Effect of Stay-suture on Peripheral Nerve Tension

Baek, Goo Hyun; Chung, Moon Sang; Lee, Han Koo; Lee, Sang Hoon; Chung, Yong Jin

Abstract

The purpose of this study is to confirm the effectiveness of stay-suture which is commonly used in the procedure of end to end anastomosis, to find out general biomechanical properties of peripheral nerve with gradual stretching and to evaluate the histological difference after breakage of the nerve. The sciatic nerves of adult rabbits were excised and they were grouped by I and II. Group I was composed of 14 normal sciatic nerves and group II, 14 sciatic nerves sutured with 5-0 nylon after transection. They were stretched on the "Instron" universal testing machine at a constant rate of 200mm/min until breakage took place and the results were compared. The mean maximal tensile strength was 13.6N in group I and 2.1N in group II, representing about one seventh value. The mean ultimate tensile strength was 4.2MPa in group I and 0.9MPa in group II, representing about one fifth value. In load-elongation curve of group I, viscoelastic property was noted as all other biological tissues have. The mean modulus of elasticity was 19 in normal sciatic nerves, which is somewhat lower value than other tissues, indicating superior elastic property of peripheral nerves. Transverse histologic examination showed that epineurium lost its continuity earlier than perineurium, implying perineurium is a more resistant structure than epineurium. However, to confirm this, it is thought to be necessary to examine the nerves serially during distraction at each different status. In conclusion, stay-suture provided about one fifth of ultimate tensile stress, implying its usefullness of resisting excessive tension in end to end anastomosis of peripheral nerves. Normal sciatic nerves showed viscoelastic property with mean modulus of elasticity of 19.