Prediction of Progression in Idiopathic Scoliosis of Moderate Severity in Adolescent Girls

 

Patient population: adolescent girls ages 10-15 with an initial curve 25-35 degrees

Endpoints are either skeletal maturity or increase in curvature by 6 degrees or more

 

Parameters:

(1) Risser's sign

(2) apical vertebra

(3) chronological age in years

(4) balance

 

Parameter	Finding	Points
Risser's sign	2 to 5	0
	0 or 1	1
apical vertebra	12th thoracic or 1st lumbar	0
	8, 10 or 11 thoracic	1
chronological age in years	> 13 years	0
	<= 13 years	1
imbalance	<= 10 mm to either side	0
	> 10 mm to either side	1

 

where:

• Risser's sign refers to the chronological progression in the ossification of the iliac crest apophysis. Grade 0 indicates an age < 13 years, Grade 1 at 13 years, Grade 2 at 14 years, Grade 3 at 15 years, Grade 4 at 16 years and Grade 5 at 17-18 years.

• Imbalance is measured as the perpendicular distance (towards the midline) from a plumb line dropped from a spinous process of the 7th cervical vertebra to the crena ani (internatal cleft).

 

logit (P) =

= (-3.61) + (2.33 * (points for Risser sign)) + (2.35 * (points for apex)) + (0.80 * (points for chronological age)) - (0.85 * (points for imbalance))

 

probability of progression in scoliotic curve more than 6 degrees =

= EXP (logit(P)) / (1 + (EXP(logit(P)))