eMedicine Specialties > Radiology > Pediatrics

Scoliosis, Idiopathic

Prabhakar Rajiah, MD, MBBS, FRCR, Registrar, Department of Radiology, Central Manchester and Manchester Children's University Hospitals, UK

Updated: Mar 26, 2009

Introduction

Background

Scoliosis is the presence of 1 or more lateral rotatory curves of the spine in the coronal plane. Although defined as a side-to-side deformity, it is a 3-dimensional (3D) rotational deformity. Many causes of scoliosis are known; however, 80% of them are idiopathic. Idiopathic scoliosis is a diagnosis of exclusion.

Mild juvenile scoliosis.

Moderate scoliosis.

Severe infantile scoliosis.

• Indications for radiography include alterations in normal spinal alignment on physical examination, evaluation of spinal curvature progression, and follow-up of treatment.
• For a scoliosis survey, the preferred method is a posteroanterior radiograph with the patient in the upright position.
• For those patients who are being assessed or are being clinically treated for scoliosis, other images include right and left lateral bending images, lateral vertical beam image, and a posteroanterior image of the left wrist and the hand for bone age.
• Radiographic analysis should identify the presence, direction, location, and apex of the curvature.
• Skeletal maturity determination is important because mild to moderate scoliotic curves do not progress after cessation of growth.

Pathophysiology

Development and biomechanics of scoliosis

The development of scoliosis can be explained biomechanically on the basis of the Heuter-Volkmann law, which states that pressure on epiphysis retards the rate of growth and that tension increases the rate of growth. Hence, the leading edge of the deformity grows more rapidly than trailing edge, increasing the rate of progression.

In scoliosis, the essential deformity is lordosis, with the spinous process deviated to the concavity of the lateral curve. As the rotation progresses, the load on the epiphysis on the side of body that is more anterior increases, resulting in a lateral deformity. Thus, scoliosis is a deformity of lordosis, rotation, and lateral wedging of the vertebrae.^{[2 ]}

Types of scoliosis

Scoliosis is broadly divided into 2 types: postural and structural. Idiopathic scoliosis is a type of the structural form.

Postural scoliosis

Postural scoliosis is a flexible deformity due to faulty positioning and is confirmed by spontaneous correction when the patient bends toward the convexity of the curve. No associated rotational deformity or wedging is observed. Although postural scoliosis is transient, it can become fixed and structural if it is habitual and chronic.

Common causes of postural scoliosis are habitual faulty posture, a shortened lower limb, disk prolapse, pain, and hysterical etiologies.

Structural scoliosis

Structural scoliosis is a rigid deformity that cannot be actively corrected by a change of posture.

Structural scoliosis has various causes, as follows:

• Idiopathic causes
• Congenital causes
  • Failure of formation - Wedge vertebra, hemivertebra
  • Failure of segmentation - Fused vertebra, fused ribs, unilateral fused bar
  • Combination of both failures
• Mesodermal causes
  • Neurofibromatosis (NF)
  • Osteogenesis imperfecta
  • Mucopolysaccharidosis
  • Marfan syndrome
• Neuromuscular causes
  • Spinal dysraphism
  • Myelomeningocele
  • Syringomyelia
  • Diastematomyelia
  • Tethered cord
  • Arnold-Chiari malformations
  • Muscular dystrophy
  • Poliomyelitis
  • Friedreich ataxia
  • Cerebral palsy
  • Arthrogryposis multiplex congenita
  • Motor neuron disease
  • Congenital hypotonia
• Radiation therapy
• Skeletal dysplasias
  • Spondyloepiphyseal dysplasia
  • Diastrophic dwarfism
  • Metatrophic dwarfism
  • Chondrodysplasia congenita
• Infections
  • Pyogenic osteomyelitis
  • Tuberculosis
  • Brucellosis
• Tumors
  • Osteoid osteoma
  • Osteoblastoma
  • Meningiomas
  • Neurofibromas
  • Astrocytomas
  • Ependymomas
  • Metastasis
• Miscellaneous causes
  • Congenital heart disease
  • Coarctation of the aorta
  • Cyanotic heart disease
  • Congenital torticollis
  • Ocular torticollis
  • Spondylolisthesis
  • Malignant hyperpyrexia
  • Familial dysautonomia
  • Metabolic bone disease
  • Endocrine bone disease

Idiopathic scoliosis

Idiopathic scoliosis is the most common type of scoliosis, accounting for 80% of cases. It occurs in 3 forms: infantile, juvenile, and adolescent.

The infantile form is seen in patients as old as 3 years, and it is more common in boys than in girls. It usually involves the thoracic region with convexity to the left side. Faulty positioning of the infant in cot is one of the theories of formation. This type is uncommon in America and more common in Europe and Asia. It is associated with skull and pelvic abnormalities. Although infantile scoliosis often spontaneously resolves, some cases can progress, especially in the first 18 months during the growth spurt of infancy.

The juvenile form occurs between 4 and 9 years of age. Most cases involve the dorsolumbar region with convexity to the left side. This type is usually progressive. Some of these cases are either slowly progressing infantile scoliosis that is diagnosed late or adolescent scoliosis that is diagnosed early.

The adolescent form is seen between 10 years of age and maturity. This is the most common type of idiopathic scoliosis, accounting for 80% of all cases. It is more common in female adolescents (95%) than in male adolescents. Most cases involve the thoracic region with convexity to the right side; the apex of the curve commonly at the level of T7 or T8. This form can occur in the lumbar vertebrae, which is commonly concave to the right side. Theoretically, most of these curves originate in juveniles and later manifest in adolescents.

In the simple Dickson classification, idiopathic scoliosis is divided into early-onset ( <5 y) and late-onset (>5 y) types.

The exact etiology of idiopathic scoliosis is not yet known. Many theories of formation have been proffered, implying the disease is likely to be multifactorial. Contributing factors are growth asymmetry, hormonal factors, abnormal equilibrium system in the brainstem, genetic factors, and soft tissue abnormalities.^{[3,4 ]}

Autosomal dominant inheritance is proposed, but multifactorial inheritance is most likely. Type I fibers in the erector spinae muscle on the concave side of scoliotic curve may be involved in idiopathic scoliosis. These fibers, which are resistant to fatigue, play an important role in sustained tonic activities, and a decrease in these fibers may be an etiologic factor.

Frequency

United States

The prevalence of idiopathic adolescent scoliosis is approximately 4.5%. The overall prevalence is 3-5%, for curves less than 20° and 0.5% for curves more than 20°. The prevalence of scoliosis more than 25° is 1.5 cases per 1000 population. Scoliosis is most common in tall and heavy people.

International

The prevalence of idiopathic scoliosis requiring treatment is 0.1-0.3%. Adolescent scoliosis is widely distributed all over the world. The prevalence of curves more than 10° is 2.5 cases per 100 population. The prevalence of curves more than 20° is 1 case in 2500.

The prevalence of scoliosis is 11% in first-degree relatives of patients with diagnosed scoliosis, 2.4% in second-degree relatives, and 1.4% in third-degree relatives.

Infantile scoliosis is uncommon in America and more common in Europe and Asia.

Mortality/Morbidity

The mortality rate in patients with scoliosis is twice than that of healthy population. The mean age at death is 45-60 years.

• Scoliosis produces cosmetic deformity, disability, pain, and severe restriction of the patient's capacity to work.
• Cardiovascular compromise occurs in severe scoliosis (curves >60°). One third of patients with curves of 60-100° and one half of those with curves of more than 100° have cardiac complications. Cardiac involvement is more common with thoracic curves than with curves in other locations.
• Respiratory failure, cor pulmonale, restrictive lung disease, and right-sided heart failure are common cardiopulmonary complications. The risk of cardiovascular complications is highest in individuals with early-onset, large-curve scoliosis. The risk is low in late-onset scoliosis, even if the curve is severe.

Race

Infantile scoliosis is uncommon in America and more common in Europe and Asia.

Sex

The overall female-to-male ratio is 1.25:1. With curves of 6-10°, the ratio is almost 1:1, but with curves more than 20°, the ratio is 5.4:1.

• The infantile type is most common in boys, but the adolescent type is more frequent in female adolescents (95 %).
• Progression of the curve is more common in female individuals than in male individuals. The disease progresses in approximately 15.4% of female patients with scoliosis of more than 10°, compared with the general rate of 6.8%.
• The prevalence of scoliosis in daughters of mothers with scoliosis is 15-27%.

Age

• Scoliosis is characterized by progression with age. The rate of progression depends on the cause and the patient's rate of growth, with the incidence of progression of 5-79%. Progression is marked during accelerated growth in infancy and adolescence. Approximately 60% of rapidly growing curves can worsen.
• Progression usually stops when maturity is attained, particularly if the curve is less than 30°. Curves of more than 30° can grow at the rate of 1° per year after maturity.
• The infantile type affects infants and children as old as 3 years. The juvenile type affects children aged 4-9 years. The adolescent type occurs between 10 years and adulthood, and the adult form occurs between ages 20 and 50 years. In the Dickson classification, scoliosis is identified as early onset ( <5 y) or late onset (>5 y).

Anatomy

Anatomy of the spine

A normal spine has a typical curvature of lordosis in the cervical and lumbar regions and kyphosis in the thoracic and sacral region. A straight line can be drawn through the cervicothoracic, thoracolumbar, and lumbosacral junctions.

Development of the spine

The spinal curvature varies in different stages of life. At birth, the spine has a single curve, which is concave anteriorly. In infants, the cervical lordosis is established when they start to keep their head in erect position. The lumbar lordosis develops in the second year, when the child develops the ability to stand erect.

The spine continues to grow mainly by means of the proliferation of the cartilage in the superior and inferior aspects of the primary ossification center in the vertebral body. The annular cartilages develop independent of the primary ossification center and do not contribute to longitudinal growth. This center fuses with the body only after it is completely developed. By puberty, the normal adult curve is established, with the cervical and lumbar lordoses and the thoracic and sacral kyphoses.

Presentation

Clinical findings

On clinical evaluation, patients with scoliosis have a lateral bending of the spine that cannot be corrected by a change of posture. On bending forward, the prominence of the posterior ribs on the convex side of curve becomes most obvious. The spine deviates from the midline in all the 3 planes. The displacement is lateral in the frontal plane, with lordosis in the sagittal plane and rotation of the vertebrae about their own axis toward the convex side of the curve.

Idiopathic scoliosis does not produce symptoms such as pain and disability. An asymmetrical spine is the only finding. The ribs and scapula are prominent on 1 side, with a raised shoulder or hip protrusion on the other side. The deformity is most obvious when the curve is high, especially in the thoracic position. In combined thoracolumbar curves, the visible deformity is lessened as a result of balancing of the curves, but shortening of the trunk is visible.

On occasion, the clinical and imaging features are not typical of idiopathic scoliosis. Comprehensive clinical and neurologic examination and imaging are indicated in these atypical cases.

Scoliosis is atypical if the patient is male or has a left-sided thoracic curve, rapid progression of the curve, neurologic deficits, headache, neck ache, backache, and/or foot deformity.

Complications

Pulmonary function can be affected in severe scoliosis. The deformity affects expansion of the lungs, resulting in a restrictive defect apparent on pulmonary function tests. Although dyspnea is not common in children, it can occur in adults, depending on the severity of scoliosis.

Cardiac anomalies can be associated with idiopathic scoliosis. Idiopathic scoliosis is seen in 1-5% of patients with congenital heart disease; the incidence is highest in those with cyanotic heart disease.

Progression

Progression is indicated when the curve grows more than 5° per year. Scoliosis progresses with age at variable rate of 5-79%. The rate depends on the cause and the patient's rate of growth. Progression is marked during accelerated growth in infancy and adolescence, and 60% of rapidly growing curves can worsen.

The vertebrae continue to grow on the convex side and inhibited on the concave side. Curves less than 30 ° do not progress after maturity. Curves of 30-50° progress if they are rotated more than 25°, at the rate of 1° per year. Curves more than 50-75° progress regardless of maturity.

Other problems to consider

Neuromuscular curve

This is usually a long curve and C shaped.

Neurofibromatosis

Neurofibromatosis usually involves a short, sharply angulated curve. The 2 most common types of NF are type I (NF-I) and type II (NF-II). NF-I, or von Recklinghausen disease, is characterized by peripheral neurofibromas, plexiform neurofibromas, café au lait spots, Lisch nodules in the iris, optic-nerve gliomas, bone dysplasias, and scoliosis. NF-II is characterized by bilateral acoustic neuromas, meningiomas, schwannomas, and posterior subcapsular cataracts. The defect in type I is on chromosome 17, and in type II, the defect is on chromosome 22.

Congenital heart disease

Congenital heart disease can be associated with scoliosis (1-5%). Unlike idiopathic scoliosis, scoliosis with this involvement is most common in male individuals and usually convex to the right side (3:1). It is more common and severe with cyanotic heart disease than with acyanotic heart disease. The incidence of congenital heart disease with aortic coarctation is high. The spine and skull can be thick and dense as a result of hypoxia due to cardiac failure.

Scoliosis in the elderly

This is a type of scoliosis seen in men older than 60 years. Scoliosis in the elderly has no particular cause, though it is believed to be secondary to severe degenerative disease. Unlike the curve in idiopathic scoliosis, the curve in elderly scoliosis is short, segmental, and without any lateral wedging or abnormalities of the neural arch.

Management of scoliosis

The management of scoliosis depends on the maturity of the skeleton and on the degree of curvature. With curves of less than 25° in an immature skeleton or less than 30° in a mature skeleton, management is conservative and includes regular follow-up and radiography. Curves less than 25° require management when they are rapidly progressive, especially in preadolescents. With curves of 25-50°, orthotic devices (eg, braces) are used to restore the curvature to acceptable levels and to prevent progression.^{[5,6 ]}However, such devices are not used if the patient has respiratory or neurologic compromise.

Intraoperative image shows screw fixation.

Harrington rods with wires, hooks, and screws.

Anteroposterior (AP) radiograph of body screws.

Spontaneous improvement occurs in approximately 3% of patients, especially when the curve is less than 10°.

Aims of surgery are to prevent curve progression, to maintain balance, to reduce pain, to preserve respiratory and neurologic function, to facilitate nursing care, to improve cosmetic appearances (eg, of the large rib bump), to address failure of bracing, and to treat curves of greater than 40-50° in a growing child.

Prognosis

The prognosis depends on the age of the patient, the onset of menarche, the degree of spinal curvature, the number of vertebrae involved, the location of the curve, the rotational deformity, the maturation of the bone (as assessed by using the Risser index), the patient's family history, and the associated anomalies.

Preferred Examination

Clinical examination

Clinical examination should include neurologic examination to assess the deformity. A scoliometer is placed over the spinous process at the apex to measure the angle of trunk rotation (ATR). The measurement is significant if it is more than 5°.

Imaging examination

Radiography is the mainstay in assessment of scoliosis. It is used to confirm the clinical diagnosis of scoliosis, to exclude underlying causes (eg, segmentation abnormalities), to assess the curves and their severity, to monitor progression, to assess skeletal maturity, and to determine a patient's suitability for surgery. This study is also useful in diagnosing postoperative complications and in follow-up.

Plain radiograph illustrates the common terms used in describing the scoliotic curve. The upper and lower end vertebrae and apical vertebra are illustrated. The vertebrae and disk spaces are smaller on the concave side and larger on the convex side. The spinous process is rotated towards the concave side. The ribs are crowded on the concave side.

Radiograph shows various grades of vertebral rotation in the spine. The pedicles are normal in the bottom vertebra, but they are moving toward the center in the upper vertebra. The spinous process is in midline in the bottom vertebra, and it is displaced in the upper vertebrae.

Bone scans in a patient with painful atypical scoliosis are normal.

Coronal reconstructions from multidetector-row CT show several hemivertebrae. Idiopathic scoliosis is diagnosed only after underlying structural conditions such as these are excluded.

3-dimensional (3D) reconstructed CT scan of the same patient as in Image above shows the hemivertebrae.

MRIs show cervical scoliosis.

Sagittal MRIs show lumbar scoliosis.

Limitations of Techniques

The main limitation of radiography is the radiation dose. The risk of carcinogenesis is increased because of the repeated examinations done to monitor curve progression. This risk can be reduced with the judicious use of radiography and proper protection techniques.

Radiography is less sensitive than bone scanning and MRI because tumors or infections are apparent only after 50% of the bone is destroyed. Radiographs cannot be used to assess abnormalities of the spinal cord.

CT scanning is not routinely indicated, but it is a good method for assessing rotation and segmentation abnormalities. Radiography can provide all of the information needed. MRI is not cost-effective, and it is not a good screening tool because its yield in depicting important clinical abnormalities that change management is minimal.

Differential Diagnoses

Other Problems to Be Considered

Neuromuscular curve
Neurofibromatosis
Congenital heart disease
Scoliosis in the elderly

Radiography

Mild juvenile scoliosis.

Anteroposterior (AP) radiograph shows mild adolescent scoliosis.

Lateral view of mild adolescent scoliosis.

Moderate scoliosis.

Severe infantile scoliosis.

Radiograph shows various grades of vertebral rotation in the spine. The pedicles are normal in the bottom vertebra, but they are moving toward the center in the upper vertebra. The spinous process is in midline in the bottom vertebra, and it is displaced in the upper vertebrae.

Right lateral bending view of a patient with scoliosis.

Findings

Indications for radiography

Radiography is performed to confirm the diagnosis of scoliosis (which is made on clinical grounds), to exclude underlying bony segmentation abnormalities, to assess the severity of the curve, monitor progression of the curve (which is done by measuring indices), assess skeletal maturity by noting the ossification of the iliac apophysis, evaluate associated cardiac and pulmonary anomalies, and to assess the patient's progress and to evaluate complications during and after surgery.^{[10,11,12 ]}

Preoperative, postoperative, and follow-up imaging is also discussed in Surgical radiographic assessment, below.

Radiographic findings in idiopathic scoliosis

Radiographic findings and assessments in idiopathic scoliosis can be described as listed below.

• Lateral curvature to the spine is present and described in terms of the convex or concave side.^{[13 ]}
• Four patterns are seen in idiopathic scoliosis: (1) thoracic curve, (2) lumbar curve, (3) thoracolumbar curve on the same side, and (4) thoracic and lumbar curves on opposite sides.
• The number of vertebrae involved in the curve should be assessed.
• In a healthy person, a straight line can be drawn through the cervicothoracic, dorsolumbar, and lumbosacral junctions. The degree of deviation in the cervicothoracic angle from the sacral center is measured.
• Hypokyphosis of less than 20° or lordosis is present. The normal thoracic kyphosis is 20-45°.
• The apical vertebrae show increased height in the anterior aspect of vertebral body and decreased height in the posterior aspect.^{[14 ]}
• Vertebral bodies and intervertebral disk spaces are wider on the convex side than on the concave side.
• The posterior ribs are pushed posteriorly on the convex side, where they produce a hump. They are positioned anteriorly on the concave side.
• The ribs are closely approximated on the concave side and separated on convex side.
• At the end of the curve, the disk spaces are equal or widened on the concave side. The vertebrae and neural arches are thick on the concave side.
• The spinous process is shifted toward the concave side, and the pedicle and vertebral body are shifted toward the convex side.
• The rotation is marked at the apex of the curve and almost neutral at the end vertebrae. Rotation can be intersegmental (between vertebrae) or intrasegmental (between elements of 1 vertebrae); the latter is uncorrectable.
• The psoas shadow is absent on the concave side of the curve.

Radiographic classification systems

Many classification systems are used to describe the types of scoliotic curves. Classification helps surgeons in deciding appropriate management because the prognosis and treatment of the various curves differ.

Ponseti-Friedman classification

The Ponseti-Friedman classification has 5 types: I is a single major lumbar curve at T11-L3 with an apex at L1-2 (This is the most benign type and affects 23% of patients). II is a single major dorsolumbar curve at T6-7 to L1-2 with an apex at T11-12 (16%). III is combined thoracic and lumbar (37%) with a dorsal curve on the right side at T5-6 or T10-11 and an apex at T7-8 and a lumbar curve on the left side at T10-11 to L3-4 with an apex at L1-2. IV is a single major thoracic curve at T5-6 to T11-12 with an apex at T8-9 (22%). V is cervicothoracic at C7-T1 or T4-5 with an apex at T3.

King-Moe classification

The King-Moe classification has 4 types: I, which is lumbar dominant and S shaped (10%); II, which is thoracic dominant and S shaped (33%); III, which is thoracic where the thoracic and lumbar curves do not cross the midline (33%); and IV, long thoracic or double thoracic with T1 tilted into the upper curve where (the upper curve is structural (10%).^{[15 ]}

Lenke classification

The Lenke classification has 3 components: (1) type of curve, (2) lumbar modifier, and (3) sagittal thoracic modifier. Type of curves are as follows: I, primary thoracic; II, double thoracic scoliosis; III, double major scoliosis; IV, triple major scoliosis; and V, dorsolumbar-lumbar scoliosis. The lumbar modifier is based on the relationship of the central sacral vertical line to the apex of the lumbar curve and is classified into A, B, and C categories. The sagittal thoracic modifier is the sagittal curve measurement from T5-12; designations are - for less than 10°, N for 10-40°, and + for greater 40°.^{[16,15,17 ]}

Radiographic views

The classic views obtained in the evaluation of scoliosis are listed below.

• Posteroanterior (PA) erect view of the entire spine from cervical to sacral spine and including the iliac crest: This view is ideally obtained with the patient's shoulders outstretched.
• AP recumbent view of entire spine, cervical to sacral
• Lateral view of dorsolumbar spine: The patient's forearm must be kept horizontal by resting it on a stand.
• Lateral profile at the apex of scoliosis to eliminate kyphosis and show the true extent of the scoliosis
• Stagnara image (planed election view) perpendicular to the true coronal plane of the apical vertebra
• Leeds image, a true lateral view 90° perpendicular to the Stagnara view
• Left and right lateral bending views: These are obtained to exclude postural scoliosis. Postural scoliosis disappears when bending toward the side of convexity. These views are also used to assess structural scoliosis, asymmetry and loss of normal mobility of primary curve,^{[18 ]}and wedging rotation of individual vertebra, and to dynamically assess the postural nature of secondary compensatory curves in the preoperative period and to select fusion levels.
• AP view of the left hand to assess bone age
• Biplanar views with digital enhancement
• Ferguson view perpendicular to the L5-S1 disks to detect anomalies at this junction
• Coned views of focal vertebral anomalies

In routine practice, not all these views are necessary. Full-length frontal and lateral views, as well as right and lateral bending views, are enough.

Common views obtained before surgery are PA and lateral image, which are obtained with long-cassette film to cover the whole spine beginning from the craniocervical junction and including the pelvis to assess the Risser grade; supine, standing, or sitting images if patient is unable to stand; and lateral bending views to assess the extent of compensatory curves.

For subsequent follow-up imaging, the frontal PA view is sufficient, and lateral views are required only if a superimposed kyphotic element is present.

Terminology used to describe scoliosis

The apical vertebra is the vertebra that is displaced and rotated most. Its endplates are least tilted.

The end vertebrae are the most superior and inferior vertebrae in the curve. These bones are least displaced and rotated, with maximal tilting of the endplates toward the concavity of the curve. They are laterally wedged, longer in the convex side and compressed on the concave side.

The neutral vertebra is not rotated on the anteroposterior (AP) image.

The stable vertebra is bisected by the central sacral line.

The primary curve the structural curve, with wedging, angulation, rotation, and an abnormal position. The primary curve is deformed and develops structural changes simultaneously. It is not corrected spontaneously or with mechanical correction. The following characteristics are helpful in identifying the primary curve: (1) The vertebrae are deviated to the convexity of the curve. (2) If 3 curves are present, the middle one is usually the primary curve. (3) If 4 curves are present, the middle 2 are the primary ones. (4) The primary curve may be the greatest curve.

The secondary curve is the nonstructural curve that develops in response to the primary structural curve. The structural changes in this curve occur slowly. It can be corrected spontaneously, and any mechanical correction is retained. The vertebrae are displaced to the concavity of the curve.

The compensatory curves are curves formed to balance the primary curve. If a primary curve is formed in 1 direction, another curve of same magnitude should be formed in the opposite direction to fully compensate for the deformity. For example, if the primary curve is 50°, 1 or 2 compensatory curves may be present and add to equal 50° in the opposite direction.

A decompensated curve is a compensatory curve that does not fully correct the deformity. An example is a 40° compensatory curve for a 50° primary curve results in decompensation.

An overcompensated curve is a compensatory curve that is more than the primary curve. An example is a 60° compensatory curve or a combination of curves adding to 60° that overcompensates for a 50° primary curve.

Indices used to assess scoliosis

The following techniques, measures, and indices are used to assess scoliosis: the Cobb-Webb technique, the Ferguson technique, the Greenspan method, the Nash-Moe technique of measuring vertebral rotation, the Cobb method of assessing vertebral rotation, the Risser index, the observation for ossification of the vertebral ring apophysis, the difference in the rib-vertebral angle, the Perdriolle method, the Lytilt method, and other methods of assessing skeletal maturity.

Cobb-Webb technique

This is the most commonly used technique to measure the severity of scoliosis. The result determines further management and helps in predicting the prognosis.

The superior and inferior end vertebrae of the scoliotic curve are identified by carefully observing the rotation of vertebral bodies and the width of the intervertebral space. The intervertebral space is almost normal, and the vertebrae are in neutral position without substantial rotation in the superior and inferior end vertebra.

Lines are drawn tangential to superior endplate of the superior end vertebra and the inferior endplate of the inferior vertebra. The Cobb-Webb angle is the angle formed at the intersection of these lines or the angle formed at the intersection of the lines perpendicular to these lines. A Cobb angle of at least 10° is essential for diagnosing scoliosis.

Limitations of Cobb-Webb angle include the following:

• Uniplanar measurement of a 3D deformity
• Interobserver variation
• Diurnal variation, with angles 5° greater in the afternoon than in the morning
• Variations that occur with changes in supine and upright positioning, rotation, body shape, and radiographic technique
• Spinal growth of 1° per month during periods of rapid growth (Frequent assessments (eg, every 3-4 mo) are need for accurate measurements of the curve.)
• Angle of curvature determined only by the orientation of the end vertebra
• Values higher than those obtained with other measurement techniques

A 10° measurement difference should be present to be 95% confident that the curve is progressing.

The Lippman-Cobb classification of scoliotic curvature is as follows:

Line diagram illustrates measurement of the Lippman-Cobb angle.

Radiograph shows measurement of Lippman-Cobb angle.

Line diagram illustrates measurement of the Cobb angle by using a modified technique.

Radiograph shows modified Cobb angle.

• I = Less than 20°
• II = 21-30°
• III = 31-50°
• IV = 51-75°
• V = 76-100°
• VI = 101-125°
• VII = Greater than 125°

Ferguson technique

A line is drawn from the center of the apical vertebra to the center of the superior end vertebra. Another line is drawn from the center of the apical vertebra to the center of the inferior end vertebra.

Line diagram shows the Risser-Ferguson technique.

Radiograph shows measurement by using the Ferguson technique.

Greenspan index

This technique provides a measurement of the scoliotic curve more comprehensive than that obtained with other methods. The midpoint of the vertebra above the upper end vertebra and the midpoint of the vertebra below the lower end vertebra are joined to form a vertical spinal line. Lines are drawn from the center of each vertebra in the scoliotic curve to the vertical spinal line. The value of these individual lines are added and divided by the length of the vertical spinal line. A correction factor is added for magnification.

Line diagram illustrates the Greenspan technique.

Radiograph shows measurement of the Greenspan index of scoliosis.

Nash-Moe technique of assessing vertebral rotation

This is a measure of rotational deformity of the vertebra.

Line diagram shows the Nash-Moe method of measuring vertebral rotation.

Cobb method of assessing vertebral rotation

The Cobb technique uses the position of spinous process for assessing the degree of vertebral rotation. The vertebra is divided into 6 equal segments by drawing 5 vertical lines.

Line diagram illustrates the Cobb method of measuring vertebral rotation.

Risser index

The Risser index is used to measure ossification of the iliac apophysis, which is graded as follows: Grade I is ossification of the lateral 25% of the iliac apophysis. Grade II is ossification of the lateral 50%. Grade III is ossification of the lateral 75% of the apophysis. Grade IV is ossification of the entire apophysis. Grade V is fusion of ossified epiphysis to the iliac wing.

Line diagram illustrates the Risser index.

After ossification, the apophysis fuses with iliac crests in 2 years in girls and slightly faster than this in boys. Progression usually does not happen after grade IV maturity of iliac apophysis is achieved. If the curve is 50-80° at the time of maturity, it tends to progress even after the apophysis fuses, especially if the curve is in the thoracic and lumbar region. However, this progression is far slower than the progression that occurs during adolescence.

Limitations of Risser index can be summarized as follows: (1) Ossification starts earlier than previous thought; hence, this index is not reliable. (2) The index is less reliable in male patients than in female patients because their ossification starts early. In male patients, growth should be considered completed when a Risser index of only 5 is achieved. (3) Recent data indicate that this index is not an accurate measure of completed maturity, spinal growth, or progression of the deformity.

Observation for ossification of the vertebral ring apophysis

This is an alternate method for assessing skeletal maturity.

Vertebral apophysis maturation. Left image shows the ossification center. Ossification is complete in the middle image. Right image shows fusion indicating vertebral maturation.

Difference in the rib-vertebral angle

This parameter is useful in predicting the progression of the curve in the idiopathic infantile type of scoliosis.

Line diagram shows rib–vertebral angle difference (RVAD) (Mehta, 1976).

Radiograph shows measurement of difference in the rib-vertebral angle.

In thoracic curves, the angle is usually smaller on the convex side than the concave side because of the greater obliquity of the ribs on the convex side. In combined thoracic and lumbar curves, the angle is low at level of apical thoracic vertebra and can be greater on the convex side. This curve can be further negative because of the associated drooped 12th rib on the concave side of the curve.

In resolving curves, the angle is less than 20° and more than 20° in progressive curves. Subsequent images obtained after 2-3 months show a decreased angle in resolving curves and the same or increased angle in progressive curves.

Perdriolle method

The Perdriolle method is used to measure apical vertebral rotation.

Lytilt method

The Lytilt method is used to measure the angle between the L4 vertebra and a line connecting the iliac crests.

Other methods of assessing skeletal maturity

Ossification and maturation of the epiphysis of the left hand and wrist are compared with standards. Two main methods are used. The first is the Greulich-Pyle method in which the radiograph of hand and wrist is compared with standard radiographs in the atlas. The second is the Tanner-Whitehouse method in which the epiphysis of the hand and wrist are compared with those of the atlas. A score is assigned to each of them, and the sum is compared with values on standard tables. Thus, bone age is assessed.

Surgical radiographic assessment

Immediate preoperative radiographic assessment

The immediate preoperative assessment should include Chest radiographs for cardiovascular assessment, supine and recumbent AP views of the spine, right and left lateral bending images, and traction views.

The bending and traction views are helpful in assessing the site of fusion, the degree of correction required, and the placement of spinal devices.

Surgeries for scoliosis

• Surgeries for scoliosis include the following techniques:
• A single rod can be used to fix the upper and lower end of curves with a posterior approach. Disadvantages are prolonged immobilization or use of braces and suboptimal results.^{[5,6 ]}
• Two Harrington or Luque rods can be used to accomplish segmental stabilization at each level of spine using sublaminar wires.
• Use of the Cotrel-Dubousset system with multiple hooks with rods may improve 3D results.
• Use of pedicular screws to fix the spine increases fixation, reduces the number of levels fused, and reduces the number of junctional problems above and below the fused vertebra.^{[7,19 ]}
• An anterior approach can be used with thoracotomy or thoracoscopy in which single or double rods with screws are attached to each vertebral body. Better results. Results are better than those of other methods, and this approach treats the rib bump at same time.

Postoperative radiographic assessment

In the immediate postoperative period, chest radiographs are used to assess for complications. Frontal and lateral spinal images are required to assess the postoperative pine. The degree of correction of the curve can also be evaluated.^{[20 ]}

Recognized complications are damage to the rods or wires, dislocation or migration of the rods, loosening of a device, spondylolysis, pseudoarthrosis, aortic aneurysm, retroperitoneal fibrosis, gastric volvulus, and progression of the deformity (crankshaft phenomenon). This last complication occurs when surgery is performed before maturity (Risser index <1 and age <10 y). The unfused vertebrae and portions of the vertebrae not included in the fusion continue to grow, producing progressive deformity. This effect is marked in posterior fusion, in which the anterior portions of vertebra continue to grow and produce a new curve.

Follow-up assessment

Follow-up assessment should be routinely performed until the patient reaches maturity.

Radiation protection

The radiation dose is an important factor in evaluation of scoliosis. Studies by Nash et al indicate that the risk of carcinogenesis is mildly increased.

Techniques for radiation protection include the use of the following: PA view to reduce exposure to the breast; rare-earth screens; high kilovolt setting; high speed film; filters for upright views; tube head filters; good beam collimation; digital radiographic techniques; and breast, gonad, and thyroid shields.

Computed Tomography

3-dimensional (3D) reconstruction of mild scoliotic curve without segmentation anomaly.

Coronal reconstructions from multidetector-row CT show several hemivertebrae. Idiopathic scoliosis is diagnosed only after underlying structural conditions such as these are excluded.

3-dimensional (3D) reconstructed CT scan of the same patient as in Image above shows the hemivertebrae.

CT is good for assessing rotation of the vertebra.

CT scan illustrates the indices useful for assessing the extent of rotation.

Findings

CT findings

The scoliotic deformity can be visualized on CT scans of the thorax and abdomen. Associated lesions, such as osteoid osteoma, osteoblastoma, infection, tumors, disk prolapse, and costovertebral dislocation, can be found.

CT techniques

With modern multidetector-row CT scanners, thin sections of the whole body can be obtained within a few seconds and reconstructed in any plane: sagittal, coronal, oblique, or axial. Even 3D reconstruction with shaded-surface display or volume rendering is possible.

CT myelography is not routinely done, and it is not needed in idiopathic scoliosis. This is useful for evaluating intraspinal lesions, such as diastematomyelia, a tethered cord, or intraspinal tumors. Compression of the spinal cord can also be assessed.

Role of CT in evaluating scoliosis

CT is performed for an evaluation of segmentation abnormalities with 3D reconstructions, though MRIs have largely replaced these scans. CT is also used to evaluate postoperative complications because MRIs may show metallic artifacts. In addition, CT helps in evaluating intrinsic rotational deformity. Scoliotic deformity can be visualized on CT scans of the thorax and abdomen. Associated lesions, such as osteoid osteoma, osteoblastoma, infection, tumors, disk prolapse, and costovertebral dislocation, can be found. Finally, associated rib-cage deformity is best assessed with CT scans. The rib-cage deformity is well correlated with the longitudinal deformity at the level of the apical vertebra.

CT myelography is done to assess suspected radiculopathy, intraspinal lesions, or cord compression.

Indices used to assess rib-cage deformity

The apical vertebra of the primary curve is identified by using plain radiography. CT scans are then acquired at this level to help in assessing the longitudinal deformity. Several lines are used.

Line 1 is drawn from the center of the posterior aspect of the vertebral foramen to the center of the vertebral body and extended to the anterior chest wall. Line 2 extends from the center of the posterior aspect of vertebral foramen to the anterior midline of the body. Line 3 is a horizontal line extending through the center of the posterior aspect of the vertebral foramen. A perpendicular is then drawn from the center of the posterior aspect of vertebral foramen to meet the anterior chest wall.

Line diagram illustrates measurement of the CT index.

Line diagram illustrates measurement of the CT rib-hump index.

RAML is the sum of RASag and Mldev.

Rib-hump index

The rib-hump index is measured at the level of the rib hump by using several lines. Line 1 is a horizontal line drawn through the center of the posterior aspect of the vertebral foramen to the lateral chest wall on both sides. Line 2 is a horizontal line parallel to the first; this line passes through the peak of the inner rib cage on the hump side. Line 3 is parallel to the first and passes through the peak of the inner rib cage on the side opposite the hump. Line 4 is a perpendicular line drawn from the peak of the inner rib cage on the hump side to meet the first line at point 0.

The rib-hump index is defined as (X - Y)/Z, where X is the distance between line 1 and line 2, Y is the distance between lines 1 and 3, and Z is the distance between point 0 and the center of posterior aspect of the vertebral foramen.

The rib-hump index is directly correlated with RASag.

Postoperative CT

Postoperative CT scanning can be done to assess for the development of complications such as hemorrhage, fracture, or pseudoarthrosis.

Magnetic Resonance Imaging

MRIs show cervical scoliosis.

Sagittal MRIs show lumbar scoliosis.

Axial MRI shows apical vertebra.

Sagittal MRI shows an Arnold-Chiari I malformation and syringomyelia.

Findings

Role of MRI in evaluating idiopathic scoliosis

MRI is not used for diagnosing scoliosis. It is useful for assessing other etiologic factors, especially spinal-cord anomalies, that can change the diagnosis. Such anomalies are most common in the infantile and juvenile types and include syringomyelia, hydromyelia, spinal-cord tumors, dysraphism, a tethered cord, diastematomyelia, lipomas, neurofibromas, and Chiari malformations.

Idiopathic scoliosis is diagnosed only after its differential diagnoses are excluded. In 1 study, 50% of all cases previously designated as being idiopathic involved some spinal lesion.

Untreated syringomyelia contributes to paraplegia after surgery.

MRI is also used to investigate occult intraspinal tumors, which can occur with scoliosis but without any neurologic symptoms or signs; to exclude other underlying abnormalities, such as tumors, infections, and disk prolapse; to evaluate atypical scoliosis or an atypical curve in a child with normal neurologic findings; to evaluate the patient before surgery because assessment of the spinal cord in patients with postoperative neurologic symptoms can be difficult because surgical devices that produce artifacts; to evaluate rotational deformity and distinguish intervertebral from intravertebral rotation (Standard derotational surgery is suboptimal in those with predominant intravertebral rotation.); and to ascertain the severity of the curve.

Atypical features for which MRI is warranted includes the following:

• Abnormal neurologic finding
• Painful scoliosis
• Signs of dysraphism
• Neck pain, headache
• Weakness, pes cavus, ataxia
• Back pain
• Atypical curves (left-sided thoracic curve, juvenile onset)
• Rapid progression
• Associated lower-limb deformity
• Increased kyphosis
• Thoracic deformity
• Wide spinal canal
• Thin pedicles
• Abnormal somatosensory evoked potentials

In 2001, Do et al found that only 7 of 327 patients with diagnosed idiopathic scoliosis had other abnormalities on routine MRI.^{[9 ]}None of the newly diagnosed pathologies were clinically important in terms of future management.

MRI technique

MRI is performed in the sagittal, axial, and coronal planes by using T1- and T2-weighted sequences. Proper technique is difficult, especially if the patient has more than 1 curve.

Postoperative MRI

MRI is indicated if the patient develops neurologic deficits after the procedure. If MRI is being done for the first time, occult spinal and cord lesions cannot be detected. Imaging might be difficult because of the presence of spinal instruments. Hemorrhage, pseudoarthrosis, and tumors can be detected.

Degree of Confidence

Important considerations are intraspinal tumors. Intraspinal tumors occasionally cause scoliosis and no other symptoms. In such cases, idiopathic scoliosis might be diagnosed. Only MRI can depict intraspinal tumors. The identification of notable neurologic and other diseases alters management.

If the patient develops neurologic symptoms postoperatively, assessment of the spinal cord is difficult because of the surgical devices, which produce artifacts. Hence, a routine preoperative MRI is considered useful.

False Positives/Negatives

Although MRI has been advocated in patients with atypical scoliosis, data confirming the benefit of this approach are lacking.

MRI can depict a number of findings; however, a recent study revealed no significant difference in the incidence of anomalies between those with atypical findings and patients without atypical findings. Even if anomalies such as syringomyelia and Chiari malformation are found, they do not affect management. Therefore, the effectiveness of MRI as a diagnostic tool is questioned.

Some centers still routinely use MRI, and others use it only if surgery is contemplated or if atypical signs are present.

Ultrasonography

Sonogram in the same patient as in Image 52 in Multimedia shows a small collection adjacent to the rib, which was drained.

Findings

Ultrasonography has only limited application in scoliosis. If scoliosis is seen in a neonate or child with spina bifida, a sonogram of the spine can be obtained to assess the spinal cord. The position of the cord, including tethering, can be evaluated. Associated lesions, such as myelomeningocele, lipomas, epidermoids, those due to diastematomyelia, are also seen.

It can be useful to assess soft-tissue complications, such as hematomas and abscesses, after surgery.

Nuclear Imaging

Findings

Bone scanning is not routinely performed in idiopathic scoliosis. Bone scans are obtained to evaluate atypical or painful scoliosis and to exclude infection. Focal hot spots can be seen in osteoid osteomas, osteoblastomas, infections, and other primary tumors that can cause painful scoliosis. Bone scans may also help in assessing for surgical complications including infection. A WBC scan may be required to differentiate infection from postoperative changes in the spine. Focal hot spots are also seen in stress fractures, spondylosis, and pseudoarthrosis in the fused segments.

Degree of Confidence

Bone scanning is highly sensitive in the diagnosis of bone lesions. Osteoid osteoma is the most common cause of painful scoliosis. Bone scanning is helpful in assessing this condition and for showing increased uptake.

Multimedia

Media file 1: Mild juvenile scoliosis.

Media file 2: Anteroposterior (AP) radiograph shows mild adolescent scoliosis.

Media file 3: Lateral view of mild adolescent scoliosis.

Media file 4: Moderate scoliosis.

Media file 5: Severe infantile scoliosis.

Media file 6: Severe typical scoliosis.

Media file 7: Line diagram illustrates the common terms used in describing scoliosis.

Media file 8: Plain radiograph illustrates the common terms used in describing the scoliotic curve. The upper and lower end vertebrae and apical vertebra are illustrated. The vertebrae and disk spaces are smaller on the concave side and larger on the convex side. The spinous process is rotated towards the concave side. The ribs are crowded on the concave side.

Media file 9: Line diagram illustrates measurement of the Lippman-Cobb angle.

Media file 10: Radiograph shows measurement of Lippman-Cobb angle.

Media file 11: Line diagram illustrates measurement of the Cobb angle by using a modified technique.

Media file 12: Radiograph shows modified Cobb angle.

Media file 13: Line diagram shows the Risser-Ferguson technique.

Media file 14: Radiograph shows measurement by using the Ferguson technique.

Media file 15: Line diagram illustrates the Greenspan technique.

Media file 16: Radiograph shows measurement of the Greenspan index of scoliosis.

Media file 17: Line diagram shows the Nash-Moe method of measuring vertebral rotation.

Media file 18: Line diagram illustrates the Cobb method of measuring vertebral rotation.

Media file 19: Radiograph shows various grades of vertebral rotation in the spine. The pedicles are normal in the bottom vertebra, but they are moving toward the center in the upper vertebra. The spinous process is in midline in the bottom vertebra, and it is displaced in the upper vertebrae.

Media file 20: Line diagram shows rib–vertebral angle difference (RVAD) (Mehta, 1976).

Media file 21: Radiograph shows measurement of difference in the rib-vertebral angle.

Media file 22: Line diagram illustrates the Risser index.

Media file 23: Vertebral apophysis maturation. Left image shows the ossification center. Ossification is complete in the middle image. Right image shows fusion indicating vertebral maturation.

Media file 24: Right lateral bending view of a patient with scoliosis.

Media file 25: Left lateral bending of the same patient as in image 24 shows persistence of the scoliotic curve, which indicates its structural nature.

Media file 26: MRIs show cervical scoliosis.

Media file 27: Sagittal MRIs show lumbar scoliosis.

Media file 28: Axial MRI shows apical vertebra.

Media file 29: Sagittal MRI shows an Arnold-Chiari I malformation and syringomyelia.

Media file 30: 3-dimensional (3D) reconstruction of mild scoliotic curve without segmentation anomaly.

Media file 31: Coronal reconstructions from multidetector-row CT show several hemivertebrae. Idiopathic scoliosis is diagnosed only after underlying structural conditions such as these are excluded.

Media file 32: 3-dimensional (3D) reconstructed CT scan of the same patient as in Image above shows the hemivertebrae.

Media file 33: CT is good for assessing rotation of the vertebra.

Media file 34: Line diagram illustrates measurement of the CT index.

Media file 35: Line diagram illustrates measurement of the CT rib-hump index.

Media file 36: CT scan illustrates the indices useful for assessing the extent of rotation.

Media file 37: Bone scans in a patient with painful atypical scoliosis are normal.

Media file 38: Intraoperative image shows screw fixation.

Media file 39: Intraoperative image shows screw fixation.

Media file 40: Harrington rods with wires, hooks, and screws.

Media file 41: Harrington rods with wires, hooks, and screws as shown on a lateral radiograph.

Media file 42: Anteroposterior (AP) view of fixation by using pedicle screws.

Media file 43: Lateral view of pedicle screws.

Media file 44: Coronal CT appearance of pedicle screws.

Media file 45: Axial CT appearance of a normal pedicular screw after surgery.

Media file 46: Anteroposterior (AP) radiograph of body screws.

Media file 47: Normal appearance of body screws on a lateral view.

Media file 48: Axial CT appearance of a screw in a vertebral body.

Media file 49: Displaced pedicular screw indenting the descending thoracic aorta.

Media file 50: Anteriorly displaced screw in the parenchyma of the right lower lobe of the lung.

Media file 51: Postoperative focal hot spot in the spine due to infection.

Media file 52: CT scan of the same patient as in Image 51 shows right rib destruction and underlying pulmonary infection. Left-sided pleural effusion is also shown.

Media file 53: Sonogram in the same patient as in Image 52 in Multimedia shows a small collection adjacent to the rib, which was drained.

Media file 54: Cardiomyopathy with bilateral pleural effusion after surgery.

References

1. American College of Radiology. ACR Practice Guideline for the Performance of Radiography for Scoliosis in Children. American College of Radiology. Available at http://www.acr.org/SecondaryMainMenuCategories/quality_safety/guidelines/pediatric/scoliosis.aspx. Accessed March 26, 2009.

2. Kouwenhoven JW, Castelein RM. The pathogenesis of adolescent idiopathic scoliosis: review of the literature. Spine. Dec 15 2008;33(26):2898-908. [Medline].

3. Gurnett CA, Alaee F, Bowcock A, Kruse L, Lenke LG, Bridwell KH, et al. Genetic linkage localizes an adolescent idiopathic scoliosis and pectus excavatum gene to chromosome 18 q. Spine. Jan 15 2009;34(2):E94-100. [Medline].

4. Little JP, Adam CJ. The effect of soft tissue properties on spinal flexibility in scoliosis: biomechanical simulation of fulcrum bending. Spine. Jan 15 2009;34(2):E76-82. [Medline].

5. Negrini S, Grivas TB, Kotwicki T, Rigo M, Zaina F. Guidelines on "Standard of management of idiopathic scoliosis with corrective braces in everyday clinics and in clinical research": SOSORT Consensus 2008. Scoliosis. Jan 16 2009;4(1):2. [Medline].

6. Rivett L, Rothberg A, Stewart A, Berkowitz R. The relationship between quality of life and compliance to a brace protocol in adolescents with idiopathic scoliosis: a comparative study. BMC Musculoskelet Disord. Jan 14 2009;10:5. [Medline].

7. Lonner BS, Auerbach JD, Estreicher M, Milby AH, Kean KE. Video-assisted thoracoscopic spinal fusion compared with posterior spinal fusion with thoracic pedicle screws for thoracic adolescent idiopathic scoliosis. J Bone Joint Surg Am. Feb 2009;91(2):398-408. [Medline].

8. Coonrad RW, Murrell GA, Motley G, et al. A logical coronal pattern classification of 2,000 consecutive idiopathic scoliosis cases based on the scoliosis research society-defined apical vertebra. Spine. Jun 15 1998;23(12):1380-91. [Medline].

9. Do T, Fras C, Burke S, et al. Clinical value of routine preoperative magnetic resonance imaging in adolescent idiopathic scoliosis. A prospective study of three hundred and twenty-seven patients. J Bone Joint Surg Am. Apr 2001;83-A(4):577-9. [Medline].

10. Cassar-Pullicino VN, Eisenstein SM. Imaging in scoliosis: what, why and how?. Clin Radiol. Jul 2002;57(7):543-62. [Medline].

11. Oestreich AE, Young LW, Young Poussaint T. Scoliosis circa 2000: radiologic imaging perspective. I. Diagnosis and pretreatment evaluation. Skeletal Radiol. Nov 1998;27(11):591-605.

12. Gu SX, Wang CF, Zhao YC, Zhu XD, Li M. Abnormal ossification as a cause the progression of adolescent idiopathic scoliosis. Med Hypotheses. Jan 10 2009;[Medline].

13. Driscoll M, Aubin CE, Moreau A, Villemure I, Parent S. The role of spinal concave-convex biases in the progression of idiopathic scoliosis. Eur Spine J. Feb 2009;18(2):180-7. [Medline].

14. Aaro S, Dahlborn M. The longitudinal axis rotation of the apical vertebra, the vertebral, spinal, and rib cage deformity in idiopathic scoliosis studied by computer tomography. Spine. Nov-Dec 1981;6(6):567-72. [Medline].

15. Richards BS, Sucato DJ, Konigsberg DE, Ouellet JA. Comparison of reliability between the Lenke and King classification systems for adolescent idiopathic scoliosis using radiographs that were not premeasured. Spine. Jun 1 2003;28(11):1148-56; discussion 1156-7. [Medline].

16. Lenke LG, Betz RR, Harms J, et al. Adolescent idiopathic scoliosis: a new classification to determine extent of spinal arthrodesis. J Bone Joint Surg Am. Aug 2001;83-A(8):1169-81. [Medline].

17. Sangole AP, Aubin CE, Labelle H, Stokes IA, Lenke LG, Jackson R, et al. Three-dimensional classification of thoracic scoliotic curves. Spine. Jan 1 2009;34(1):91-9. [Medline].

18. Cobb JR. The problem of the primary curve. Am J Orthop. Dec 1960;42-A:1413-25. [Medline].

19. Sarlak AY, Atmaca H, Buluç L, Tosun B, Musaoglu R. Juvenile idiopathic scoliosis treated with posterior arthrodesis and segmental pedicle screw instrumentation before the age of 9 years: a 5-year follow-up. Scoliosis. Jan 6 2009;4(1):1. [Medline].

20. Smyrnis PN, Sekouris N, Papadopoulos G. Surgical assessment of the proximal thoracic curve in adolescent idiopathic scoliosis. Eur Spine J. Feb 14 2009;[Medline].

Keywords

idiopathic scoliosis, abnormal curvature, bends, lateral curvature, curved spinal, spinal curvature, postural scoliosis, structural scoliosis, Dickson classification, Heuter-Volkman law, infantile idiopathic scoliosis, juvenile idiopathic scoliosis, adolescent idiopathic scoliosis, lordosis, kyphosis, angle of trunk rotation, ATR, Ponseti-Friedman classification, King-Moe classification, Lenke classification, Cobb-Webb technique, Cobb angle, Cobb-Webb angle, Nash-Moe, Ferguson technique, Risser index, rib-vertebral angle, Perdriolle method, Lytilt method, crankshaft phenomenon, rib-hump index

Contributor Information and Disclosures

Author

Prabhakar Rajiah, MD, MBBS, FRCR, Registrar, Department of Radiology, Central Manchester and Manchester Children's University Hospitals, UK
Prabhakar Rajiah, MD, MBBS, FRCR is a member of the following medical societies: American Roentgen Ray Society, North American Society for Cardiac Imaging, Radiological Society of North America, Royal College of Radiologists, Society for Cardiovascular Magnetic Resonance, and Society of Cardiovascular Computed Tomography
Disclosure: Nothing to disclose.

Medical Editor

Henrique M Lederman, MD, PhD, Consulting Staff, Department of Radiology, LeBonheur Children's Medical Center and St Jude Children's Research Hospital; Professor of Radiology and Pediatric Radiology, Chief, Division of Diagnostic Imaging in Pediatrics, Federal University of Sao Paulo, Brazil
Henrique M Lederman, MD, PhD is a member of the following medical societies: Society for Pediatric Radiology
Disclosure: Nothing to disclose.

Pharmacy Editor

Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand
Disclosure: Nothing to disclose.

Managing Editor

Kieran McHugh, MBBCh, Honorary Lecturer, The Institute of Child Health; Consultant Pediatric Radiologist, Department of Radiology, Great Ormond Street Hospital for Children, London, UK
Kieran McHugh, MBBCh is a member of the following medical societies: American Roentgen Ray Society and Royal College of Radiologists
Disclosure: Nothing to disclose.

CME Editor

Robert M Krasny, MD, Consulting Staff, Department of Radiology, Resolution Imaging Medical Corporation
Robert M Krasny, MD is a member of the following medical societies: American Roentgen Ray Society and Radiological Society of North America
Disclosure: Nothing to disclose.

Chief Editor

Felix S Chew, MD, MBA, EdM, Professor, Department of Radiology, Vice Chairman for Radiology Informatics, Section Head of Musculoskeletal Radiology, University of Washington
Felix S Chew, MD, MBA, EdM is a member of the following medical societies: American Roentgen Ray Society, Association of University Radiologists, and Radiological Society of North America
Disclosure: Nothing to disclose.

Related eMedicine topics

Adolescent Idiopathic Scoliosis

Idiopathic Scoliosis

Infantile Scoliosis

Juvenile Idiopathic Scoliosis

Neuromuscular Scoliosis

Clinical guidelines

ACR Practice Guideline for the Performance of Radiography for Scoliosis in Children

Screening for idiopathic scoliosis in adolescents: recommendation statement.
United States Preventive Services Task Force.  1996 (revised 2004 Jun).  4 pages.  NGC:003625

Summary of recommendations for clinical preventive services.
American Academy of Family Physicians.  1996 Nov (revised 2007 Aug).  15 pages. [NGC Update Pending] NGC:006077

Clinical trials

Phase IV Comparing Rods of Yield Strengths to Correct Adolescent Idiopathic Scoliosis.

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