For example, Chang explains, one patient had a spine that had curved into an S shape. The deformation was composed of three curves, so it was necessary to insert over 20 screws from the first thoracic vertebra to the third lumbar vertebra in order to get a satisfactory correction.
張國華舉例，有一位脊椎呈 S 型側彎，又有駝背、骨骼旋轉的病患，是 3 個弧度的合併畸型，得從胸椎第一節到腰椎第三節打上二十多根鋼釘，才能達到滿意的矯正效果。