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