颅面多骨缝固定对颅颌形态影响的实验研究
张力平 仲山 管宇 刘丽
【摘要】 目的 通过固定幼兔颅骨缝，模拟颅骨多骨缝早闭，观察固定后颅颌面生长方式的变化及相互影响的关系。方法 采用牙科釉质粘合剂固定2周龄幼兔冠状缝、矢状缝和额间缝，模拟颅骨多骨缝早闭。术后不同时期测量颅穹窿长度、高度、面中部高度、上颌骨长度、面角、腭角和颅底角。结果 多骨缝早闭后，颅穹窿高度和长度明显减少，使颅骨变短且扁平。面中部高度和上颌骨长度增大，整个面中骨结构有整体向上移动趋势。面、腭和颅底角增大，这与颅穹窿变浅，面中部高度增大相对应。结论 兔出生后10周前是颅骨缝扩张性生长高峰期，在此期间，某些原因影响颅骨正常生长，必然导致颅面畸形。实验结果与临床颅骨骨缝早闭后表现类似，和主张早期手术矫正畸形观点一致。
【关键词】 颅缝上闭 颅骨生长 骨缝
An experimental study on the effect of multiple vault suture closure on craniofacial growth in rabbits Zhang Liping, Zhong Shang, Guo Yu, et al. Department of Maxillofacial Surgery. The Second Clinical Hospital, China Medical University, Shenyang 110003
【Abstract】 Objective To investigate the change and the relationship of craniofacial bone growth pattern after immobilization of the coronal, sagittal, and inter-frontal sutures in the young rabbits of two weeks.Methods Premature closure of three major vault sutures was induced by immobilization of the coronal, sagittal, and inter-frontal sutures in young rabbits. The heights and lengths of the vault, mid-facial heights and maxillary lengths, and facial angle, palatal and cranial base angle were measured in different periods after surgical fixation of the sutures.Results After multiple cranial suture immobilization the heights and lengths of the vault were greatly reduced. As a result, the vault in the experimental animals became short and flattening. Mid-facial heights and maxillary lengths were significantly increased. Facial angle, palatal angle, and cranial base angle were increased. The changes in angular relationship of mid-face to cranial base were related to the flattening of the cranial vault and the increasing of mid-facial heights. Conclusion The findings of the study indicated that the premature closure of multiple cranial vault sutures resulted in significant alteration in craniofacial growth and morphology. Expansive growth of cranial sutures can reach a high peak in the first ten weeks after the birth of rabbits. During this period of time, if the normal growth of cranial sutures was affected, the result would be craniofacial deformity. The experimental result were similar to the clinical manifestation of multiple cranifacial craniostenosis.
【Key words】 Craniosynostosis Skull growth Cranial suture
颅缝早闭是最常见的颅面畸形，脑组织正常发育受到限制，严重损害中枢神经系统，颅缝早闭所累及的骨缝数量和部位变异较大，临床表现各异，病因和发病机理尚未明确。颅颌面整形外科国内起步较晚，有关基础研究甚少。我们通过固定幼兔冠状缝、矢状缝和额间缝，模拟临床所见颅骨多骨缝早闭，旨在探讨颅面多颅缝固定后颅颌生长方式的变化及相互影响的关系。
材料和方法
一、实验动物与分组
健康2周龄新西兰大白兔40只，随机分成2组，每组20只。对照组：手术显露冠状缝、矢状缝和额间缝后缝合切口。实验组：用釉质粘合剂固定冠状缝、矢状缝和额间缝。
图1 冠状缝 矢状缝 额间缝固定示意图
二、实验模型制作
在8 mg/kg氯氨酮肌肉注射麻醉下，腹卧位固定于实验台。头顶部脱毛、消毒、沿头顶正中纵行切开至骨面，分离显露额间缝、冠状缝和矢状缝。分离时注意保护骨膜。对照组显露各缝后即关闭切口。实验组显露各骨缝后，用牙科小球钻分别于额间缝、两侧冠状缝和矢状缝正中磨成表浅的凹凸面。用牙科酸蚀剂酸蚀骨面，冲洗干燥后，用釉质粘合剂制成厚约1 mm、长6 mm、宽3 mm固定带(图1)。待完全凝固后，缝合骨膜，关闭切口。术中术后所有实验动物肌注庆大霉素5 mg／只，每天1次，连续5天，预防感染。全部实验动物在同样饲料同一环境的笼中饲养。
三、测量指标和方法
术前和术后2、8、14、20、28周时（出生后30周时兔颅面骨骼发育成熟）用氯氨酮麻醉实验动物，测量体重。将头部固定于特制的架内。用DGX-3型软X线机，40 KV，0.08 s，普通X线片盒，分别摄取头颅侧位片，测量颅穹窿长度、高度，面中部高度，上颌骨长度，面角、腭角和颅底角［1］(图2)。
图2 兔头颅侧位片各侧量点示意图
1.枕外隆突点 2.人字缝尖 3.筛额骨交界点
4.鼻根点 5.鼻前点 6.颅底点
7.蝶枕骨交界点 8.视神经孔 9.上磨牙后点
10.上磨牙前点 11.上牙槽后点
测量直线距离：①颅穹窿长度：点1～3距离；②颅穹窿高度：点2～7距离；③面中部高度：点4～10距离；④上颌骨长度：点9～11距离。测量角度：面角A：面平面4～5连线延长线与颅底平面6～8连线延长线相交角。腭角B：腭平面11～10连线延长线与颅底平面延长线相交角。颅底角C：上磨牙咬牙合平面延长线与颅底平面延长线相交角。每张头颅侧位片测量3次。取平均值以便减少误差。测得数据用（±s）表示，组间比较采用t检验法。
结果
在实验期间各动物组的体重无明显变化，提示手术本身对兔整体发育没有产生明显影响。术前测量头颅侧位片上各标志点结果表
表1 颅颌面各角度变化情况（±S，N=10 单位：度）
角 组别 8 周 14 周 28 周
面角 对照组
实验组 94.6±4.2
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