The aim of this study was to establish finite element models of free fibular flap reconstruction of different types of mandibular defects. The finite models was created from CT image. The finite element method was used to carry out biological analysis. Comparative analysis of the stress distribution characteristics and the displacement changes in mandible were carried out. From the stress distribution nephogram, it could be concluded that the stress was mainly concentrated in the bilateral

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... lar neck, the anterior and posterior edges of the mandibular ramus, and the joint between the posterior end of the fibula and the mandible. The more mandibular defects that were present, the greater the corresponding stress on the contralateral condyle. Displacement nephogram: the inward displacement of the condyle on the affected side of a type B defect was more obvious than that of the normal mandible, and the most obvious in the X-axis direction, with a displacement of 1.61 mm; the BSS defect crossed the midline, and the bilateral condyles shifted inward causing posterior displacement; the displacement results of RBS and CRBS defects showed whether the condyle was involved in the bone defect, and the displacement changes after reconstruction were not significantly different. After mandibular reconstruction, the loss of attachment muscles can cause postoperative condylar displacement, resulting in postoperative occlusal disorder, opening deviation and other complications. The mandible, as a movable bony scaffold underlying the lower 1/3 of the face, not only maintains the facial contour, but also is closely related to the functions of chewing, breathing and swallowing. In radical surgery for mandibular tumors, a large number of muscles attached to the mandible are stripped, resulting in a lack of coordination of the chewing muscles, resulting in complications such as limited mouth opening, jaw deviation, joint clicking and disorder of occlusal relationship. [1] [2] [3] In the past, the most commonly-used repair methods were titanium plate and personalized prosthesis,which are prone to complications such as titanium plate exposure and fracture after long-term observation. Therefore, it was gradually replaced by free iliac or rib grafts. 4,5 In 1989, Hidalgo first applied a free fibular flap for jaw defect repair. 6 Since then, the vascularized fibular J o u r n a l P r e -p r o o f