Orthopaedic Surgery - Scoliosis

Basics

Scoliosis is a:

Three-dimensional deformity of the spine

characterized by lateral curvature together with:

Vertebral rotation

and changes in the normal sagittal alignment.

Although often described on an:

AP or PA spinal radiograph

the deformity is not purely lateral.

Definition

Radiographic scoliosis is conventionally defined as a spinal curve measuring:

More than 10° by the Cobb method.

Both the:

Thoracic

and

Lumbar spine

may be involved.

Classification

Scoliosis can be classified according to:

Etiology

Location of the curve

and, in idiopathic cases,

Age at onset.

Classification by Etiology

Major categories include:

Idiopathic

Congenital

Neuromuscular

Connective-tissue associated

Degenerative

Classification by Curve Location

The curve is named according to the level of its:

Apex.

Common categories are:

Thoracic

Thoracolumbar

Lumbar

Idiopathic Scoliosis by Age

Idiopathic scoliosis may be subdivided into:

Infantile scoliosis – younger than 3 years

Juvenile scoliosis – 3–10 years

Adolescent scoliosis – approximately 11 years to skeletal maturity

Epidemiology

The most common form is:

Idiopathic scoliosis.

Scoliosis may appear at:

Any age.

Adolescent idiopathic scoliosis is most commonly recognized between approximately:

10 and 13 years of age.

Prevalence

Curves greater than:

10°

occur in approximately:

2–3% of the population.

Sex

Small idiopathic curves occur at approximately similar rates in:

Boys and girls.

However, girls are approximately:

3–4 times more likely

to develop significant:

Curve progression.

Bracing and Surgery Prevalence

Historical estimates suggest that approximately:

0.3%

develop curves large enough to require:

Brace treatment.

Approximately:

1 in 1,000

may ultimately require:

Surgical treatment.

Risk Factors for Progression

Factors associated with increased risk of curve progression include:

Female sex

Positive family history

Skeletal immaturity

Premenarchal status

Larger curve magnitude at presentation

Neuromuscular Risk Factors

Progressive deformity is also common in patients with:

Severe spinal cord injury before adolescence

Paralysis

Cerebral palsy with extensive involvement

and other severe neuromuscular disorders.

Genetics

Idiopathic scoliosis has a significant:

Familial component.

Older descriptions suggested an:

Autosomal-dominant pattern with incomplete penetrance and variable expression

in some families.

Modern understanding supports a more:

Complex polygenic and multifactorial inheritance.

Etiology

Idiopathic Scoliosis

By definition, there is no single identifiable cause.

Proposed mechanisms have included abnormalities involving:

Connective tissue

Neuromuscular control

Growth regulation

Neurohormonal signaling

and

Genetic susceptibility.

Congenital Scoliosis

Congenital scoliosis results from abnormal vertebral development.

Examples include:

Hemivertebra

and

Failure of segmentation or congenital vertebral fusion.

Neuromuscular Scoliosis

Neuromuscular scoliosis may occur with:

Cerebral palsy

Traumatic paralysis

Spina bifida

Poliomyelitis

Friedreich ataxia

Charcot–Marie–Tooth disease

Duchenne muscular dystrophy

and many other neurologic or muscular disorders affecting:

Trunk control.

Connective-Tissue Associated Scoliosis

Scoliosis may occur with disorders such as:

Marfan syndrome

Ehlers–Danlos syndrome

Neurofibromatosis

Down syndrome

and other systemic connective-tissue conditions.

Associated Conditions

Almost any disorder that affects:

Neurologic control of the trunk

or

Connective-tissue integrity

can predispose to scoliosis.

Diagnosis

Diagnosis is based on:

Standing physical examination

and

Standing spinal radiographs.

Signs and Symptoms

Symptoms vary with:

Curve location

Curve magnitude

Age

and

Underlying cause.

Thoracic Curves

Thoracic curves cause rotation of the:

Rib cage.

On the convex side, the ribs rotate posteriorly, producing a:

Rib prominence or rib hump.

The scapula on the same side may also appear:

More prominent.

Thoracolumbar and Lumbar Curves

These curves may produce:

Waist asymmetry

and an apparent:

High hip.

One side of the pelvis or flank may appear more prominent.

Pain

Many adolescents have:

Little or no pain.

Some develop mild back discomfort, but substantial pain is not typical of uncomplicated adolescent idiopathic scoliosis and should prompt evaluation for:

Other causes.

Adult Symptoms

In adulthood, patients may develop:

Mechanical back pain

Degenerative changes

and occasionally:

Nerve-root symptoms.

Growth History

In girls, menstrual history is useful because:

Menarchal status

helps estimate remaining skeletal growth and therefore risk of:

Curve progression.

Physical Examination

The examination should be performed with the patient:

Standing.

Inspection

Assess for asymmetry of:

Shoulders

Scapulae

Rib cage

Waist

Pelvis

Leg Length

Measure both lower extremities because:

Leg-length discrepancy

can produce an apparent functional scoliosis or pelvic tilt.

Adams Forward-Bend Test

The:

Adams forward-bend test

is one of the most useful screening maneuvers.

The patient bends forward with:

Knees straight

and the examiner looks along the spine for asymmetry of the:

Ribs

or

Lumbar paraspinal region.

Rib Prominence

Scoliosis causes rotational deformity that becomes more obvious during:

Forward flexion.

A thoracic curve may produce a:

Rib hump

on the convex side.

Scoliometer

A:

Scoliometer

can quantify trunk rotation.

A trunk rotation measurement around:

5–7° or greater

commonly prompts consideration of:

Radiographic evaluation

depending on age, clinical context, and screening protocol.

False-Positive Forward-Bend Test

Some patients have:

Trunk asymmetry

without a radiographic scoliosis greater than 10°.

Therefore, an abnormal forward-bend test alone does not establish:

Structural scoliosis.

Sagittal Alignment

Observe for abnormal:

Kyphosis

and

Lordosis.

Skin Examination

Inspect the skin over the spine for:

Dimples

Hairy patches

Vascular markings

or other cutaneous stigmata that may suggest:

Underlying spinal dysraphism or congenital abnormality.

Ligamentous Laxity

Generalized:

Joint hypermobility

should be assessed when connective-tissue disease is suspected.

Neurocutaneous Findings

Look for:

Café-au-lait macules

Neurofibromas

or other findings suggestive of:

Neurofibromatosis.

Neurologic Examination

A careful neurologic examination is essential.

Assess:

Gait

Strength

Sensation

Reflexes

and

Abdominal reflexes.

Functional Neurologic Assessment

Useful screening observations include:

Heel walking

Toe walking

Single-leg hopping

and overall:

Gait symmetry.

Abdominal Reflexes

Asymmetric or absent abdominal reflexes may raise concern for:

Underlying spinal cord pathology

such as:

Syringomyelia.

Physical Maturity

Growth potential should be assessed using:

Secondary sexual characteristics

Menarchal status

Height changes

and radiographic indicators of:

Skeletal maturity.

Serial Height

Height should be measured over time because rapid growth is associated with a higher risk of:

Curve progression.

Imaging

Standing Spinal Radiographs

The standard study is a:

Standing posteroanterior full-length spinal radiograph.

This allows measurement of:

Curve magnitude

Coronal balance

and

Skeletal maturity.

Cobb Angle

The:

Cobb angle

is measured between the most tilted vertebrae at the:

Upper and lower ends of the curve.

A curve greater than:

10°

meets the radiographic definition of scoliosis.

Lateral Radiograph

A standing lateral view is useful when evaluating:

Kyphosis

Lordosis

or other sagittal deformity.

Risser Stage

The iliac crest apophysis can be used to estimate:

Skeletal maturity.

The:

Risser stage

ranges from:

0 – little or no iliac apophyseal ossification

to

5 – complete ossification and fusion.

Greater Risser stage generally indicates:

Less remaining spinal growth.

Triradiate Cartilage

An open:

Triradiate cartilage

of the pelvis indicates substantial:

Skeletal immaturity

and that the major growth period is not yet complete.

MRI

MRI is not routinely required for every patient with typical adolescent idiopathic scoliosis.

It is indicated when there is concern for:

Spinal cord abnormality

Neurologic findings

Atypical curve pattern

Significant unexplained pain

or other suspicious features.

Early-Onset Scoliosis

MRI is commonly obtained for clinically significant:

Infantile

and

Juvenile scoliosis

because the likelihood of underlying:

Neural-axis abnormalities

is higher.

Pathological Findings

In structural scoliosis, the vertebrae undergo:

Rotation

toward the convexity of the curve.

Vertebral Remodeling

As the child grows while the spine remains curved, individual vertebrae may become:

Asymmetrically shaped

or

Wedged.

The deformity therefore becomes increasingly:

Three-dimensional.

Differential Diagnosis

Important alternatives include:

Isolated rib asymmetry

Kyphosis

Leg-length discrepancy

Sprengel deformity

Clavicular deformity or previous fracture

Postural scoliosis

Functional Scoliosis

Leg-length inequality can produce an apparent:

Pelvic tilt and compensatory spinal curve.

Unlike a true structural scoliosis, this may improve when the:

Pelvis is leveled.

Kyphosis

Kyphosis is primarily a deformity in the:

Sagittal plane.

It can occasionally be mistaken clinically for scoliosis when shoulder or trunk asymmetry is prominent.

Treatment

General Principles

The spine in uncomplicated scoliosis is:

Not mechanically unstable.

Patients should generally remain:

Active.

Bone Health

Adequate:

Calcium

and

Vitamin D

should be maintained through diet or supplementation when indicated.

Exercise

Exercise may improve:

Strength

Conditioning

Posture

and

Back discomfort.

It does not reliably correct the structural Cobb angle by itself.

Observation

Growing children with relatively small curves, generally:

Less than approximately 20–25°

are usually managed with:

Observation and serial examination.

Skeletally Mature Patients

A patient with a small stable curve who has reached:

Skeletal maturity

may no longer require routine pediatric deformity follow-up.

Bracing

Bracing is generally considered for:

Moderate idiopathic curves

in children who still have significant:

Growth remaining.

Typical Bracing Range

Brace treatment is commonly used for curves around:

25–40°

in skeletally immature patients.

Goal of Bracing

The goal is not necessarily to permanently straighten the spine.

The primary aim is to:

Reduce the risk of curve progression

and decrease the likelihood of:

Surgery.

Brace Effectiveness

Full-time brace treatment has been shown to reduce progression risk in appropriately selected:

Growing adolescents with idiopathic scoliosis.

Effectiveness depends heavily on:

Brace wear time

and

Remaining growth.

Large Curves

Curves greater than approximately:

40–45°

should be evaluated by an:

Orthopaedic spine specialist.

Surgical Threshold

Surgery is commonly considered for progressive adolescent idiopathic curves around:

45–50° or greater

particularly when substantial growth remains or progression is documented.

Infantile Scoliosis

Selected children with progressive infantile scoliosis may benefit from:

Serial corrective casting.

Casting may be continued over:

Several months

and can occasionally substantially correct early flexible curves.

Physical Therapy

Physical therapy may help patients with:

Pain

Stiffness

Poor conditioning

or postural difficulty.

Exercise Program

Exercises may include:

Core strengthening

Spinal extensor strengthening

Flexibility work

Postural training

Aerobic conditioning.

Curve-Specific Exercises

Specialized scoliosis-specific exercise programs may help with:

Postural control

Trunk symmetry

and function in selected patients.

They are generally considered an adjunct rather than a replacement for:

Observation, bracing, or surgery when otherwise indicated.

Complementary Therapies

Yoga or similar flexibility and conditioning activities may help with:

Back discomfort

and general well-being.

They have not been shown to reliably correct a significant structural curve.

Surgery

The goal of surgery is to:

Correct deformity

Prevent further progression

and maintain overall:

Spinal balance.

Posterior Instrumentation and Fusion

A common operation uses:

Posterior spinal instrumentation

with rods, screws, and bone graft.

The curved portion of the spine is:

Corrected and fused.

Fusion Levels

Only the necessary portion of the spine is included in the fusion to preserve as much:

Spinal mobility

as safely possible.

Bone Graft

Bone graft is placed along the instrumented segment to promote:

Solid vertebral fusion.

Neurologic Risk

Major neurologic injury is:

Uncommon

with modern techniques and intraoperative neurologic monitoring.

Historical estimates placed the risk at:

Less than approximately 1%.

Follow-Up

Children with scoliosis should generally be followed until:

Skeletal maturity

or until the curve is clearly stable.

Growing Children

During periods of rapid growth, patients are commonly reviewed every:

4–6 months.

Adult Follow-Up

Adults with established curves may be followed every:

1–5 years

depending on:

Symptoms

Curve magnitude

and

Evidence of progression.

Congenital Scoliosis

Patients with congenital scoliosis require assessment for associated abnormalities involving:

Spinal cord

Kidneys

Heart

and other organ systems depending on the vertebral anomaly.

Prognosis

Prognosis depends on:

Curve magnitude

Curve type

Remaining growth

Underlying diagnosis.

Adult Progression

Many untreated curves greater than approximately:

40–50° at skeletal maturity

continue to progress slowly during adulthood.

Pulmonary Function

Major pulmonary compromise is uncommon in typical moderate adolescent idiopathic scoliosis.

It becomes a concern particularly with:

Very severe thoracic curves

especially those exceeding approximately:

70–100°.

Neuromuscular and Congenital Curves

Severe congenital or neuromuscular scoliosis may produce:

Restrictive pulmonary disease

and, in extreme cases:

Cor pulmonale.

Back Pain

Curves greater than approximately:

40°

may be associated with an increased frequency of:

Back pain in adulthood.

However, many adults with scoliosis remain highly functional.

Complications

Potential complications of severe untreated scoliosis include:

Progressive deformity

Chronic back pain

Degenerative changes

Radiculopathy

Reduced pulmonary function in severe thoracic curves

Surgical Complications

Potential complications include:

Neurologic injury

Infection

Pseudarthrosis or failure of fusion

Implant problems

Loss of correction

Patient Monitoring

Growing patients should be monitored for:

Curve magnitude

Curve progression

Skeletal maturity

Height

Neurologic status

Brace compliance when applicable

Radiographic Monitoring

Serial standing radiographs are used to document:

Cobb angle progression

while minimizing unnecessary radiation exposure.

Key Principle

Scoliosis is a three-dimensional spinal deformity defined radiographically by a Cobb angle greater than 10°.

The most common form is:

Adolescent idiopathic scoliosis.

Management is determined primarily by:

Curve magnitude, skeletal maturity, and risk of progression.

Small curves are generally:

Observed, moderate progressive curves in growing children may require:

Bracing, and curves approaching or exceeding approximately:

45–50°

may require consideration of:

Surgical correction and spinal fusion.