翼外肌在髁突矢状骨折愈合中对髁突形态的影响

Morphological effects of lateral pterygoid muscles in healing process of sagittal fracture of mandibular condyles

目的探讨翼外肌在髁突矢状骨折愈合过程中对髁突形态的影响。方法将16只1岁龄的成年山羊随机分为保留翼外肌组和切断翼外肌组,每组8只。所有的山羊均应用超声骨刀对髁突矢状造成骨折,先剪断关节盘的前后附着然后将其推至内侧。观察动物术前术后的一般状况,并分别在术前及术后1周的全麻状态下测量并记录实验动物的体重、最大开口度、前伸和左右侧方运动度,并观察咬合关系存在的变化。每组动物分别于术后4周(各2只)、12周(各3只)、24周(各3只)处死。在处死后进行CT检查,CT三维重建以观察髁突的形态,并且对颞颌关节进行解剖以观察髁突形态。结果所有动物均能耐受手术,且无伤口感染,在术后饮食均较正常。截骨术前和术后1周的体质量、最大开口度、前伸距离、左侧运动距离和右侧运动距离的差异无统计学意义(P>0.05);所有手术侧髁突内外径及前后径均有增大,尤其是保留翼外肌组的髁突的内外径和前后径的增大较切断翼外肌组明显,差异具有统计学意义(P<0.05);保留翼外肌组比切断翼外肌组有更多、更不规则的新骨形成,髁突形态的改变更为严重。结论该模型的建立,证实了翼外肌在髁突矢状骨折愈合过程中对髁突形态的改变具有重要的影响。

Objective To explore the morphological effects of the lateral pterygoid muscles in healing process of sagittal fracture of mandibular condyles.Methods 16 1 years old sheep were randomly divided into group A kept the lateral pterygoid muscle and group B cut off the lateral pterygoid muscle.The sagittal condylar fractures of the sheep were broken with ultrasound bone knife.The general conditions of the animal before and after surgery were observed.The general anesthesia,weight,maximum opening,protrusion and lateral movement were measured and recorded before and after operation.Each animal was respectively executed in 4 weeks after operation （2 in each group）,12 weeks （3 in each group）,24 weeks （3 in each group）.CT examination and three-dimensional reconstruction of the CT was performed to observe the condylar morphology.The temporomandibular joint was dissected to observe the morphology of condyle.Results All animals were able to tolerate the operation,and no wound infection.Their postoperative diet was normal.Osteotomy before and after 1 weeks of body mass,maximum mouth opening,protrusion distance difference,the left moving distance and right movement distance had no statistical significance （P〉0.05）.Internal and external operation all side of the condylar diameter and anteroposterior diameter increased,especially the internal and external pterygoid muscle group retained condyle path and the anteroposterior diameter increases with group B,obviously （P〈0.05）.The group A had more new bone formation than group B.Conclusion The establishment of the model confirm that lateral pterygoid muscles has important morphological effects on healing process of the sagittal fracture of mandibular condyles.