下顎骨二次重建手術的困難之處是如何復原殘存下顎骨的相對位置、如何量測下顎骨缺損範圍、如何決定腓骨的分段，以及如何導引腓骨鋸切，以重建出理想的下顎骨外型。 本研究以電腦斷層影像建構出下顎骨三維模型，製作出相似下顎骨的紙模型，利用紙模型作為彎折金屬骨板的參考，且骨板運用於實際手術中固定殘存下顎骨的相對位置，而殘存下顎骨經由初始對位與疊代最近點(Iterative closest point, ICP)演算法，得到與原始下顎骨的轉換關係，殘存下顎骨恢復位置後可決定缺損範圍大小，並規劃腓骨段數決策。設計輔助器械測量下顎骨缺損範圍，再導引鋸切腓骨，以完成下顎骨重建手術，且輔助器械亦能用於初次重建。 在下顎骨二次重建手術中，利用紙模型作為彎折金屬骨板的參考，殘存下顎骨模擬對位結果，其相對應點最遠距離為5.04mm，而使用輔助器械導引腓骨鋸切結果，其腓骨片段的切面貼和間係小於1mm。 The difficulties of second mandibular reconstruction come from the restore of the remnant mandibular relative position, the measurement of the defect size, the determination of the fibula bone segment, the guidance of the fibula bone saw, and the mandibular reconstruction of the ideal shape. In this research, we reconstructed 3D mandible model from CT images to make a paper model similar to the mandibular, and used the paper model as a reference to bending the metal plate, and the plate fixed relative position of remaining mandibular in the actual operation. The remnants of mandible have obtained the transformation between the original mandibles through the Initial Contraposition and Iterative Closest Point (ICP) algorithm.then, the remaining mandibleof the recovery position would be decided the size of the injured part, and be planed the number of segments making fibula. We designed the assistive devices to measure the range of the injured mandible. In addition, we guided cutting the fibula in order to complete mandibular reconstruction, and assistive devices also used for the initial mandibular reconstruction. In the second mandibular reconstruction, we not only used the paper models as a reference to bending metal plate, but also simulation the contraposition of the remaining mandible. According to this research results, the distance of corresponding point was up to 5.04mm. The gap between the segments of two neighboring fibula was less than 1 mm, while we used the assistive devices to guided the fibulas operation.
