Scoliosis is the abnormal curvature of the spine. Normally, the spine runs in a straight line from the neck down the back. With scoliosis, however, the spine curves to the side. This can cause the spine to be shaped like a “C” or an “S.” Scoliosis can affect the upper (thoracic) and/or lower (lumbar) portions of the spine.

While scoliosis can affect people at any age, it most commonly begins in children between ages 10 and 15. According to the National Scoliosis Foundation, scoliosis is estimated to affect 7 million people in the United States—around 2% to 3% of the population.

Often, the amount of spinal curvature is mild and doesn’t cause symptoms or require any special treatment beyond regular monitoring. Less commonly, however, the curve can be severe, causing back pain and making breathing difficult. Fortunately, treatments can improve the condition, including braces, physical therapy, and surgery.

Scoliosis is an abnormal sideways curvature of the spine that also twists abnormally. The side-to-side curvature can cause changes in posture, such as uneven shoulders and/or hips, while the twisting of the spine can cause the rib cage on one side of the body to protrude more than usual.

Often, the curve of the spine in people with scoliosis is stable, meaning it does not change over time. Sometimes, however, it worsens over time, often requiring treatment. For example, the curve of the spine may become more severe in adolescents undergoing periods of rapid growth during puberty. Also, in general, spines with a greater degree of curvature are at a higher risk of progressing.

Scoliosis most commonly starts in childhood or adolescence but can also occur in infants and adults. In adults, the condition may have first developed during childhood or adolescence and then continued to progress into adulthood. In other cases, scoliosis can develop in adulthood due to degenerative changes to the spine, osteoporosis, neuromuscular disorders, injury, or other medical conditions.

There are several types of scoliosis, including:

• Idiopathic scoliosis. An “idiopathic” medical condition is one for which there is no known cause. Idiopathic scoliosis is the most common type, accounting for roughly 80%-90% of cases. It equally affects boys and girls, but when it occurs in girls, it is 10 times more likely to progress. Idiopathic scoliosis is further categorized based on the age at which the condition first occurred.
  • Infantile idiopathic scoliosis occurs in children between ages 0 and 3 years.
  • Juvenile idiopathic scoliosis occurs in children between ages 4 and 9 years.
  • Adolescent idiopathic scoliosis occurs in children and adolescents between ages 10 and 18.
• Congenital scoliosis. In this type of scoliosis, spinal curvature occurs due to spine abnormalities that are present at birth.
• Neuromuscular scoliosis (NMS). This type of scoliosis occurs in people with disorders that affect the muscles and/or nerves, including cerebral palsy, Duchenne muscular dystrophy, or a spinal cord injury. It can begin in people of any age.
• Degenerative scoliosis. This type of scoliosis is due to degenerative changes to the spine; it usually affects adults over 50.

When scoliosis occurs in children under 10, it is sometimes called early-onset scoliosis (EOS).

Most people with mild scoliosis have no symptoms, though some experience back pain.

Signs of scoliosis may include:

• A curved spine
• One shoulder and/or hip that is higher than the other
• One shoulder blade that is more prominent than the other
• A ribcage on one side that protrudes more than the other side (it may be more noticeable when bending over)
• A person’s head that is not centered over their pelvis
• Extra space between the body and a loosely hanging arm on one side of the body

People with severe scoliosis, with greater degrees of spinal curvature, may have difficulty breathing and back pain. The breathing problems occur, in part, because the chest cannot fully expand during inhalation and exhalation. People with scoliosis as well as spinal cord or nerve root compression caused by kyphosis (a forward curve of the upper spine that causes a hunched back) and/or a spinal cord abnormality in addition to scoliosis may have additional symptoms, including:

• Incontinence (loss of bladder/bowel control)
• Weakness or numbness in the legs
• Erectile dysfunction

Doctors diagnose scoliosis by reviewing a patient’s medical history, performing a physical exam, and running one or more diagnostic tests. Scoliosis may first be detected during routine screenings at middle schools or at checkups with primary care doctors.

The doctor will ask about symptoms and the patient’s spinal curve, including when it was first noticed and whether it has worsened over time. They may also ask whether there is a family history of scoliosis.

During a physical exam, the doctor will examine the patient’s back and spine to check for a curvature of the backbone, differences in the level of the shoulders and hips, whether the head is centered over the pelvis, and other signs of scoliosis. The doctor will ask the patient to bend forward to check whether the ribs on one side of the body or other parts of the back stick out more than usual. During this test, known as the Adams forward bend test, the doctor may use a sociometer—a device similar to a level—to measure the degree of spinal rotation.

X-rays of the spine are needed to confirm a diagnosis. They also help doctors determine the type of scoliosis and the risk of its progression. The doctor will use the X-rays to determine the Cobb angle, a measure of the degree of sideways spinal curvature. (Scoliosis is diagnosed when the Cobb angle is over 10 degrees.) In some cases, the doctor may also order additional imaging tests, such as a magnetic resonance imaging (MRI) scan or computed tomography (CT) scan of the spine.

Treatment for scoliosis varies based on several factors, including the patient’s age, type and severity of scoliosis, and risk for progression.

In general, the goals of treatment are to prevent progression of the spinal curve, relieve any symptoms, and reduce the degree of spinal curvature.

Treatments for scoliosis include:

• Observation. Doctors may recommend monitoring the spine for people with mild scoliosis. Observation may involve seeing a health care provider regularly for a physical exam and X-rays of the spine. If the curve worsens, other treatments may be necessary.
• Braces. A brace may prevent or slow the progression of the spinal curve in growing children and adolescents with moderate scoliosis. There are several types of braces, including a rigid, plastic one known as the Boston brace (it was developed at Boston Children’s Hospital) and a nonrigid, flexible one. Some braces, including the Boston brace, can be worn under clothing and during many sporting activities.
• Casts. Infants and toddlers with scoliosis may wear a plaster cast as part of their treatment. Casts can help correct spinal curves. Every two to four months, a new cast is fitted to accommodate the child’s growth.
• Physical therapy. Scoliosis-specific physical exercises to improve range of motion and strength may help prevent the progression of the condition.
• Steroid injections. Epidural spinal injections of steroids and/or local anesthetics may be used to temporarily relieve pain caused by scoliosis in adults.
• Halo-gravity traction (HGT). HGT may treat children and adults with severe spinal curvature caused by scoliosis (and other conditions). In HGT, pins attach a “halo”—a ring made of metal, carbon, or other materials—to the patient’s skull. The halo is then attached to a weighted pulley system that pulls upward on the patient’s head, straightening the spine. Usually, the halo remains in place for two to 12 weeks.
• Surgery. Doctors may recommend surgery for children or adolescents with significant and/or progressing spinal curves. Surgery may also be used to treat adults with scoliosis. Surgical procedures include:
  • Spinal fusion, a procedure in which two or more vertebrae—the small bones that make up the spine—in the curved portion of the spine are fused together to become a single, larger bone. The surgeon inserts bone grafts—pieces of bone taken from elsewhere in the patient’s body, from a donor, or made of artificial materials—into spaces around the vertebrae. Metal rods are usually attached to the spine using screws, hooks, or wires to hold it in place while the bones fuse together. In most cases, the metal rods remain attached to the spine after the bones have fused. The goal of this procedure is to straighten the parts of the spine that are curved.
    
    Spinal fusion stops growth in the fused section of the spine.
  • Growing rods may be used to correct spinal curves in growing children with scoliosis. In this procedure, the surgeon attaches “growing rods”—special metal rods that can be extended—above and below the curved section of the spine using screws or hooks. Every six months, the growing rods are lengthened during a surgical procedure. This allows continued growth of the spine and development of the lungs.
    
    Magnetic growing rods may also be used in this procedure. These rods do not require a surgical procedure to be lengthened. Instead, they can be lengthened in the doctor’s office—without sedation or anesthesia—using a remote controller.
    
    Usually, when the child’s growth is complete, a surgeon removes the growing rods and performs spinal fusion surgery.
  • Vertebral body tethering (VBT), a minimally invasive technique that helps correct spinal curvature while allowing for continued physical growth of the spine. In VBT, the surgeon attaches a tether device to the spine using screws. During the procedure, the surgeon applies tension to the tether to reduce the spinal curve. As the child’s spine grows, the tether pulls on the spine, helping to straighten it. The tether is not removed unless problems occur such as damage to the tether or overcorrection of the spinal curve.
  • Spinal decompression, a surgical procedure that relieves pressure on nerves in the spine, may be used to treat adults with scoliosis.

The outlook can vary greatly and depends on a number of factors, including the age when the condition began, the age at diagnosis, the severity of the spinal curve, whether the spinal curvature is stable or progressing, and the underlying cause of the condition.

People with mild scoliosis typically do not experience any symptoms and do not need treatment. In some cases, however, treatment is necessary to reduce the spinal curve and prevent progression of the condition. With appropriate treatment, most people with scoliosis can lead physically active, normal lives.

This article was medically reviewed by Dominick Tuason, MD, a Yale Medicine pediatric orthopedic surgeon with a subspecialty in early onset, adolescent, neuromuscular, and complex spinal deformity.