What Is Adolescent Idiopathic Scoliosis?
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Adolescent Idiopathic Scoliosis - Classification, Causes, Diagnosis, and Treatment

Published on Sep 16, 2022 and last reviewed on May 11, 2023   -  4 min read


Adolescent idiopathic scoliosis is an abnormal curving of the spine. Read the article to know about the causes, types, diagnosis, and management in detail.


The word scoliosis is derived from "skoliosis," which means crooked. Adolescent idiopathic scoliosis (AIS) is the most common form of spinal deformity in adolescents between 10 to 18 years of age. Girls are affected more than boys. It is also known as late-onset idiopathic scoliosis.

What Is Adolescent Idiopathic Scoliosis?

Adolescent idiopathic scoliosis is the "C" or "S" shaped curving of the backbone (spine). The spine is curved at a 10-degree angle sideways (primarily right side), and it is also characterized by a flat back (hypokyphosis) or rounded back (hyperkyphosis).

How Is Scoliosis Classified?

1) Based on the Age of the Child, It Is Classified As:

  • Early-onset scoliosis: occurs before the age of 10 years.

  • Late-onset that happens in children above ten years till the maturity stage.

2) Scoliosis Is Also Classified As:

  • Congenital scoliosis is the abnormal spine curving that occurs by birth and is caused by improper backbone development.

  • Neuromuscular scoliosis is associated with nerve and muscular disorders (muscular dystrophy, cerebral palsy) that cause muscle weakness involved in backbone support.

  • Idiopathic scoliosis: The leading cause of scoliosis is unknown, and it is further classified as follows:

  1. Infantile idiopathic scoliosis is rare and affects babies until three years of age.
  2. Juvenile idiopathic scoliosis is found in children of 3 to 10 years.
  3. Adolescent idiopathic scoliosis occurs in children above ten years of age.

What Causes Adolescent Idiopathic Scoliosis?

The causative factor of idiopathic scoliosis is unknown. However, it may be caused due to,

  • Genetic Factors - Many genes are responsible for the defective curving of the spine. The children also have chances of developing scoliosis if their parents or siblings have it.

  • Environmental Factors like hormonal problems, nerve and muscular diseases, and abnormalities in bone growth can predispose to scoliosis.

What Are the Clinical Features of Adolescent Idiopathic Scoliosis?

Most of the symptoms remain unnoticed and are found during screening and physical examination. It includes:

  • Children with idiopathic scoliosis usually present with back pain.

  • Ribs are found to be more prominent on one side than the other.

  • The shoulder looks tilted, with one side higher than the other.

  • Uneven hips.

How Is Adolescent Idiopathic Scoliosis Diagnosed?

The various diagnostic methods of idiopathic scoliosis are as follows:

  • Physical Examination involves assessing the patient's age, gender, the status of the menstruation cycle, details on back pain, and complete family and medical history. The details of maturity are collected as it is associated with the progression of the spinal curve.

  • Adam's Forward Bend Test is also done during the clinical examination. The adolescent is asked to bend forward with feet together, knees straight, and arms hanging down freely. The doctor checks for the pattern of spinal curve, level of shoulders, hip tilts, and evenness. The classical sign includes the prominence of the rib (rib hump), mainly on the convex side of the curve. The rib hump and rotation of the backbone are measured using an scoliometer. The scoliosis is confirmed if the device shows 7-degree rotation.

  • Sitting Test: The patient sits and bends forward. It is done to detect any discrepancy in the leg length as it may cause abnormal spinal curvature.

  • Whole Spine X-Ray is taken to measure the degree of scoliosis, which is known as Cobb angle. The x-ray also includes pelvic region, which is helpful in assessing the bone formation (ossification) to estimate the growth and development of bone. It is referred to as Risser's sign. Radiographs from the side (lateral) are also done to view hypo-or hyperkyphosis.

  • Cobb Method: It is used to measure the degree of scoliosis. In this method, the small bones of the spine (vertebrae) above and below the curve are selected. Two lines are drawn from the top portion of the vertebrae above and the lower part below. An angle is formed along the intersection of these two lines, which is referred to as the Cobb angle.

How Is Adolescent Idiopathic Scoliosis Treated?

The treatment depends on the child's age, degree, and severity of the spine's curve. It includes:

  • Observation of the patient for six to 12 months is done if the curve is less than 25 degrees. The patient is followed up with regular radiographs and clinical examination.

  • Braces (orthosis) are made of plastics and designed to fit the body comfortably. It is preferred when the degree of the curve is between 25 and 45. The braces do not correct the curve; instead, they prevent further progression. Presently, there are various braces available, namely the Milwaukee brace, Boston brace, etc. It can be worn overnight or throughout the day and removed during physical activities. It is found effective, but the main drawback is children are affected psychologically.

  • Surgery is planned to prevent the curve progression for cosmetic purposes and if the degree of the curve is more than 45. It corrects the structural deformities (rotation, fusion) of the spine. The various approaches involved are:

  1. An anterior approach is used to correct rigid curves, but it often leads to complications after surgery.
  2. The posterior approach is widely preferred as the complications are less, correcting the curve better than the anterior approach.
  3. Spinal fusion is another type of surgery done to realign the bones involved in the spinal curve. The bones are correctly aligned and fused using bone grafts (small transplanted bones), and it grows appropriately over time. Metal rods are attached to the spine using screws or wires that hold the bones during the fusion. Later the bones get healed into a solid segment of the spine.


Adolescent idiopathic scoliosis is a joint presentation seen in children. The quality of life is not disturbed in case of mild to moderate spinal curvature. The severe curving of the spine can sometimes progress and cause complications. Therefore early recognition of the deformity along with appropriate management is essential to lead a better life. "Catch young, treat young."

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Last reviewed at:
11 May 2023  -  4 min read




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