Can Scoliosis Kill You? What the Long-Term Studies Actually Show

If you have just been told you have scoliosis, or you have lived with a curve for years and it seems to be changing, it is natural to wonder how serious it can get. The short answer is reassuring for most people, and the details below explain exactly when a curve becomes a real health risk and when it does not.

For the great majority of people, no. A 50-year study of adults with untreated late-onset idiopathic scoliosis, the common kind that appears around adolescence, published in JAMA in 2003, found their estimated survival was about the same as the general population's. Scoliosis becomes dangerous only in a small group: very large curves in the chest part of the spine, which can restrict the lungs, and curves that start in early childhood or are caused by another serious condition affecting the nerves or muscles. Even then, the harm builds over years, not overnight.

The one sign that should never wait: new or worsening shortness of breath in someone with a large curve. Sudden breathing trouble, chest pain, or new weakness or numbness in the legs needs an emergency room.

Scoliosis is a sideways curve of the spine, measured on an X-ray as a Cobb angle. A curve of 10 degrees or more counts as scoliosis. Most curves are mild, and the National Institute of Arthritis and Musculoskeletal and Skin Diseases notes that most children and teens with mild scoliosis have no symptoms or pain.

A mild or moderate curve changes the shape of your back. It does not squeeze your heart, damage your organs or shorten your life. What it can do, especially as you get older, is cause back pain, stiffness and, in some adults, pressure on nerves. Those are real problems worth treating, but they are quality-of-life problems, not life-threatening ones.

The risk comes from the ribs. Your ribs attach to the vertebrae in the middle of your back, the thoracic spine. When a curve there becomes very large and the spine rotates, the rib cage twists and the space your lungs have to expand shrinks. That is called restrictive lung disease.

Not all scoliosis behaves the same way. A Swedish study that followed 115 people with untreated scoliosis, born between 1902 and 1937, found higher death rates overall, with 21 of the 55 deaths due to respiratory failure. The increase was seen in curves that began in infancy or childhood, before adolescence, and in curves linked to other conditions such as polio or rickets. Mortality was not significantly increased in the group whose scoliosis began in adolescence, the most common kind.

The Scoliosis Research Society says the same about early-onset scoliosis, which starts before age 10: when severe and untreated, it may be associated with an increased risk of early death due to heart and lung disease. A curve that starts that young has years of growth to worsen while the lungs are still developing.

Neuromuscular scoliosis, caused by conditions such as cerebral palsy or muscular dystrophy, carries more risk for a related reason: the underlying condition often weakens the muscles used for breathing as well. In these cases the overall health picture depends as much on the condition as on the curve.

If you are an adult whose curve was found in your teens, or whose curve developed later in life from wear in the spine, you are in the lower-risk groups.

One of the longest follow-up studies is the University of Iowa study published in JAMA. Researchers followed up 117 people with untreated late-onset idiopathic scoliosis, about 50 years after they were first seen, and compared them with 62 people of the same age and sex. The patients' estimated probability of survival was about 0.55, against 0.57 expected for the general population, and the expected figure fell inside the study's margin of error.

The same study found these adults were productive and functioning at a high level. Back pain was more common: 61% reported chronic back pain, against 35% of the comparison group. But most of those with pain described it as little or moderate. The authors concluded that this kind of scoliosis, left untreated, causes little physical impairment other than back pain and concerns about appearance.

Two cautions. These were older cohorts, followed since the 1930s and 1940s, and the patients were mostly women. And the findings apply to late-onset idiopathic scoliosis, not to the early-onset or neuromuscular types above.

Yes, some do, and this matters more for most adults than the question of survival. In a long-term study of 102 patients followed for an average of 40.5 years, 68% of curves progressed after the skeleton stopped growing. Curves under 30 degrees at the end of growth tended not to progress, whatever their pattern. Curves between 50 and 75 degrees at that point, especially in the thoracic spine, progressed the most.

Adults can also develop a new curve. Adult degenerative scoliosis forms as the discs and small joints of the lower back wear unevenly. It rarely affects breathing, because it sits below the ribs, but it can narrow the spaces around the nerves, a problem called spinal stenosis. That can cause leg pain, numbness or weakness, especially when standing or walking.

Because curves can change slowly, the practical answer is monitoring: periodic standing X-rays to measure whether the angle is moving, rather than guessing from how your back looks in the mirror.

Your number alone does not tell the whole story, but it does tell you which questions to ask. As a general guide:

• Under 30 degrees: no threat to your life or your lungs. Curves this size at the end of growth tended not to progress in the long-term study above. Pain, if you have it, is the thing to treat.
• 30 to 50 degrees: still not a danger to your life, but worth regular follow-up, because some curves in this range keep moving in adulthood.
• Over 50 degrees: this is where curves are most likely to progress and where surgery starts to be discussed. The Scoliosis Research Society says surgery is generally reserved for curves greater than 50 degrees in adolescents and adults.
• Over 80 degrees in the chest: the range linked with shortness of breath. Breathing should be part of every check-up.

What changes the picture: a curve in the thoracic spine rather than the lower back, a curve that is measurably growing, and symptoms such as leg pain, trouble standing upright or breathlessness. In adults, balance, nerve pressure and function often matter more than the angle, as explained in what degree of scoliosis requires surgery.

It is a fair question. Scoliosis surgery, usually a spinal fusion that straightens and joins part of the spine with rods and screws, is a major operation. Its risks include infection, bleeding, nerve injury, problems with the hardware or with the bones joining, and, rarely, death. Risk is higher in adults than in teenagers, and higher again in people with other health problems.

That is exactly why surgery is not offered by default. It is recommended when a curve is causing, or is likely to cause, harm that outweighs those risks: a large curve that keeps progressing, nerve compression that is costing you the ability to stand or walk, or a curve threatening breathing. For many adults, physical therapy, activity changes and pain management, including injections, are enough. The options are laid out in adult scoliosis treatment options, and what treatment can and cannot change is covered in can scoliosis be fixed in adults.

Most changes in a curve are slow. These are the exceptions.

An evaluation answers the questions this article cannot answer for you: how large your curve is, where it sits, whether it is changing, and whether it is affecting your nerves or breathing. Expect a review of your history and any old X-rays, an exam of your posture, balance, strength and reflexes, and standing X-rays of the whole spine to measure the Cobb angle. An MRI is added when symptoms point to nerve pressure.

Bring any earlier X-rays or reports you have. Comparing an old measurement with a new one is the most reliable way to know whether a curve is progressing. If you are not sure you have scoliosis at all, start with how to know if you have scoliosis.

For most people, scoliosis is a back problem to manage, not a threat to life. The goal is to know your curve: its size, its direction of travel, and what it is doing to your nerves and breathing. The spine surgeons at Mountain Spine & Orthopedics see adults with scoliosis and can measure your curve, explain what it means for you, and walk you through options from monitoring and physical therapy to injections and surgery when it is truly needed. Book an evaluation, or if you have already been told you need surgery, request a second opinion.