Adolescent Idiopathic Scoliosis (AIS) is a term used to denote an abnormal curvature of the spine in the coronal plane (left side <--> right side) commonly noted in teenagers. It is usually not a cause of pain and is usually noted incidentally by a physician during a school physical or by a family member. The term 'idiopathic' denotes that the cause of this spinal condition is unknown. It is noted to present 6X more commonly in females than in males and should be classified and treated differently than scoliosis that develops as one ages (see separate talk on Lumbar Deformity).
The nature of the curve and the age of the patient usually makes the diagnosis of AIS pretty straightforward. There are actually three curves present in the spine of most adolescents with AIS. The first curve is in the upper part of the chest (proximal thoracic region) and is usually minor. The second curve is in the chest/ribcage area and this is typically the largest, most noticeable curve (main thoracic curve). The third curve is in the lower back area and is usually quite small and usually in the opposite direction from the main thoracic curve (lumbar or thoracolumbar curve). The spine is also considerably rotated in the patient with AIS, which explains most of the asymmetry in the shoulder blades, ribs, etc.
Usually, the only tests needed in someone with AIS are xrays. The xrays allow the curves to be measured precisely and followed over time. The curves can be measured within 5 degrees on a reliable basis. If the xrays and/or physical examination demonstrate any findings atypical for AIS, then an MRI of the entire spine and brain should be performed.
The treatment of an overwhelming majority of AIS is observation until the patient has completed his/her skeletal growth. For a female, this is usually till about 2 years after the beginning of her regular menstrual periods. In males, it can be a little harder to gauge when skeletal growth has been completed. If the curve(s) start to progress and there is still significant chance of further progression with continued skeletal growth, then bracing can be considered to prevent the progression of the curve(s). These brace are usually worn at all times and there is significant debate as to whether these braces actually prevent the progression of the curve. Surgery is reserved for when the curve(s) have significantly progressed and are likely to continue to progress throughout the course of the patient's adult life. For the main thoracic curve, a curve is considered to require surgical treatment when it increases to >45-50 degrees. In the lumbar/thoracolumbar region, it is considered to be >30 degrees. These surgeries are quite large and complex, and generally it is recommended that these surgeries - if necessary - be done when the patient is younger and healthier. The goal of the surgery is to fuse the spine and thus prevent the curve(s) from worsening. It is usually not possible to completely straighten out the spine and make it normal.
For more information and/or specific questions, please consult a fellowship trained orthopedic spine surgeon or a pediatric orthopedic surgeon.