目的·评估上颌骨前段牵引成骨（anterior maxillary segmental distraction osteogenesis，AMSDO）在治疗唇腭裂继发上颌骨发育不足中的作用以及3D打印导板在截骨中的精度。方法·收集12例接受了AMSDO治疗的唇腭裂患者的病例资料。手术前在患者的三维模型上进行虚拟手术，并通过3D打印将患者的截骨线制成牙支持式导板。术前（T0）、巩固期结束（T1）以及巩固期后6个月（T2）进行头影测量以评估AMSDO的效果及稳定性。导板的精度通过术后即刻CT与术前设计CT进行叠加，并通过计算位置和角度误差进行评估。结果·所有患者都顺利完成了牵引治疗，没有发生严重的并发症。SNA（S-N-A角）和覆盖从T0到T1以及T0到T2都发生了显著的改变。ANB（A-N-B角）、面部突度、硬腭长度都发生了变化，但是差异没有统计学意义。SNB（S-N-B角）基本没有发生变化。从T1到T2，所有的参数都没有发生明显变化。导板截骨精度在矢状向的线性均方根误差为0.90 mm，角度均方根误差为5.07°。结论·AMSDO是治疗唇腭裂继发上颌骨发育不足的一种有效方法。3D打印的截骨导板具有良好的精度，在减少手术并发症的同时降低了手术的难度。

Objective ·To evaluate the effects of anterior maxillary segmental distraction osteogenesis (AMSDO) in treating sagittal maxillary hypoplasia in cleft lip and palate (CLP) patients and to report a 3D-printed surgical guide to facilitate the osteotomy. Methods ·Twelve patients with CLP who underwent AMSDO were included in this study. Virtual osteotomy was performed in a 3-dimensional model and the osteotomy line were fabricated into a tooth-borne surgical guide by using 3D-printing technique. Lateral cephalograms taken before surgery (T0), at the end of consolidation (T1) and six months after consolidation (T2) were used to evaluate the effects of AMSDO. The accuracy of the osteotomy guide was measured by superimposing the postoperative CT data to virtual planning. Results ·All the patients went through surgery without serious complications. SNA and overjet changed significantly both from T0 to T1 and from T0 to T2. ANB, facial convexity, and palatal length changed without significance from T0 to T1 and from T0 to T2. SNB remained stable. All the variables remained relatively stable from T1 to T2. The anteroposterior linear root-mean-square deviation (RMSD) between planning and actual results was 0.90 mm, while the angular RMSD in the sagittal plane was 5.07°. Conclusion ·AMSDO is an effective treatment for maxillary hypoplasia secondary to CLP. The accuracy of this 3D-printed osteotomy guide is clinically acceptable, and this can simplify the surgery with fewer complications.