Natural History of Postoperative Adding-On in Adolescent Idiopathic Scoliosis: What Are the Risk Factors for Progressive Adding-On?

Figure 1

(a) A 13-year-old girl with Lenke 1A curve. L2 was SSV; Risser grade was 0. (b) First erect radiograph postoperatively with fusion to L1, one level proximal to SSV. (c) 3-month postoperative radiograph shows adding-on; the angulation of the first disc below the instrumentation was 6.8°. (d) 4-year postoperative radiograph shows adding-on progressed; the disc angulation increased to 12.2°.

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