Kofod Thomas, Cattaneo Paolo M, Dalstra Michel, Melsen Birte
Department of Oral and Maxillofacial Surgery, Aarhus University Hospital, Nørrebrogade 44, Bygn. 9D, 8000 Aarhus C, Denmark.
J Craniofac Surg. 2005 Jul;16(4):586-93. doi: 10.1097/01.scs.0000157305.60505.b5.
Distraction osteogenesis has been accepted as an alternative treatment modality for hypoplastic mandibles. Knowledge about the changes occurring in the temporomandibular joint region during mandibular distraction osteogenesis is, however, limited and controversial. Stress distribution in the temporomandibular joint region during unilateral vertical mandibular ramus distraction was studied using a finite element model. The finite element model was based on computed tomography scans and magnetic resonance imaging scans of a patient with unilateral hypoplasia of the right mandibular ramus caused by juvenile idiopathic arthritis. The character of stress distribution in the temporomandibular joint and mandible was analyzed quantitatively at different intervals of the vertical mandibular ramus elongation. During the distraction phase, the condyles, articular disks, and glenoid fossa regions were loaded with a differentiated stress pattern. The affected right condyle, disk, and fossa were submitted to increasing loads with increasing elongation compared with the contralateral temporomandibular joint. Loading on the unaffected left side shifted posteriorly and slightly laterally, because the left condyle was the center of rotation. The loading of the temporomandibular joint regions was low during the active distraction phase, although local areas were subjected to elevated peak stresses.
牵张成骨已被公认为是治疗下颌骨发育不全的一种替代治疗方式。然而，关于下颌骨牵张成骨过程中颞下颌关节区域所发生变化的相关知识却有限且存在争议。本研究使用有限元模型，对单侧垂直下颌升支牵张过程中颞下颌关节区域的应力分布情况展开了研究。该有限元模型是基于一名因幼年特发性关节炎导致右侧下颌升支单侧发育不全患者的计算机断层扫描和磁共振成像扫描构建而成的。在垂直下颌升支延长的不同阶段，对颞下颌关节和下颌骨中的应力分布特征进行了定量分析。在牵张阶段，髁突、关节盘和关节窝区域呈现出不同的应力模式。与对侧颞下颌关节相比，随着延长幅度的增加，患侧右侧的髁突、关节盘和关节窝承受的负荷不断增加。由于左侧髁突是旋转中心，未受影响的左侧所承受的负荷向后并略微向外侧转移。尽管局部区域承受着较高的峰值应力，但在积极牵张阶段，颞下颌关节区域的负荷较低。
