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Does Scoliosis Affect the Heart and Lungs?

teen girl
Lung function is how well the lungs are working. It is also called pulmonary function. Lung function is assessed with tests done in a pulmonary function lab. Testing may be done if your teen is booked for surgery. Mild-to-moderate curves don’t usually require testing.

How is lung function tested?

Several tests can be done. In general, these tests look at:

  • How much air your teen can move in and out of her lungs
  • How fast she can move this air in and out of her lungs
  • The stiffness of her lungs and chest wall. The chest wall includes the rib cage, diaphragm, and abdominal wall.
  • Physical exercise tests on treadmills or stationary bikes. These are done in certain circumstances such as during a research study.

Can certain types of curves affect breathing?

In general, only thoracic curves (mid-back) have the potential to affect your teen’s lungs. Smaller thoracic curves that are between 20 and 45 degrees can cause decreased lung function during heavy exercise. In one exercise study, teens with and without scoliosis walked on a treadmill at increasing speeds and incline until they were unable to continue. Teens with curves between 20 and 45 degrees (average curve of 33 degrees) reached a lower average speed. Their breathing was also less efficient when compared to teens without scoliosis. This reduction in lung function was only noted during maximum exercise. Scoliosis is unlikely to affect your teen’s ability to do daily activities or moderate exercise.

Another study looked at teens being booked for surgery with thoracic (mid-back) curves between 45 and 88 degrees. The average curve size in this study was 60 degrees). These teens had decreased lung function as measured by pulmonary function tests. The researchers also had some teens do a six-minute walk test. In this test, the teens had to walk as far and fast as possible for six minutes. Using this test, the researchers found that teens with scoliosis had decreased ability to do moderate exercise.

The same study checked whether a four-month physical exercise program would improve lung function. This program consisted of three training sessions a week. Each training session included 40 minutes of training on the bike or treadmill. Patients worked at 60% to 80% of their maximum heart rate. The training program improved lung function significantly in these patients before they went for surgery but did not restore lung function to completely normal levels.

Despite all our best efforts in terms of education, we still see some patients presenting late with curves over 100 degrees. Curves greater than 100 degrees reduce lung capacity by 50%. Curves greater than 120 degrees can lead to right-sided heart failure. They can also cause breathing difficulties in everyday activities.

Early onset scoliosis can affect breathing

Early onset scoliosis is scoliosis that occurs in children before the age of five years. The cause is not known. While many of these curves remain stable and even disappear on their own, others may increase in size quickly. Without treatment, early onset scoliosis can lead to deformity of the chest and spine. This can lead to problems with breathing. Active treatment is needed for these cases.

If you want to learn more about the long-term follow-up of scoliosis patients, see the link below. In this page, some of the studies report on 50 years of follow-up in scoliosis patients.

For more information

Sandra Donaldson, BA

Reinhard Zeller, MD, ScD, FRCSC