Difference of Fistula Maturation Degree and Physical Property by the Types of Tube Material: An Experimental Study

ABSTRACT

PURPOSE: We recently experienced 3 consecutive cases of bile peritonitis due to tract rupture following T-tube removal at about 6 weeks after choledocholithotomy with using a new tube (1.1% silica-filled rubber). These unexpected cases of bile peritonitis have raised questions related to the tube material factor for the rupture. The aim of this study was to compare three kinds of T-tubes [ (100% silicone (SIL), 1.1% silica-filled rubber (SFR), and 100% rubber (RUB) ] from the point of view of fistula maturation as is related to the physicochemical properties of the tube materials. METHODS: SIL, SFR and RUB tubes were implanted into the subcutaneous space in rats. Histologically, the degree of fistula maturation was estimated by an inflammation score, the thickness of inflammation and the fibrosis. The physical properties of the tube materials were estimated by their modulus and elasticity. RESULTS: SFR and RUB tube had no statistically significant difference for the thickness of the inflammation and fibrosis. Yet there were difference in their modulus and elasticity. The modulus, elasticity, thickness of the inflammation and the fibrosis were difference in the SIL versus SFR and the SIL versus RUB. CONCLUSION: There were no statistically significant differences in the degree of fistula maturation between the SFR and RUB tubes. The rubber tube tended to show a more severe inflammatory reaction and better maturation of the fistula. Moreover, the flexibleness of the RUB tube make easy to experience collapse of the tube. The degree of maturation mostly depends upon the chemical property of the tube materials. However, the tract rupture that happens is due to the physical properties rather than the chemical properties of the tube. We recommend RUB for the T-tube to prevent the tube related complication such as tract rupture.