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Polyglycolic acid (PGA) tube stented, silastic stented and non-stented anastomoses were compared in 18 ureteroureterostomies performed in 13 dogs. Urinalysis, urine culture, BUN and serum creatinine and intravenous pyelograms were done periodically from 1 day to 6 months postoperatively and ureteral dynamics were performed at 6 months. Normal intravenous pyelograms were observed following 10 of 11 PGA stented, 3 of 4 silastic stented and 2 of 3 unstented anastomoses. PGA stents prevented extravasation and dissolved within 7 days without stone formation. Urodynamic and histopathologic studies revealed no significant differences among the 3 groups. The data suggest that PGA stents are as effective as silastic stents and do not require additional procedures for removal. [ABSTRACT FROM AUTHOR]

The treatment of urinary lithiasis has been revolutionized during the last three decades. Minimally invasive therapies in the form of endoscopic surgery in companion with the advent of shock wave lithotripsy have diminished the role of open stone surgery. Laparoscopy, another minimally invasive treatment, is continuously gaining place in the treatment of urinary stones, mainly replacing open surgery. We have tried to identify the level of the evidence and grade of recommendation, according to the evidence-based medicine criteria, in studies supporting the laparoscopic approach to stone extraction. The highest level of evidence (IIa) was found for laparoscopic ureterolithotomy. It is technically feasible with the advantage of being minimally invasive and having lower postoperative morbidity compared to open ureterolithotomy. It is mostly recommended (grade B) for large impacted stones or when endoscopic ureterolithotripsy or shock wave stone disintegration have failed. Laparoscopic pyelolithotomy is feasible but rarely indicated in the present era (III/B). Laparoscopic nephrolithotomy may be indicated to remove a stone from an anterior diverticulum or when PNL or flexible ureteroscopy have failed (III/B).

Several genes contribute to the development of calcium oxalate nephrolithiasis as it is a polygenic disease. To explore the influence of genetic factors on oxalate excretion we have examined the distribution of oxalate excretions in 101 normal individuals who consumed self-selected diets. The distribution was apparently trimodal, consistent with the existence of three classes of oxalate excretors reflecting two allelic genes determining high and low oxalate excretion occurring with frequencies of 0.32 and 0.68 respectively. The pattern of inheritance in eight families was compatible with the expression of a pair of codominant alleles. A comparison of the distribution of excretory classes among the 101 normal individuals with that of 101 calcium oxalate stone formers suggests that high oxalate excretion may be associated with a 4-fold increased risk of stone disease and intermediate excretion with a 1.6-fold increase. Control of dietary factors influencing oxalate excretion apparently improved the discrimination between excretory classes in 17 individuals but the intra-individual variability in oxalate excretion was not reduced in four of nine individuals in whom this parameter was evaluated. More stringent dietary control than that applied in this study may be required before more extensive genotyping of individuals is attempted.