应用牵张成骨术后退腭部的实验研究

目的　应用自制的腭部牵张装置后退腭裂犬的腭部 ,探讨治疗腭咽闭合不全的新方法。方法　用 7只健康青春期杂种雄性犬为实验对象。手术形成腭裂模型 ,在实验侧行牵张成骨术。手术当天 ,术后 7、1 8、6 0d分别取印模 ,灌注石膏模型。制作术后 6 0d头颅骨标本。在模型和颅骨标本上测量各标志点间的距离。结果　实验过程中未观察到明显错牙合畸形 :实验结束时 ,动物实验侧硬腭后缘均有不同程度的后退 ,牵张间隙内为新生骨组织 ,上颌骨的两侧结构保持对称。结论　应用牵张成骨术可后退腭裂模型犬的硬腭后缘 ,且对咬合关系及上颌骨短期内的生长发育无明显影响

DISTRACTION OSTEOGENESIS FOR RETREATING OF THE PALATE IN THE ADOLESCENT CANINE CLEFT PALATE MODEL: AN EXPERIMENTAL STUDY

Objective This study attempts to explore a new concept of retreating the palate in cleft palate patients for velopharyngeal incompetence. Methods Seven adolescent, mix bred dogs were used. A 5 mm wide strip of tissue, including oral and nasal mucoperiosteum as well as a part of the horizontal process of the maxillary and palatal bone midline strip was removed from the hard palate of each animal. A transverse osteotomy was then made in random side of the defect to separate the posterior segment of the hard palate from the anterior segment. Lateral osteotomy was also made parallel to the defect so that the posterior segment was mobile. A custom made intraoral distractor was fixed to the anterior hard palate and the mobilized posterior hard palate with titanium miniscrews that were also used as bone markers. After a 7 day latency period, the distractor was expanded 0.9 mm per day until it had been lengthened 10 mm. Distractors were left for an additional 6 weeks. Then all the animals were sacrificed and their craniofacial bones were harvested to measure the distance of the bone marks. Additionally, impressions of the jaws were taken on 0d, 7d, 18d, and 60d postoperative respectively to examine plaster cast changes in the dental occlusion. Homogeneity of variance was also assessed using measurements of maxillary length from dental cast on 0d postoperative. Results The dental casts on 0d postoperative demonstrate all animals were homogenous with regard to facial structure in length before distraction. And the measurements of the harvested craniofacial bones show that the length of hard palate in distraction side increased at about 5.50±0.71 mm (the rage is from 4.50 mm to 6.50 mm) and the posterior segment of the hard palate increased at about 5.30±1.26 mm (from 3.50 mm to 6.50 mm), while there were no significant differences in other variables between the normal control and distracted sides. And no significant difference in occlusion was recorded during the experiment. Conclusion The hard palate of the adolescent canine cleft palate model can be retreated by distraction osteogenesis, while the growth and development of the maxillofacial is unaffected.