Morphologic changes in the canine urinary tract after ureteral reconstruction with the tunica albuginea (experimental study).

OBJECTIVES: The problem of ureteral reconstruction has not been fully solved, despite dramatic developments in surgical methods. Many attempts to repair a ureteral damage with autologous or homologous organ grafts, or with organic substitutes have not really been satisfactory. Also, attempts to use alloplastic and heteroplastic prostheses made of synthetic materials have been equally disappointing. Experimental studies, particularly in dogs, indicate great regenerative abilities of ureters when appropriate surgical techniques are used.
MATERIALS AND METHODS: In our experimental study, suitability of the tunica albuginea for reconstruction of the middle part of the ureter was investigated in 20 dogs. The dogs were divided into two groups according to a type of ureteral damage: partial (a patch graft) or complete (a tube graft). The ureteral damage was 2-3 cm long in 10 dogs and 3-3.5 cm long in the subsequent 10 dogs. Each dog underwent two operations. The first operation involved a fenestrating incision in the ureter, 23.5 cm long, so as to preserve the ureteral continuity, and then the produced injury was repaired with a patch of the tunica albuginea, with the 4 Charr catheter being inserted in the ureter. The second operation involved a complete excision of ureteral segments, 2-3.5 cm long, on the contralateral side. The excised length of the ureter was substituted with a tube graft of the tunica albuginea, also using the 4 Charr catheter. Thus, in 21 cases, a partial damage of the ureteral wall was repaired with a patch graft of the tunica albuginea. In 19 cases, a complete damage of the ureter was repaired with a tube graft of the tunica albuginea.
RESULTS: Four dogs died after the tube-graft implantation due to urinary infiltration and/or purulent inflammatory changes in the kidneys. Autopsies were performed in all the dogs after they had been put to sleep. Definitely poor results were obtained in case of the complete reconstruction of the ureteral loss with a tube graft of the tunica albuginea, 3-3.5 cm long. Within the graft area, we observed inflammatory infiltrates of varied intensity, fibrosis, cicatricial strictures or ureteral obstruction. Occasionally, necrotic foci, degenerative changes or hydronephrosis were found. In case of the reconstruction with a shorter tube graft, i.e. 2-3 cm long, similar changes were observed, however, they were less intense. Satisfactory results were obtained following the partial reconstruction of the ureteral loss with a patch graft of the tunica albuginea. In this case, we observed generally normal regeneration not only of the transitional epithelium but the muscular layer and ureteral structure as well, with full patency of the ureter preserved. The findings obtained in our study are compatible with the findings of other authors.
CONCLUSIONS: (1) The success of reconstructive procedures in the ureters can be achieved if the continuity of the ureter is preserved and the catheter is removed after 14 days. (2) The substitution of a complete ureteral loss with a tube-graft of the tunica albuginea results in necrosis of the graft and restenosis.