骨髓內釘固定孔定位系統的研發

Abstract

骨髓內釘為目前治療長骨骨折的主要的方式。在手術的過程中，必須將鎖定螺絲通過固定孔並鎖在硬質骨上，因此如何在看不見骨釘的的情況下，正確的找到固定孔的位置與方向，是手術中最耗時的步驟。在臨床上，使用移動式Ｘ光機可以直接的找到固定孔的位置，但此方式使得醫療人員必須暴露在高輻射的環境中，健康產生危害。 在無輻射定位的文獻中，大多數的定位方法只能定位出固定孔的位置，並無法定位出固定孔的方向，而在少數可以同時定位固定孔的位置與方向的方法中，皆採用主動式的定位，系統較複雜。所以我們提出一個兩階段式的被動式磁力定位系統，依序為初步定位與細部定位，在不使用輻射線的情況下，可以找到固定孔的位置與方向，並有警示功能，在定位的過程中可即時觀測。在使用上必須將含有目標磁鐵的骨髓內釘打入骨髓腔中，再進行定位步驟。初步定位是使用兩個磁鐵快速定位目標磁鐵所在的區域；而細部定位裝置主要包含了三組磁針和導電板，當磁針受到目標磁鐵吸引時，可以自由轉動並指向目標磁鐵。可由此三組磁針定位出目標磁鐵的位置與方向，並藉由磁針與導電板的接觸，觸發警示系統，即時觀測。 本研究中針對外徑12mm的脛骨骨釘做定位的設計，並成功製作出定位裝置，在移動目標磁鐵量測定位誤差的情況下，其工作範圍為垂直距離15-20mm，水平定位誤差在3mm以內，角度定位誤差在10°以下。在三維空間定位操作上，定位執行時間為五分鐘以內，成功縮短手術時間並驗證其三維空間定位能力。

Intramedullary nailing is a common surgical operation to repair fractures of long bones. One difficult part of the surgery is to locate the accurate drilling position and direction for interlocking screws, which is invisible to the naked eyes. In clinical case, medical professional can use manoeuvrable X-ray machine to locate drilling position. However, the high radiation environment is harmful. In the previous literatures of non-radiation position, most approaches only locate drilling position, not the drilling direction. Only few of them used active system to locate drilling position and direction at the same time. Here a novel and simple design using passive magnets is proposed to locate drilling position and direction to simplify the distal locking process in intramedullary nailing operation in a more intuitive way. The device consists of three magnetic pins and an electrical conductive board. The three symmetrically placed magnetic pins can rotate freely and point to the permanent magnet inside the nail. The drilling position and direction can be obtained by moving the device with those magnetic pins to align with the magnet in the nail. The alignment can be detected through the contact between magnetic pins and upper conductive board. When the device is not aligned with the magnet in the nail properly, either in position or direction, the pins then will contact with the board to trigger a light-emitting diode for alarming. It is shown that the accuracies in position and direction are 3 mm and 10 degrees, respectively, with remote vertical distance of 15mm-20mm, which takes less than 5 minutes to complete and verifies the feasibility of the proposed design.