1. Retrospective Review of Shoulder Balance Comparing Adolescent Idiopathic Scoliosis (AIS) to Early Onset Scoliosis (EOS)
Patrick J. Cahill
William Lavelle
Swamy Kurra
Stephen A. Albanese
Randal R. Betz

2. Hypothesis Study Design
Compare AIS and EOS populations to see if surgical techniques used had an effect on the ultimate alignment of the shoulder girdle.
Study Design
Retrospective study (n = 145):
2 prospectively collected databases
HARMS Study Group
Children’s Spine Study Group
Reviewed AIS and EOS patients involved in definitive fusions

3. Background Treatment of spinal deformity can be challenging.
AIS surgical distraction techniques, EOS (growing rods or VEPTRs) and final definitive fusion all focus on improvement of spinal deformity.
Few studies have investigated the effect of corrective measures on overall alignment of the shoulder girdle.

5. Methods Study categorized into:
AIS Group (n = 111)
EOS Group (n = 34)
Compared prior and post definitive fusion radiographic shoulder balance parameters between groups (AIS vs. EOS)
T1 tilt angle
Kuklo clavical angle
Coracoid height difference (CHD)
Clavicular tilt angle difference (CRAD)
Clavicle-rib intersection difference (CRID)

6. T1 Tilt angle
Kuklo Clavicle angle
Angle formed between superior end plate of T1 and horizontal line
Angle between horizontal line and the line connecting highest point of clavicle

7. Clavicle Tilt Angle difference
Differences of the left and right clavicle tilt angles. Clavicle Tilt angle is the angle between the horizontal angle and the line passing along the middle of clavicle.

8. Clavicle height difference Coracoid height difference
Difference between the points where right and left clavicle intersect ribcage, respectively
Right and left coracoid height difference

9. Methods Preop and Postop Compared groups by ANOVA test
Measured major and minor coronal Cobb angles
Measured sagittal imbalances
Measured percentage of corrections from lateral and posterioranterior (PA) standing radiographic films
Compared groups by ANOVA test
P < 0.05 considered statistically significant

10. Results Mean age at definitive fusion: AIS = 11.3 years
EOS – 12.6 years
Post definitive fusion shoulder girdle measurements were statistically significant. (Table 1)
Though measurements were significant, but no significant difference in post definitive means between groups. (Table 1)
Mean post definitive fusion major Cobb corrections were greater in AIS vs. EOS:
AIS Group:
59.36o preop to 20.18o postop
EOS Group:
67.26o preop to 50.7o postop
Post definitive fusion p< between groups

11. Post Definitive Fusion
Table 1
T 1 Tilt CA
CTAD
CRID
CHD
Mean
Mean (cm)
Post Definitive Fusion
AIS
-5.38o
-2.33o
-4.23o
-1.092
-1.255
EOS
1.63o
0.52o
0.8o
0.153
0.225
Normal Population (a)
1.3o
(+1.4o)
2.2o
(+1.7o)
4.0o
(+3.2o)
0.48
(+0.36)
0.69
(+0.58)
(a) Normal population of non-scoliosis patients in Akel I, et al. Evaluation of shoulder balance in the normal adolescent population and its correlation with radiographical parameters. Eur Spine J Mar; 17(3):

12. Conclusion
Both AIS and EOS surgical techniques are effective in maintaining proper shoulder girdles alignment.
AIS techniques show more success in terms of Cobb angle correction than EOS techniques.