Effects Of Gradual Deceleration Lengthening The Femur On Rabbit Sciatic Nerve

Background and objectiveThe repair of peripheral nerve defects has always been a clinical problem Autologous nerve transplantation as a gold standard for repairing peripheral nerve defects,postoperative functional recovery is still not satisfactory.In recent years,the study of indirect prolongation of nerve repair peripheral nerve defects by limb lengthening has attracted people's attention.However,peripheral limb injury is often associated with limb prolongation with Ilizarov technique.In order to reduce the complications of peripheral nerve injury during limb extension,this study proposes a new method of peripheral nerve elongation,gradual deceleration lengthening,and explores the effect of this method on peripheral nerves,providing a reference for clinical repair of nerve defects.Materials and methodsTwenty-four 10-week old male New Zealand white rabbits were randomly divided into three groups(A?B?C),namely the 2cm elongation group(n=8),the 3cm elongation group(n=8)and the blank control group(n=8),respectively.These groups were divided into two subgroups(the gradual deceleration elongation group and the gradual uniform elongation group).Except the C group,the other animals were prolonged 5 days after osteotomy.The A1 group was extended by 1 mm/d for 10 days and extended by 0.75 mm/d for 14 days.The B1 group was extended by 1 mm/d for 10 days,extended by 0.75 mm/d for 14d and extended by 0.5 mm/d for 19d;A2 and B2 groups were extended by 20d and 30d at a speed of 1 mm/d.Neuro-electrophysiological tests,wet-weight measurements of the gastrocnemius muscle,and neuromuscular laboratory tests were performed in all animals after the initial 10-week extension,and the average density of myelinated nerve fibers and the average diameter and number of the axons were calculated.The length of bilateral sciatic nerves was measured and the rate of nerve elongation was calculated(PNE =(left-right)*100%/original nerve length).ResultsAccording to the data obtained,the rate of nerve elongation[PNE=(left-right)*100%/original nerve length]was calculated.The gradual deceleration and uniform lengthening groups were respectively 23.79%and 25.52%in the 2cm group,and 37.11%and 39.27%in the 3cm group.According to the statistical results,A1?B1 group compared with A2?B2,A2?B2 group compared with the blank control group,rabbit sciatic nerve action potential amplitude,motor nerve conduction velocity,gastrocnemius muscle wet weight,average density of myelinated nerve fibers and The difference in the average diameter of the axons was statistically significant(P<0.05).However,A1?B1 group compared with the blank control group,he difference between the above indicators was not statistically significant(P>0.05).ConclusionThe rabbit sciatic nerve has the potential to be stretched by passive stretching.When the length of the sciatic nerve of rabbit exceeds a certain limit(2?3cm),the gradual deceleration lengthening has less effect on rabbit sciatic nerve than the gradual uniform lengthening,which can further reduce the complications during nerve elongation and promote the recovery of target organ function.