What is the definition or description of: pyeloplasty?

Remove Blockage: Pyeloplasty is an operation to correct a blockage that has occurred between the kidney and the ureter, which is the tube that drains the kidney into the bladder. By removing the blockage, urine will be able to drain freely from the kidney to the bladder. Source: http://www.Umm.Edu/robotics/pyeloplasty.Htm.

Ureteral repair: Ureteral blockage can occur at the junction between the ureter and the kidney (the ureteropelvic junction). This can be acquired (ie from stone disease or injury) or congenital (due to development). Pyeloplasty involves surgery on the ureter from the outside, usually detaching the kidney from the ureter and reconstructing. Endopyelotomy involves cutting the area of blockage from inside the ureter.