健侧C7神经移位术后大脑运动皮层功能重组的功能MRI研究

Functional reorganization of human motor cortex after unaffected side C7 nerve root transposition

目的利用功能MRI(fMRI),观察健侧C7神经移位术后大脑运动皮层的变化特征。方法随访经临床和手术证实的因全臂丛神经损伤而接受健侧C7神经移位术者13例,左侧损伤者10例,右侧者3例。根据手部运动功能的恢复情况,将病例分为2组:a组10例,患手不能自主运动。b组3例,患手可以自主运动。另外,选择12名健康志愿者作为对照。所有受检者均接受了fMRI,扫描方法采用平面回波血氧水平依赖(BOLD)序列,利用SPM99软件对图像进行处理分析。结果患者健侧和患侧上肢运动诱发激活区最强信号体素主要出现于对侧半球初级运动皮层(PMC),健侧肢体运动诱发同侧PMC激活者10例,患侧肢体运动诱发同侧PMC激活者7例;a组受检者健侧上肢运动诱发对侧PMC激活区形态正常者9例,手部运动诱发平均激活区大小为3159个体素,肩部运动诱发平均激活区大小为1746个体素。患侧手部和肩部运动诱发对侧PMC激活区扩大者各有6例;b组受检者患肢运动诱发双侧PMC出现激活者1例,对侧PMC激活者2例。结论外周神经损伤可以引起大脑运动皮层的改变;患肢躯体代表区可以在神经损伤以后相当长时期内存在并对运动的心理表达产生应答;健侧C7神经移位术后中枢神经系统重组可能发生在多种水平上,并且可以受到多种因素影响。

Objective To assess the characteristics of neuronal activity in human motor cortex after the seventh cervical nerve root transposition of the unaffected side by using functional MRI （fMRI）. Methods Thirteen patients who accepted the seventh cervical nerve root transposition of the unaffected side, due to total brachial plexus traction injury diagnosed by manifestation and operation, were examined retrospectively by using fMRI. 10 patients were injured on the left side and 3 on the right side. According to functional recovery of the affected hand, all subjects can be divided into 2 groups. The patients of the first group could not move the affected hand voluntarily. The patients of the second group could move the affected hand self-determined. 12 healthy volunteers were also involved in this study as control. The fMRI examinations were performed by using echo-planer BOLD sequence. Then the SPM 99 software was used for post-processing. Results The neuronal activation induced by the movement of both unaffected and affected upper limb was seen in the contralateral PMC in all patients; Neuronal activation in the ipsilateral PMC evoked by movement of the unaffected extremity was seen in 10 cases, and induced by movement of the affected limb was seen in 7 cases. In the first group, the sharp of clusters in the contralateral PMC resulted by movement of the unaffected extremity showed normal in 9 cases, the average size of clusters resulted by the unafected hand was 3159 （voxel）, and resulted by the unafected shoulder was 1746（voxel）. The sharp of clusters in the contralateral PMC resulted by the affected shoulder or hand were revealed enlargement in 6 cases of each. In the second group, 1 case showed neuronal activation induced by movement of the affected limb in the PMC in both sides of motor cortex, and 2 cases showed neuronal activation in the contralateral PMC. Conclusions Peripheral nerve injury was able to cause changes of motor cortex in human brain. Cortical area devoted to the affected extremity seems to persist for a long time with response to mental representation of movement. The functional reorganization of central nerve system may be present in several levels of the central nerve system and may be affected by multiple factors.