應用電磁感應式之定位方法於互鎖式骨髓內釘螺絲孔定位之研究

Abstract

現今在治癒斷裂之長管狀骨頭時，最廣泛使用的即是在傷者的骨髓腔內植入一互鎖式骨釘，利用其方便且可支撐斷骨的優點以達成斷骨癒合之目的。為使斷骨可順利癒合，骨釘需具有良好的固定性，故當其被植入後，能準確地找到其上用來固定之螺絲孔的位置是極為重要的。目前臨床上常使用X光片做為位置判斷之輔助工具，但卻導致須暴露於高輻射劑量環境之風險。 為避免上述之風險，本論文提出一電磁感應式定位系統，其包含一發射端及接收端，首先將施加一電流於發射端使其周圍產生磁場分布，之後接收端會感應此磁場並產生一感應電場繼而輸出感應電壓值，此電壓值會因發射端及接收端的相對位置改變而改變，藉由觀察電壓值之變化以判斷出螺絲孔所在之位置。 此外，本論文亦進行一以系統規格主導之分析方法，以期在骨釘尺寸變換時，可以迅速的訂立出適合之零件尺寸並分析其分布趨勢。

Nowadays, the most common method treating a long bone fracture is to insert an interlocking-nail into the patient’s medullary canal to support the fractured bone. In order to heal the bone successfully, the nail’s interlocking function must be accurately performed. Thus, after the nail is inserted, it is important to precisely figure out the location and orientation of the screw holes of the nail relative to the fracture bone for further screw-fixation. To achieve this, surgeons usually use X-ray imaging method to figure out the screw hole. However, using X-ray imaging causes surgeons to be exposed to a high dose of radiation. To avoid the X-ray radiation, an electromagnetic-induction locating system is proposed in this thesis. The system consists of an emitter and a detector. An AC current is applied to the emitter to produce a magnetic field due to the electromagnetic induction. The detector is used to detect the magnetic field and consequently induce correspond voltage due to the electromagnetic induction. The amplitude of the induced voltage varies while the relative location and orientation between the emitter and the detector are changed. Through analyzing the difference of the induced voltages, screw hole is able to be located. Moreover, a modeling of the locating approach is investigated by using finite element method to avoid numerous try-and-error tests for optimizing the approach when the specification of the nail is changed to different manufacturing models.