Repair Of The Nerve Defect With A Direct Gradual Lengthening Of Nerve Stumps In Rabbits

Objective: To establish experimental model of the sciatic nerve defect in rabbit. The defect was repaired by three kinds of operative approach: a direct gradual lengthening of proximal and distal nerve stumps method, a direct gradual lengthening of proximal nerve stump method and a autogenous nerve grafting method. To observe and compare the effect of repair among the three methods. The experimental basis was provided for clinical application with a direct gradual lengthening nerve stump method.Methods: 30 healthy adult rabbits were randomly devided into three group with 10 rabbits in each group. The rabbits with left sciatic nerve defect 20 mm were taken as model. At the 14 th day after removing the nerve, the defect was repaired by a direct gradual lengthening of proximal and distal nerve stumps method in the lengthening of nerve proximal and distal stumps group. In the lengthening of nerve proximal stump group, the defect was repaired by a direct gradual lengthening of proximal nerve stump method at the 28 th day after removing the nerve. The defect was repaired by a autogenous nerve grafting method in the autografting group immediately after removing the nerve. Gastrocnemius wet weight examination, electrophysiological test and histological study and were performed at the 16 th week after first opearation.Results: 1. Gastrocnemius wet weight:the three groups of animals were left leg muscle atrophy in varying degrees after surgery. The wet weight of the gastrocnemius muscle was significantly greater in the lengthening of nerve proximal and distal stumps group and in the lengthening of nerve proximal stump group than in the autografting group. The difference was statistically significant(P<0.05). However, there was no significant differences found in the lengthening of nerve proximal and distal stumps group and the lengthening of nerve proximal stump group(P>0.05).2. Electrophysiological results: at the 16 th weeks after first surgery, the motor nerve conduction velocity in the lengthening of nerve proximal and distal stumps group and in the lengthening of nerve proximal stump group was significantly higher than in the autografting group. The difference was statistically significant(P<0.05). However, there was no significant differences were found in the lengthening of nerve proximal and distal stumps group and the lengthening of nerve proximal stump group(P>0.05).3. Histological manifestation: the total number of medullated fibers(motor neurone) and the mean axonal diameter were significantly bigger in the lengthening of nerve proximal and distal stumps group and in the lengthening of nerve proximal stump group than in the autografting group. The difference was statistically significant(P<0.05). However, differences between the lengthening of nerve proximal and distal stumps group and the lengthening of nerve proximal stump group were not significant(P>0.05).Conclusions: the direct gradual lengthening of proximal and distal nerve stumps method has no obvious advantages over the direct gradual lengthening of proximal nerve stump method. However, the two method are both obviously superior to the autogenous nerve grafting method. The nerve-lengthening method has proved to be effective and safe. Direct-lengthening method in the treatment of the segmental peripheral nerve defect will be a new method for repairing nerve defect in the clinical.