Carlson D S, Ellis E, Dechow P C
Am J Orthod Dentofacial Orthop. 1987 Aug;92(2):134-43. doi: 10.1016/0889-5406(87)90368-4.
The suprahyoid musculature has been implicated as one of the major factors responsible for relapse after mandibular advancement surgery. Previous studies have also indicated that the muscle and connective tissues comprising the suprahyoid complex must adapt to increased length brought about by mandibular advancement for skeletal stability to be achieved. The purpose of this study was to provide quantitative data concerning the immediate changes and long-term adaptations that take place within the suprahyoid complex over a 2-year period after mandibular advancement. Mandibular advancement was performed on ten adult Macaca mulatta monkeys with and without suprahyoid myotomy (n = 5/group). Six animals were used as controls. Mandibular length and changes in the length of the various anatomic regions of the suprahyoid complex were evaluated radiographically with the aid of radiopaque bone, muscle, and tendon markers implanted preoperatively. The results for the nonmyotomy group showed that the suprahyoid complex was elongated approximately two thirds the amount of mandibular lengthening, the major immediate adaptations within the suprahyoid complex after the surgical procedure occurred at the muscle-bone interface and the muscle-tendon interface, the change in length at the muscle-tendon junction was maintained throughout the 2-year follow-up period, indicating that significant long-term adaptations took place primarily at that location, and no significant short-term changes or long-term adaptations were seen within the anterior digastric muscle or the intermediate digastric tendon. Within the myotomy group, it was found that the suprahyoid complex recoiled immediately after myotomy such that the anterior belly of the digastric muscle became separated from the advanced distal mandibular segment by more than twice the amount of mandibular lengthening, the anterior digastric muscle remained essentially at this posterior position throughout the 2-year follow-up period, and though not significant, there was a trend for a decrease in the length of the anterior digastric muscle belly. On the basis of these results, it was concluded that both short-term changes and long-term adaptations to lengthening of the suprahyoid complex as a result of mandibular lengthening occur primarily within the connective tissues comprising the muscle-tendon and muscle-bone interfaces, not within the muscle fibers themselves.
舌骨上肌群被认为是下颌前徙手术后复发的主要因素之一。先前的研究还表明，构成舌骨上复合体的肌肉和结缔组织必须适应下颌前徙带来的长度增加，才能实现骨骼稳定。本研究的目的是提供有关下颌前徙后2年内舌骨上复合体内发生的即时变化和长期适应性变化的定量数据。对10只成年恒河猴进行下颌前徙手术，其中5只进行舌骨上肌切断术，5只不进行（每组n = 5）。6只动物作为对照。借助术前植入的不透射线的骨、肌肉和肌腱标记物，通过放射照相评估下颌长度以及舌骨上复合体各个解剖区域的长度变化。非肌切断术组的结果显示，舌骨上复合体拉长约为下颌拉长量的三分之二，手术后舌骨上复合体内的主要即时适应性变化发生在肌肉-骨界面和肌肉-肌腱界面，肌肉-肌腱连接处的长度变化在整个2年随访期内保持不变，表明主要在该位置发生了显著的长期适应性变化，而在二腹肌前腹或二腹肌中间腱内未观察到明显的短期变化或长期适应性变化。在肌切断术组中，发现肌切断术后舌骨上复合体立即回缩，使得二腹肌前腹与前移的下颌远心段分离的距离超过下颌拉长量的两倍，在整个2年随访期内二腹肌前腹基本保持在这个后位，并且尽管不显著，但二腹肌前腹长度有缩短的趋势。基于这些结果，得出的结论是，由于下颌拉长导致舌骨上复合体长度增加的短期变化和长期适应性变化主要发生在构成肌肉-肌腱和肌肉-骨界面的结缔组织内，而非肌肉纤维本身。
