| 摘要: | 近年來植體植入手術已廣泛由牙科植體推廣至四肢截肢、顏面五官 等植體植入，臨床普遍認為術後的骨整合 (植體穩固度) 好壞為判斷手術成功與否的依據。本研究開發植體骨整合檢測裝置，以下肢截肢植體術後骨整合檢測為具體對象，並依據常規肢體植入手術流程，設計相關模擬情境，藉由裝置提供客觀量化數值，以建立有效評估方式，協助臨床醫師即時治療，降低手術失敗的風險。
下肢截肢植體於骨髓腔中，可視為懸臂梁結構。此一近似懸臂梁結構的骨整合狀態越好，意即植體周圍剛性越強，則共振頻率高；反之，則較低。本檢測裝置以200至10k Hz的交流小波訊號輸入至疊層類型激勵線圈，使之產生變動的磁力激振植體上方的磁性配件，使其振動。基於霍爾效應，磁場通過線性霍爾元件，產生感應電動勢。透過頻率響應函數計算探頭組及參考組霍爾電壓後，獲得該懸臂梁結構的共振頻率，據此判斷骨整合情況之好壞。
開發一檢測裝置並確認其規格至為重要，裝置以激勵線圈做激振源，依照第三章第一節元件選用準則篩選，最終選用疊層激勵線圈；以線性霍爾元件為響應量測元件，依照第二章所定義訊雜比來選擇適用的霍爾元件，最終選用霍爾元件。並對所設計電路中氧化金屬膜電阻進行探討，為防止電阻消耗功率過高，導致裝置外殼融化，以1伏特作為本檢測裝置驅動電壓，此時產生0.1瓦特消耗功率。透過以上元件選用後，計算出檢測裝置靈敏度為0.48 mV/mA，而在裝置頻率響應範圍內，系統誤差值皆為0.90%。
以努比亞山羊後肢股骨作為裝置驗證in-vitro骨整合實驗骨塊，使用不同比例環氧樹脂及玻璃纖維粉模擬股骨不同階段緻密骨增生的介面組織，並另製激振植體之磁性配件NCUpeg，同時和比對Osstell® 的磁性配件Smartpeg。在Smartpeg量測下，共振頻率值為高頻(9k Hz)，數值模擬結果顯示植體僅頂端局部振動；NCUpeg量測下，共振頻率值為低頻(1.3k Hz)，數值模擬結果為植體及山羊股骨整體振動。為了能真實反應股骨及植體間骨細胞整體增生情況，故使用NCUpeg作為日後檢測磁性配件。三種骨整合狀態設計為 (1) 植體植入手術後初始穩固度；(2) 復健期緻密骨骨細胞增長狀況；(3) 植體植入後6個月時，骨整合接近完成狀況。量測結果，不管在任何方向下量測，介面組織為環氧樹脂加30%玻璃纖維粉調和液 (楊氏係數5.1 GPa) 共振頻率值最高，而無任何介面組織模擬術後初始穩固度之股骨標本最低。此結果證實了當植體周圍剛性越強，則共振頻率上升，骨塊量測結果也符合原先預期。
本檢測裝置以簡易電路設計達成縮小體積、手持式設計的目標，對所設計之裝置進行一系列規格驗證，且比較Smartpeg與NCUpeg量測數據，並對照數值模擬結果，NCUpeg能具體呈現實際骨整合狀態。藉本研究開發之檢測裝置預期可提供臨床醫師作為各階段療程的評估工具，建構更完善療程規劃，並提高手術效益。期盼未來能將本裝置列為肢體植入手術流程重要環節。
;In recent years, implantation surgery has been widely used from dental implants to implantation of limbs, amputations, facial features, etc. Clinically, it is generally believed that the postoperative osseointegration (implant stability) is the basis for judging the success of the operation. This research develops an osseointegration detection device for lower limb amputation implants, and design related simulation scenarios based on limb implantation surgery procedures, establish effective evaluation methods by providing objective quantitative values through this device, assist physicians in immediate treatment and reduce the risk of surgical failure.
Lower limb implant knocks into femur, can be considered as cantilever structure. The better the rigidity of the cantilever beam, the stronger the rigidity around it, the higher the resonance frequency; otherwise, the lower the resonance frequency. This device inputs 200 to 10k Hz AC wavelet signal to the laminated type actuator coil, make it produce exchanged magnetic force to excite the magnetic fitting above the implant, and make it vibrate. Based on the Hall effect, the magnetic field passes through a linear Hall element to generate an induced electromotive force. After the Hall voltage of the probe group and the reference group is calculated by the frequency response function, to get the resonance frequency of the structure, judge the degree of osseointegration accordingly.
It is important to develop a detection device and confirm its specifications, the device uses the excitation coil as the excitation source, according to the standard in Chapter 3, the DFE322512C laminated excitation coil was finally selected. Using linear Hall elements as response measurement elements, select the applicable Hall element according to the noise ratio in Chapter 2, finally choose WSH135 this Hall element. And discuss the oxide metal film resistance RSF2WS in the designed circuit, to prevent the resistor from consuming too much power and causing the device case to melt, the driving voltage of this device is 1 volt, generates 0.1 watts of power consumption. After element selection, calculated the detection device sensitivity is 0.48 mV/mA, in the frequency response range, the system error value is 0.90%.
Using the femur of the hindlimb of Nubian goat as the experimental object, use different proportions of epoxy resin and glass fiber powder to simulate different stages of osseointegration, and make magnetic accessories NCUpeg, and compare Osstell® magnetic accessories Smartpeg. In Smartpeg measurement, the resonance frequency is high frequency (9k Hz), the numerical simulation results show that the implant only vibrates locally at the top; In NCUpeg measurement, the resonance frequency is low frequency (1.3k Hz), the numerical simulation results are the overall vibration of the implant and goat femur. In order to reflect the overall proliferation of bone between the femur and the implant, so choose NCUpeg as the accessory. Bone block design: (1) Initial stability after implantation; (2) the growth of cortical bone cells during rehabilitation; (3) At 6 months after implantation, osseointegration is almost complete. Regardless of the measurement results in any direction, the interface structure is the highest resonance frequency of epoxy resin and 30% glass fiber powder (Young′s coefficient 5.1 GPa), and without any interface, tissue resonance frequency is the lowest. This result confirms that the stronger the rigidity around the implant, the resonance frequency is higher, the measurement results also conform expectations.
The goal of this device is to simplify the circuit design to achieve reduced size and handheld, perform a series of specification verifications on the designed device, compare Smartpeg and NCUpeg, and compare the numerical simulation results, NCUpeg can show the actual state of osseointegration. The development of this device hopes to provide physicians as an evaluation tool for various stages of treatment, building a more complete treatment plan, and improve surgical effectiveness. Expect this device as an important part of the limb implantation procedure in the future. |
