There are different types of scoliosis that can develop, with each type having either an unknown or known cause. The mystery behind the etiology of the condition’s most common form, adolescent idiopathic scoliosis (AIS) is part of the reason scoliosis is often considered a ‘mysterious’ condition.
When it comes to scoliosis causes, depending on condition form, they may or may not be clearly identified. Adolescent idiopathic scoliosis accounts for 80 percent of known diagnosed cases, with no known single cause. The remaining 20 percent have known causes that vary based on the type of scoliosis.
Before we get into the specifics of different types of scoliosis that can develop and whether or not their causes are known or unknown, let’s first have a general discussion about scoliosis itself.
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When a person develops scoliosis, part of their diagnosis will include further classifying the condition based on a number of important patient and condition characteristics; classifying a condition helps streamline the treatment process, including designing the best possible treatment plan.
Let’s touch on the characteristics that help classify a condition as this will give us a better understanding of the condition as a whole, before we move on to the different types of scoliosis and their causes.
A patient’s scoliosis is classified based on the patient’s age, curvature location, condition severity, and cause.
Patient age is an important factor in scoliosis and scoliosis treatment for multiple reasons.
Not only does patient age give a good indication of a patient’s overall health/fitness and ability to handle the rigors of treating, and living with, scoliosis, it also addresses a key characteristic of the condition itself: progression.
Scoliosis is an incurable and progressive spinal condition: meaning it’s in its very nature to worsen over time, especially if left untreated.
While we can’t 100-percent predict how quickly, or slowly, one person’s condition will progress compared to another’s, we can use patient age to help us predict a patient's ‘likeliest’ rate, and this helps us shape our treatment plans moving forward.
In children and adolescents who have not yet reached skeletal maturity, we know they are at risk of rapid-phase progression because growth is the condition’s number-one trigger for progression.
In adults who are no longer growing, we know that, generally, progression tends to slow down, at least until spinal degeneration comes into play.
Just as scoliosis can develop at any age, it can also develop anywhere along the spine.
There are three main sections to the spine: cervical (neck), thoracic (middle and upper back), and lumbar (lower back).
While thoracic curvatures are the most common, they can also affect the cervical and lumbar sections as well.
In addition, we know that certain curvature patterns, such as thoracic curves, tend to progress faster, so not only does curvature location tell us where we need to concentrate our treatment efforts, especially in terms of scoliosis-specific chiropractic care, it can also give us clues about a patient’s potential progressive rate.
Once we know where the most-tiled vertebrae (bones of the spine) are located, we know which vertebrae are the most misaligned and in need of re-alignment with the rest of the spine to help restore its healthy curves.
Scoliosis is not always a simple condition to treat for many reasons, but mainly because it varies so much from patient to patient.
One of the main condition characteristics that play into how a person experiences life with scoliosis is condition severity, and this is determined by what’s known as ‘Cobb angle’.
A patient’s Cobb angle is a measurement obtained via X-ray that tells me just how far out of alignment their scoliotic spine is.
In order for a person to be diagnosed with scoliosis, they have to have an abnormal sideways curvature of the spine, with rotation, that has a minimum Cobb angle measurement of 10 degrees.
Cobb angle is determined by drawing lines from the tops and bottoms of a curvature’s most-tilted vertebrae, and the resulting angle is measured in degrees.
Generally speaking, the higher the Cobb angle, the more severe the condition, and the more likely it is to produce noticeable postural changes, pain (in adults), and the potential for related complications.
The Cobb angle measurement places a condition on its severity scale of mild, moderate, severe, or very severe.
Just by considering the range of numbers above, you can see how much a condition can vary from one patient to the next; in fact, I’ve never used the exact same treatment plan twice, and the largest curvature I have seen was in the very-severe category at 150 degrees.
This is why there is no one-size-fits-all scoliosis treatment plan as the very nature of the condition necessitates an integrative approach: one that combines different treatment disciplines to address the many unique patient/condition characteristics.
Here at the Scoliosis Reduction Center, we offer just that: an integrative scoliosis-specific chiropractic-centered approach that allows for full customization while prioritizing correction and function.
As we’ve looked at patient age, curvature location, and condition severity, we are now moving on to causation (the last main classification point) and answering the question, ‘what causes scoliosis’?
Now, just as there are different severity levels of scoliosis, there are also different types of scoliosis a person can develop, so let’s move on to the different forms of scoliosis, their prevalence, and their causes, when known.
One of the defining features of a person’s scoliosis is condition form/type, and the reason behind its development. However, we don’t always understand the etiology of certain forms of the condition.
Let’s start our discussion of different scoliosis causes with the condition’s most prevalent form: adolescent idiopathic scoliosis.
Adolescent idiopathic scoliosis is by far the most common form of scoliosis that is diagnosed. It affects adolescents between the ages of 10 and 18 and accounts for 80 percent of known diagnosed cases.
Although the condition’s most prevalent form, it is also the most mysterious as despite the amount of research and studies done on the subject of causation, we have yet to clearly isolate a single-known source that explains its initial onset.
The ‘idiopathic’ designation means, quite simply put, that we just don’t know why it develops. While there are many theories on the subject of idiopathic scoliosis etiology, they remain just that: theories.
An important distinction to understand is that just because a ‘single’ source hasn’t been clearly identified, that doesn’t mean AIS couldn’t have multiple causes. In fact, AIS is generally considered to be ‘multifactorial’, meaning its onset could be attributed to multiple variables, or how certain variables interact, and these factors can differ from person to person.
Something I find myself repeating often to patients, and the families of adolescents recently diagnosed with idiopathic scoliosis, is that despite not knowing what caused its development, I most certainly know how to respond to it and manage it effectively.
Individuals diagnosed with AIS are at risk of rapid-phase progression. This is because this age group is in, or entering into, the stage of puberty characterized by rapid and unpredictable growth spurts.
As we know that growth is the condition’s number-one trigger for progression, we know that treating these patients’ scoliosis through this stage of growth of development is going to involve a lot of monitoring to see how growth is affecting their spine and treatment.
If we can get these patients through this stage without significant progression, amazing results can happen. In fact, the earlier AIS is diagnosed, the better the chances of successful treatment are, although that can never be guaranteed.
Treatment is always a process of give and take, and this is why a customized treatment plan is so beneficial, and even if we knew the cause of this highly-prevalent form of scoliosis, that doesn’t necessarily mean it would change the treatment plan moving forward.
As mentioned, AIS accounts for 80 percent of known diagnosed cases, but what about the remaining 20 percent? The types of scoliosis that fall into that group are forms associated with known causes.
In forms of scoliosis with known causes, the causes sometimes help shape the design of the chosen treatment plan.
The 20 percent of scoliosis forms associated with known causes are congenital, neuromuscular, degenerative, and traumatic.
Congenital Scoliosis Causes
Congenital scoliosis affects newborns and/or infants who are born with the condition due to a bone malformation that occurs in utero.
Congenital scoliosis affects approximately 1 in 10,000 infants, and the causes for this form are clearly attributed to two main types of abnormal spinal development.
Failure of formation occurs when sections of one or more vertebrae don’t grow together as they should while the fetus develops. When this happens, the spine is unstable in the affected areas and can lead to the development of a hemivertebrae: a sharp angle of bone in the spine that disrupts its alignment.
Errors in segmentation can also cause the development of congenital scoliosis, and this occurs when the bony sections of the vertebral column don’t grow into separate segments as they should and end up fused together.
Both causes involve abnormal development that can affect multiple areas of the spine and usually dominate one side more than the other. It’s this resulting asymmetry that causes the abnormal spinal curvature to develop in the womb.
As the spine’s surrounding muscles and ligaments develop around it, the force they exert on the spine is responded to differently on each side of the spine, due to the asymmetry introduced.
So, once again, the cause of congenital scoliosis is abnormal spinal development.
Neuromuscular Scoliosis Causes
Neuromuscular scoliosis is the second most common spinal disorder, after idiopathic scoliosis.
In neuromuscular scoliosis (NMS), the scoliosis that develops is a related complication of an underlying neuromuscular condition adversely affecting the muscles and/or connective tissues that support and help stabilize the spine.
The severity level of NMS is attributed to the amount of nerve/muscle involvement related to the patient’s particular neuromuscular condition. While it’s not a guarantee that everyone with a neuromuscular condition will develop scoliosis, it is a fairly common complication.
Common neuromuscular conditions that can lead to the development of scoliosis include, but are not limited to, cerebral palsy, muscular dystrophy, and spina bifida.
These types of cases are difficult to treat because the underlying cause of the scoliosis, the neuromuscular condition, has to be the guiding force of treatment.
While we can always work towards varying degrees of improvement, with my neuromuscular scoliosis patients, the added complication of the underlying condition makes it harder to reach the same level of treatment success that we work towards with less-complex condition forms.
So the cause of neuromuscular scoliosis is the underlying neuromuscular condition that causes the development of scoliosis as a related complication.
While we know that adolescents are the age group most commonly diagnosed with scoliosis, adults can develop it too.
Degenerative Scoliosis Causes
A common form of scoliosis affecting adults is degenerative scoliosis, and this form has a known cause: spinal degeneration.
While spinal degeneration can also be caused by other conditions such as osteoporosis, spondylolisthesis, and/or osteoarthritis, it can also be caused by the cumulative effect of certain lifestyle choices and degenerative changes associated with aging.
Degenerative scoliosis is most common in adults over the age of 40, and negative lifestyle choices that can contribute to its onset include not maintaining a healthy weight or activity level, poor posture, and/or repeatedly lifting heavy objects incorrectly and straining the spine.
Over time, the cumulation of many seemingly-small negative choices can affect the overall health and function of the spine.
Women are also more prone to develop degenerative scoliosis because of factors related to menopause such as changing hormones and bone-density levels.
Most commonly, it’s the spine’s intervertebral discs that are vulnerable to degenerative changes and cause the development of degenerative scoliosis.
The vertebrae are separated by discs; they act as cushions preventing friction during movement, help facilitate spinal flexibility thanks to their soft gelatinous interior, and their hard durable outer layer helps provide the spine with structure and support.
Once the intervertebral discs are adversely affected by declining spinal health and degeneration, the spine’s ability to maintain its natural and healthy curvatures is compromised, leading to the development of degenerative scoliosis.
So the cause of degenerative scoliosis is degenerative changes experienced by the spine that impair its ability to maintain a healthy alignment.
Now, when it comes to the other common form of adult scoliosis, we are talking about idiopathic scoliosis in adults, and in these cases, we know the cause is the progression of adolescent idiopathic scoliosis into maturity.
Idiopathic Scoliosis in Adults
In cases of adult idiopathic scoliosis, these patients had scoliosis in adolescence but were unaware, and their condition progressed into maturity. While it might be hard to imagine how a person could live with scoliosis for so many years without knowing, it’s easier than you might think.
If you recall the wide range of Cobb angles and corresponding severity levels, on the mild side of that range, visual symptoms, such as postural changes, can be very subtle. It’s not uncommon for only experts who know exactly what to look for, in terms of spotting the early telltale signs of the condition, to recognize its presence.
In addition, in terms of scoliosis-related pain, there is a big difference in how it’s experienced by patients who are still growing, or in adults who have reached skeletal maturity.
When a person is still growing, their spine is experiencing a constant lengthening motion, and that motion counteracts the compressive force of the curvature, and their spine has not yet settled due to gravity and maturity; in adults who have reached skeletal maturity, their spines are no longer growing, meaning they are subject to the compressive force of the curvature felt by the spine and its surrounding muscles, vessels, and nerves.
It’s this compression that causes pain, and as skeletal maturity is reached, not only has the condition naturally progressed, especially if unnoticed and untreated, but it can also start to become painful, and this is what leads most of my adult patients in for a diagnosis.
Unfortunately, had these patients been diagnosed during adolescence and received treatment, their spines would be in better shape than by the time most of them come to see me. Still, it’s never too late to start treatment and work towards an improvement.
So in this form of scoliosis (adult idiopathic scoliosis), while the initial cause of its onset is unknown, as it is in AIS when the condition initially develops, we do know that adult idiopathic scoliosis is an extension of adolescent idiopathic scoliosis, and this is the most common form of scoliosis affecting adults.
Traumatic Scoliosis Causes
Traumatic scoliosis is caused by a significant trauma experienced by the spine.
Causes can include surgery, accidents, or other body traumas that adversely affect the spine, such as the presence of tumors pressing against it, exposing the spine to uneven forces and adverse spinal tension.
So now that we have covered the main form of scoliosis without a known cause and the forms with known causes, let’s address one of the most common questions regarding scoliosis causation: is scoliosis genetic?
When a condition is classified as ‘genetic’, we understand its causation. We know that its onset is connected to the presence of a specific gene, or genetic mutation, passed down from the parent/parents to their offspring.
Many patients, and their families, who are processing a recent scoliosis diagnosis turn to genetics for answers, and while I understand the drive behind this, it doesn’t provide the certainty they crave.
The truth is in the condition’s most common form, AIS, its development is thought to be the result of multiple factors, and not one specific source, like a gene.
While some experts agree that there is likely a ‘genetic predisposition’ associated with idiopathic scoliosis development, this is not the same as a condition being classified as ‘hereditary’.
In addition, families share a lot more than just their genes. Common responses to stress, shared socioeconomic factors, environmental factors, body types, posture, diet, and lifestyle can also account for the possibility of what appears to be a ‘genetic predisposition’.
There are also cases of twins where one twin develops scoliosis, while the other does not, despite sharing the same genes, or cases where a set of twins develops scoliosis, but with completely different curvature patterns and/or Cobb angles.
If scoliosis causation was purely genetic, these twin studies would produce different findings.
I like to explain this particular complex scoliosis-causation topic in relation to other medical conditions. Let’s consider heart disease for a minute. If a person comes from a long line of family members who had developed heart disease, are they likely going to be more susceptible or predisposed to its development: yes, it’s more likely. However, through healthy choices that include heart-friendly diet and exercise, those chances can be lowered.
Put simply, there are just too many factors that contribute to the development of idiopathic scoliosis to attribute it solely to genetics. In addition, if there was a specific ‘scoliosis gene’ present, one has to wonder why it hasn’t been discovered yet.
So is scoliosis classified as a hereditary condition caused by genetics? No, it is not. While scoliosis has been seen to run in families, this is not always the case and could be related to many other shared familial factors, nor has there been a specific gene found that accounts for the condition’s development.
What causes scoliosis is a common condition-related question. One of the hardest things about giving an idiopathic scoliosis diagnosis is explaining that its cause is unknown.
One of the hardest things about receiving an idiopathic scoliosis diagnosis are the feelings of powerlessness that can accompany it.
I understand the drive of patients and their families wanting clear answers as I think part of that drive is governed by a need to regain some control and power over the situation, but unfortunately, those answers aren’t always clear or forthcoming.
When it comes to the condition’s most common form, adolescent idiopathic scoliosis, we quite simply can’t clearly connect its onset to a single definitive source, hence its ‘idiopathic’ designation; however, this doesn’t mean the condition can’t have multiple causes, hence its ‘multifactorial’ designation.
When it comes to forms of the condition with known causes, we are talking about congenital, neuromuscular, degenerative, and traumatic scoliosis, but these cases only account for 20 percent of known diagnosed cases; the remaining 80 percent are considered idiopathic.
What do these numbers mean in terms of treatment efficacy? In terms of the 80 percent of idiopathic scoliosis cases, surprisingly, very little. While I might not fully understand its etiology, I know what to do once it's developed: treat it proactively with a scoliosis-specific functional chiropractic-centered approach, which we provide here at the Scoliosis Reduction Center.
In terms of the other 20 percent with known causes, the associated causes can help shape treatment plans, especially when the underlying cause of the condition’s development is attributed to a different force or condition.
This is particularly the case with neuromuscular scoliosis as we know there is a larger neuromuscular disease causing the development of the abnormal spinal curvature, so in order to attempt addressing NMS, the underlying neuromuscular cause has to be the guiding force of treatment.
Ultimately, regardless of causation, once scoliosis becomes structural, in order to treat it effectively, the condition has to be impacted on a structural level.
Discussing scoliosis causes is a complex topic because I don’t have all the answers. While I can’t deny a desire to fully understand all aspects of the condition, including its etiology, what I fully understand is how to proactively increase chances of treatment success: by customizing treatment plans that work towards varying levels of improvement by addressing the specifics of unique patient/condition characteristics.
