Scoliosis originates from the Greek word “scolios” means crooked or curved and has been used since the time of Hippocrates to describe an abnormal lateral curvature of the spine. Today, scoliosis is recognized as more than a simple lateral deviation of the spine but rather one that includes vertebral axial rotation and an alteration of the normal kyphosis/lordosis. The diagnosis of “scoliosis” is best defined as a complex “three-dimensional torsional deformity of the spine and trunk.”
Scoliosis can be classified as “congenital” (i.e. vertebral malformation present at birth), “secondary” to another disorder (i.e. spinal muscular atrophy) or “idiopathic”. The latter accounts for 85% of all cases of scoliosis. As its name implies, the cause of idiopathic scoliosis is not well understood but is likely multifactorial. A genetic component is suspected since scoliosis tends to run in families. Like other genetic disorders, scoliosis is more common in children born to older mothers. Some researchers have connected the etiology of scoliosis to a systemic mucopolysaccharide and protein synthesis disorder resulting in reduced serum melatonin.
The prevalence of scoliosis reported in the literature varies widely, depending upon the age of the population studied and the criteria used to define the disease. When using the widely accepted definition for scoliosis of a Cobb angle greater than 10 degrees, the prevalence ranges between 1 and 3%- making it the most common spinal deformity requiring orthopedic management.
Scoliosis may develop at any time between birth and adulthood but is most common during times of rapid skeletal growth. (6-24 months, 5-8 years, and 11-14 years) Scoliosis may be subclassified based upon the age of onset:
0-5 years of age Congenital scoliosis
6-12 years of age Early onset scoliosis
13-18 years of age Adolescent idiopathic scoliosis
The classification of “congenital scoliosis” (0-5 y/o) includes “infantile idiopathic scoliosis,” which develops within the first two years of life. This condition differs markedly from other types of scoliosis in that it is more common in boys and typically produces a left thoracic curvature. It is thought to have a prevalence of 0.5% in North America. It is more common in those of European descent. Interestingly, ¾ of all infantile idiopathic scoliosis cases resolve spontaneously, while the remainder progress.
“Early onset scoliosis” mimics the adolescent version of the disease, in that it is more common in females and typically demonstrates a right thoracic curve. It is considered by some to be a malignant sub-type of adolescent idiopathic scoliosis due to its high degree of progression (95%) with the majority of patients (64%) requiring spinal fusion. Patients with early onset scoliosis frequently demonstrate neural axis abnormalities, including Chiari type malformations.
“Adolescent idiopathic scoliosis” (AIS) represents the most common type of scoliosis overall. The onset of adolescent scoliosis is insidious, and its progression varies somewhere between unnoticed and lethal. Approximately ¼ of all adolescent idiopathic scoliosis curves will progress. The chance of progression increases in relation to the magnitude of the curve and decreases in proportion to skeletal maturity. Less severe curves tend to remain stable, while large curves are more likely to progress. Small curves in skeletally mature patients have a low risk of progression (2%), while large curves in immature patients progress much more frequently. (70%) The degree of skeletal maturity is defined by the Risser sign (0-5), closure of the tri-radiate cartilage, the onset of menarche, and reaching one’s peak height.
Patients with double or multiple curves are more likely to progress than those with a single curve. Curve progression is more common in females. The gender discrepancy widens in proportion to the magnitude of the curve. In patients with Cobb angles between 10 and 20 degrees, females are affected only slightly more frequently (1.3:1), increasing to 5.4:1 for Cobb angles between and 20 and 30 degrees and 7:1 when the curve is above 30 degrees. Lonstein has proposed and published the following formula for the prediction of progression in idiopathic scoliosis: Progression factor = (Cobb angle – (3 x Risser sign)/Patient age).
The typical presentation for idiopathic scoliosis is an otherwise healthy adolescent whose parents have become aware of trunk asymmetry while observing their child at the pool or through a scoliosis screening. The quality of a patient’s life can be significantly impacted by their recognition and perception of aesthetic deformity. This stress comes at a time when children are most sensitive to these issues.
Approximately 23% of scoliosis patients have back pain at the time of presentation. The majority of patients with mild to moderate scoliosis are asymptomatic, and those presenting with pain require more aggressive work up. In scoliosis patients presenting with concurrent back pain, an underlying condition can be identified in almost 10% of cases – primarily spondylolysis and spondylolisthesis.
Although scoliosis is most commonly asymptomatic in children, the presence of the disease more than triples one’s risk for developing spine pain as an adult. High angle curves (above 30-50 degrees) increase one’s risk for pain and other health problems in adult life. Thoracic curves above 50 degrees may impair respiratory function, and curves reaching 90 degrees often lead to cardiorespiratory failure. (8)
The clinical history should include questions to inquire whether other family members have the disorder and an attempt to determine the patient’s level of maturity (i.e. menarchy, growth spurts, etc.)
Clinical assessment begins with observation and palpation. Clinicians should make note of site and side of curvature(s), unleveling of shoulders and hips, rib humps, and scapular protrusion. The most common curvature is a right thoracic, which is consistently associated with the right shoulder being rotated anteriorly with right scapular winging. The presence of a rib hump may incorrectly appear as a hyperkyphosis, however, in most cases, scoliosis is associated with a loss of the normal thoracic kyphosis. (49,50,77) Imbalances are more dramatic when there is no secondary curve to compensate. The use of a scoliometer may help measure curvature. Specific sites of muscle hypertonicity often include the hamstring, psoas, and paraspinal muscles.
Plain film radiographs are the criterion standard for assessing scoliosis. The mere presence of a lateral deviation of the spine does not constitute “scoliosis”. The diagnostic criteria for scoliosis is a Cobb angle greater than 10 degrees and axial rotation of vertebral bodies. The Cobb angle is measured by drawing a line perpendicular to the upper end plate of the uppermost vertebra and the lower endplate of the lowest vertebra then measuring the angle between the two lines.
The radiographic monitoring of adolescent idiopathic scoliosis should be performed yearly during Risser stages 0-3 and every 18 months for Risser stages 4-5. Early onset scoliosis and juvenile scoliosis should be monitored at six-month intervals. Repeat radiographs have been shown to increase scoliosis patients’ risk of developing various cancers including leukaemia, GI, lung, and breast. The increased risk of breast cancer may be reduced from 110% to less than 4% if PA films are taken as opposed to AP films. MRI may be appropriate in cases of “early onset scoliosis” to screen for neural axis abnormalities. (i.e. Arnold Chiari malformation)
The primary treatment goal for scoliosis is to stop curve progression. Additional objectives are to improve postural aesthetics and manage any associated spinal pain or respiratory dysfunction. Curve correction is possible through conservative care, however, conservative management of scoliosis can prove challenging, with some cases slowed or even reversed through appropriate management while others progress relentlessly. Conservative management typically includes bracing, manipulation, and exercise.
The earliest recorded treatment of scoliosis by Hippocrates focused on spinal manipulation and traction. Incorporation of chiropractic care, including spinal manipulation, has been shown to lead to a reduction in Cobb angles in scoliosis patients. Benign post-manipulation soreness is relatively common in scoliosis patients, however, a study of 533 manipulation treatments demonstrated only one moderate side effect and no serious adverse reactions requiring medical attention.
A systematic review of 20 studies has shown that exercise is an effective treatment for scoliosis. Proper exercise “can prevent a worsening of the curve and may decrease the need for bracing”. The most effective exercise programs employ “autocorrection” – reducing scoliotic deformity through the patient’s active and autonomous postural realignment in three dimensions. The “Scientific Exercises Approach to Scoliosis” (SEAS.06) is a proven and tested exercise regimen for the treatment of scoliosis. The application of the SEAS.06 exercise protocol is described and detailed in a paper by Romano, including exercise pictures and descriptions.
Patients at high risk for curve progression may benefit from bracing. Brace treatments are typically reserved for curves between 30 and 40 degrees in patients who are still growing with a chance for progression. Bracing has been shown to decrease the need for surgery by slowing curve progression but does not decrease existing curves. Braces are successful at preventing surgery in approximately three out of four patients. Bracing compliance is critical, but the number of hours a day the brace should be worn varies in the literature from 12-23. Recent studies suggest that wearing the brace for longer periods of time improves outcomes. Exercises are often used in contemporaneously with a brace to enhance the chance of maintaining correction when weaning from the brace.
A major consideration in the determination of surgical appropriateness is the assessment of skeletal maturity to determine the likelihood of progression. Less than 0.3% of all scoliosis cases require surgical correction. Consideration for surgical intervention is generally reserved for curves that exceed 40 degrees. The current standard method of surgical correction involves 3-column fixation with pedicle screws.