分娩性臂丛损伤创伤性神经瘤的病理研究

Pathological study of neuroma-in-continuity in obstetric brachial plexus palsy

目的为早期神经瘤切除、臂丛修复治疗产瘫提供理论依据。方法对44例早期产瘫手术患儿,术中作臂丛上干神经电生理测定( 3 7例) ,随后切除神经瘤、行神经移植和移位修复臂丛术。对神经瘤进行如下检测大体观察、LuxolFastBlue髓鞘染色、Van Gieson胶原纤维染色、透射电镜观察、神经丝蛋白的单克隆抗体标记以计数轴索等。另取2 3侧新鲜婴儿尸体的臂丛上干进行对照研究。结果术中发现臂丛上干神经瘤呈梭形或“双峰骆驼”形,瘤长1.2～1.5cm ,质硬。神经瘤近端可见大量的有髓神经纤维;远端的神经外膜、束膜内胶原纤维明显增生,束内再生的有髓神经纤维分布不均。神经瘤和正常上干内胶原纤维相对面积分别为( 63 73 %±12 2 7, x±s ,下同)和42 .3 8%±11.18% ,差异有统计学意义(P<0 .0 1)。透射电镜观察显示,不同髓鞘厚度的神经纤维和脱髓鞘病变分布于神经瘤远、近端和中央段。神经瘤近端和正常上干神经纤维数的差异有统计学意义(P <0 .0 1) ;神经瘤内再生神经纤维的通过率41.67%±8.0 0 %。根据被检肌肉(冈下肌、三角肌、肱二头肌)能否引出复合动作电位(CMAP)将患儿分为三组,被检肌肉波幅均有明显下降。但方差分析表明,三组再生神经纤维通过神经瘤的比率差异无统计学意义(P >0 .0 5 )。

Objective To provide the pathological basis for early neuroma resection and nerve repair in obstetric brachial plexus palsy(OBPP). Methods Forty-four surgically treated OBPP cases were involved. Electromyographic (EMG) and nerve conduction study of neuromas of the upper trunk were carried out prior to neuroma resection and nerve repair. Gross observation and histologic examinations by Luxol Fast Blue staining, Van-Gieson staining, immunohistochemical staining with monoclonal antibody of neurofilament, and transmitting electron microscopic observation of the neuromas were done. Twenty-three brachial plexus upper trunk samples of fresh infant cadavers served as control. Results Neuroma was seen at the upper trunk of all cases studied, being fusiform in shape, 1.2～1.5 cm in length and 0.7～1.2 cm in diameter with a hard texture. A great number of myelinated nerve fibers were located in the proximal part of the neuroma. In the distal part, obvious collagen hyperplasia was observed in the epineurium or perineurium. The regenerated myelinated nerve fibers were unevenly distributed within fascicles. The area percentage of collagen fiber in the neuroma and normal upper trunk were 63.73%±12.27% and 42.38%±11.18%, respectively. The difference was statistically significant (P<0.01). Electron microscopic observation showed nerve fibers of various myelin shealth thickness and demyelination distributed in the proximal, middle and distal parts of the neuroma. Nerve fiber count in the proximal part of the neuroma and normal upper trunk were 26903±1648 and 37214±2164 respectively, the difference being statistically significant (P<0.01). The passing rate of regenerative nerve fibers in the neuroma was 41.67% ± 8.00%. EMG study categorised all cases into 3 groups depending on whether compound muscle action potential (CMAP) of the infraspinatus, deltoid and biceps could be elicited while stimulating C_~5,6 roots proximal to the neuroma: CMAP positive in all muscles, CMAP positive in some muscles, and CMAP negative in all muscles. Analysis of variance suggested the differences in the number of nerve fibers in the proximal part of the neuroma and the passing rate were of no statistical significance among the three groups (P>0.05). Conclusion Neuroma resection and nerve reconstruction is highly recommended in OBPP patients indicative of early surgical intervention regardless of conductivity of the neuroma.