What is Scheuermann’s kyphosis?
Scheuermann’s kyphosis is a “developmental” type of kyphosis, meaning that it happens during growth and causes the vertebral bodies to wedge forward. Normal vertebrae are rectangular-shaped and stacked on top of one another like building blocks, with a soft cushion between each one. If the front of the vertebrae wedges closer together in a triangular shape, the spine starts to curve forward more than normal. This disease develops in adolescents while their bones are still growing. It happens to about one percent of this age group, affecting an equal number of boys and girls.
What causes Scheuermann’s kyphosis?
The cause of Scheuermann’s kyphosis has not been discovered, but there are many possible theories about its development. Scheuermann, a Danish radiologist, proposed that the problem started because cartilage of the spinal bones ring died from a lack of blood supply. He suggested that this interrupted bone growth during development, leading to wedging of the affected vertebrae.
Most researchers think that some sort of damage to the growth area of the vertebrae starts the process. The abnormal growth produces wedging of the vertebrae, which eventually leads to problems of kyphosis. For instance, there may be a vertebral disorder during the rapid growth spurts of adolescence, which causes abnormal bone growth.
Spine mechanics + abnormalities
Many spine specialists also suspect that a problem with the mechanics of the spine (the way it is put together and functions) plays a part in Scheuermann’s kyphosis. Others suggest mild osteoporosis could contribute to the deformity. Muscle abnormalities have also been considered as a possible cause. And there does seem to be a high genetic predisposition to this disease.
Scheuermann originally 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 extra 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 making the problem worse. Therefore, correcting postural problems can sometimes help improve the abnormal kyphosis.
History and physical exam
When you visit the doctor, you will initially be asked for a history of your condition. After taking a history, the physician will give you a physical exam. This helps the doctor to rule out possible causes of kyphosis, including Scheuermann’s kyphosis, and to try to determine what is causing the spinal deformity.
An X-ray of the spine will probably be taken. The extra 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 vertebrae 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 through the endplates of the vertebrae). Arthritis may show up on X-rays in adults with extra thoracic kyphosis. These changes generally coincide with an increase in pain.
Symptoms of Scheuermann's kyphosis generally develop around puberty, between the ages of 10 and 15. The disease is often discovered when parents notice the onset of poor posture, or slouching, in their child. The adolescent might experience pain and fatigue in the mid back. The pain is rarely disabling or severe at this point, unless the deformity is severe.
The extra kyphosis is generally slow to develop. When it progresses to the point the rounded curve becomes noticeable, a concerned parent or teacher will suggest a doctor visit. By comparison, adults who developed Scheuermann's early in life tend to seek help because pain from the deformity becomes unbearable.
A rigid curve in the spine is common with Scheuermann's kyphosis. The curve gets worse with bending over and only partially corrects when standing up straight. Pain typically increases with time and severity of the deformity. Some patients with Scheuermann's kyphosis also have scoliosis-about one third. People who have Scheuermann's kyphosis usually don't have nerve problems from the spinal deformity. However, a severely rounded spine can squeeze the contents of the chest and abdomen. The disorder may eventually put pressure on the heart, lungs, and abdomen. This can mean chest pain, shortness of breath, and a loss of appetite.
If possible, the deformity will be treated without surgery. One option is bracing. The goal of bracing is to try to "guide" the growth of the vertebrae in order to straighten the spine. The brace will only successfully straighten the spine in patients who are still growing. The brace is designed to hold the spine in a straighter, upright posture. This is thought to work by taking pressure off the front half of the vertebra, allowing the growth of the bone in the front to catch up with the growth in the back. A brace may be used in older patients to support the spine and relieve pain, but it will not improve the curve.
If young patients are consistent in wearing the brace, worsening of the curve can be limited and there may be correction of the deformity within two years. The brace allows remodeling and corrected growth of the developing spine. The brace is usually worn from 16 to 24 hours each day for one year, then just at night for two years.
The doctor may prescribe physical therapy. A well-rounded rehabilitation program assists in calming pain and inflammation, improving mobility and strength, and making daily activities easier. People who are prescribed a brace tend to benefit even more when physical therapy is included. The goals of physical therapy are to help:
- Learn correct posture and body movements to counteract the effects of kyphosis
- Maximize range of motion and strength
- Foster aerobic fitness
- Learn ways to manage your condition
Fusion surgery is mainly used to correct Scheuermann's kyphosis. The operation has two parts. One operation is done on the front of the spine (anterior), and another one is done on the back (posterior). These two surgeries used to be done about one week apart. Now many doctors are doing both operations on the same day.
The anterior operation is usually done to "release" tight ligaments along the front of the spine. Cutting these ligaments and removing the discs between the vertebrae increases flexibility in the spine. This allows the spine to be straightened easier when rods are put in from the back of the spine. Next, the surgeon begins the posterior procedure by working from the back of the spine. This is where the actual correction of the spinal curve happens. Rods are attached along the spine to align the spine and hold the spine in its corrected position.
Because most surgeries to correct kyphosis involve a rigid spine, both anterior and posterior procedures are generally needed. There are some cases of kyphosis, however, that can be corrected by the posterior procedure alone. In fact, some surgeons are performing posterior-only surgery for Scheuermann's kyphosis regardless of the size of the curve.
For the posterior-only approach, pedicle screws are used at each spinal level to be fused. Rods are connected to the screws, allowing a large amount of correction to occur. When this approach is chosen, the anterior procedure is not used. For some patients, the posterior procedure alone can realign the spine.
The doctor will advise which type of surgery is best. The surgical approach used will depend upon the age of the patient, the flexibility of the spine, the location and degree of the curve, and whether there is pressure on any of the nerve roots.
Procedures / Surgeries
Surgery is usually only recommended if X-rays show a kyphosis over 75 degrees. A curve less than 75 degrees is usually treated with observation or a brace. Surgery is occasionally performed for cosmetic reasons. Because the surgery is serious and involves the spine, it generally is not recommended just to improve appearance.