Ortiz Monasterio F, Molina F, Andrade L, Rodriguez C, Sainz Arregui J
Department of Plastic Surgery, Hospital General Dr. Manuel Gea Gonzalez, Mexico City, Mexico.
Plast Reconstr Surg. 1997 Sep;100(4):852-61. doi: 10.1097/00006534-199709001-00005.
Mandibular elongation by gradual distraction in patients with hemifacial microsomia is a simple and effective procedure to correct facial asymmetry. The two-pin system joined by a softer distracting screw achieves elongation in vertical and sagittal directions as well as medial rotation. The changes in mandibular shape result in changes in dental occlusion. These are minimal in children because of the rapid growth of the maxilla and can be corrected easily with minor orthodontic work. Mandibular distraction in adults with hemifacial microsomia, who usually have stable dental occlusion, produces good aesthetic results but also severe alterations in the occlusion requiring complex orthodontic treatment over a long period. To avoid this problem, an incomplete Le Fort I osteotomy is done simultaneously with the mandibular corticotomy. Intermaxillary fixation is done on the fifth postoperative day, and distraction is initiated. In a series of seven patients, the maxilla was distracted simultaneously with the mandible, preserving the preexisting stable occlusion. Preoperative deviation of the occlusal plane from the horizontal varied from 12 to 18 degrees. The plane became horizontal in four patients, and deviation of 2 degrees persisted in three. The distance from the inferior orbital rim to the occlusal plane on the affected side was increased in all patients, achieving 100 percent correction (compared with the normal side) in four patients and 95, 96, and 97 percent in the other three.
通过渐进性牵引延长治疗半侧颜面短小畸形患者的下颌骨，是一种纠正面部不对称的简单有效方法。由较软的牵引螺钉连接的双针系统可在垂直、矢状方向以及内侧旋转方面实现延长。下颌骨形态的改变会导致牙合关系的变化。由于上颌骨生长迅速，儿童的这种变化最小，通过轻微的正畸治疗即可轻松纠正。对于通常具有稳定牙合关系的成年半侧颜面短小畸形患者，下颌骨牵引可产生良好的美学效果，但也会导致严重的牙合改变，需要长期进行复杂的正畸治疗。为避免此问题，在进行下颌骨皮质切开术的同时进行不完全Le Fort I截骨术。术后第5天进行颌间固定，并开始牵引。在一组7例患者中，上颌骨与下颌骨同时进行牵引，保持了原有的稳定牙合关系。术前咬合平面与水平面的偏差为12至18度。4例患者的咬合平面变为水平，3例患者的偏差持续为2度。所有患者患侧眶下缘至咬合平面的距离均增加，4例患者实现了100%的矫正（与正常侧相比），另外3例患者分别实现了95%、96%和97%的矫正。
