the normal spine has gentle natural curves that round the shoulders and make the lower back curve inward, scoliosis typically involves a three-dimensional deformity of the spinal column and rib cage. To varying degrees, the spine curves from side-to-side, and some of the spinal bones may rotate slightly, making the hips or shoulders appear uneven. It may develop in the following way:

As a single primary side-to-side curve (resembling the letter C), or
As two curves (a primary curve along with a compensating secondary curve that forms an S shape).

Scoliosis most commonly develops in the area between the upper back (the thoracic area) and lower back (lumbar area). It may also occur only in the upper or lower back. The doctor attempts to define scoliosis by the following characteristics:

The shape of the curve.
Its location.
Its direction.
Its magnitude.
Its causes, if possible.

Click the icon to see an image of scoliosis.

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The severity of scoliosis is determined by the extent of the spinal curvature and by the angle of the trunk rotation (ATR) and is usually measured in degrees. Curves of less than 20 degrees are considered mild and account for 80% of scoliosis cases. Curves that progress beyond 20% require medical attention. However, such attention usually involves periodic monitoring to make sure the condition is not becoming worse.

Scoliosis affects approximately 2-3% of the population (about 6 million people in the United States). It can occur in adults but is more commonly diagnosed for the first time in children aged 10 to 15 years. About 10% of the adolescent population has some degree of scoliosis, but less than 1% develops scoliosis that requires treatment. The condition also tends to run in families. Among persons with relatives that have scoliosis, about 20% develop the condition.

Among adults, previous reports have indicated a prevalence of scoliosis of up to 32%. But a recent study of 75 healthy adults aged 60 years and older with no known history of scoliosis or prior spine surgery suggested a rate of 68%. However, scoliosis was not linked to physical or social impairment in this population.

Defining Scoliosis by the Shape of the Curve

Scoliosis is often categorized by the shape of the curve, usually as either structural or nonstructural.

In structural scoliosis, the spine not only curves from side to side, but the vertebrae also rotate, twisting the spine. As it twists, one side of the rib cage is pushed outward so that the spaces between the ribs widen and the shoulder blade protrudes (producing the rib-cage deformity, or hump). The other half of the rib cage is twisted inward, compressing the ribs.
A nonstructural curve does not twist but is a simple side-to-side curve.