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What Is Adolescent Idiopathic Scoliosis?

Scoliosis is a condition in which a person’s spine is curved from side to side. Although it is a complex three-dimensional deformity, when viewed from the rear, the spine of an individual with scoliosis may look more like an “S” or a “C” than a straight line.


It is typically classified as either congenital (caused by vertebral anomalies present at birth), idiopathic (cause unknown, sub-classified as infantile, juvenile, adolescent, or adult according to when onset occurred) or neuromuscular (having developed as a secondary symptom of another condition, such as spina bifida, cerebral palsy, spinal muscular atrophy or physical trauma). About 2% of women and 0.5% of men have scoliosis. This condition affects approximately 20 million people in the United States.

Adolescent idiopathic scoliosis (AIS) is the most common form of scoliosis (over 80% of cases) that has no clear causal agent. The cause is thought to be multifactorial, and genetics are believed to play a role. It affects more teenage (thus the term “adolescent”) girls than boys (about 70% of the time), and their curves tend to be more progressive. Patients are advised to seek treatment if they notice worsening of scoliosis since it may cause significant deformity, as well as physical and emotional distress. Some severe cases of scoliosis can lead to diminishing lung capacity, putting pressure on the heart, and restricting physical activities.

Signs and Symptoms

AIS is usually not painful, although patients may experience significant emotional distress. It is often found during routine medical examination by the pediatrician or at school health screenings. Some of the signs of scoliosis include:

  • uneven musculature on one side of the spine
  • a rib prominence and/or a prominent shoulder blade
  • uneven hips/leg lengths
  • slow nerve action in some cases
  • head is not centered directly above the pelvis
  • uneven waistline
  • leaning of entire body to one side


Dr. Cho carefully examines every patient who initially presents with scoliosis to determine whether there is an underlying cause of the deformity. During the exam, the patient is typically asked to remove his or her shirt and bend forward (known as the Adams forward bend test) to assess shoulder and/or rib prominence.


Patients are often sent for x-rays to confirm the diagnosis.


Special tools like a scoliometer are used to assess the magnitude of the curve. CT scan or MRI of the spine is often helpful to determine the three-dimensional nature of the deformity and to look for any spinal cord anomalies. Recently, a genetic testing for AIS has become available which may help determine the likelihood of curve progression.

Non-surgical Treatment

Management of AIS is determined, in part, by the severity of the curvature and skeletal maturity, which together help predict the likelihood of progression.

For small curves (15-20 degrees), simple observation is all that is needed to see whether the curve worsens over time. For bigger curves (20-40 degrees), a lightweight thoracolumbosacral (TLSO) brace is often recommended to stop the curve from getting worse.


The Scoliosis Research Society (an international medical society dedicated to studying scoliosis) recommends bracing for curves progressing to larger than 25 degrees, curves presenting between 30 and 45 degrees, Risser Sign 0, 1, or 2 (an x-ray measurement of a pelvic growth area), and less than 6 months from the onset of menses in girls.

Surgical Treatment

Surgery may be recommended when the curve is bigger than 40 degrees. Spine surgery for AIS has been shown to be an effective method to correct the curve and avoid greater deformity. Traditionally, surgeons performed the procedure from either the front (anterior) or the back (posterior). Anterior surgery requires going through the chest or the abdomen. To avoid this, Dr. Cho performs the surgery all from the back of the spine using the latest, scientifically proven techniques and appropriate implants such as pedicle screws and rods to correct the spinal deformity and immobilize the spinal segments as they fuse and heal in the newly corrected position. Unlike some spine surgeons who routinely take patient’s own bone graft from the iliac crest of the hip, which may lengthen recovery time and increase pain, Dr. Cho prefers to use local bone graft from the spine, along with bone bank bone and biologic proteins – another advanced technique that improves the fusion success rate and avoids pain for his patients.

For more details regarding surgery, please see Posterior Spinal Instrumented Fusion for AIS.

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