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What is EOS


What to Expect



What is EOS?

Early onset scoliosis (EOS) is a term that is currently recognized by pediatric orthopaedic and spine surgeons for patients presenting with scoliosis prior to 10 years of age. Historically we have described patients with idiopathic scoliosis as having infantile (0-3 years), juvenile (4-10 years), and adolescent or adult onset scoliosis. As health care providers, the most common age that we see scoliosis is in the pre-teen and adolescent years. For most of these patients, the vast majority of their thoracic growth is complete. For children less than 10 years of age, this is generally not true. As a consequence, the treatment for children under the age of 10 with a progressive scoliosis tends to be different than the child who is closer to skeletal maturity. This is the primary reason there is a differentiation between early onset and more typical adolescent or adult onset scoliosis.

There are several sub-categories of early onset scoliosis that are commonly recognized. Included are idiopathic, neuromuscular, syndromic, congenital, as well as scoliosis associated with tumors, infection, prior surgery or trauma. Congenital scoliosis is associated with the abnormal formation of the spinal vertebrae themselves and tends to be the most challenging to treat.

This can also include malformation or fusion of the ribs of the chest wall, which can also lead to problems with lung development and a condition known as thoracic insufficiency syndrome (TIS). Syndromic scoliosis is associated with specific underlying syndromes and genetic conditions. Neuromuscular scoliosis is an abnormal curve associated with injury or disease of the central nervous system and is most commonly seen in children with spastic quadraplegia and cerebral palsy. Idiopathic scoliosis also occurs in early onset cases and like their adolescent counterpart, the etiology for these curves is not well understood.

Essential Anatomy

As with adolescent idiopathic scoliosis, early onset scoliosis can affect any region within the spine. From an anatomic and descriptive standpoint, the spine is divided into 4 general regions including the cervical, thoracic, and lumbar spine. The forth region, which includes the sacrum and coccyx, are often considered together as they are essentially immobile and functionally part of the pelvis. In patients with early onset scoliosis, abnormal curves in the spine can occur in the cervical, thoracic, or lumbar spine and can span multiple regions of the spine including the pelvis. It is important to realize that scoliosis is a multi-plane deformity. Not only is there an abnormal curvature in the coronal plane, but in general, there is abnormal alignment in the sagittal plane with variation from normal values in terms of cervical and lumbar lordosis, thoracic kyphosis, and pelvic tilt. There can also be a significant amount of axial rotation, which typically manifests as a rib hump.

From an anatomic standpoint, smaller curves do not generally cause problems, but large curves can result in decreased room in the chest for the lungs and heart, decreased room in the spinal canal for the spinal cord or exiting nerve roots, or decreased room in the abdomen for organs. For patients already physiologically challenged by an underlying condition, the crowding of the lungs and organs can result in increased respiratory complications and failure to thrive.


Many children with early onset scoliosis look and function fairly normally. If the curves are mild, it can be very difficult to distinguish a child with early onset scoliosis from children without spinal deformity. The key to evaluating for a curve or curve progression is to pay close attention to symmetry:

  • Shoulders should be level
  • Shoulder blades should be the same height and shape
  • Spine should run down the center of the back
  • Head should be centered over the pelvis
  • Head should be level
  • Waist should have symmetric contour
  • Hips should appear level
  • There should be no abnormal fullness in one side of the thoracic or lumbar spine on standing or when bent over at the waist
  • They should not lean to one side

A well performed and documented neurological exam is mandatory in the evaluation of any child with scoliosis, but this is especially true of children with early onset scoliosis. When able, a complete sensory and motor examination should be performed with graded motor strength. Additionally, all major reflexes should be evaluated including abdominal reflexes. Back pain is generally not a significant complaint unless the curve is quite large. Likewise, numbness, weakness or loss of bowel or bladder control would not normally be expected. If these symptoms do appear, emergent evaluation in the emergency department is essential.


The underlying medical conditions of patients with early onset scoliosis help determine the prognosis and treatment. Some patients with neuromuscular conditions such as cerebral palsy or spina bifida have a very different prognosis and treatment than patients without other medical problems even if the scoliosis appears similar in size and shape. In this section we will discuss the broad groups of conditions associated with early onset scoliosis.

Neuromuscular Scoliosis

These are patients who develop scoliosis in association with conditions that affect their muscles or their nervous system. The nervous system can be affected centrally (in the brain or spinal cord) or peripherally. These conditions are usually associated with a higher rate of scoliosis than children without the condition. Also, the likelihood that the curves will get worse is higher and the effectiveness of non-surgical treatments such as bracing or casting are not as good. Some of the conditions that affect the muscles leading to scoliosis are muscular dystrophy, congenital myopathies, and hypotonia (generalized weak muscles). Some of the conditions that affect the central nervous system are chiari malformation, cerebral palsy, and spina bifida. Conditions that affect the peripheral nervous system include Charcot-Marie-Tooth disease and polio.

Syndromic Scoliosis

Syndromic scoliosis is associated with specific underlying syndromes and genetic conditions. These conditions are not associated with muscles or nerves. Some of these conditions affect the bones such as osteogenesis imperfecta (brittle bone disease). Other conditions affect connective tissues. Examples of connective tissue disoprders that are associated with scoliosis are arthrogryposis, Ehlers-Danlos syndrome, or Marfan syndrome. Certain conditions are associated with spinal deformity but it is not exactly known how they affect the spine. These conditions include neurofibromatosis and a group of conditions called the mucopolysaccharidosis (Hurler Syndrome, etc).

Congenital Scoliosis

Congenital scoliosis is a condition that is not technically an early onset scoliosis subset but rather its own category. This is because the age of onset is prenatal and not between 0 and 5. In this condition, one or more bones in the spine are severely malformed or missing. Spinal deformities in these patients have different treatments and prognoses based on the severity of deformation of the bone or bones, the pattern of deformity and whether the abnormal bones become more deformed as the child grows. Congenital scoliosis and congenital kyphosis cannot be corrected with bracing or casting. Bracing and casting, however, may be recommended for patients with congenital scoliosis and kyphosis as a means to delay progression allowing for growth and development prior to surgery. If the curves are large enough and/or worsening, the only treatments involve surgery. Fortunately, many of these patients never get worse and therefore never need surgery. If your child has this condition, it is important that you discuss an evaluation of your child’s kidneys and heart since there are often problems in these areas too.

Idiopathic Scoliosis

Patients with idiopathic scoliosis have scoliosis without any of the other conditions discussed above. The cause of scoliosis in this group remains unclear. This is one of the most common forms of scoliosis in early onset scoliosis. If the child is diagnosed between birth and age 3, he/she is sub-classified as having infantile idiopathic scoliosis. If the child is diagnosed between 3 and 10, he/she is considered to have juvenile idiopathic scoliosis. Without treatment, the curvature has a very high chance of progressing and worsening . Untreated infantile idiopathic scoliosis patients will typically have a shorter life span and this is likely due to their spine curvature restricting lung development and function (breathing). Fortunately, idiopathic scoliosis seems to respond better to treatment than other forms of scoliosis and the chances of complications with treatment seem to be lower.