不同程度老年人萎缩性无牙颌下颌骨骨折的内固定方式选择及相关生物力学分析

Selection of way of internal fixation and biomechanical analysis for edentulous mandibular fractures with different atrophy degrees in elderly population

目的:比较3种不同程度萎缩性无牙颌下颌骨骨折的不同内固定方式及其效果。方法:构建不同程度的萎缩性无牙颌下颌骨体部骨折治疗模型,进行三维有限元分析,比较相同应力条件下骨折段位移的改变以及钛板的应力分布情况。结果:下颌骨Ⅲ度萎缩,采用1块2.0 mm 4孔钛板在下颌骨上缘进行固定,其骨折处移位较其余6种工况明显增大;相同萎缩程度的下颌骨,采用重建板固定比采用其他内固定方式骨折断端位移明显减少。Ⅲ度萎缩的下颌骨采用小型钛板固定,钛板所受应力分别接近及超过钛板的屈服极限。结论:对于Ⅰ度萎缩的无牙颌下颌骨骨折病例,下颌骨外侧双板固定以及下颌骨下缘重建板固定均能取得较为满意的固定稳定性,对于Ⅱ及Ⅲ度萎缩的无牙颌下颌骨骨折病例,下颌骨下缘重建板固定可以获得更好的固位稳定性。

PURPOSE： To compare the result of different treatment methods（way of internal fixation） for edentulous mandibular fractures with 3 different atrophy degrees. METHODS： We established a biomechanical model of atrophic edentulous mandibular fracture and analyzed the displacement of the fracture and the stress on titanium plate with different treatment via finite element analysis. RESULTS： For atrophic mandibular fracture of class III, the displacement of using 1 miniplate in superior border of mandible was larger than other 6 conditions; For the same degree of atrophic mandibular fracture, the displacement of using reconstruction plate was smaller than other kinds of internal fixation; For atrophic mandibular fracture of class III, the stress on the titanium plate was near or above the yield limit for using 1 miniplate. CONCLUSIONS： For atrophic mandibular fracture of class I, both 2 miniplates and 1 reconstruction plate can achieve satisfactory results. For atrophic mandibular fracture of class II and III, 1 reconstruction plate can achieve more satisfactory results.