牵张成骨对半侧颜面发育不全患者颌骨生长的影响

半侧颜面发育不全（hemifacial microsomia,HM）的发生率为1／5000^[1]。又称为半侧小颜面畸形、Goldenhar综合征、第一和第二鳃弓综合征（the first and second arch syndrome）、眼-耳-脊柱发育不良（oculo-ariculo-vertebral spectrum）等^[2]。HM是一种临床表现多样、进展性的、不对称性的颅面部畸形。     

下颌骨牵引成骨与直接延长术的组织学比较

目的：通过对下颌骨牵引成骨与直接延长术组织学变化的对比研究分析，探讨牵引成骨的成骨机制。方法：24只狗随机分为牵引成骨组和直接延长组各12只，用HE染色光镜组织学检查方法分别观察牵引第6天、牵引后固定2、8周不同时期的两组组织学变化。结果：牵引组在牵引后固定第8周，牵引区几乎完全由新生的骨组织连接修复，成骨方式是以膜内成骨为主，伴有少量的软骨内成骨；而直接延长组仅早期在两骨断端附近可见活跃的膜内成骨，两周以后则以软骨内成骨为丰，中间区域仍为大量的纤维结缔组织，8周以后成骨量增加．但中央仍为软骨组织和纤维组织间隔。结论：牵引成骨以膜内成骨为主，达到良好的骨愈合，直接延长成骨效果不稳定，容易导致成骨不良。     

大鼠下颌牵张成骨模型的建立

目的：建立具有良好可行性及可重复性的大鼠下颌牵张成骨模型，为颅面部牵张成骨的深入研究奠定基础。方法：对153只雄性SD大鼠施以单侧从乙状切迹至下颌骨下缘的纵向骨切开，在下颌角舌侧放置预制的甲基丙烯酸树脂块，安放并固定口外牵张器。经过3d的潜伏期，进行连续5d的牵张加力，之后进入固定期。结果：全部实验步骤已被SD大鼠耐受。大鼠体重在平均术后9．2d即恢复正常，后逐渐增长。伤口无感染，牵张装置足够稳定，产生并维持了所需的牵张距离。结论：新型的大鼠下颌牵张成骨模型已建立，并具备很好的可重复性。     

Hard and Soft Tissue Changes Following Maxillary Distraction Osteogenesis and Mandibular Setback with Bilateral Sagittal Split Osteotomy

Aims of this Study

(1) To highlight the role of intraoral submerged device in distraction osteogenesis (DO) of patients requiring two jaw surgeries for the correction of severe developmental maxillary hypoplasia (MH) and mandibular prognathism (MP) (2) To analyse the hard and soft tissue changes following maxillary DO and mandibular setback with bilateral sagittal split osteotomy (BSSO) in patients with severe MH and MP requiring two jaw surgeries.

Materials and Methods

During the period Jan 2004 to Dec 2006, five patients with severe developmental MH along with MP were treated. In 1st stage maxillary distraction was done. Distraction started on 6th postoperative day, 1 mm distraction was carried out for 10–15 days on either side. Serial radiographs were taken immediate postoperative period for baseline comparison, post-distraction and at the end of distraction. After a period of 3–4 months of distraction 2nd stage was done. In 2nd stage, mandibular setback was done with BSSO and distractors were removed under general anesthesia. Radiographs were taken immediately and at 4 months post-operatively. Cephalometric tracings were carried out preoperatively, post DO and finally after mandibular setback with BSSO.

Results

The mean horizontal movement of maxilla was 11.4 mm at ANS and 9.6 mm at A point. Upper incisor edge was advanced by 8.8 mms. SNA increased by 8.4° and SNB decreased by 4.6°. Nasal projection advanced by 4°. Nasolabial angle normalized in all patients, mean change achieved was 10.8°. Upper lip moved forward by 5.4 mm. Lower lip moved backward by 5.4 mm. Mandible positioned backward by 4 mm at B point. No vertical change occurred in the position of A, ANS and upper incisor edges. Mean increase in skeletal angle of convexity was 26.4°. Concave profile was significantly changed to convex in all patients.

Conclusion

Maxillary DO and mandibular setback with BSSO was associated with improved facial balance and esthetics.

     

山羊双侧下颌骨牵引成骨动物模型的建立

目的:建立一个可行性良好的山羊下颌骨牵引成骨模型。方法:将6只山羊的下颌骨截断,安置牵引器,延迟期4 d后以0.5 mm/次,2次/d的速度牵引10 d;随后进入固定期。分别于固定期的2、4、6、8周处死动物,进行大体标本和放射学观察。结果:牵引过程被所有山羊耐受,牵引长度达到预期效果。结论:山羊是一种良好的牵引成骨动物模型;该模型有助于DO临床的应用及研究。     

生物细胞因子在下颌骨牵引成骨中的应用研究进展

牵引成骨是上个世纪发展起来的一种矫形外科技术．它根据Ilizarov提出的著名张力拉力法则．通过牵张性机械刺激诱导切开骨断段间的骨形成．从而达到延伸骨长度或增加骨高度的目的。由于颅颌面骨胚胎起源及血液供应的特点，牵引成骨技术更适用于口腔颅颌面外科领域，但该过程持续时间长．且可能出现骨不连等并发症。通过对其成骨机理及分子生物学方面的深入理解和研究．将生物细胞因子应用到牵引成骨中，从而对其进行干预和调控是牵引成骨技术更广泛应用于临床的基础。本文就生物学细胞因子在牵引成骨中的作用及应用研究进展作一综述。     

下颌骨牵引成骨过程中VEGF及其受体的表达

目的:通过建立兔下颌骨牵引成骨实验动物模型,研究下颌骨牵引成骨过程中血管内皮生长因子(vascular endothelial growth factor,VEGF)及其受体的表达及意义。方法:选用新西兰白兔30只,随机选取6只动物作空白对照组,24只动物右侧下颌骨植入外置式颌骨牵引器。经7d延迟期后,按1mm/d速率延长下颌骨7d,固定期8周。在延迟期第7d,牵引期第2、4、7d,固定期第1、3、6、8周分别处死3只动物,采用免疫组化方法,检测VEGF及其受体FLT-1(fms-like tyrosine kinase-1)、FLK-1(fetal liver kinese-1)的表达变化。结果:VEGF及其受体FLT-1、FLK-1的表达贯穿下颌骨牵引成骨全过程。下颌骨牵引成骨过程中不同时相多种组织细胞参与表达VEGF及其受体FLT-1、FLK-1,但在表达的变化上存在一定的差异。结论:VEGF通过与其受体特异性结合,在下颌骨牵引成骨血运重建及新骨生成过程中发挥重要作用。