模拟一次加压延长治疗先天性胫骨假关节胫骨前肌的变化

Changes of the tibialis anterior muscle after combined bone lengthening and compressing in the treatment of simulant model of congenital pseudoarthrosis of tibia

目的：研究在一次加压延长治疗先天性胫骨假关节过程中由大幅度肢体延长所带来的肌肉组织损害问题。方法：将２０只绵羊分成３个实验组，在胫骨下段分别切除胫骨全长的１０％ 、２０％ 和３０％ ，模拟制成切除先天性胫骨假关节后形成的大块骨缺损模型，断端少量髓芯植骨，利用自制改良 Ｉｌｉｚａｒｏｖ 外固定器械加压固定，在下段形成软组织堆积，干骺端－ 骨干部截骨延长，取径骨前肌标本，以肌纤维大小变化、肌纤维细胞核的内在化、肌纤维变性、再生、纤维化为基准，建立相应的组织病理学评分标准系统，研究各项参数的变化规律。结果：１０％ 组仅出现肌纤维大小的显著变化，而２０％ 、３０％ 组出现了反映不可逆损害的肌纤维细胞核内在化、肌纤维变性、肌纤维再生，肌纤维内膜纤维化等参数的显著变化。结论：骨延长超过一定限度，以常规１０ ｍ ｍ ／ｄ，４次／ｄ 速率，即使下段有软组织堆积的情况下，同样也不能缓解上段因超限延长所带来的肌肉组织不可逆性损害。

Objective:To study changes of the tibialis anterior muscle after combined bone lengthening and compressing in the treatment of simulant model of congenital pseudoarthrosis of tibia, model of large bone loss in the distal third of the tibia of sheep was formed,autogrifted,compressed by self designed external fixation of Ilizarov technique to form the muscle accumulation,and bone was lengthened by metaphyseotomies.The change of the tibialis anterior muscle in relation to the percentage of lengthening of the tibia of sheep was observed.Methods:Twenty sheep were divided into three lengthening groups,10,20 and 30 percent lengthening,respectively.Histopathologic observations,based on the fiber size variation,internalization of the nuclei,degeneration,regeneration and endomysial fibrosis of muscle fibers,was done. Results:Substantial change occurred in the 20% and 30% groups.conclusion:Under the condition of muscle accumulation,permanent soft tissue damage occur if the lengthening is beyond a certain safe limit.