Consequences to the upper urinary tract after ureteric torsion.

The effects of ureteric torsion on the upper urinary tract were studied in 8 pigs. With 5 pigs the distal ureter was mobilised, torted 1 to 5 times and reimplanted into the bladder. With three pigs the proximal ureter was torted 1 to 3 times and re-anastomosed to the renal pelvis. It was shown that a torsion of 1 or 2 times in the distal ureter does not result in ureteral obstruction. However, as little as 360 degrees torsion in the proximal ureter may lead to dysfunction secondary to mechanical obstruction. Histological examination of the ureter showed ischaemic changes only after multiple torsions.