What is Scoliosis?
Scoliosis is a condition where the spine is curved sideways. To clarify the concept, the reader should note that this is different from kyphosis, where the spine is curved forward (as in round-back), and lordosis, where the spine is curved backward (as in sway-back).

What Causes It?
Scoliosis can be non-structural and caused by factors unrelated to the spine, e.g., poor posture, leg length discrepancy, back muscle spasm. The scoliosis disappears once the cause is removed.

Scoliosis which is structural is usually due to a cause that resides within the spine, even though it may initially have started somewhere else. For example, neuromuscular problems like muscular dystrophy and poliomyelitis cause muscle imbalance, which initially cause a non-structural scoliosis. Over time, however, secondary changes occur in the spine which then leads to a structural scoliosis.

Scoliosis due to problems in the spinal column include congenital defects of spine development like congenital hemivertebra, where one half of the vertebral body fails to develop. With asymmetric growth, scoliosis is bound to develop. In other instances, two or three vertebral bodies during development stay unsegmented.

If only one half of the vertebral bodies stay unsegmented, symmetric growth and scoliosis will develop. While congenital scoliosis (due to vertebral abnormalities) are serious problems that often require early surgery, they are rare.

The commonest form of structural scoliosis encountered is Idiopathic scoliosis. Idiopathic scoliosis can occur during the first 3 years of life (called Infantile idiopathic scoliosis), from 4 to 10 years of age (called Juvenile idiopathic scoliosis), or from 10 to 15 years of age (called adolescent idiopathic scoliosis).

Adolescent idiopathic scoliosis, which occurs during puberty, is by far the commonest type of structural scoliosis encountered.