代用尿路に関する実験的研究

Abstract

Arterial polytetrafluoroethylene (Gore-Tex) prosthesis (called G tubes hereafter) was transplanted into the urinary tract of dogs to substitute for the ureter or urethra. Preliminary studies showed that the G tube was implanted more easily and fit better in the tissue when it was first transplanted as a substitute for part of the femoral artery or embedded subcutaneously before use. The surfaces of the G tubes anastomosed to the femoral artery or transplanted subcutaneously were covered by connective tissue with neogenesis of capilaries at week 4-27, and were soft. This suggests that the tube is accepted by the tissue. Histologically, fibroblast cells were attached to the inside and to the outside of the G tube. These cells had invaded in the direction of the Gore-Tex mesh, sometimes accompanied by the capillary vessel. Histologically, there was no substantial difference between the two types of operations. For ureteral substitution, the G tubes that had been transplanted subcutaneously for 6 weeks before operation were found to be preferable. Ureteral transplants: Two to six cm of the lower ureters of 13 dogs was removed, and the G tube was anastomosed end to end to the ureter with the other ends connected to the bladder or ureter. The dogs were observed for 4-18 weeks. A ureteral catheter could be passed through the ureters removed from only 4 dogs killed at week 4, 6, 16 or 18. IVP showed kidney function to be normal in only the two dogs killed at week 4 or 6. Histologically, mucosal regeneration had advanced to the outside of the G tube: After the mucus was regenerated, the G tube was gradually pushed into the bladder, and tended to be eliminated. Then, the transplantation site in the ureter became constricted, and hydronephrosis advanced rapidly. Histologically, mucosal regeneration appeared on the outside of the G tube in the dogs with urethral substitution as well. The newly generated mucus was abundant and plicate. The G tube was eliminated after mucosal regeneration even in 2 of the 4 dogs in which operation was thought to be successful. Urethral transplants: Three to four cm of the anterior or posterior urethra excluding the area near the baculum of 12 dogs was removed, and the G tube was anastomosed end to end to the urethra, Operation on the posterior urethra, a difficult procedure, was often not successful. Thus, the posterior urethra was used most often. The dogs were observed for 17 weeks at most. Four of the 8 dogs that had transplants to the posterior urethra had no abnormalities in urinary excretion at week 14-17, and a catheter could easily be passed through. The operation was considered successful, but on the urethra X-ray, a slight stricture-like appearance was detected where the transplant had been made.