不同胸腰椎補骨術之生物力學評估

Biomechanical Evaluation of Different Types of Bone Graft Surgery in Thoracolumbar Vertebrae

謝淑娟(Shu-Jiuan Hsieh)

指導教授 ： 陳文斌

中原大學/工學院/醫學工程研究所/碩士(2002年)

https://doi.org/10.6840/cycu200200031

摘要

在胸腰脊椎手術上，補骨是常被使用來增加骨融合和提供椎體穩定的方式，而腸骨則是經常被使用的自體骨。在胸腰椎手術施行時，肋骨通常必須被移除，因此也被認為是作為補骨的另一種選擇，然而，肋骨使用在胸腰椎前位補骨的生物力學效果並未在文獻上有報導。因此本研究的目的是在建立完整的胸腰椎有限元素模型，來評估使用腸骨、一截肋骨或是兩截肋骨，且有加入或是沒加入胸腰椎內固定器對於補骨本身的影響。我們採用T10到L2五節椎體的斷層掃描的影像，影像的取得為每隔3毫米取一片，總共54片，經由轉檔後建立出完整的實體模型，不過在此研究中我們只選用T12和L1兩節椎體作為分析模擬之用。由於在此為討論前位補骨，因此我們將椎間盤移除，並在椎體的左方植入三種補骨的材料作為模擬。在此我們假設在三種補骨術中皆已產生骨融合，且所有的補骨材料性質皆為相同，所有的接觸面皆為完全固定，因此沒有介面間滑動的問題。從分析結果中顯示，當只有使用一截肋骨做為補骨時，在補骨上的應力值會較使用兩截肋骨或腸骨為補骨時要大，且必須要配合使用脊椎內固定器，這顯示當使用一截肋骨做為補骨時會較早發生毀壞，但是當我們加入內固定器之後，一截肋骨上的應力分佈和使用腸骨時的應力分部會相近；當使用兩截肋骨或腸骨時，其補骨上的應力分布極為相似，因此我們知道當骨融合已經產生之後使用兩截肋骨做為補骨應該是可行的，但是腸骨依然是比較安全的選擇。

關鍵字

補骨 ； 有限元素法 ； 胸腰椎 ； 脊椎內固定器

並列摘要

In spinal fusion surgery, bone grafts are commonly used to enhance bone fusion and to provide stability. In practice, autologous bone graft, such as, iliac bone crest is most often adopted. In thoracolumbar vertebral surgery, the ribs are often dissected and may be an alternative choice for bone graft besides iliac bone. However, the biomechanical efficacy of rib bone graft used in thoracolumbar anterior bone fusion was not reported in literature. The purpose of this study was to use a finite element model to evaluate the effects of using iliac bone; one rib or two ribs bone graft, with and without instrumentation in thoracolumbar vertebral bone graft surgery. Fifty-four transverse plane CT scan images were obtained at 3 mm intervals and used to create a T10 to L2 five-segment, three-dimensional finite element model. Only the T12-L1 motion segment was used for this study. The intervertebral disc in the segment was removed and anterior bone graft surgery was simulated. The bone fusion was assumed for all models, therefore, the iliac bone and rib bone were assigned with the same material property. All interfaces were assumed to be bond with no micromotion. Based on the stress results, we found that when only one rib bone was used, the stress in the graft was higher than that of the iliac bone graft and the two ribs bone graft conditions and spinal instrumentation must be applied. This implies that early collapse may occur when only one rib bone graft was applied. But if spinal instrumentation was applied, the stress on the one rib bone graft was similar with the two ribs bone graft and iliac crest bone graft. The stress distributions for the iliac bone graft and the two ribs bone graft were similar whether using spinal instrumentation or not. Therefore, two ribs bone graft may be an acceptable alternative besides iliac bone graft if fully bone fusion is established. If bone fusion is not established, then iliac bone graft may still be a safer choice than rib bone graft.

並列關鍵字

spinal instrumentation. ； bone graft ； thoracolumbar spine ； finite element analysis

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