INTRODUCTION:
When performing posterior spinal fusion for adolescent idiopathic scoliosis (AIS), it is of major importance to address both coronal and sagittal deformities. Although several techniques have been described, few data exist comparing them. Our objective was to compare four techniques (in situ bending (ISB), rod derotation (RD), cantilever (C) and posteromedial translation (PMT)) for the correction of spinal deformity in AIS including thoracic deformity.

MATERIAL AND METHODS:
We conducted a multicenter retrospective study including 562 AIS patients with thoracic deformity with at least 24-month follow-up. Radiographic analysis was performed preoperatively, postoperatively and at last follow-up. The main outcomes were main curve correction and thoracic kyphosis restoration (TK).

RESULTS:
Coronal correction rate was significantly different among the four treatment groups (ISB 64% vs C 57% vs RD 55% vs PMT 67%, p <  0.001). Multivariate regression revealed that correction technique did not influence correction rate, whereas implant density, convex side compression and use of derotation connectors did. TK increase was significantly higher in the PMT group (average + 13°) than in DR (+ 3°), while ISB (-3°) and cantilever (-13°) resulted in TK decrease (p <  0.001). Multivariate analysis revealed that TK increase was only influenced by the reduction technique (p <  0.001) and preoperative TK (p <  0.001).

DISCUSSION:
The four techniques had the same ability to correct spinal deformity in the coronal plane. Three factors were identified to improve correction rate: implant density, convex compression and use of derotation connectors. On the other hand, PMT was more effective in restoring TK, particularly in hypokyphotic patients.





Polls results
1

On a scale of 1 to 10, rate how much this article will change your clinical practice?

NO change
BIG change
52% Article relates to my practice (11/21)
28% Article does not relate to my practice (6/21)
19% Undecided (4/21)
2

Will this article lead to more cost-effective healthcare?

42% Yes (9/21)
23% No (5/21)
33% Undecided (7/21)
3

Was this article biased? (commercial or personal)

9% Yes (2/21)
85% No (18/21)
4% Undecided (1/21)
4

What level of evidence do you think this article is?

0% Level 1 (0/21)
4% Level 2 (1/21)
85% Level 3 (18/21)
9% Level 4 (2/21)
0% Level 5 (0/21)