Gateno Jaime, Engel Eric R, Teichgraeber John F, Yamaji Kyoko E, Xia James J
The University of Texas Health Science Center, Houston, TX 77030, USA.
J Oral Maxillofac Surg. 2005 Jan;63(1):148-54. doi: 10.1016/j.joms.2004.09.010.
The purpose of this pilot study was to test a new Le Fort I internal distraction device.
A new internal Le Fort I distraction device designed by 1 of the authors was used in 3 patients with cleft lip and palate and severe maxillary hypoplasia who needed maxillary advancements in excess of 12 mm. Presurgical planning used CASSOS (SoftEnable Technology, Ltd, Hong Kong SAR, China) prediction tracing software and a stereolithographic model to calculate the distraction vector. The distractors were pre-bent and installed on the stereolithographic model and activated to advance the maxilla. Surgery was performed in a conventional manner, and distraction was started after a 7-day latency phase at the rate of 1 mm/day and continued until the presurgical plan was achieved. The distractor was removed after a 3-month consolidation phase. Cephalometric radiographs were taken at the completion of each phase.
This new Le Fort I internal distraction device successfully distracted the maxillae as planned in all 3 patients. At the end of the distraction phase, the maxillary advancement was measured at 15.8 mm, 15.8 mm, and 13.5 mm, respectively. In each patient, a clockwise rotation of the maxilla was observed with a tendency to a posterior open bite. Postoperative radiographs also showed that the actual distraction vectors differed from the planned vectors. After the consolidation phase, radiographs showed a relapse of 2.6 mm, 0 mm, and 5.0 mm, respectively. There was no further relapse on 3-month follow-up radiographs. Each case showed radiographic evidence of excellent new bone formation at the osteotomy sites.
The new Le Fort I internal distraction device produced the necessary advancement in all 3 patients. The study also showed that the actual distraction vector differed from the planned vector. This discrepancy was caused by a clockwise rotation of the maxilla during the distraction. Finally, the study showed a variable relapse rate not previously reported in maxillary distraction.
本初步研究的目的是测试一种新型的Le Fort I型内牵张装置。
由一位作者设计的新型Le Fort I型内牵张装置用于3例唇腭裂伴严重上颌骨发育不全且需要上颌骨前移超过12mm的患者。术前规划使用CASSOS（SoftEnable Technology, Ltd, 中国香港特别行政区）预测追踪软件和实体模型来计算牵张向量。牵张器预先弯曲并安装在实体模型上，激活后使上颌骨前移。手术按常规方式进行，在7天的延迟期后以每天1mm的速度开始牵张，持续至达到术前规划。在3个月的巩固期后取出牵张器。在每个阶段结束时拍摄头颅侧位片。
这种新型Le Fort I型内牵张装置在所有3例患者中均成功按计划牵张上颌骨。在牵张阶段结束时，上颌骨前移分别测量为15.8mm、15.8mm和13.5mm。在每例患者中，均观察到上颌骨顺时针旋转并有后牙开牙合倾向。术后X线片还显示实际牵张向量与计划向量不同。在巩固期后，X线片显示分别有2.6mm、0mm和5.0mm的复发。在3个月的随访X线片上未见进一步复发。每个病例在截骨部位均显示出新骨形成良好的影像学证据。
新型Le Fort I型内牵张装置在所有3例患者中均产生了必要的前移。该研究还表明实际牵张向量与计划向量不同。这种差异是由牵张过程中上颌骨的顺时针旋转引起的。最后，该研究显示出上颌骨牵张中以前未报道过的不同复发率。
