Scoliosis is a disorder that causes an abnormal curve of the spine, or backbone. The spine has normal curves when looking from the side, but it should appear straight when looking from the front. Kyphosisis a curve seen from the side in which the spine is bent forward. There is a normal kyphosis in the middle (thoracic) spine. Lordosis is a curve seen from the side in which the spine is bent backward. There is a normal lordosis in the upper (cervical) spine and the lower (lumbar) spine. People with scoliosis develop additional curves to either side, and the bones of the spine twist on each other, forming a "C" or an "S" shape in the spine.
Scoliosis is about two times more common in girls than boys. It can be seen at any age, but it is most common in those over 10 years of age. Scoliosis is hereditary in that people with scoliosis are more likely to have children with scoliosis; however, there is no correlation between the severity of the curve from one generation to the next.
What causes scoliosis?
Scoliosis can affect about 2% of females and 0.5% of males. In most cases, the cause of scoliosis is unknown (idiopathic). This type of scoliosis is described based on the age when scoliosis develops. If the person is less than 3 years old, it is called infantile idiopathic scoliosis. Scoliosis that develops between 3 and 10 years of age is called juvenile idiopathic scoliosis, and people that are over 10 years old have adolescent idiopathic scoliosis. More than 80% of people with scoliosis have idiopathic scoliosis, and the majority of those are adolescent girls.
There are three other main types of scoliosis:
Functional: In this type of scoliosis, the spine is normal, but an abnormal curve develops because of a problem somewhere else in the body. This could be caused by one leg being shorter than the other or by muscle spasms in the back.
Neuromuscular: In this type of scoliosis, there is a problem when the bones of the spine are formed. Either the bones of the spine fail to form completely or they fail to separate from each other during fetal development. This type of scoliosis develops in people with other disorders, including birth defects, muscular dystrophy, cerebral palsy, or Marfan's disease. People with these conditions often develop a long C-shaped curve and have weak muscles that are unable to hold them up straight. If the curve is present at birth, it is called congenital. This type of scoliosis is often much more severe and needs more aggressive treatment than other forms of scoliosis.
Degenerative: Unlike the other forms of scoliosis that are found in children and teens, degenerative scoliosis occurs in older adults. It is caused by changes in the spine due to arthritis known as spondylosis. Weakening of the normal ligaments and other soft tissues of the spine combined with abnormal bone spurs can lead to an abnormal curvature of the spine. The spine can also be affected by osteoporosis, vertebral compression fractures, and disc degeneration.
Others: There are other potential causes of scoliosis, including spine tumors such as osteoid osteoma. This is a benign tumor that can occur in the spine and cause pain. The pain causes people to lean to the opposite side to reduce the amount of pressure applied to the tumor. This can lead to a spinal deformity.
