Kyphosis refers to the natural curve of the thoracic spine, which normally has a forward curve of 20 to 40 degrees. In fact the thoracic spine’s curve is called kyphotic because of its shape, which is a regular “C” curve with the opening of the C in the front. The thoracic spine is made up of the middle 12 vertebrae of your spine.
These vertebrae connect to your ribs and form part of the back wall of your thorax (the ribcage area between the neck and the diaphragm).
Though the thoracic spine is supposed to be curved, if the curve in a person’s thoracic spine is more than 40 to 45 degrees, it is considered abnormal or a spinal deformity.
Sometimes this deformity is described as “round back posture” or “hunchback”. There are many causes of excessive kyphosis, including problems with posture, such as slouching.
Problems that are more serious include: healed vertebrae fractures, rheumatoid arthritis, osteoporosis, or Scheuermann’s kyphosis.
Scheuermann’s kyphosis is a “developmental” type of kyphosis, meaning that it occurs during growth. Wedging of the vertebrae causes this condition.
The vertebrae are normally rectangular-shaped and stacked on top of one another like building blocks with a soft cushion in between each one.
If they wedge closer together in a triangular shape, as with Scheuermann’s kyphosis, it causes the spine to curve more than normal.
This disease develops in adolescents while the bones are still growing. Males are twice as likely to develop this type of kyphosis than females.
The normal spine has an “S”-like curve if you look at it from the side. This shape allows for an even distribution of weight. The “S” curve helps a healthy spine withstand all kinds of stress.
The cervical spine curves slightly inward, the thoracic curves outward, and the lumbar curves inward.
Even though the lower portion of your spine holds most of the body’s weight, each segment relies upon the strength of the others to function properly.
As described above, the normal thoracic spine can has a curvature, or kyphosis, of between 20 to 40 degrees. A greater (or lesser) degree of curve is considered a spinal deformity.
When the thoracic portion of the spine curves 45 degrees or more, it is considered a problematic type of thoracic kyphosis. With Scheuermann’s kyphosis, the thoracic curve is usually 45 and 75 degrees.
There will also be vertebral wedging of greater than five degrees of three or more vertebrae that are next to each other.
The vertebrae in these cases have a triangular appearance, so they wedge together and cut down the normal space between vertebrae.
With Scheuermann’s disease, there are sometimes additional abnormalities of the affected vertebrae. These abnormalities are called “Schmorl’s nodes”.
These nodes are areas where the disc (cushion) between each vertebra pushes through the bone at the bottom and the top of the vertebra. This area of the vertebra is called the vertebra’s endplate.
Many spine specialists have noticed that in patients with Scheuermann’s kyphosis, the ligament that runs along the front of the spine is thickened.
Ligaments are the structures that connect bones to bones together, including vertebrae. This ligament is called the anterior longitudinal ligament.
Some spine specialists believe that the tightness of this ligament may help cause the spinal deformity.
The thickened ligament may affect the growth of the vertebra during childhood leading to too much growth on the back of the vertebra and too little in the front.
The imbalance of growth between the front and the back results in a wedged vertebra.
The cause of Scheuermann’s kyphosis has not been discovered, but there are many possible theories about its development. Scheuermann, the Danish radiologist for whom the disease is named, was the first to notice the problem.
He proposed that the problem was a result of a process of “avascular necrosis” of the cartilage ring of the vertebral body.
This means the cartilage of the spinal bone’s ring died because it lacked the necessary blood supply. Scheuermann believed that this interrupted bone growth during development, leading to wedge-shaped vertebrae.
Most researchers think that some sort of damage to the growth area of the vertebrae starts the process. The abnormal growth that follows is what causes the excessive kyphosis.
For instance, there may be a vertebral disorder during the rapid growth spurts of adolescence, which then leads to abnormal bone growth.
Many spine specialists also suspect that problems with the mechanics of the spine (the way it is put together and functions) play a part in Scheuermann’s kyphosis. Muscle abnormalities have been considered as a possible cause.
There also seems to be a high genetic predisposition to this disease, which means that it runs in families.
Originally, Scheuermann noticed this spinal deformity in agriculture workers who were frequently hunched or bent over.
This of course led to the question of whether poor posture could lead to excessive kyphosis. While this is a logical question, the connection between posture and this deformity has never been confirmed. However, poor posture has been shown to play a role in the making the problem worse.
Therefore, correcting postural problems can help improve the abnormal kyphosis.
Symptoms of Scheuermann’s kyphosis generally develop in the early teens – around puberty, which occurs between the ages of 10 and 15.
When the problem actually begins is hard to determine because X-rays will not show the changes until the patient is around 10 or 11.
The disease is often discovered when parents notice the onset of poor posture, or slouching, in their child. Alternatively, the adolescent might experience fatigue and some pain in the mid-back.
The pain is rarely disabling or severe at this point, unless the deformity is severe.
The onset of excessive kyphosis is generally slow.
The progressive appearance of kyphosis (round back or hunchback) is what leads many patients to seek medical help. People are more likely to visit a physician as the curvature becomes increasingly noticeable.
With Scheuermann’s disease, there is generally a rigid deformity or curvature. It worsens with flexion (bending over), and partially corrects with extension (standing up straight).
Pain typically increases with time and length of the deformity.
In some cases, a patient with Scheuermann’s kyphosis also has scoliosis. Scoliosis is another type of spinal deformity that usually occurs in teenagers.
In scoliosis, the curve of the spine curves from side to side. On X-rays taken front-to-back, the spine with scoliosis looks more like an “S” or “C” than a straight line. It is estimated that about one third of people with Scheuermann’s kyphosis also have scoliosis.
For more information on scoliosis, you may wish to review the document, entitled:
Adolescent Idiopathic Scoliosis
About five percent of the population suffers from Scheuermann’s kyphosis. Those who have it generally are neurologically normal, which means they do not have any nerves in the spine that have been damaged by the deformity.
However, the disorder can cause decreased lung and cardiac functions.
The curve of the spine causes the chest to have less room inside the chest cavity. If the deformity is severe, the chest cannot expand fully when you breathe. Eventually, the heart can be affected by the poor lung function.
When you visit the doctor, you will initially be asked for a complete physical history of your condition. This may begin by filling out a written form asking a number of questions relating to your problem.
The more information you share with your health care provider, the easier your spinal problem will be to diagnose.
The history of the problem is important because it helps your doctor understand when the progression of kyphosis or pain began.
The doctor will questions about: anything that could have caused an injury, your activity level and lifestyle, physical factors that might be causing the kyphosis, and any family history of similar problems.
After reading through your written history, your physician will ask more questions that relate to the information you have given.
After taking your history, the physician will give you a physical examination. This helps the doctor to rule out possible causes of kyphosis besides Scheuermann’s kyphosis, and to try to determine what is causing your spinal deformity.
An X-ray of the complete spine will probably be taken. The excessive kyphosis will show up on the X-ray and can be measured in degrees.
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 at least five degrees each.
In addition, the X-ray will show if there are Schmorl’s nodes (the small herniations of disc in the endplates of the vertebrae).
Later in age, arthritic changes may appear on the X-rays of people with excessive kyphosis. The changes generally coincide with an increase in pain.
The normal curvature of the thoracic spine is between 20 and 50 degrees. A curvature of more than 50 degrees, where the spine has three contiguous vertebral bodies that have wedging of 5 degrees or more, constitutes Scheuermann’s disease.
Postural roundback in adolescents is most often caused by posture and not by structural changes to the spine.
Postural roundback can be easily distinguished from Scheuermann’s kyphosis by the fact that the deformity goes away when the patient lies down.
Typically, patients with true Scheuermann’s kyphosis need to sleep on two or three pillows at night to stay comfortable because there deformity remains when they lie down.
Most patients with Scheuermann’s also have a mild scoliosis (when the spine curves to the side). These mild scoliosis curves rarely require treatment. As with scoliosis, an X-ray is used to confirm a diagnosis of Scheuermann’s disease.
Treatment Options for Scheuermann’s Disease
Treatment of Scheuermann’s disease is indicated to relieve pain, to correct an unacceptable cosmetic deformity, and to prevent potential progression or worsening of the curve.
Treatment will vary depending on the size of the curve, the flexibility of the curve, the patient’s age and the patient’s preferences.
Conservative Treatments for Scheuermann’s Disease
Types of Scoliosis Braces
For patients with more than one year of growth left, the kyphosis can be partially reversed by wearing a brace (e.g. a Milwaukee brace).
The brace can improve the curve during the growing years by restoring height to the front of the vertebral body and sometimes can reduce pain if present.
Depending on the severity and progression of the curve, patients may be prescribed a brace for one to two years.
For patients who are already skeletally mature, bracing is not an effective treatment.
An exercise program, including specific strengthening and hamstring stretching exercises, may be recommended in conjunction with bracing.
While exercise won’t correct the deformity, it can be helpful in alleviating back pain and fatigue.
Surgery for Scheuermann’s Disease
Surgery is rarely needed for Scheuermann’s disease. It may be considered for patients with severe deformities (e.g. more than 70 degrees for thoracic kyphosis), if neurological deficits are present, and occasionally if pain is present with the deformity.
The goal of the surgery is mostly to reduce the deformity, although some feel it can lessen pain if present.
Surgery will typically include:
A front thoracotomy (approach through the chest) to release the tissues, remove the discs, and place bone graft in the spaces to fuse the thoracic spine;
During the same surgery, the spine is then approached from the back and instrumentation (such as rods, bars, wires, or screws, which hold the spine straight during the fusion process) is put in place.
After surgery, provided the fusion is successful, all of the affected segments will be fused into one continuous bone that will not progress into kyphosis.
Because Scheuermann’s disease usually occurs in the thoracic spine, which has almost no motion, a fusion in this area does not affect the normal motion of the spine and typically does not lead to pain later in life.
Most of the motion in the spine is in the lumbar spine, and it is usually not necessary to fuse this area.
This is important to avoid overstressing the other lumbar spinal segments and causing early breakdown at adjacent levels.
What is Kyphosis?
In general, in a skeletally mature patient, Scheuermann’s kyphosis is not progressive. This is different from adolescent scoliosis, which can continue to progress (if the deformity is more than 50 degrees) going into adulthood.
For adults with Scheuermann’s kyphosis, the treatment is usually observation, anti-inflammatory drugs or reconstructive surgery, depending on the severity of the symptoms.