End-to-side neurorrhaphy: the mechanism of nerve regeneration

神经端侧吻合后神经再生的机制尚待进一步研究。手术后神经再生有三种可能性。首先，通过手术受损的神经再生为移植的神经。第二，受体神经分支。第三，侧枝发芽后，再生神经逐渐修剪，以避免双重支配。有人提出用双标记技术或Y型硅胶管制作差距模型，可使供神经侧支发芽。在完全无损伤的大鼠模型中，我们证实了轴突出芽来源于完整的供体神经侧支。将成年Wistar大鼠坐骨神经解剖移植于左右正中神经之间。A组：采用非损伤性技术将受体神经与切断的供神经端侧吻合。B组将神经包埋于筋膜内，非损伤性缝合。C组在缝合处切除神经外膜后缝合。术后30、60天分别行双侧前臂屈肌肌电图检查，评价神经再生情况。为了进行形态学评价，解剖出接合部位，并将荧光染料（DiI）晶体附着到收获的供体神经的近侧。然后在37 ℃下孵育3周。我们在共聚焦显微镜下观察了这个标本的横截面。即使在完全无损伤的模型中，神经电生理再生。荧光染料（Dil）染色接合部位以外的再生神经。这些结果支持了端侧吻合术中神经再生是由供体神经长出的侧支再生的观点。

The mechanism of nerve regeneration after the end-to-side neurorrhaphy is yet to be studied. There are three kind of possibilities of nerve regenerating after the procedure. First, the nerve which was damaged through the procedure regenerates to the transplanted nerve. Second, recipient nerve sprouts collaterally. Third, after the collateral sprouting, the regenerated nerves were pruned gradually to avoid double domination. Some suggested the possibility of collateral sprouting from the donor nerve by the double-labelling technique or the gap model using the Y-shaped silicone tube. With the complete non-injury rat model, we proved that the axonal sprouting originates from the intact donor nerve collaterally. The sciatic nerve of adult wistar rat was dissected and transplanted between the left and right median nerve. In group A, recipient nerve was neurorrhaphied end- to-side with the divided donor nerve by non-injury technique. In group B, these nerves were wrapped in the faascia and neurorrhaphied non-injuriously. In group C, the epineurium was removed at the suture site and then neurorrhaphied. Thirty and sixty days after the operation, we evaluated nerve regeneration with electromyography of bilateral flexor muscle at the forearm. For morphometric evaluation, coaptatoin site was dissected out and fluorescent dye(DiI) crystal was attached to the proximal side of the harvested donor nerve. It was then incubated in 37 degree for 3 weeks. We observed cross section of this specimen under a confocal microscope. Even in a complete non-injury model, nerve regenerated electrophysically. Fluorescent dye(Dil) stained the regenerated nerve beyond the coaptation site. These results supported that in the end-to-side neurorrhaphy the nerve regenerated by the collateral sprouting from the donor nerve.