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What is EOS



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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.


In the evaluation of a child with early onset scoliosis, imaging will be required not only to understand the nature of the problem but to follow progression over time. The best imaging modality is the standard x-ray. The appropriate image to order is the full length PA and lateral x-ray of the thoracic and lumbar spine taken in the standing or sitting position if possible. It is helpful to include the upper portion of the pelvis as well as the shoulders for the purpose of evaluating sagittal and coronal balance. The Cobb method of measuring curve magnitude in the sagittal and coronal plane is generally preferred.

Advanced imaging is usually ordered at some point for these patients. This might include a CT scan to evaluate bony anatomy in congenital curves or for surgical planning, or an MRI to better access for intra-canal pathology. Typically these should be ordered by the treating orthopaedist or neurosurgeon.

Associated Conditions

There are a number of conditions associated with early onset scoliosis. When taking care of children with these known issues, care should be taken to pay close attention to their spine. The following list includes several conditions know to have early onset spinal deformity. It is by no means complete, and conditions not on the list can still have associated spinal anomalies and progressive deformity.

  • Cerebral palsy
  • Chiari malformation
  • Congenital diaphragmatic hernia
  • Charcot–Marie–Tooth disease
  • CHARGE syndrome
  • Down's syndrome
  • Ehlers–Danlos syndrome
  • Escobar's syndrome
  • Familial dysautonomia
  • Friedreich's ataxia
  • Fragile X syndrome
  • Hemihypertrophy
  • Marfan's syndrome
  • Muscular dystrophy
  • Nail–patella syndrome
  • Neurofibromatosis
  • Osteogenesis imperfecta
  • Prader–Willi syndrome
  • Proteus syndrome
  • Spina bifida
  • Spinal cord tether
  • Spinal muscular atrophy
  • Spinal tumors
  • Syringomyelia
  • Trisomy 8