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

Figure 3

(a) A 15-year-old boy with Lenke 2A curve, who received primary surgery in another hospital. L1 was SSV; Risser grade was 2. (b) 2-year postoperative radiograph shows adding-on; the deviation of the first vertebra below the instrumentation (LIV + 1) from the CSVL was 45.5 mm. LIV was 2 levels proximal to SSV. (c) 4-year postoperative radiograph shows adding-on progressed; the LIV + 1 deviation increased to 53.2 mm. Shoulders were level with RSH of 4.24 mm. (d) Postrevision radiograph shows left shoulder elevated with RSH of 37.44 mm.

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