Scoliosis (pronounced sko-lee-o-sis) is a three-dimensional abnormality that occurs when the spine becomes rotated and curved sideways.
Most often this condition has no known cause, in which case it is called idiopathic scoliosis.
While the cause is unknown, idiopathic scoliosis does tend to run in families. The specific genes involved have not all been identified yet, and there could be factors beyond genetics as well.1
Some people mistakenly think that carrying heavy book bags or sleeping on the side could cause scoliosis, but that is not the case.
About 3% of the population is estimated to have idiopathic scoliosis.2
3 Types of Idiopathic Scoliosis
Typically, idiopathic scoliosis is categorized by the age at which the deformity developed:
- Infantile idiopathic scoliosis: develops from birth to 3 years old
- Juvenile idiopathic scoliosis: develops from 4 to 9 years old
- Adolescent idiopathic scoliosis: develops from 10 to 18 years old
Adolescent scoliosis comprises approximately 80% of all idiopathic scoliosis cases. Adolescence is when rapid growth typically occurs, which is why the detection of a curve at this stage should be monitored closely for progression as the child’s skeleton develops.
Early Stages Rarely Have Signs or Symptoms
Any sideways — or lateral — spinal curvature of at least 10 degrees, as measured on an X-ray of the spine, is considered scoliosis. However, that small curve size would not show signs or symptoms.
As the curve progresses to 20 degrees or beyond, there is an increased chance that the person or an observer, such as a parent or teacher, might notice abnormalities such as clothes hanging unevenly or the body tilting to one side.
The idiopathic scoliosis in and of itself is generally not thought to cause significant pain, especially in adolescents and young adults. However, a scoliosis curve can cause trunk imbalances and other issues that increase the likelihood for muscle spasms and other issues, which can in turn lead to pain.
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Common Types of Curves
A scoliosis curve usually looks a bit like a backward C shape and involves the spine bending sideways to the right, which is also called dextroscoliosis. Sideways spinal curvature on the left side of the back is more like a regular C shape and called levoscoliosis. Here are four common types of scoliosis curves:
- Right thoracic curve. If a straight line were drawn down the center of the back, this curve bends to the right side of the upper back (thoracic region).
- Right thoracolumbar curve. This curve bends to the right side—starting in the upper back (thoracic) and ending in the lower back (lumbar).
- Right lumbar curve. This curve bends to the right side—starting and ending in the lower back.
- Double major curve. Typically, a double curve involves right thoracic curve on top and left lumbar curve on bottom. People who have a double major curve may initially have a less obvious deformity because the two curves balance each other out more.
Several other types of curves are possible, such as a left thoracic curve. There have also been rare scoliosis cases with triple curves.
When Idiopathic Scoliosis Needs Treatment
Treatment options for idiopathic scoliosis could include:
- Observation. Typically, a doctor will advise observation for a scoliosis curve that has not yet reached 25 degrees. Every 4 to 6 months, the doctor will take another X-ray of the spine to see if the scoliosis is progressing or not.
- Bracing. If the scoliosis has progressed past 20 or 25 degrees, a back brace could be prescribed to be worn until the adolescent has reached full skeletal maturity. The goal of bracing is to prevent the curve from getting worse and to avoid surgery.
- Surgery. If the curve continues to progress despite bracing, surgery could be considered. The most common surgical option for scoliosis today is a posterior spinal fusion, which can offer better corrections with fewer fusion levels (preserving more back mobility) than what was done in years past.
Watch: Spine Fusion Surgery Video
Approximately 90% of people identified with idiopathic scoliosis have curves that never progress enough to require bracing or surgery.