Idiopathic scoliosis, the most common type, does not have a known cause. Children who have this type of scoliosis usually first develop symptoms between the ages of 8 and 10.1 Most cases of scoliosis are mild, involving small curves in the spine that do not get worse. Small curves usually do not cause pain or other problems. Usually a doctor examines the child every 4 to 6 months to watch for any changes.
In moderate or severe cases of scoliosis, the curves continue to get worse. During periods of growth, such as during the teenage growth spurt, the curves may get worse. Curves of less than 30 degrees often stop progressing when the skeleton stops growing, while larger curves may get worse throughout adulthood unless they are treated.
Only about 10% of children who are diagnosed with scoliosis require treatment (either bracing or surgery).3
Factors that may indicate the potential growth of a curve include:
- The age of the child and the development stage, or maturity, of his or her skeleton when scoliosis is diagnosed. The less mature the skeleton is when scoliosis starts, the greater the chance that scoliosis will get worse. Skeletal age, as determined by the Risser sign, is also used to determine the risk that the curve will get worse.
- The size of the curve. The larger the curve, the greater the risk that it will get worse.
- The location and shape of the curve. Curves in the upper back are more likely to get worse than curves in the lower back.
Girls are more likely than boys to have larger curves and more severe scoliosis.
As scoliosis gets worse, the bones of the spine rotate toward the inner part of the curve. If the upper part of the spine is affected, the ribs may crowd together on one side of the body and become widely separated on the other side. The curve may force the space between the spinal bones to narrow. The spinal bones may also become thicker on the outer edge of the curve.
In severe curves, misshapen ribs may reduce the amount of air the lungs can hold and may cause the heart to work harder to pump blood through the compressed lung tissue. Over time, this can lead to heart failure.
Although it is uncommon, babies can be born with scoliosis (congenital) or can develop it during the first 3 years of their lives (infantile scoliosis). Scoliosis that is present at birth or that develops in infants may be worse in the long run than scoliosis that develops later in life. This is because the more growing the skeleton has to do, the worse the curve may get. However, in some cases, congenital curves do not get worse and some curves that are present during infancy get better on their own without treatment.