Elongation Of Peripheral Nerve With Tissue Expansion

Peripheral nerve defects can be overcome and the severed nerve repaired with various surgical management with unstable results. In nerve repair, tension-free end-to-end suture is a fundamental requirement. This paper presents the effect of elongation of sciatic nerve with tissue expansion in 100 rabbits. Blood circulation, morphologic and functional changes of elongated nerve and muscles innervated by the nerve were investigated with by means of isotope tracing, electrophysiology, muscle biomechanics and physiology, histology, histochemistry and electron microscope. The results showed: 1. In the rabbit sciatic nerve model, elongation of nerve by expansion was possible with an expansion rate of 36 %, the elongation rate of 24% and the elastic limit of the nerve 10—12%. 2. Elongation degree of the nerve of larger calibre was less than smaller one. 3. The length of elongated nerve gradually reduced with time after removal of expander. 4. Blood circulation in elongated nerve was not diminished as compared with the control nerve. 5. Nerve conduction velocity of the nerve was reduced when a large volume of water was injected into the expander at one time. 6. Nerve conduction velocity was moderately reduced during expansion and returned to normal in 3 to 6 months after removal of expander. 7. The function of the expanded nerve was not significantly impaired as compared with the control by measuring the muscle contractibility. 8. The function of stretched muscle was not affected ; 9. Characteristics of the muscle contractive property were well kept; 10. Axon regeneration of elongated nerve through site of anastomosis was 80% of the normal nerve; 11. Elongated nerve could be used as nerve graft material; 12. The neurofilament observation demonstrated that one coaptation is better than two; 13. Intermediate rate of injection with three days interval for elongation was considered appropriate; 14. elongation of nerve by expansion may be considered in clinical application according to the condition of the nerve gap, skin defect and joint mobility.