What Is Scheuermann's Disease?

Scheuermann's disease, also called Scheuermann's kyphosis or Scheuermann's juvenile kyphosis, is a congenital skeletal deformity characterized by an exaggerated curve (kyphosis) of the thoracic (middle) spine, Symptoms of Scheuermann's disease include pain and poor posture that arise during adolescence, at which point the condition can be diagnosed with an X-ray. Scheuermann's disease can be treated with stretching, lifestyle changes, non-steroidal anti-inflammatory drugs (NSAIDs) for pain and discomfort, and in some situations, a back brace. Rarely, heart and lung function may be impaired. Between .5% and up to 10% of the population is thought to have Scheuermann's kyphosis.

Types of Scheuermann's Disease

The upper and middle areas of the spine, called the thoracic spine, consist of the 12 vertebrae below the seven that make up the cervical spine. The thoracic spine connects to the rib cage, which protects the heart, lungs, and other organs. The five vertebrae below the thoracic spine make up the lumbar spine. Each area has a normal curvature. The outward curve in the thoracic spine is called a kyphosis.

There are two types of Scheuermann's disease:

Type I: "Classic" Scheuermann's disease is the most common type, affecting the area between the seventh and ninth thoracic vertebrae. 

Type II: Type II, or "atypical" Scheuermann's disease, is less common, affecting the lower thoracic spine (also known as the thoracolumbular spine) and sometimes the lumbar spine. The pronounced area, or apex, of the curve is between the 10th and 12th vertebrae.

Symptoms

The disease is often discovered when parents notice a child slouching or exhibiting extremely poor posture; a teen might complain of fatigue and mid-back pain. Pain typically increases with time. In some cases, a person with Scheuermann's kyphosis also has scoliosis, another type of spinal deformity that is not uncommon in teenagers. In scoliosis, the spine curves from side to side.

Back pain is the most common symptom of Scheuermann's disease, especially early on, with the pain being more severe in type II. Pain may be located at the highest part of the kyphotic curve. People with Scheuermann's may also have tight hamstring muscles.

In severe cases of kyphosis, in which the curvature of the spin is so extreme as to decrease the space inside the chest cavity, it may limit the ability of the chest to expand fully. This can interfere with lung and cardiac functions. Eventually, the heart can be affected by poor lung function.

Causes

Many theories have been proposed for the cause of the disease, but the exact cause is unknown. There seems to be a high genetic predisposition, and development of the disease tends to correspond to the timing of the growth spurt in adolescence.

Normally, the vertebrae are rectangular, with flexible cartilage in between them. In Scheuermann's, the front part of the affected vertebrae grow more slowly than the back edge. This causes the wedge-shaped vertebra and the excessive rounding of the back that are the hallmarks of this condition.

Some research has indicated that the anterior longitudinal ligament, a ligament that runs along the front of the spine, may be unusually thick and tight in people with Scheuermann's disease, and that the ligament may affect the abnormal growth of the vertebra. Muscle abnormalities in the spinal region may also be involved in causing the abnormality.

Diagnosis

Most children are diagnosed with type I between 12 and 15, and type II between 15 and 18.

To make a diagnosis of Scheuermann's, a doctor will perform a physical exam in which a child is asked to stand up and bend forward at the waist. The doctor will observe the child's body from the side, which is the vantage point from which an abnormal kyphosis is more obvious.

Kyphosis due to Scheuermann's does not correct when the person stands upright. People with a postural type of kyphosis in the thoracic spine (often caused by imbalances between the muscle groups that control shoulder, chest, and upper back movements) generally have symmetrical growth of their vertebrae. In this case, the kyphotic curve does disappear when they stand up straight.

The next step is an X-ray of the spine. If the problem is simply due to postural problems, nothing else abnormal will show up on the X-ray. But if the kyphosis is due to Scheuermann's disease, the X-ray will show three or more adjacent vertebra that are wedged together by at least five degrees each.

Everyone's anatomy is unique, and there is no "normal" range for kyphosis of the thoracic spine. A diagnosis of Scheuermann's disease is made when there are three or more adjacent vertebrae with at least five degrees of anterior wedging. In type II, the kyphosis needs to be only 30 degrees for a diagnosis to be made.

In some cases, a doctor will recommend magnetic resonance imaging (MRI) to rule out an infection or a tumor that could be causing the pain; pulmonary function tests may be done if breathing seems to be affected.

Treatment

The majority of teens with Scheuermann's kyphosis will find relief with some combination of stretching exercises, lifestyle modifications, physical therapy, and NSAIDs.

In the case of Scheuermann's kyphosis that is either moderate or severe (55 to 80 degrees) while the bones are still growing, it may be necessary to wear a brace designed to hold the spine in a straighter, upright posture in order to "guide" the growth of the vertebrae and straighten the spine. This is thought to work by taking pressure off the front half of the vertebra, allowing the growth of the bone in front to catch up with the growth in the back of the vertebra.

Typically, a brace is worn between 16 and 24 hours a day for a year, then only at night for two years. Physical therapy might also be recommended to strengthen the back and improve posture, though it is not clear if that is beneficial.

Surgery is sometimes recommended when the kyphosis exceeds 75 degrees as measured on X-rays. Surgery typically consists of a fusion of the abnormal vertebrae and is usually done with the patient lying on their stomach. 

A Word From Verywell

If your child is diagnosed with Scheuermann's kyphosis, they may be physically uncomfortable or even self-conscious if the curvature is extreme enough to be noticeable to others. As a parent, you may be worried about your child's prognosis or treatment. Note, however, that Scheuerman's kyphosis is not life-threatening and usually can be successfully treated—even if that means wearing a brace for a few years. During this time, the condition should not interfere with your child's daily activities, nor should it be a problem that follows them into adulthood.