Experimental study in the function reserve of peripheral nerve repaired in different size by small gap briding

Objective To study the functional change of peripheral nerve after repaired in different size by small gap briding(the proximal end is smaller than the distal in size ), compared with epineurium suture in the same size. To explore the effect of functional reserve of peripheral nerves and the best situation for the reserve of nerve functional. Methods 10 Wistar rats served as the donors of arteris for briding. 80 Wistar rats (female), aging 2 months and weighing 200-250 g, were randomized into the 4 groups (n=20 per group). The group A was the control group , with only explosion of the right sciatic nerves. In group B, the right sciatic nerves were cut off at the level of 1.5cm distal to infrapiriform foramen, and received epineurium suture. In group C and D, the right sciatic nerves were cut off at the same level and 1cm segment of the common fibular nerves were removed from the proximal ends , the remaining were repaired with epineurium suture in group C, and with 3 mm gap artery sleeve bridging in group D. 16 weeks after operation, SFI was determined by walking tract analysis. Observation under microscope of the nerve repaired site; nerve electrophysiological parameters (motor nerve conduction velocity, NCV and amplitude, AMP), TSCI(triceps surae muscle cuadros index) and the muscle force parameters, morphological features of re-innervated musculus triceps surae were detected respectively. Results All the rats survived without infection and all the ulcer in the limbs recovered. The vessels beyond the epineurium at the repairded site, are more regular and less adhesive in group D compared with that in group B and C. In group A,B,C,D, SFI are (-12.2±7.5), (-41.3±9.2) , (64.7±5.8) , (-53.1±6.4) respectively.The recover rates of amplitude (AMP%) are (100.9±24.5%) , (71.5±5.6%) , (47.3±4.5.%) , (69.4±3.1%), The recover rates of motor nerve conduction velocity (MNCV%) are (96.0±7.6%) , (63.5±10.2%) , (48.3±6.5%) , (59.6±17.1%). All the rats survived without infection and all the ulcer in the limbs recovered. The vessels beyond the epineurium at the repaired site, are more regular and less adhesive in group D than that in group B and C. There is obvious difference in SFI between group A, B, C and D group(P<;0.05). In terms of recover rates of AMP and MNCV , There is obvious difference between group C and group B,D(P<; 0.05), and no obvious difference between group B and D (P >; 0.1 ) . There is significant difference between the various experimental groups and the control group in each parameters (P <; 0.05). It is in the same condition in terms of TSCI , the muscle force parameter , morphological features of re-innervated musculus triceps surae Conclusion The functional reserve of the nerve existes after repaired when the proximal end is smaller than the distal in size. The repaired nerve can recover the function almost at the same level compared with the direct epineurium suture in the same size. And the small gap bridging provides a better situation for nerve function reserve.