周围神经断端桥接后数量放大效应的研究

目的证实周围神经横截面不对等修复时神经纤维数量的放大效应。方法选用雄性Sprague-Dawley大鼠50只,分为A、B、C、D、E5组。A、B、C3组将大鼠坐骨神经切断后,A组近端保留完整断端与远端坐骨神经用甲壳质套管留置2mm间隙套接,B组在近端5mm处将坐骨神经中的腓总神经束结扎切断,将胫神经束与远端坐骨神经套接,C组在近端5mm处将坐骨神经中的胫神经束结扎切断,将腓总神经神经束与远端坐骨神经套接;D、E两组将胫神经在分叉处远端5mm组将胫神经切断;D组结扎切断2／3近端纤维,将剩余神经纤维与远端胫神经进行甲壳质套管套接,E组将全部近端纤维与远端胫神经进行甲壳质套管套接。1、2、4、12周后分别取材进行组织学和电生理研究。结果采用SPSS软件进行统计学分析。结果12周后电生理检查发现,各组诱发出的最大波幅下面积B、C两组小于A组（均P〈0．05）,D组小于E组（P〈0．05）。A组与B、C组之间,D、E组之间感觉神经传导速度相近。锇酸染色有髓神经纤维计数：各组远端均大于近端：A组远端比近端增加34．4％,B组增加39．6％,C组增加80．4％,D组增加101．1％,E组增加48．9％（P〈0．05）。结论在周围神经桥接后,远端神经纤维数量明显大于近端,存在神经纤维数量的放大;同源的神经桥接的放大效应大于非同源的神经。临床上较细神经修复远端粗大神经是可能的。

Magnifying effect of conduit bridging in number of nerve fibers of broken peripheral nerves: experiment with rats

OBJECTIVE: To observe the magnifying effect of conduit bridging in number of nerve fibers of broken peripheral nerves. METHODS: Fifty Sprague-Dawley rats were randomly divided into five equal groups. Group A underwent transection of the sciatic nerves and bridging of the complete proximal sciatic nerve stump and the distal sciatic stump in a conduit sutured with 8 - 0 nylon chord with a 2-mm gap. In Group B, the sciatic nerve was transected, the proximal stump was divided into tibial nerve and common peroneal nerve bundles 5 mm proximal to the transection site, the common peroneal nerve bundle was ligated and transected, and then the proximal stump of the tibial nerve and the distal sciatic stump were bridged with a conduit with a 2-mm gap. In Group C, the sciatic nerve was transected, the proximal stump was divided into tibial nerve and common peroneal nerve bundles 10 mm proximal to the transection site, the tibial nerve bundle was ligated and transected, and then the proximal stump of the common peroneal nerve and the distal sciatic stump were bridged with a conduit with a 2-mm gap. In group D, the tibial nerve was transected 5 mm distal to the branch site, 2/3 of the tibial nerve fibers were ligated and transected, and then the remnant 1/3 fibers of the proximal stump of tibial nerve were bridged to the distal stump of tibial in a conduit. In Group E the tibial nerve was transected 5 mm distal to the branch site, and then the complete proximal tibial nerve stump was bridged to the distal stump of tibial nerve in a conduit Electrophysiological examination was conducted 1, 2, 4, and 12 weeks later. Pathological examination was performed with immunohistochemistry, HE staining and osmic acid staining. RESULTS: One week after surgery, edema and ulcer in the hind limbs were found in most rats; toe necrosis was seen in part of the rats, and since 3 weeks later these pathological changes began to disappear gradually. The motion of hind limbs recovered since 4 weeks after the surgery. Osmic acid staining 12 weeks later showed that the numbers of distal myelin sheath at the distal end were more than that in the proximal end by 34.4% in Group A, 39.6% in Group B, 80.4% in Group C, 101.1% in Group D, and 48.9% in Group E. CONCLUSION: The axon number distal to the transaction site becomes significantly more than that at the proximal end after bridging. The magnification effect of the bridging of homologous nerve is greater than that of non-homologous nerve. It is possible to repair the thicker nerve at the distal broken end with thinner nerve at the proximal end clinically.