Congenital Scoliosis

Definition

 

Lateral curvature of the spine 2° to vertebral anomaly

- causes an imbalance in longitudinal spine growth

 

Epidemiology

 

True incidence unknown

 

F > M

 

Typically Thoracic

 

Inheritance

 

No association in twins / suggests not inherited

5% risk in family if complex multi-level

 

Aetiology

 

Occurs during mesenchymal development 4-8/52  

- unknown foetal insult

- high incidence other anomalies 

- VECTRAL"

 

V vertebral and spinal abnormalities

E endocrine

C cardiac

T tracheo-esophageal fistulas

R renal

R radial club hand

A anus imperforate/ urogenital (cloacae abn)

L limb Sprengel shoulder, club hand, CTEV

S single umbilical artery

 

Associations

 

Referrals

- neurosurgery

- cardiology

- urology

 

Spinal Dysraphism (25%)

- failure of neural tube closure

- diastematomyelia , syrinx, tethered cord, arnold chiari malformation, fibrous dural bands, intradural lipoma, SB

- clinically associated with hair patches, dimples, lipomas, tails

- all should have MRI especially presurgery

- can have rib abnormalities / fusions

- can have posterior element abnormalities

 

Genitourinary 25%

- 6% have obstructive uropathy

- horse shoe kidneys

- lifethreatening

- all have ultrasounds +/- urology opinion

 

Cardiac 10%

- all murmurs should be investigated

- ASD, VSD, PDA, Tetralogy Fallot

- all patients have echo prior to surgery

 

Limbs

- radial club hand

- congenital amputations

- cavovarus foot / CTEV

 

Klippel-Feil 25%

 

Classification 

 

International  Spine Society / MacEwen

- failure formation

- failure of segmentation

- mixed

- unclassifiable

 

Most common

- unilateral bar

- fully segmented hemivertebrae

- semi segmented hemivertebrae

 

Failure of Formation

 

A.  Partial / Wedge Vertebra (5%)

 

B.  Complete / Hemivertebra (30%)

 

Fully Segmented

- common

- open disc above & below

- greatest growth disturbance

 

Semi Segmented

- 1 growth plate (either above or below)

 

Non Segmented / Incarcerated

- no disc above or below

- minimal growth potential

 

Failure of segmentation

 

A.  Unilateral / Unilateral Unsegmented Bar (50%)

 

B.  Bilateral / Block Vertebra (5%)

 

Mixed

 

Combination both / Commonest

 

Unclassifiable (20%)

 

NHx

 

Anomaly present at birth but may not become evident until later life

 

Diagnosed < 3 or 9-14 years old

 

Associated with most rapid growth periods for the spine

- in utero

- from birth to 5 years

- puberty

 

Progression

 

Progression occurs if differential growth

- if more physis on one side 

- count number of physes

 

25% show no progression

 

50% progress rapidly

 

25% progress slowly

 

Prognostic Features

 

Type

 

Age

- worst prognosis with clinical deformity in first year of life

 

Location

- higher in the spine, less likely to progress

- upper thoracic curve best

- lumbar worst

 

Worst  10° / year

 

Unilateral unsegmented bar + fully segmented contralateral hemivertebrae

- over 14 years can get 140 - 180o curve

 

Intermediate 5˚

 

Unilateral unsegmented bar 

 

Fully segmented hemivertebra

- most common

- usually a problem

- 2 growth plates

- 2 consecutive hemivertebra a problem

 

Semisegmented hemivertebrae

- second most common

- single growth plate

- curve at maturity usually < 40o

 

Consecutive Hemivertebrae

 

Best < 2˚

 

Block vertebra best

- bilateral growth impairment

 

Non segmented / incarcerated hemivertebrae

- may produce slowly progressive curve

 

Unpredictable

 

Single hemivertebra unpredictable

- act as enlarging wedge

- often small with limited growth potential (incarcerated)

 

Xray

 

Lesion often difficult to interpret

 

See fused ribs

 

3D CT 

 

Excellent guide to anatomy

 

MRI

 

Should be performed before operative intervention

- assess for vertebral abnormality (40%)

- exclude Diastematomyelia / Tethered cord / Syrinx / Arnold Chiari Malformation

 

Other

 

Renal ultrasound

Echo

 

Management

 

Key is identification of curves likely to progress to prevent severe deforrmity

 

Non-operative

 

Bracing not indicated

 

Observe each 6/12

- look for progression

- examine for neurology

- continue until skeletal maturity

 

Operative

 

Indications

- progressive > 4-6o per year

- >40°

- high likelihood severe deformity i.e. unilateral unsegmented bar

- unbalanced child e.g. L5 hemivertebrae

 

Options

- fusions (posterior, anterior/posterior)

- hemi-epiphysiodesis

- hemivertebrae excision

- corrective osteotomy + instrumentation

- growing rods

- expansion thoracoplasty

 

Growth Inhibition

 

Each vertebrae contributes 1 cm in height in normal spine

 

Not true in abnormal spine

- delaying fusion actually makes patient shorter due to increasing deformity

- best to operate early

- unbalanced growth centres don't contribute to vertical height

 

Principle 

 

Fully segmented hemivertebrae

 

1.  Stop growth on affected side

- segments above & below fused unilaterally on side of hemivertebra

- hemi-epiphyseodesis performed anterior & posterior

- effectively produce contralateral unsegmented bar above & below

 

2.  Excision of hemivertebrae

- more common

- especially at lumbosacral junction

 

Unilateral bar

 

Stop growth on other side

- hemi-epiphyseodesis anterior / posterior on  convex side 

- < 5 years

- segment effectively converted to block vertebra

 

Other options

 

Growing Rods

 

For patient < 5

- long segment involved

 

Expansion Thoracoplasty

 

Fused ribs common

- excise fusion

- vertical expandable titanium rib

- allows chest expansion and normal development of ribs