Schulten Alcuin, Lim Asher A T, Bruun Richard A, Hayes Catherine, Mulliken John B, Padwa Bonnie L
Department of Orthodontics, Harvard School of Dental Medicine, Boston, MA, USA.
J Oral Maxillofac Surg. 2006 Jan;64(1):23-30. doi: 10.1016/j.joms.2005.09.009.
Gradual midfacial advancement, applying the principle of distraction osteogenesis, reduces the restriction of the soft tissues and results in bony consolidation without need for grafting. The midface can be distracted by either pushing it forward, using semiburied devices, or pulling it forward by a rigid external device. For each method there are inherent technical problems, such as controlling the vector of movement, symmetry of advancement, and differential movement of the upper/lower face. We have used a combination of the 2 methods, called "push-pull," in an effort to control the distraction process. The purpose of this paper is to describe our push-pull distraction technique and summarize our early experience.
Ten patients (5 males and 5 females) with a mean age of 11 years 2 months underwent midfacial advancement using push-pull distraction. Two orthodontists, blinded for landmark identification, traced preoperative and postoperative cephalograms and determined linear and angular measurements of midfacial position. A Student t test was used to assess differences between the cephalometric measures on the 2 radiographs. Interexaminer reliability was calculated by an intraclass correlation coefficient.
Postdistraction cephalograms were taken a mean of 10 months (range, 3 to 20 months) after removal of the devices. Patients exhibited improvement at all levels of the midface after distraction. There was a statistically significant sagittal advancement from the infraorbital rim to dentoalveolus. The central midface was sufficiently advanced as shown by an improved convexity, nasolabial angle, and upper labial protrusion. There were no significant differences between examiners for any of the measurements in this study.
Push-pull distraction permits 1) equal movement at both the upper and lower facial levels, 2) advancement of the central midface, and 3) symmetric movement of the zygomaticomaxillary complexes. This method also provides a backup, in case one device malfunctions. In combination, the advantages of each device are additive; whereas the weaknesses are not. The push-pull technique is a practical method for midfacial distraction until a better single device is fabricated.
应用牵张成骨原理进行渐进性面中部前移，可减少软组织的限制，实现无需植骨的骨愈合。面中部可通过使用半埋入式装置向前推或通过坚固的外部装置向前拉来进行牵张。每种方法都存在固有的技术问题，如控制移动向量、前移的对称性以及上/下面部的差异移动。我们采用了两种方法的组合，即“推拉”法，以控制牵张过程。本文旨在描述我们的推拉牵张技术并总结我们的早期经验。
10例患者（5男5女），平均年龄11岁2个月，采用推拉牵张法进行面中部前移。两名正畸医生在不知标记位置的情况下，对术前和术后的头颅侧位片进行描图，并确定面中部位置的线性和角度测量值。采用学生t检验评估两张X线片上头颅测量指标的差异。通过组内相关系数计算检查者间的可靠性。
拆除装置后平均10个月（范围3至20个月）拍摄牵张后的头颅侧位片。牵张后患者面中部各层面均有改善。从眶下缘至牙槽突有统计学意义的矢状向前移。中央面中部充分前移，表现为凸度、鼻唇角和上唇突度改善。本研究中检查者之间的任何测量值均无显著差异。
推拉牵张可实现1）上下面部水平的等量移动，2）中央面中部的前移，3）颧上颌复合体的对称移动。该方法还提供了一种备用方案，以防一个装置出现故障。综合起来，每种装置的优点是相加的；而缺点则不是。在制造出更好的单一装置之前，推拉技术是面中部牵张的一种实用方法。
