本研究旨在探討青少年脊椎側彎的矯正手術流程之力學分析，特別考慮大變形分析與椎間盤的超彈性材料性質的情況。本研究透過有限元素法(Finite Element Method, FEM)模擬脊椎側彎矯正手術流程，對矯正器械和脊椎結構之交互作用進行了詳細力學分析，以預測手術結果並優化手術規劃。
研究首先建立了包含腰椎至骨盆的詳細有限元素模型，考慮到各種材料的機械性質對其做不同的材料性質設定，模型包括腰椎、骨盆、椎間盤、韌帶、矯正器械等結構。為了正確模擬手術過程，本研究在模型中設置適當之邊界條件、接觸行為、負載條件。本研究同時考慮了不同參數對於模擬之影響，例如有無腰椎韌帶、不同矯正桿直徑及小變形與大變形(幾何非線性)之分析。
研究結果顯示，腰椎韌帶對脊椎穩定性有重要影響，並可減緩螺釘鬆脫之風險。而增大矯正桿直徑會因其剛性增強，進而防止脊椎在矯正後回彈過多的位移量，然而較大直徑之矯正桿會增加螺釘之軸向力，使螺釘鬆脫風險增高。本研究亦強調了開啟幾何非線性分析的重要性，因為它對於準確模擬手術後的生物力學變化至關重要。本研究通過有限元素模擬，提供青少年脊椎側彎矯正手術的見解，為臨床手術提供結果參考，有助於臨床醫師在手術前改善手術計畫並制定更為周全的手術策略。

Scoliosis is a three-dimensional deformity of the spine that strongly affects patients' quality of life. Adolescent Idiopathic Scoliosis (AIS) is the most common type of scoliosis in children aged 10 to 18. Finite Element Analysis (FEA) has demonstrated its potential in simulating the spinal deformities. This study aims to simulate the adolescent idiopathic scoliosis correction surgery with Finite Element Method (FEM).
The geometric model of L2 to the pelvis, including the lumbar vertebrae, intervertebral discs, endplates, sacrum, iliac, screws, and rods were established from the CT scan data according to a patient with adolescent scoliosis by using CAD software. The finite element mesh was generated using the commercial software ABAQUS. The analysis process during the adolescent idiopathic scoliosis correction surgery including vertebrae movement, contact between correction rods and screws, and the spring back of vertebrae were also simulated by ABAQUS.
The results shows that larger diameter correction rods increase the stiffness of the entire correction device, which reduces spinal displacement postoperative but also raises axial forces on the screws, increasing the risk of screw loosening and bone fracture. The presence of lumbar ligaments plays a significant role in reducing both stresses on the cortical bones and the risk of screw loosening. All stress values in the simulation remained within safe limits according to tensile strength of bones in literature, indicating no significant risk of bone fractures. These insights are critical for optimizing surgical planning, rod selection, and minimizing potential complications in AIS correction procedures.

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