Infantile Idiopathic

Epidemiology

 

< 4 years by definition

 

M : F

 

75% left thoracic

 

Actually very uncommon 

- likely most patients once had spinal dysraphism (Arnold-chiari / syrinx / tethered cord)

- reduced by prenatal folate

 

Progression

 

Age < 1

- 90 % spontaneously regress

- very important

- 10% progress to severe deformities

 

Age > 1

- 80% progress

- more likely to cause cardio / respiratory compromise

- alveoli not developed til age 8

- lungs need room to develop

- high associated with other abnormalities

 

Progression Risk

 

1.  Mehta Angle / Rib-vertebral angle difference / RVAD

 

Difference in angle at which rib meets spine at Apex of curve on either side on AP x-ray

-  > 20° likely to progress 

 

Phase one and phase two

- phase 2 : rib head overlaps and angle cannot be measured

- risk of progression high

- indicative of rotation

 

2.  Degree of Curve

 

Likely to progress if curve > 25°

 

CT

 

Exclude congenital scoliosis

 

MRI

 

Mandatory

- 20% incidence intraspinal pathology

- syrinx / tethered cord / diastematomyelia / ACM

 

Management

 

Non operative

 

Indications

 

Curve < 25o and RVAD < 20o

- resolve spontaneously

- no need for treatment

 

Curve > 25o and RVAD > 20o

- brace

 

Bracing

 

Serial cast < 1 year

 

Brace > 1 year 

- Milwaukee brace can be curative

- younger age group more likely to tolerate this brace than adolescents

- brace must be worn until curve maximally & permanently corrected

- infantile growth spurt continues till ~ age 4-5

 

Operative

 

Indications

 

Curves > 35o

Progressive curves 5o in 6/12 

 

Issue

 

Patient < 10 years or before PHV

- high risk crankshaft effect 

- fusions must be anterior and posterior

 

Options

 

1.  Posterior growing rods

- obtain correction whilst maintaining truncal growth 

- subcutaneous Harrington rod / Growth Rods / Luque rods

- spine exposed at ends for hook insertion with submuscular or subcutaneous rod insertion

- requires surgical adjustment every year (can be done up to 5 times)

- surgery each time adds to scar and increases risk of problems including infection and cut out

- posterior fusion at later age 

 

2.  Hemiepiphyseodesis

- fusion of convex side of apical vertebrae

- is difficult to obtain half disc fusion

- may be used supplementary to growing rods

 

3.  Staples / guided growth hemiepiphyseodesis

- can be done endosopically

 

4.  Posterior instrumented fusion

- not indicated in young children as causes crankshaft effect due to anterior growth continuing

- can be safely performed at age 12 (girls) or 14 (boys)

 

5.  Anterior & Posterior instrumented fusion

- avoids crankshaft effect

- inhibits truncal growth