What is Adolescent Idiopathic Scoliosis?
There are several types of scoliosis, and their names reflect either the age at which they occur, their cause, or both. Adolescent idiopathic scoliosis (AIS) is in the last category. By convention, anyone older than 10 years old and younger than 18 years old is considered to be an adolescent.
“Idiopathic” refers to the fact that the cause of this type of scoliosis is not known. Unlike some other types of scoliosis there is not a malformation of one or more vertebrae, grossly abnormal muscular control, or asymmetric degeneration of the spine.
Despite an initially normal-appearing spine, over time a spinal deformity (scoliosis) develops in about 1 percent of adolescents. AIS typically does not cause any symptoms. Health professionals including pediatricians and nurses try to detect the presence of AIS before the curve becomes large in order to institute treatment, if necessary.
The primary goal of scoliosis screening and treatment is to keep scoliotic deformities from growing so large that they endanger the health of the child, cause symptoms, or are likely to continue to progress through adulthood. Scoliosis of less than approximately 40 degrees is unlikely to cause significant problems in adulthood or to progress significantly once the skeleton has fully matured.
Many people remember being checked for a spinal curvature in middle or high school. The simplest way to detect scoliosis is the forward bending test. This clinical test, in which the subject bends forward as though she is trying to touch her toes but stops with her back parallel to the floor, makes use of the fact that there is usually a posterior chest wall deformity (“rib hump”) associated with scoliosis.
Having the patient bend forward makes it easier to see if there is an asymmetry in the chest wall. Other signs of scoliosis include a shoulder imbalance (one shoulder higher than the other) or an asymmetry in the waistline.
If it is thought that an adolescent may have scoliosis the next step is usually evaluation by a spinal specialist. Usually this neurosurgeon or orthopaedic surgeon will order special x-rays that show the entire spine from the base of the skull to the pelvis. These x-rays are the definitive test to determine if, in fact, scoliosis is present.
The treatment of scoliosis is somewhat complex and depends on multiple factors including the patient’s age, skeletal maturity, and body type and the size of the scoliosis. The doctor uses information from published studies to try to estimate the potential of the scoliosis to increase in size before the patient completes her skeletal growth.
Some curves, such as those of a small size or in patients very near completion of their growth, may be observed with sequential x-rays. Curves of a moderate size, or in a patient with a significant amount of growth left, may be braced with an external brace. Bracing is generally instituted to try to prevent a further increase in the size of the scoliosis, not to correct the curve and straighten the spine.
Patients with curves of large magnitude (the exact size depends on multiple factors) may be recommended to undergo spinal surgery to correct the spinal deformity.
If surgery is necessary for the correction of a scoliotic curve it may be performed from either an anterior (through an incision over the ribcage) or posterior (through an incision in the middle of the back) approach. The decision making and surgical planning are complex and are discussed in detail by the surgeon with the patient and her family.
Depending on the procedure and individual patient factors, most normal activities can be resumed between 3 and 6 months after surgery and competitive sports, except highly physical contact sports, can be resumed within one year of surgery.