What Causes Scoliosis?

Conditions list medically reviewed by George Krucik, MD, MBA

Scoliosis is an abnormal curvature of the spine. The normal shape of a person’s spine includes a curve at the top of the shoulder and a curve at the lower back. If your spine is curved from side to side or in an “S” or “C” shape, you might have... Read More

Scoliosis is an abnormal curvature of the spine. The normal shape of a person’s spine includes a curve at the top of the shoulder and a curve at the lower back. If your spine is curved from side to side or in an “S” or “C” shape, you might have scoliosis.

According to the American Association of Neurological Surgeons (AANS), about 80 percent of scoliosis cases have no identifiable cause. The condition is often diagnosed during the first seven years of a child’s life. Common causes, when they can be pinpointed, are:

  • birth defects
  • neurological abnormalities
  • genetic conditions

What are the common types of scoliosis?

The largest category of scoliosis is idiopathic scoliosis, a term used to refer to cases that have no definite cause. Idiopathic scoliosis is broken down by age group:

  • infant: 0 to 3 years
  • juvenile: 4 to 10 years
  • adolescent: 11 to 18 years
  • adult: 18+ years

Of these, adolescent idiopathic scoliosis is the most common, according to the AANS.

Doctors identify a cause for an estimated 20 percent of scoliosis cases. These consist of different types of scoliosis, including:

  • congenital, in which spinal deformities are apparent at birth
  • neurological, when nerve abnormalities affect muscles in the spine

Scoliosis can also be categorized as either structural or nonstructural. In structural scoliosis, the spine’s curve is caused by a disease, injury, or birth defect, and is permanent. Nonstructural scoliosis describes temporary curves that can be fixed.

What are the symptoms of scoliosis?

Symptoms vary depending on the degree of scoliosis. Common symptoms associated with scoliosis include:

  • one shoulder blade that is higher than the other
  • one shoulder blade that sticks out more than the other
  • uneven hips
  • a rotating spine
  • problems breathing because of reduced area in the chest for lungs to expand
  • back pain

What causes scoliosis?

The cause of scoliosis often can’t be determined. Common causes that doctors may identify include:

  • cerebral palsy, a group of nervous system disorders that affect movement, learning, hearing, seeing, and thinking
  • muscular dystrophy, a group of genetic disorders that result in muscle weakness
  • birth defects that affect an infant’s spinal bones, such as spina bifida
  • spinal injuries or infections

People with a family history of scoliosis are more likely to develop the condition. Girls are more likely to have a more severe form of scoliosis than boys.

How is scoliosis diagnosed?

A physical exam of your spine is the first step your doctor takes to see if you have scoliosis. Your doctor may also order some imaging tests to get a closer look at your spine.

Physical exam

Your doctor will observe your back while you stand with your arms at your sides. They’ll check for spine curvature and whether your shoulders and waist area are symmetrical. Next, your doctor will ask you to bend forward, looking for any curvature in your upper and lower back.

Imaging

Imaging tests your doctor may order to look for scoliosis include:

  • X-ray: uses small amounts of radiation to create a picture of your spine
  • MRI scan: uses radio and magnetic waves to get a detailed picture of bones and the tissue surrounding them
  • CT scan: takes X-rays at a variety of angles to get a 3-D picture of the body
  • bone scan: detects a radioactive solution injected into your blood that concentrates in areas of increased circulation, highlighting spinal abnormalities

What are the treatment options for scoliosis?

Treatment depends on numerous factors, the degree of spine curvature being a major one. Your doctor will also take into consideration:

  • your age
  • whether you are likely to continue growing
  • the amount and type of curvature
  • the type of the scoliosis

The primary treatment options are bracing and surgery.

Bracing

According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases, a person with scoliosis may need to use a brace if:

  • They’re still growing and the curvature is more than 25 to 30 degrees.
  • They’re still growing and the curvature is between 20 and 29 degrees, but the curvature is getting worse.
  • The curvature is between 20 and 29 degrees and the person has at least two more years to grow (also applies to girls who haven’t begun menstruation).

Braces won’t straighten the spine, but they can prevent the curvature from increasing. This method of treatment is more effective for cases that are detected early.

Those requiring a brace need to wear it 24 hours a day for maximum effectiveness. As an exception, children may remove their braces to participate in exercise and sports activities.

Doctors usually recommend that children wear their braces until they reach adolescence and are no longer growing.

There are two main types of braces:

  • Underarm: Made of plastic and fitting close to the body, this brace is virtually invisible. It’s used to treat lower spine curves and fits around the lower part of the body.
  • Milwaukee: This brace starts at the neck and covers the entire torso, with the exception of the legs and arms. It’s used for curves that the underarm brace can’t address.

Surgery

Surgery is usually reserved for people with curves greater than 45 or 50 degrees. However, talk to your doctor about this option if you’ve been diagnosed with scoliosis and feel the curvature is interrupting your daily life or causing you discomfort.

Spinal fusion is the standard scoliosis surgery. In this procedure, the doctor fuses your vertebrae together using a bone graft, rods, and screws. The bone graft consists of bone or a material like it. The rods keep your spine in a straight position, and the screws hold them in place. Eventually, the bone graft and vertebrae fuse into a single bone. Rods can be adjusted in children as they grow.

Some of the risks of spinal fusion surgery include:

  • excessive bleeding
  • failure to heal
  • infection
  • pain
  • nerve damage

What is the long-term outlook for scoliosis?

The long-term outlook for scoliosis depends on how severe the curvature is. For mild to moderate cases, the condition won’t interfere with everyday activities and functions. Individuals with severe forms of scoliosis may have physical limitations.

Living with scoliosis can be difficult. If you’re looking for help managing your scoliosis, you may want to seek out a support group. Support groups allow you to meet others who are experiencing the same things, and you can find encouragement and advice about dealing with the condition on a daily basis.

The National Scoliosis Foundation is a good starting point for finding resources.

Medically reviewed by University of Illinois-Chicago, College of Medicine on November 14, 2016Written by Shannon Johnson


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This feature is for informational purposes only and should not be used to diagnose. Please consult a healthcare professional if you have health concerns.

Conditions list medically reviewed by George Krucik, MD, MBA