Scoliosis is a congenital skeletal system disorder resulting in a curvature of the spine. It most often develops in children and teenagers and the cause is frequently unknown. It can vary from subtle to severe, producing different symptoms and requiring diverse treatments.
Types and Cause
There are two types of scoliosis: nonstructural and structural scoliosis. Nonstructural scoliosis occurs when there is a curve in the spine without rotation that is reversible. This can cause, pain or a muscle spasm, an inflammatory condition, and a difference in leg length. Structural scoliosis involves a curve in the spine, with rotation, that is irreversible. The cause of it, however, is unknown.
Up to 80% of cases are idiopathic (occurring without known cause). It frequently seems to be related to genetics, as it often runs in families (most likely from the mother's side).  Some other suggestions of cause include imbalances in muscles around the vertebrae and high arches, which may make children susceptible to spinal distortions as they grow. An incidence of abnormally high arches in the feet in people with idiopathic scoliosis, is suggestive that altered balance may be a factor in certain cases. It mostly appears in children or teenagers.
Symptoms vary depending on the degree of severity of the curvature. It may be so subtle that only a screen test will detect it. More severe forms are painful especially when standing for long periods of time or walking. Other symptoms include are uneven musculature, a rib "hump" or shoulder blade (meaning it sticks out), uneven hip and shoulder levels, unequal distance between arms and body, and in some cases slow nerve action. 
In treating scoliosis there are a few options, including observation, surgery, and brace. Observation are suggested when the curvature of the spine is minimal. During their observation the patients are seen by a spine specialist about every six months, or until skeletal maturity is reached. The brace helps control any worsening of a spine curvature. However, they do little to correct an existing deformity. Surgery is often the best options for more severe curves. Depending on the the curve and the degree of curvature. If you choose the surgery option you can pick between two options.  One is spinal fusion which is used to stabilize and reduce the size of the curve and stop the curve from getting worse by permanently joining the vertebrae into a solid mass of bone. You can also choose the instrumentation without fusion. This is when they attach devices such as metal rods to the spine to stabilize a spinal curve without actually fusing the spine together. 
If the spine curvature in severe then surgery is the greatest option. The spinal fusion is augmented with a bone graft. This may be obtained from your child or it can be from a donor. An incision is made in the middle of the back. The muscles are then moved to the side to expose the spine, and the joints between the vertebrae are removed. Then the vertebrae is roughened up so the body can respond by producing new bone. The new bone eventually bridges the gaps between the vertebrae and makes them fuse together. Metal implants such as rods, screws, hooks or wires are put in to hold the spine still while the vertebrae fuse. The other option is instrumentation. this preserves spinal growth. A hook is implanted at each end of the concave side of the deformity and then linked by a rod that is tunneled subcutaneously instead of below the muscle. This technique however had few good results; the rods would break. What they did to improve this was they developed a "dual-rod technique." Hooks are placed on both sides of the spine in "claw" patterns over 2 to 3 spinal levels to avoid crowing the hooks. Rods are then inserted subcutaneously on BOTH sides of the spine and are joined together on each side with extended tandem connectors. This give the back more support, stability, and less of a chance that the rod will break. 
- health nytimes New York Times
- webmd Healthwise
- orthopedics Jonathan Cluett, M.D.
- ucsfhealth Children's Hospital
- medscape Akbarnia BA and Marks DS
- Scoliosis Wikipedia