脊椎骨釘在被充分利用在脊椎的重建、固定、矯正等用途。對於骨質疏鬆的患者，傳統脊椎骨釘時常無法有效的與脊椎產生良好的鍵結，導致臨床上時常發生脊椎骨釘鬆脫或被拔出等問題。骨水泥錨定型脊椎骨釘被設計來提升骨頭與脊椎骨釘間的結合力以解決此類問題。骨水泥錨定型脊椎骨釘的設計導入了一個中心孔與三個滲漏溝槽，在使用時骨水泥可以在骨水泥錨定型脊椎骨釘已經植入脊椎椎節中的狀況下藉由中心孔施打，並由三個滲漏溝槽擴散至椎節中。這個設計可以使骨水泥被有效的應用於增加骨抓力，但一個中心孔與三個滲漏溝槽卻可能對骨水泥錨定型脊椎骨釘的機械性質強度產生很大的影響。
本研究的目的是探討骨水泥錨定型脊椎骨釘的機械性質強度、了解不同幾何設計對骨釘強度的影響以及利用美敦力公司所生產市售的脊椎骨釘作為對照組進行骨水泥錨定型脊椎骨釘安全性的評估。此研究的進行方式為利用骨釘抗彎測試製造出不同的骨釘破壞模式，再根據不同的破壞模式分別比較不同脊椎骨釘組別的機械強度差異。所比較的破壞模式有靜態鎖附螺絲破壞、靜態脊椎骨釘頸部破壞、動態骨釘頸部破壞、動態滲漏溝槽破壞以上四種。抗彎測試的實驗方法參考美國材料試驗協會的測試規範F2193進行。
本研究的特定目標分成以下幾點：(1)設計並製造改良版本的骨水泥錨定型脊椎骨釘；(2)進行靜態抗彎測試並達到鎖附螺絲破壞；(3)進行靜態抗彎測試並達到脊椎骨釘頸部破壞；(4)進行動態抗彎測試並達到脊椎骨釘頸部破壞；(5) 進行動態抗彎測試並達到滲漏溝槽破壞。
研究結果顯示改良版本的骨水泥錨定型脊椎骨釘相較於舊版在各種破化模式下皆可以承受更高的彎曲扭矩，證明所做的設計變更可有效提升機械強度。相較於市售的對照組脊椎骨釘，改良版本的骨水泥錨定型脊椎骨釘一樣呈現出較高的抗彎曲扭矩能力，這表示此骨水泥錨定型脊椎骨釘若作為一個產品，它會擁有一個安全的機械強度。

Pedicle screw instrumentation has been frequently used for reconstruction, fixation, correction and coupling decompression. For osteoporotic cancellous bone, conventional pedicle screw shows inability to provide enough screw-bone interface strength resulting in loosening or failure complications. A novel bone cement anchoraged thoracolumbar pedicle screw was design to enhance fixation strength for osteoporotic spine and simplify traditional spinal surgery procedures that includes using bone cement. The design of bone cement anchoraged thoracolumbar pedicle screw introduces one central hole and three side-grooves for bone cement to pass through the interior of the screw to inject into the spinal column. However, these design features may also significantly decrease the structural strength of the pedicle screw, which may result in pedicle screw failure after implantation.
The goal of this research is to study the mechanical properties of the Cement Anchoraged pedicle screw, understand how different design features affects its mechanical performance. Also, a Medtronic manufactured pedicle screw was selected as compare group to evaluate the Cement Anchoraged pedicle screws safety level. The research is carried out by creating different failure mods by a bending test and compare relative mechanical strength under the same failure condition. The failure mods are Static setscrew failure, Static Neck failure, Dynamic Neck failure and Dynamic side groove failure. These are common or possible failure conditions on a pedicle screw. The bending test was conducted under the guidance of American Society for Testing and Materials (ASTM) testing standard F2193.
The specific aims are as follows: (1) Design and manufacture the Cement Anchoraged pedicle screws with different features; (2) Conduct Static bending test to create setscrew failure; (3) Conduct Static bending test to create Neck failure; (4) Conduct Dynamic bending test to create Neck failure; (5) Conduct Dynamic bending test to create side groove failure.
The Results shows the re-designed Cement Anchoraged pedicle screw can withstand greater maximum bending forces in all kinds of failure mode conducted compared to the original version, proofing the design modification works to increase mechanical strength. It also achieves higher load durability than the compare group, which can be considered a safe product for use.

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