It is natural for the spine to curve forward and backward to a certain degree; this is what gives the side-view of the spine its “S”-like shape. But occasionally the spine twists and develops curves in the wrong direction–sideways. When the spine twists and develops an “S”-shaped curve that goes from side to side, the condition is known as scoliosis.

Spine Detail: A side view of a spine with normal curves.

A scoliosis curve can occur in the thoracic spine, the lumbar spine, or both areas at the same time. When the vertebrae in the mid and low back curve to the side, the normal appearance and condition of the spine and its muscles changes. The severity of the scoliosis is measured in degrees by comparing the curves to “normal” angles. Curves can range in size from as little as 10 degrees to severe cases of more than 100 degrees. The amount of curve in the spine helps your doctor decide what treatment to suggest. Conservative (nonsurgical) treatment is usually suggested for curves of less than 40 degrees, while curves over this amount may require surgery.

Causes and Symptoms

Scoliosis is divided into categories based on the age when it was diagnosed:

  • Infantile scoliosis is diagnosed before age three
  • Juvenile scoliosis is diagnosed from age three to puberty
  • Adolescent scoliosis is diagnosed during puberty, usually between the ages of 10 and 15
  • Adult scoliosis is diagnosed in adulthood after the spine has stopped growing

Scoliosis is most commonly seen in adolescents and adults. Adults can also develop scoliosis as a result of degeneration.

The different types of scoliosis, including the causes and symptoms of each type, are discussed below.

Adolescent Idiopathic Scoliosis

Most cases of scoliosis are first discovered and treated in childhood or adolescence–particularly during puberty when the curvature becomes more noticeable. When an adolescent has scoliosis with no known cause, doctors call the condition adolescent idiopathic scoliosis. The word “idiopathic” means that the cause of this form of scoliosis is unknown. This form of scoliosis can affect a child who is healthy and not having nerve, muscle, or other spine problems. It is the most common form of spinal deformity doctors see, affecting about three percent of the general population.

Spine Detail: A spine with abnormal curves (scoliosis)


Adolescent idiopathic scoliosis affects children between 10 and 18 years old, and it affects girls more often than boys. In fact, girls are treated 10 times more often than boys.

There are many theories as to why this type of scoliosis develops, but the root of the condition has yet to be discovered. Some of the theories include:

  • Genetics— Scoliosis appears to run in certain families, so it may be hereditary. Significant research is ongoing in the field of genetics.
  • Growth— Curves progress rapidly during growth spurts, perhaps showing a tie to hormonal causes.
  • Structural and Biomechanical Changes— Some studies have shown increased muscular activity around the spinal curves. Differences in leg lengths have also been noted in adolescents with idiopathic scoliosis. But there is no clear evidence that this type of change causes scoliosis; it may simply be a secondary result.
  • Central Nervous System Changes— Some forms of scoliosis are associated with central nervous system disorders, so a lot of research has been focused on this topic. To date, such disorders have not been proven as the root of idiopathic scoliosis.
  • Equilibrium and Postural Mechanisms— Idiopathic scoliosis could be related to factors that affect body alignment. If a child has problems with posture, balance, and body symmetry, it could affect the way his or her spine is positioned. If the problems are chronic, it may disrupt the way the child’s spine and muscles develop.


In many cases of adolescent scoliosis, the child will not even notice the problem. Because the majority of scoliosis patients do not suffer any physical pain from this disorder, it is often not discovered until the curves have progressed to become more obvious. In fact, if the child is suffering from severe back pain, a diagnosis other than idiopathic scoliosis must be considered.

Though the spine may curve sideways, in minor cases the curves are not obvious until the person bends over. Many schools currently screen young students for scoliosis, so referrals often come from school health workers. Parents or physical education instructors are also frequently the first to notice signs of scoliosis in a child.

Signs of scoliosis may include the following abnormalities in appearance:

  • One shoulder or hip may be higher than the other.
  • One shoulder blade may be higher and stick out farther than the other.
  • These deformities are more noticeable when bending over.
  • A “rib hump” may occur, which is a hump on the back that sticks up when bending the spine forward. This occurs because the spine and ribs also rotate as the curve develops.
  • One arm hangs longer than the other because of a tilt in the upper body.
  • The waist may appear asymmetric.

Once scoliosis is diagnosed, concern may arise whether the curves will continue to grow bigger. There is no absolute way to tell, but this much is known:

  • Curves in the thoracic spine are more likely to progress than lumbar curves.
  • The likelihood of progression is linked to the size of the curve. Larger curves are more likely to get bigger.
  • If the curves start at a young age or before a girl begins her period, they are more likely to progress.
  • The higher the child’s Risser sign is at diagnosis, the less chance there is of progression. The Risser sign also measures skeletal maturity. (It is based on a 0 to 5 scale, with 5 being full skeletal maturity.) This measure is based on the iliac apophysis, which is a layer of cartilage on the flared part of the hip bone that turns to bone with age and maturity.

Adult Scoliosis

Scoliosis that occurs (or is discovered) after puberty is called “adult scoliosis.” Adult scoliosis can be the result of untreated or unrecognized childhood scoliosis, or it can arise during adulthood. The causes of adult scoliosis are usually different from the childhood types.


Most cases of adult scoliosis are idiopathic, which means that (the cause is not known. Sometimes adult scoliosis is the result of changes in your spine due to aging and degeneration. The causes of adult scoliosis are further categorized into several subtypes:

  • Idiopathic Curve— Usually there is no clear-cut reason why your spine is curved.
  • Congenital Curve— Congenital means that you were born with the problem. Many different problems in growth and development can lead to spine problems. Congenital scoliosis may not be recognized or may not be severe enough to require treatment during childhood. Although it is rare, this type of scoliosis can get worse later in life due to wear and tear around the abnormal area of your spine.
  • Paralytic Curve— This type of scoliosis is often caused by paralysis from injury to your spinal cord. Paralytic means “the muscles do not work”. When the muscles around your spine are not working your spine may be thrown out of balance, which can cause an abnormal curvature in your spine.
  • Myopathic Deformity— Myopathic means “the muscles do not work properly”. Like paralytic curves, this curve results from a muscular or neuromuscular disease, such as muscular dystrophy, cerebral palsy, or polio.
  • Secondary Scoliosis— Scoliosis that develops in adulthood can be “secondary” to other spinal conditions that affect the vertebrae. Other conditions such as degeneration, osteoporosis (loss of bone mass), or osteomalacia (softening of the bones) can cause scoliosis. Scoliosis can also appear following spinal surgery for other conditions. The surgery may cause an imbalance in your spine that leads to scoliosis.


Adult scoliosis is often painless. Patients with adult scoliosis commonly see a spine specialist because they notice a problem with the way their back looks. You may notice some of the following things about your body:

  • One shoulder or hip may be higher than the other.
  • One shoulder blade may be higher and stick out farther than the other.
  • These deformities are more noticeable when bending over.
  • A “rib hump” may occur, which is a hump on your back that sticks up when you bend your spine forward. This occurs because the ribs on one side angle more than on the other side.
  • One arm hangs longer than the other because of a tilt in your upper body.

Back pain can eventually develop as the condition progresses. The deformity may cause pressure on your nerves and possibly even on your spinal cord. This can lead to weakness, numbness, and pain in your lower extremities. In severe cases, pressure on your spinal cord may cause loss of coordination in the muscles of your legs, making it difficult for you to walk normally. If your chest is deformed due to the scoliosis, your lungs and heart may be affected, leading to breathing problems, fatigue, and even heart failure. Fortunately these severe symptoms are rare.

Degenerative Scoliosis

Degenerative adult scoliosis occurs when the combination of age and deterioration of your spine leads to the development of a scoliosis curve in your spine. Degenerative scoliosis usually starts after the age of 40. In older patients, particularly women, degenerative scoliosis is also often related to osteoporosis. Osteoporosis weakens your bones, making them more likely to deteriorate. The combination of these changes causes your spine to lose its ability to maintain a normal shape. Your spine begins to “sag” and as the condition progresses, a scoliotic curve can slowly develop.


Scoliosis developed in adulthood can be “secondary” to other spinal conditions that affect your vertebrae. Other conditions such as degeneration, osteoporosis (loss of bone mass), or osteomalacia (softening of the bones) can cause scoliosis. Scoliosis can also appear following spinal surgery for other conditions. The surgery may cause an imbalance in your spine that leads to scoliosis. Most of these secondary causes of scoliosis are considered degenerative adult scoliosis.


Degenerative adult scoliosis usually begins as low back pain. While there may also be a deformity that causes your back to look abnormal, usually pain is what motivates patients to seek treatment. The pain is probably not coming from the curve, but rather from the degeneration occurring in your spine.

A combination of the degeneration of your spine and scoliosis deformity may cause pressure on nerves and possibly even your spinal cord. This can lead to weakness, numbness, tingling and pain in your lower extremities. In severe cases, pressure on your spinal cord may cause loss of coordination in the muscles of your legs, making it difficult to walk normally.

The degeneration and the scoliosis may have caused a condition called spinal stenosis, a narrowing of your spinal canal. Spinal stenosis results from spinal degeneration that has led to the growth of bone spurs. Eventually the spurs take up space in your spinal canal, causing it to become smaller. This leads to bone pressing on your spinal cord and its nerve roots. The lack of space lessens the nerves’ supply of blood and oxygen, which can lead to numbness and pain in both legs.


If scoliosis is suspected, a diagnosis must be made before an appropriate treatment plan can be developed. Your doctor will begin by performing acomplete historyand aphysical exam. Usually afterward, your doctor will order additional diagnostic tests including an X-ray so your doctor can see the structure of your spine and measure the curve.

Depending on the outcome of your history, physical examination, and initial X-rays, other tests may be ordered to look at specific aspects of your spine. The most common tests that are ordered are an MRI to look at your nerves and spinal cord, a CT scan to get a better picture of your vertebral bones, and special nerve tests to determine whether any nerves are being irritated or pinched.

Treatment Options

Conservative Treatment

Whenever possible, nonsurgical treatments are chosen first for scoliosis. Spinal surgery will generally be a last resort due to the risks involved. Conservative treatments commonly include medication, bracing, and physical therapy and exercise.

In cases of adult and degenerative scoliosis, if osteoporosis is present, treatment of the osteoporosis may also slow the progression of your scoliosis. This can be accomplished in several ways. The current recommendations include increasing calcium and vitamin D intake, hormone replacement therapy, and weight-bearing exercises.

In cases of adolescent idiopathic scoliosis, the treatment chosen will vary depending upon the severity of the curve, the age of the patient, and how far along the child is in skeletal maturity. If the child’s curve is minor (less than 15–20 degrees), the doctor will likely choose to monitor the curve for progression. The patient will normally have X-rays taken every four to six months during rapid growth years, and then once a year.

A well-rounded rehabilitation program assists in calming pain and inflammation, improving mobility and strength, and helping with daily activities. Adolescents with idiopathic scoliosis should be encouraged to continue their normal activities, including sports.

Exercise has not proven helpful for changing the curves of scoliosis. However, it can be helpful in maintaining flexibility, especially in the hamstrings and low back. Therapy sessions may be scheduled each week for four to six weeks.

The goals of physical therapy are to help:

  • Improve back posture
  • Foster aerobic fitness
  • Maximize range of motion and strength
  • Clarify ways to manage the symptoms of scoliosis

Bracing is usually considered with curves between 25 and 40 degrees, particularly if the patient is still growing and the curve is likely to get bigger. It is important that the patient wear the brace daily for the number of hours prescribed by the doctor. Scoliosis often affects more than one area of the spine. A brace can be used to support all the curved areas that need to be protected from progression.

Sometimes an adolescent might feel self-conscious about wearing a brace. Though the brace can help the curve from getting worse, it may take some time for the patient (and caregiver) to get used to it. Adults tend to be less concerned about what their peers think, but adolescence is a time when appearance is often of great importance. Listen to the child’s concerns and look for ways to help overcome feelings about appearance.

Surgical Treatment

Surgery is generally only considered in patients who have continual pain, difficulty breathing, significant disfigurement, or a steadily worsening curve angle. After skeletal maturity occurs, curves that are less than 30 degrees tend not to progress and, therefore, do not require surgery. Curves above 100 degrees are rare, but they can be life threatening if the spine twists the body to the point it puts pressure on the heart and lungs.

If a curve is 45 degrees or more, surgery is more likely to be considered. Each case of scoliosis is somewhat different and may require a very specialized approach for optimal results. Surgery is suggested to solve the problems brought on by the scoliosis–not just to straighten your spine. The goals of most surgical procedures for scoliosis include:

  • Reducing the deformity (straighten your spine as much as possible)
  • Stopping the progression of the deformity
  • Removing any pressure from your nerves and spinal cord
  • Protecting your nerves and spinal cord from further damage

When scoliosis requires surgery, your doctor can choose from a number of different procedures including laminectomy and spinal fusion. Laminectomy is a surgical procedure used to free up or “decompress” your spinal nerves. It is sometimes called lumbar decompression, or a decompressive laminectomy of the lumbar spine. The doctor removes a small section of the bone on the back of your spine (lamina). This takes pressure off your nerve roots. Bone spurs or fragments from a degenerated disc that are pressing on the nerve are also removed. Laminectomy is commonly combined with a spinal fusion to straighten your spine and stop the progression of the curve.

The main surgery for scoliosis is spinal fusion with instrumentation. Nearly all surgeries will use some type of rods in order to help straighten your spine.

When performing spinal fusion with instrumentation, your doctor may use a posterior approach, which involves going into your spine through your back, or an anterior approach, which is performed from your front or side. The operation can also be performed from both the front and the back (a combined approach). The choice depends upon the flexibility of your spine, the location and degree of the curve, and whether there is pressure on any of your nerve roots. The age of the patient is also a factor in deciding which type of surgery is used. Patients whose spines are immature are more likely to require combined anterior and posterior fusion.

Anterior Instrumentation

An incision is made in your chest or side, and your intervertebral discs are removed in the area of the curve to make it flexible. Screws can be placed in your vertebrae, and then connected by a metal rod. A bone graft is put in place of the discs that were removed so that the vertebra sitting next to each other will fuse together. The screws attaching the metal rod are tightened down, straightening the curve.

Posterior Instrumentation

This approach is done through your back. Anchors are attached to your spine in the form of hooks, screws, or wires. These anchors are attached to spinal rods that straighten your spine. Bone grafting is done to fuse all instrumented vertebrae.

Combined Anterior/Posterior Approach

This surgery is actually two operations: one through the front, and the other through the back. The two operations may be staged on separate days or as part of one longer surgery. Staged procedures require one to two additional days in the hospital compared to a single surgical procedure.

Other Considerations

Sometimes, a patient may choose not to have surgery because of the risks, even though it is recommended to them. However, there are also risks of leaving large curves untreated. Those risks include:

  • Increased Back Pain— Patients with large, untreated curves can suffer from daily back pain.
  • Reduced Respiratory Function— Large curves lead to deformities that can decrease the space in the body for vital organs such as the lungs and heart. The reduction in space can compromise a person’s ability to breathe and for the heart to function properly. In curves of 100 degrees or more, the affects can be life threatening.

Flat-back Deformity

One possible complication specific to the surgical treatment of scoliosis is flat-back deformity. Your lumbar (lower) spine naturally has a slight inward curve called lordosis. When the vertebrae in your lumbar spine are fused together, this lordosis curve may be lost, leaving you with a “flat-back” deformity. The loss of curve may not appear right after surgery. If the surgery it is done in a young person, the loss of lordosis may not even appear until sometime between the ages of 30 and 50.

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