摘要：目的　通过X线头影测量分析了解颌骨后退与前徙对舌骨位置及咽下气道变化的影响情况，为临床治疗提供参数。方法　下颌前突患者23例与小颌畸形患者9例，分别行双侧矢状劈开后退或前徙下颌，手术前后拍摄X线头颅定位侧位片，进行头影测量，测量项目13项，测量数值配对t检验，并将下颌后退距离与各测量项目变化值作相关分析。结果　各测量项目显著差异的有：(1) 下颌前突组，下咽腔矢状面积(PSA)，舌骨垂直向变化，舌根后缘至咽后壁距离(TB-PW)，舌背高点至FH平面距离(DT-FH)，会厌谷至咽后壁距离(V-PW)，悬雍垂尖点至后咽壁距离(U-PW)，下颌颏部水平、垂直向变化(Pog-PTV,Me-FH)。舌骨垂直向变化与下颌颏部垂直向变化显著相关。(2) 小颌畸形组，舌骨垂直向变化显著。结论　下颌前突组，(1) 舌骨向下移位，舌背上抬，舌根向后移动。(2) 咽腔气道空间缩小可表现为永久性，但后气道间隙接近正常人，不会发生通气阻塞，更未出现OSAS。舌骨与下颌前部垂直向变化呈负相关。(3) 小颌畸形组，舌骨垂直向显著变化，舌骨因颏舌骨肌牵拉而上移。舌骨水平向无显著移位。除会厌谷前移外，舌体无显著移位，说明颌骨前徙对舌体形态没有大的影响。颌骨前徙对后气道无明显影响。从临床病例来看，小颌畸形愈重，前徙颌骨手术对周围组织结构的影响愈大。

关键词：舌骨；咽下气道；头影测量

　　中图分类号：R782.2　　　文献标识码：A　　　文章编号：1005-4979(1999)04-306-04

ALTERATION OF THE POSITION OF THE HYOID BONE AND THE HYPOLARYPHEAL AIRWAY PRE-AND POST-ORTHOGNATHNIC OPERATION

ZHANG Lin, GU Xiao-ming
Department of Maxillofacial Surgery,Stomatological College, the Fourth Military Medical Unviersity,Xi'an 710032
　　 Abstract： Objective　Using X-ray cephelometrics,we analyzed the effect of the setback and the advancement of the jaw bone on the position of the hyoid bone and the hypopharyngeal airway, so that we could purpose some suggestions for the clinical treatment. Methods　23 patients with mandibular prognathism and 9 with mandibular hypoplasia were undergone mandibular setback or advancement respectively by way of bilateral sagittal split osteotomy.13 parameters were measured using lateral cephalometric X-ray films taken before and post treatment.All the quantized figures were analyzed using paired t-test. The relationship between the distance of the setback of the mandibula and the change of the measured figures were also analyzed. Results　The variation which is significant is the measured figures in the following groups:1. mandibular prognathism, hypopharyngeal horizontal area (PHA), vertical change of the hyoid bone,the distance from the posterior margin of the hyoid bone to the posterior pharyngeal wall (TB-PW), the distance between the highs of the dorsum lingua to the FH plane,the distance between the epiglottal socket to the posterior pharyngeal wall (V-PW), the distance between the tip of the uvula to the posterior pharyngeal wall (U-PW), alteration of the chin of the mandibula in the horizontal and vertical direction.2. mandibular hypoplasia, alteration of the hyoid bone in the vertical direction is significant. Conclusions　Of the patients with mandibular prognathism,1. the hyoid bone shifted downward,the dorsum lingua raised and the base of the tongue moved posteriorly;2. the reduction of the airway of the pharynx maybe permanently, but the posterior airway space maybe close to the normal without respiratory blocking,not even OSAS;3. the vertical alteration of the anterior of the mandibula is negatively co-related with the hyoid bone.Of the patients with mandibular hypoplasia, the alteration of the hyoid bone in the vertical direction is significant, the hyoid bone shifted up by the traction of the geniohyoideus; the hyoid bone has no significant shifting horizontally; the corpora linguae also hasn't significant shifting but the epiglottal socket moved anteriorly. It suggests that the antedisplacement of the mandibula have no significant affect on the posterior airway space and the profile of the corpora linguae. From the clinical cases, we could conclude that the more serious the deformation of the mandibular hypoplasia, the more affection of the mandibular antedisplacement surgery to the periphery tissue constructions.
　　 Key words： Hyoid bone; Hypopharyngeal airway space; Cephalometrics
　

正颌手术不仅使颌骨和颌间相对位置发生变化，而且使周围软组织的体积和与硬组织的相对位置发生变化，这种变化直接影响咽腔气道通气量改变。有病例报道［1］认为下颌后退可能导致阻塞性睡眠呼吸暂停综合征(OSAS)，主要原因是下颌后退可致后气道间隙狭窄。颌骨前徙是治疗OSAS的重要手段，其机理是通过上下颌骨前徙扩大骨性鼻咽、口咽腔，使附着于颌骨的软组织前移，从而扩大口咽通气道，消除此区域的阻塞因素，实践证明已取得良好效果，并有较多报道［2～5］。是否颌骨后退均能导致后气道狭窄或颌骨前徙均能使后气道间隙扩大，我们选择23例下颌前突和9例小颌畸形病人(不包括OSAS)，通过X线头影测量对病人手术前后舌、舌骨位置变化和咽腔气道变化加以研究探讨。

1　材料与方法
1.1　研究对象：随访第四军医大学口腔医院自1984至1999年以来接受正颌手术的23例单纯下颌前突和9例小颌畸形病人，前组男性17例，女性6 例，手术时平均年龄23.3岁，术式均为双侧下颌骨矢状劈开后退，平均后退8mm。后组男性2例，女性7例，平均手术年龄26.1岁，术式均为双侧下颌骨矢状劈开前徙，平均前徙6mm。将两组病人术前和随访时的侧位X线头影测量片均用硫酸纸描图，经图形数字化仪输入计算机，编程测量线距和计算间隙的面积。术后时间最短为6月，最长为15年。
1.2　坐标系、定点与参照线：以FH平面作为坐标系的X轴，以Ptm点垂直于FH平面的垂线(PTV)作为坐标系的Y轴。MP：为下颌平面；PW：为咽后壁线；H：为舌骨点；TB：为舌根最后点；UTP：为舌背与PTV线的交点；MGF：为会厌高点；LTP：为过MGF点并平行于FH平面的线与舌根的交点；V：为会厌谷点；DT：为舌背最高点；U：为悬雍垂点；Me:颏下点；Pog：颏前点。