Early muscle reinnervation by means of end-to-side neurorrhaphy in an experimental model

Aim:The aim of the study was to provide early muscular reinnervation to avoid muscle atrophy and functional loss in an experimental model.Methods:Fifty rats were divided into five groups.In group 0(control group)only nerve dissection was performed.Total peroneal nerve section was performed in the remaining groups.Immediate end-to-end neurorrhaphy(EEN)was made in group 1.In group 2,an end-to-side neurorrhaphy(ESN)was performed from the tibial nerve to the peroneal nerve.In group 3,a direct EEN,plus an ESN,were used as a nerve graft as a bridge from the donor nerve(tibial);all nerve coaptations were performed through an epineural window.In group 4,only a neurotomy was made without any type of reconstruction.Results:Neural diameters were similar in groups 0,1,and 3(38±1μm,31±6μm,32±3μm).Neural fibers in group 3 had an 18%increase in the number of axons(P<0.001)when compared to group 0.Group 2(28±1μm)and group 4(19±3μm)had diminished diameters with a lower index of muscle regeneration.Animals in group 4 presented with'clawed'lower extremities and had difficulty with ambulation.Neural graft diameters was similar in groups 2 and 3(33±4μm,31±3μm),but axon density was significantly higher in group 3(53±6μm,39±8μm)(P<0.001).Axon density was 36%higher when the combination of EEN and ESN with a neural graft through an epineural window was performed.Conclusion:This study revealed that the combination of EEN and ESN repairs with the addition of a neural graft provides a lower index of muscle fiber destruction,and can be a reliable method for reconstruction in high neural injuries.