Structural vs Functional Scoliosis: Understanding the Key Differences

When you or your loved one is diagnosed with scoliosis, one of the first things doctors need to determine is what type of scoliosis it is. At Sancheti Hospital in Pune, we often see patients who are confused about the difference between “structural” and “functional” scoliosis. Understanding this difference is crucial because it completely changes how we treat the condition.

This guide will help you understand these two types of scoliosis in simple terms, how doctors tell them apart, and what treatment options are available for each type.

What is Scoliosis?

Before we dive into the differences, let’s quickly review what scoliosis is. Scoliosis is a sideways curve of the spine that measures 10 degrees or more when viewed on an X-ray. While a normal spine appears straight from behind, a scoliotic spine curves to the left or right, often creating an “S” or “C” shape.

Understanding Structural Scoliosis

What is Structural Scoliosis?

Structural scoliosis is a fixed three-dimensional spinal deformity that involves actual changes to the spine bones (vertebrae). Think of it as a permanent change in the spine’s shape that doesn’t go away when you change positions or lie down.

Key Features of Structural Scoliosis:

The spine bones have actually rotated and twisted
The curve stays the same whether you’re standing, sitting, or lying down
Often causes a visible “rib hump” on one side of the back
Cannot be corrected by changing posture or removing external causes

Types of Structural Scoliosis:

Idiopathic Scoliosis (Most Common)
- “Idiopathic” means we don’t know the exact cause
- Accounts for about 80-85% of all scoliosis cases
- Usually develops during childhood or teenage years
Congenital Scoliosis
- Present from birth due to spine bones that didn’t form properly
- Caused by problems during baby’s development in the womb
Neuromuscular Scoliosis
- Caused by conditions that affect muscles or nerves
- Examples include cerebral palsy or muscular dystrophy
Adult/Degenerative Scoliosis
- Develops in adults due to wear and tear of the spine
- Often related to aging and arthritis

Understanding Functional Scoliosis

What is Functional Scoliosis?

Functional scoliosis, also called “nonstructural scoliosis,” is a flexible lateral curve that appears due to an external cause. Think of it as the spine’s way of compensating for a problem somewhere else in the body. The good news? When you fix the underlying problem, the curve often goes away.

Key Features of Functional Scoliosis:

The spine bones themselves are normal and haven’t rotated
The curve can disappear when you change positions or fix the underlying cause
No rib hump or spine rotation is present
Typically reversible with proper treatment

Common Causes of Functional Scoliosis:

Leg Length Difference
- When one leg is shorter than the other, the pelvis tilts
- The spine curves to keep the head level
- This is one of the most common causes of functional scoliosis
Muscle Spasms
- Back muscle spasms can pull the spine to one side
- Often caused by injury, inflammation, or pain
- Usually temporary and improves as the spasm resolves
Poor Posture
- Long-term poor posture habits can create apparent curves
- Common in people who work at desks or carry heavy bags on one side

How Doctors Tell Them Apart: The Clinical Examination

At Sancheti Hospital, our orthopedic specialists use several methods to distinguish between structural and functional scoliosis:

Adam’s Forward Bend Test

This is a simple but powerful test:

Patient bends forward at the waist with arms hanging down
Doctor looks for a “rib hump” – one side of the back that’s higher than the other
Structural scoliosis: Rib hump is clearly visible
Functional scoliosis: Back appears even with no rib hump

Positional Testing

Sitting vs. Standing: Functional curves may improve when sitting
Lying Down: Functional curves often disappear when lying flat
Heel Lift Test: For suspected leg length differences, a heel lift under the shorter leg can make functional curves disappear

X-Ray Examination

Standard X-Rays:

Standing full-spine X-rays are taken from front and side views
Show the curve angle (called Cobb angle)
Reveal if spine bones have rotated (structural) or are just tilted (functional)

Special X-Rays:

Side-bending X-rays: Patient bends to each side while X-rays are taken
In structural curves, the curve remains even when bending
In functional curves, the curve often straightens out completely

Advanced Imaging:

EOS imaging provides detailed measurements of leg length differences
Helps doctors make more accurate treatment decisions

Treatment Approaches: Why the Difference Matters

The treatment for structural and functional scoliosis is completely different, which is why getting the right diagnosis is so important.

Treating Functional Scoliosis

The key to treating functional scoliosis is addressing the underlying cause:

For Leg Length Differences:

Shoe lifts or heel inserts to even out leg lengths
Custom orthotics may be recommended
Most functional curves improve significantly or disappear completely with proper leg length correction

For Muscle Spasms:

Physical therapy to address muscle imbalances
Anti-inflammatory medications if appropriate
Heat therapy and gentle stretching
Treatment of underlying injury or inflammation

For Postural Issues:

Ergonomic improvements at work or school
Strengthening exercises for core and back muscles
Postural awareness training
Physical therapy

Timeline for Improvement:

Recent studies show that functional curves can be eliminated or greatly reduced once the underlying cause is addressed
Improvement often begins within weeks to months
No bracing or surgery is typically needed

Treating Structural Scoliosis

Treatment depends on several factors including age, curve size, and progression risk:

Observation:

Small curves (under 25-30 degrees) in children and teens
Regular check-ups every 4-6 months
X-rays to monitor for progression

Bracing:

Growing children and teens with curves 25-40 degrees
Prevents progression but doesn’t reverse existing curves
Must be worn 16-23 hours per day for maximum effectiveness

Surgery:

Curves over 45-50 degrees or those that continue to progress
Spinal fusion surgery to straighten and stabilize the spine
Reserved for more severe cases or when other treatments haven’t worked

Prognosis and Long-Term Outlook

Functional Scoliosis Prognosis

The outlook for functional scoliosis is generally excellent:

Most cases are completely reversible when the underlying cause is corrected
No risk of progression if the root cause is addressed
Patients can return to all normal activities
No long-term restrictions or limitations

Structural Scoliosis Prognosis

The outlook varies depending on the type and severity:

Small curves: Often remain stable throughout life
Moderate curves: May require ongoing monitoring
Large curves: May progress and require intervention
With proper treatment: Most people with structural scoliosis live full, active lives

Importance of Specialized Care

At Sancheti Hospital, we understand that distinguishing between structural and functional scoliosis requires expertise and experience. Our orthopedic specialists use a combination of:

Detailed clinical examinations
Advanced imaging techniques
Comprehensive medical history review
Collaborative care with physiotherapists and other specialists

Why Choose Sancheti Hospital for Scoliosis Care:

Leading orthopedic hospital in Pune with decades of spine expertise
Advanced diagnostic capabilities including EOS imaging
Comprehensive treatment options for both structural and functional scoliosis
Multidisciplinary team approach
Personalized treatment plans for each patient

Taking the Next Step

If you or your loved one has been diagnosed with scoliosis, the first step is determining whether it’s structural or functional. This diagnosis will guide your entire treatment journey and help set realistic expectations for outcomes.

Signs You Should See a Scoliosis Specialist:

Visible curve in the spine or uneven shoulders/hips
Back pain that doesn’t improve with rest
One leg appears shorter than the other
Clothes don’t hang evenly on the body
Rib hump visible when bending forward

What to Expect at Your First Visit:

Comprehensive medical history
Detailed physical examination including the Adam’s forward bend test
Standing spine X-rays
Discussion of treatment options based on your specific type of scoliosis

Conclusion

Understanding the difference between structural and functional scoliosis is important for getting the right treatment. While structural scoliosis involves permanent changes to the spine bones and may require bracing or surgery, functional scoliosis is often completely treatable by addressing the underlying cause.

The key takeaway is that early, accurate diagnosis makes all the difference. At Sancheti Hospital in Pune, we’re committed to providing precise diagnosis and personalized treatment plans for every type of scoliosis.

Remember, functional scoliosis has an excellent prognosis when properly treated, while structural scoliosis can be effectively managed with appropriate care. Don’t let confusion about your diagnosis delay treatment – our experienced team is here to guide you through every step of your scoliosis journey.

If you have concerns about scoliosis or need a second opinion on your diagnosis, contact Sancheti Hospital’s orthopedic specialists today. Together, we can determine the best path forward for your spine health.

Frequently Asked Questions

1. Can functional scoliosis turn into structural scoliosis if ignored?

It’s rare, but possible—especially in growing children or teens. If a functional curve (like from a leg length difference) is left untreated for years, the spine may start to adapt permanently, leading to actual bone changes. That’s why it’s important to address the root cause early, particularly during growth spurts.

2. Will my child outgrow functional scoliosis on their own?

Not always. While some mild postural curves may improve as habits change, functional scoliosis caused by things like a true leg length discrepancy or chronic muscle imbalance usually won’t fix itself. It often needs targeted help—like shoe lifts or physical therapy—to fully resolve.

3. Can chiropractic adjustments fix structural scoliosis?

No. Chiropractic care might help with temporary pain or muscle tension, but it cannot reverse the actual bone rotation or curvature in structural scoliosis. Relying only on adjustments for a structural curve can delay effective treatment like bracing or monitoring, especially in growing kids.

4. How do I know if my uneven shoulders or hips are from functional or structural scoliosis?

A quick clue: lie flat on your back. If your shoulders or hips even out when you’re lying down, it’s likely functional. If they stay uneven, it may be structural. But the only sure way is a proper exam with forward-bend testing and X-rays—don’t guess based on appearance alone.

5. Can scoliosis be caused by carrying a heavy backpack or sitting wrong?

Poor posture or heavy bags might cause temporary muscle strain that mimics scoliosis (a functional curve), but they don’t cause true structural scoliosis. Idiopathic scoliosis is genetic and not your fault—so don’t blame yourself or your child for “bad habits.”

6. Is it possible to have both structural and functional scoliosis at the same time?

Yes. Some people have a structural curve in one part of the spine and a compensatory functional curve above or below it. For example, a fused or curved lower spine might cause the upper back to lean the opposite way to keep the head balanced. Treatment must address both components.

7. Do I need an MRI if I’m diagnosed with functional scoliosis?

Usually not—if the diagnosis is clear and the curve fully corrects with position changes or heel lifts. But if there’s any doubt, or if you have unusual symptoms like numbness, weakness, or rapid curve progression, doctors may order an MRI to rule out hidden neurological or spinal cord issues.