The mechanism of double innervation with End-to-Side Neurorrhaphy

（引言）我们研究了双神经支配，两个不同的神经支配一个肌肉，使用端侧神经缝合模型。（材料与方法）将坐骨神经切断，以端侧方式移植于左右正中神经之间。第1组不修复左侧正中神经，第2组切断后立即修复左侧正中神经。180天后，我们根据动作电位、肌电图、干肌肉重量和组织学评估神经再生。还使用DiI和DiA神经示踪剂对端侧神经缝合（远端侧）进行了形态计量学研究。（结果）第二组动作电位和肌电图结果提示存在双神经支配。此外，在左侧正中神经远端观察到来自移植坐骨神经和正中神经的再生轴突。（讨论）因此，建议存在双重神经支配的单一肌肉;然而，仍需要进一步研究有关单个肌纤维的细节。

〔Introduction〕 We investigated double innervation, two different nerves to innervate a single muscle, using an end-to-side neurorrhaphy model.〔Materials and Methods〕 The sciatic nerve was dissected, and transplanted between the left and right median nerve in an end-to-side fashion. Then, the left median nerve was transected proximal to the neurorrhaphy, In group one, the left median nerve was not repaired In group two, the left median nerve was repaired immediately after transection. After 180 days , we evaluated nerve regeneration based on action potential, electromyography, dry muscle weight and histology. The end-to-side neurorrhaphy(distal side) was also studied morphometrically with DiI and DiA neural tracers.〔Results〕 In group two, the existence of the double innervation was suggested by the results of action potential and electromyography. In addition, regenerating axons from both the grafted sciatic and median nerves were observed in the distal left median nerve.〔Discussion〕 The existence of double innervation to a single muscle was thus suggested ; however, studying further details about the individual muscle fibers is still required.