Bendrihem Rivka, Vacher Christian, Fohlen Audrey, Pelage Jean-Pierre
Department of Radiology, Faculté de Médecine de Caen, CHU de Caen, Avenue de la côte de nacre, 14000, Caen, France.
Department of Anatomy, Faculté de Médecine, Paris-Diderot, Paris, France.
Surg Radiol Anat. 2017 Nov;39(11):1209-1214. doi: 10.1007/s00276-017-1870-7. Epub 2017 May 20.
In Le Fort 1 osteotomy when a maxillary impaction is necessary, surgeons have to face different anatomical problems. (1) To determine the best bone resection route, they have to consider the situation of dental roots, infraorbital foramen and maxillary artery. (2) In case of Le Fort 1 osteotomy combined with a mandibular sagittal split osteotomy, the palate has to be replaced in horizontal position although there is no anatomical landmark. (3) In case of Gummy smiles, it can be due to either long face or short upper lip. The main objective was to identify safe bony landmarks to perform a Le Fort I osteotomy and to find a reliable way for repositioning the palate horizontally; the secondary objective was to determine the upper lip normal length.
The study was based on 178 facial CT examinations. The following parameters have been used: the vertical length of the upper lip, the vertical heights of the anterior nasal spine, the canine and molar roots, the inferior limit of the pterygomaxillary fossa and the vertical height of the infraorbital foramen on both sides.
The vertical length from the subnasal point to the upper vermilion was 15.06 ± 3.09 mm, and to the junction of the upper and lower lips was 23.94 ± 3.79 mm. The vertical length from the anterior nasal spine to the incisor alveolar border was 19.70 ± 3.17 mm. The height of the canine root was 17.11 ± 2.60 mm. The height of the highest lateral root of first or second maxillary molars was 11.71 ± 1.83 mm. The vertical length from the inferior limit of the pterygomaxillary fossa (pti point) to the alveolar border of the pterygomaxillary suture was 19.86 ± 3.45 mm. The height from the center of the infraorbital foramen to the alveolar border of the maxilla on a vertical line was not statistically different on right and left sides.
According to our results, in impaction Le Fort 1 osteotomy, the bone resection must pass 20 mm above the alveolar border in canine area, and 15 mm above the alveolar border in molar area. The resection has to end less than 20 mm above the inferior border of the pterygomaxillary suture. The vertical height of the infraorbital foramen is a consistent landmark for repositioning of the palate in a horizontal plane.
在进行上颌骨Le Fort 1型截骨术且需要上颌骨整体上移时，外科医生会面临不同的解剖学问题。（1）为确定最佳的骨切除路径，他们必须考虑牙根、眶下孔和上颌动脉的情况。（2）在Le Fort 1型截骨术联合下颌矢状劈开截骨术的情况下，尽管没有解剖学标志，但腭部必须恢复到水平位置。（3）对于露龈笑，可能是由于长脸或上唇过短。主要目的是确定进行Le Fort I型截骨术的安全骨性标志，并找到一种可靠的方法将腭部水平重新定位；次要目的是确定上唇的正常长度。
本研究基于178例面部CT检查。使用了以下参数：上唇的垂直长度、前鼻棘、尖牙和磨牙牙根的垂直高度、翼上颌裂孔的下限以及两侧眶下孔的垂直高度。
鼻下点至上唇红唇缘的垂直长度为15.06±3.09mm，至上下唇交界处的垂直长度为23.94±3.79mm。前鼻棘至切牙牙槽嵴的垂直长度为19.70±3.17mm。尖牙牙根高度为17.11±2.60mm。上颌第一或第二磨牙最高侧根的高度为11.71±1.83mm。翼上颌裂孔下限（pti点）至翼上颌缝牙槽嵴的垂直长度为19.86±3.45mm。眶下孔中心至上颌牙槽嵴垂直线上的高度在左右两侧无统计学差异。
根据我们的研究结果，在进行上颌骨整体上移的Le Fort 1型截骨术时，骨切除必须在尖牙区牙槽嵴上方20mm处通过，在磨牙区牙槽嵴上方15mm处通过。切除必须在翼上颌缝下缘上方小于20mm处结束。眶下孔的垂直高度是将腭部在水平面上重新定位的一个一致标志。
