All endoureteromy procedures have in common the use of a ureteral stent as post-procedure However, the optimal stent size necessary to promote satisfactory healing is not known. Herein we compared healing of an endoureterotomy over a 7 Fr indwelling ureteral stent (IUS) with healing over a 14 Fr endopyelotomy stent( ES). A mid-ureteral stricture was created in each of 25 anesthetized, female minipigs using a retrograde electrified stone basket. Six weeks later, retrograde ureterograms(RU) revealed a stricture in 24 pigs ; ureteral incision was performed with a 24 Fr cutting balloon device. Twenty pigs were randomized to receive a 7 Fr IUS or a 14 Fr ES; 4 control pigs were performed to confirm proper stent position and the stents were removed. At 3 months. RU was repeated and the ureters were grossly examined and harvested for histological studies. Two pigs in each group had recurrent strictures. Despite a 50 years history of endoureterotomy, optimal stent size remains an endourologic unknown. Our study represents the first attempt at directly comparing stents of different size in an in vivo ureteral stricture model. There is no significant difference between 7 Fr and 14 Fr stents.
Constriction, Pathologic* ; Female ; Humans ; Stents* ; Swine ; Swine, Miniature ; Ureter*

The inability to bluntly dissect tissue inhibits the efficiency of laparoscopic surgery. To overcome this difficulty, we developed a 5mm laparoscopic pneumodissector(PD) capable of delivering brief bursts of high pressure CO2( 20-100 psi; approximately 1-7 atmosphere) for tissue dissection. After establishment of a pneumoperitoneum, 9 anesthetized female pigs underwent dissection of the right kidney and renal hilum using the PD(40-60 psi) as the primary mode of dissection. None of the study animals became hypercarbic during the use of the PD. Acute histological studies revealed marked hemorrhage in the spleen after direct contact at all pressures ; minimal ecchymoses occurred in the other tissues. No intimal damage was noted in the aorta, inferior vena cava, or renal vessels. Chronic histological studies 6 and 12 weeks after PD showed no discernible damage to liver. kidney, or perineal tissues. Also, acute and long term renal scans revealed no significant change in renal function. In this initial trial, PD at up to 60 psi( =4 atm) appeared to be a safe and effective method for rapidly expanding the perineal space and for dissecting both the perineal fat from the surface of the kidney and perihilar tissue from the renalvessels.
Animals ; Aorta ; Ecchymosis ; Female ; Hemorrhage ; Humans ; Kidney ; Laparoscopy ; Liver ; Pneumoperitoneum ; Spleen ; Swine ; Vena Cava, Inferior