椎間盤突出量與椎間核壓力之關係

Abstract

背景：隨著年齡的增加及長期負重，椎間核開始脫水變性，吸收分散壓力的能力降低，同時纖維環也開始退化龜裂，一個不當的姿勢或動作，即可能造成椎間盤突出。而大部分的脊椎傷害，是在承受過大的動態載荷所發生的，傷害的地方以胸腰椎居多，因此選擇與人體結構、體型相近的豬脊椎，取用下段胸椎作為研究對象。 目標：利用自由落體衝擊的方式，對試樣施加負載，進而模擬人體胸椎運動元在承受不同衝擊載荷下，所產生之椎間盤突出量與椎間核壓力，並深入探討二者之關係。 方法：使用24個豬胸椎的兩節運動元作為試樣，分別為11個胸椎第八節至第十節（T8∼T10）、13個胸椎第十一節至第十三節（T11∼T13），其中進行椎間盤突出量與椎間核壓力量測各為12個試樣。在均佈力負載與集中力偏心負載下，以不同的衝擊能量與接觸時間，分別使用兩支線性位移計及針型壓力感測器從試樣左側去量測椎間盤突出量與椎間核壓力。 結果：均佈力負載下，在衝擊能量3.6 J、接觸時間20ms時，最大椎間盤突出量為0.624 mm，而最大椎間核壓力為1.861 MPa。椎間核壓力與椎間盤突出量整體之相關係數為0.721。而在集中力偏心負載，衝擊能量3.6 J、接觸時間20ms時，最大椎間盤突出量為0.618 mm，最大椎間核壓力為1.945 MPa。椎間核壓力與椎間盤突出量整體之相關係數為0.518。 結論：在均佈力負載與集中力偏心負載兩種情況下，當衝擊能量越大或衝擊接觸時間越短時，椎間盤突出量與椎間核壓力就會越大。上節椎間盤其椎間核壓力與椎間盤突出量會比下節椎間盤來的大。在集中力偏心負載，衝擊點於試樣中央位置，椎間盤突出量與椎間核壓力會比前彎、後仰時大。而椎間盤突出量與椎間核壓力兩者之相關性與衝擊高度、接觸時間、兩節運動元上下節椎間盤有關。上節椎間盤其相關性比下節椎間盤還高。在集中力偏心負載，椎間盤突出量與椎間核壓力兩者之相關性特別與衝擊位置有很大的關係，在載荷位置於中央時會比前彎、後仰時高。

Summary of Background Data. It is well known that improper motions and mal-aligned postures may cause HIVD which is characterized by the bulging of the intervertebral discs and increased intradiscal pressures. However, rare studies investigate the relationship of disc bulging and intradiscal pressures. Objectives. The aim of the present study was to investigate the correlation between intradiscal pressure and disc bulging. Methods. 12 porcine thoracic porcine spine were used from which T8-T10 (n=11) and T11-T13 (n=13)were dissected as specimens. The intradiscal pressure and disc bulging were measured with two needle-type pressure sensors and two LVDTs from lateral approach under different loading condition. Results. In distributed loading regimen, the maximum of disc bulging (0.624 mm) and the largest intradiscal pressure (1.861 MPa) were measured under 3.6 J of external energy and 20ms of contact duration. The correlation coefficient of bulging and pressure was 0.721. In eccentric loading regimen, the maximum disc bulging (0.618 mm) and the largest intradiscal pressure (1.945 MPa) occurred under the same loading condition as distributed loading regimen. The correlation coefficient of bulging and pressure was 0.518. Conclusions. In either the distributed loading regimen or the eccentric loading regimen, the intradiscal pressure and disc bulging increase as the loading energy increases or the contact duration decreases. As for the two-motion segments, the intradiscal pressure and disc bulging of upper disc are both larger than the lower one under the same loading condition. When the loading is applied along the center of the specimen, the intradiscal pressure and disc bulging are larger than that in flexion and in extension. In distributed loading regimen, the correlation coefficient of intradiscal pressure and disc bulging is related to the loading energy, contact duration and the level of vertebrae. However, in eccentric loading regimen, the correlation coefficient of intradiscal pressure and disc bulging is only related to the loading position.