- 學位論文
上下顎骨折之骨釘板固定系統的生物力學探討
Investigation of biomechanics in bone-screw-plate system for maxillary and mandibular fractures
摘要
顏面骨折患者使用骨釘和迷你骨板的剛性內固定法提供患者骨頭癒合的初期穩定度以及咬合功能性。雖然客製化骨板也可以提供骨折處的固定效果，但是缺乏骨釘分布和穩定度評估，加上骨板的結構設計和強度也尚未系統的進行探討。因此本研究的目的是使用有限元素分析和假骨實驗探討骨釘數量和骨折穩定度下，找出傳統骨板固定之最佳參數組合模型，利用該骨釘數量與分布設計出創新型結構骨板，對其進行應力分析與力學功能評估。下顎骨折位置包括下顎體、下顎角、下顎髁與下顎支，至於上顎骨折位置則是Lefort I。上述骨折模型將使用傳統I 型四孔與六孔骨板搭配骨釘進行有限元素分析，各種骨折固定模型選取最佳穩定度的模型進行人工假骨實驗來進行有限元素分析結果的驗證。有限元素分析結果顯示骨折固定在下顎角以前，發現骨釘數量在上方較多的固定方式具有較好的骨折穩定度，而骨折固定在下顎角以後時，則使用骨釘數量下方較多的固定方式具有較佳的骨折固定穩定度。至於上顎Lefort I 骨折發現在鼻側區域增加骨釘，可以有效抵抗頰側方向的咬合力，增加整體骨折固定的穩定度。根據各骨折使用傳統骨板固定之最佳穩定度的骨釘分佈，設計出針對各種骨折的客製化創新骨板，創新骨板結構包括橫向強化結構設計、縱向強化結構設計、交叉強化結構設計、中空結構和實心結構五種。分析結果顯示創新骨板的骨折固定穩定度都優於傳統骨板固定，其中以實心結構具有最佳的固定效果。透過傳統骨板固定之骨釘分佈所設計出的創新骨板，能有效減少皮質骨破壞與骨釘鬆脫的風險，並能在使用較少的骨釘數量下提供比傳統骨板更好骨折固定效果。
並列摘要
The initial stability and occlusal function of bone fracture healing were provided by rigid internal fixation by bone screw and mini bone plate in patients with facial bone fractures. However, a customized bone plate can also provide the fixation effect of fracture site, but the lack of bone screw distribution and stability evaluation, coupled with the structure and strength of bone plate has not yet been systematically studied. Therefore, the purpose of this study is to find out the best parameter combination model of traditional bone plate fixation in each fracture model by evaluating with finite element analysis and sawbone experiment, and then to further design an innovative bone-plate based on number and distribution of screw insertion, and to investigate its stress distribution and biomechanical effect. The fracture positions of the mandible include mandibular corpus, gonial angle, condyle and ramus, and the fracture position of maxilla is located at Lefort I. The traditional type I in four-hole and six-hole bone plate for all of finite element model of maxillary and mandibular fractures will be investigated firstly by finite element analysis, and the best stability model of each fracture-typed group will be selected for sawbone experiment verification to verify the results of finite element analysis. The results of finite element analysis showed that the mandibular fracture fixation in the anterior region of gonial angle could provide a better fracture stability if increase screw insertions of the selected plate in the upper site was used, but the mandibular fracture fixation in the posterior region of gonial angle could provide a better fracture stability if increase screw insertions of the selected plate in the lower site was applied. As for increase screw insertions at the Lefort I fracture near nasal region could effectively resist the occlusal force in buccal site direction and rise the stability of the fracture fixation. The best stability in the screw distribution of traditional bone plate fixation in each fractured model were obtained, then five types of innovative bone plates were designed to enhance strength of bone structure, the design of innovative plate structures included horizontal strengthening structure, longitudinal strengthening structure, cross-link strengthening structure, hollow structure and the solid structure. The results showed that the stability of fracture fixation of innovative bone plate was better than that of traditional bone plate fixation, and the solid structure plate was evidenced the best fixation effect. The innovative bone plate was designed according to screw distribution of the traditional bone plate fixation to effectively reduce the risk of cortical bone fracture and screw loosening, and can provide a better fracture fixation effect than the traditional bone plate with less number of inserted screws.