Types of Scoliosis: Understanding the Different Curves and Classifications

When we talk about types of scoliosis, many people don’t realize there are actually several different forms of this spinal condition. Understanding these variations is crucial for proper diagnosis and treatment.

At Sancheti Hospital in Pune, we see patients with various forms of scoliosis daily, and each type requires a unique approach to care.

What Are the Main Types of Scoliosis?

Scoliosis isn’t just one condition – it’s actually a group of spinal disorders that cause the backbone to curve sideways. The different types of scoliosis are classified based on what causes them, when they develop, and how the curves look on X-rays.

1. Idiopathic Scoliosis – The Most Common Type

Idiopathic scoliosis is the most common form, accounting for about 80-90% of all cases. The word “idiopathic” simply means we don’t know the exact cause. This most common type of scoliosis can be further divided into age groups:

Types of idiopathic scoliosis by age:

Infantile (0-3 years): Very rare, sometimes corrects itself
Juvenile (4-9 years): Less common, may need careful watching
Adolescent (10-18 years): Most frequent, especially in girls during growth spurts
Adult (18+ years): Usually continues from adolescent type or develops due to aging

Adolescent idiopathic scoliosis affects about 2-3% of teenagers and is more common in girls, especially when curves need treatment.

2. Congenital Scoliosis

This type happens when a baby is born with spine bones that didn’t form properly in the womb. Congenital scoliosis occurs in about 1 in 10,000 births and is present from birth, though it might not be noticed right away.

Common causes include:

Missing vertebrae (spine bones)
Extra vertebrae
Vertebrae that didn’t separate properly
Ribs that are fused together

3. Neuromuscular Scoliosis

This type develops when muscles and nerves can’t properly support the spine. It’s seen in children with conditions like:

Cerebral palsy
Muscular dystrophy
Spina bifida
Spinal cord injuries

Neuromuscular scoliosis often progresses faster than other types because the muscles can’t hold the spine straight as the child grows.

4. Syndromic Scoliosis

This occurs as part of genetic conditions or syndromes such as:

Marfan syndrome
Neurofibromatosis
Connective tissue disorders

5. Degenerative (Adult) Scoliosis

This develops later in life as the spine wears down with age. Unlike childhood scoliosis, adult degenerative scoliosis is often painful and can affect daily activities.

Understanding Curve Patterns and Locations

The types of scoliosis curves are also classified by where they occur in the spine and their shape. This helps doctors plan the best treatment.

Curve Locations:

Thoracic: In the upper back (chest area)
Lumbar: In the lower back
Thoracolumbar: Where the upper and lower back meet
Double curves: Two curves in different areas

Single vs. Double Curves:

Single curves: One main curve
Double major curves: Two significant curves that balance each other
Double curves: One main curve with a smaller compensating curve

Structural vs. Non-Structural Scoliosis

This is an important distinction that affects treatment:

Structural Scoliosis

Fixed curves that don’t straighten when you bend or lie down
Involves actual rotation of the vertebrae
Requires active treatment and monitoring
Most types of scoliosis fall into this category

Non-Structural (Functional) Scoliosis

Temporary curves that can be corrected
Often caused by other problems like:
- One leg being shorter than the other
- Muscle spasms
- Poor posture
Usually straightens when the underlying cause is fixed

Classification Systems Doctors Use

For Adolescent Scoliosis: The Lenke System

The Lenke classification helps surgeons plan treatment by categorizing curves into six main types:

Lenke Types 1-6:

Type 1: Main thoracic curve
Type 2: Double thoracic
Type 3: Double major
Type 4: Triple major
Type 5: Thoracolumbar/lumbar
Type 6: Thoracolumbar/lumbar with main thoracic

For Adult Scoliosis: The SRS-Schwab System

This system helps doctors understand how adult curves affect quality of life and plan surgery. It looks at:

Curve location and size
Spine balance from front to back
Pelvic alignment

How Doctors Measure Curve Severity

The Cobb Angle

The Cobb angle is the standard way to measure how severe a curve is. It’s measured in degrees on X-rays:

10-25 degrees: Mild scoliosis
25-40 degrees: Moderate scoliosis
40-50 degrees: Severe scoliosis
50+ degrees: Very severe scoliosis

Modern 3D Imaging

New technology like EOS imaging provides 3D views with less radiation, making it safer for children who need regular check-ups.

Why Classifications Matter

Understanding the different types of scoliosis helps doctors:

Predict which curves might get worse
Plan the best treatment approach
Communicate clearly with other specialists
Track progress over time

For families, knowing the specific type helps them understand what to expect and make informed decisions about treatment.

Latest Advances in Scoliosis Classification

AI Technology: Recent studies show that artificial intelligence can now help classify scoliosis types and measure curves more accurately, reducing human error and speeding up diagnosis.

Better Outcome Prediction: New research helps doctors better predict which types of scoliosis curves are likely to get worse, leading to more personalized treatment plans.

Treatment Varies by Type

Idiopathic Scoliosis

Observation for mild curves
Bracing for moderate curves in growing teens
Surgery for severe curves

Congenital Scoliosis

Often requires early intervention
May need surgery at a younger age
Sometimes involves growth-friendly implants

Neuromuscular Scoliosis

Aggressive treatment often needed
Seating systems and mobility aids
Surgery frequently required

Adult Degenerative Scoliosis

Pain management is often the priority
Physical therapy and exercise
Surgery for severe symptoms

Expert Care at Sancheti Hospital

At Sancheti Hospital in Pune, we understand that each type of scoliosis requires specialized expertise. Our comprehensive approach includes:

Advanced Diagnosis

State-of-the-art imaging including low-dose X-rays
3D spine analysis for accurate classification
Genetic testing when appropriate for syndromic types

Personalized Treatment Plans

Conservative management for appropriate cases
Modern bracing techniques for growing patients
Advanced surgical options including minimally invasive techniques
Multi-disciplinary care involving physiotherapy and pain management

Specialized Programs

Pediatric scoliosis clinic for all childhood types of scoliosis
Adult deformity program for complex degenerative cases
Neuromuscular scoliosis expertise for complex medical conditions

Our team stays current with the latest classification systems and treatment advances, ensuring that every patient receives care customized to their specific type of scoliosis. Whether you’re dealing with the most common type of scoliosis (idiopathic) or a more complex form, we’re here to guide you through every step of your treatment journey.

Frequently Asked Questions About Types of Scoliosis

1. What do “structural” and “non-structural” mean, and how does spine rotation make a difference?

This is one of the most important distinctions in the types of scoliosis:

Structural scoliosis:

The spine bones actually rotate and the curve is fixed
The curve doesn’t go away when you bend or change positions
This is “true” scoliosis that needs medical treatment

Non-structural (functional) scoliosis:

The spine looks curved but the bones haven’t rotated
Usually caused by other problems like one leg being shorter
The curve often disappears when the underlying problem is fixed

2. How are curves named by location and what does “curve apex” mean?

Types of scoliosis curves are named by where they occur:

Thoracic curves: In the upper back (chest area) – these often affect the ribs
Lumbar curves: In the lower back – these often cause back pain
Thoracolumbar curves: Where the upper and lower back meet
Double curves: Two curves in different areas

The “curve apex” is simply the point where the curve is most severe – the top of the curve when looking at an X-ray.

3. What is the Lenke classification and what do the numbers and letters mean?

The Lenke classification is used for teenagers who might need surgery. It has three parts:

Curve Types 1-6:

Type 1: Main thoracic (upper back)
Type 2: Double thoracic
Type 3: Double major curves
Type 4: Triple major curves
Type 5: Thoracolumbar/lumbar (lower back)
Type 6: Mixed curves

Lumbar Modifiers (A, B, C): How the lower back curve relates to the center line of the body

Sagittal Modifiers (-, N, +): Whether the normal front-to-back curves are too flat (-), normal (N), or too curved (+)

4. What is the SRS-Schwab classification for adults and how do the measurements affect treatment?

The SRS-Schwab system is used for adult scoliosis and focuses on three important measurements:

PI-LL (Pelvic Incidence-Lumbar Lordosis): Measures if the lower back curve matches the pelvis shape
SVA (Sagittal Vertical Axis): Measures if the head is properly balanced over the pelvis
PT (Pelvic Tilt): Measures if the pelvis is tilted forward too much

These measurements help doctors predict pain levels and plan surgery because they affect how well a person can stand upright without getting tired.

5. Why are modern 3D and low-dose imaging methods becoming more popular?

New EOS imaging systems provide 3D views with much less radiation than traditional X-rays. This is especially important for children who need regular check-ups over many years. The 3D images also help doctors better understand how the spine is rotated, which affects treatment planning.

6. Which type of scoliosis is most likely to get worse?

Different types of scoliosis have different risks:

Idiopathic: Usually progresses slowly, more risk during growth spurts
Congenital: Can progress quickly and may affect other organs
Neuromuscular: Often progresses rapidly because muscles can’t support the spine
Degenerative: Usually progresses slowly but causes more pain

7. Can functional scoliosis become structural scoliosis?

Usually no. Functional scoliosis typically resolves when the underlying cause (like leg length difference) is treated. However, if left untreated for a very long time, some functional curves might develop structural changes.