The kidneys filter blood of wastes and produce urine, which flows down narrow tubes called ureters, into the bladder where it is stored and later evacuated through the urethra. Any obstruction in the flow of urine due to stricture (constriction), blood clots, kidney stones or a tumour can be detected by a diagnostic imaging study called antegrade pyelogram. The study may also be used to check for blockages before and after surgery.
The procedure is performed under local anaesthesia. You will lie face down and a needle is inserted through your back to reach the renal pelvis (funnel-shaped junction of the kidney and ureter) with the help of imaging. A dye is then injected into the renal pelvis. A series of X-rays are taken as the dye flows down the urinary system. Any blockages can be detected on the X-ray images. A tube or other instruments may be inserted through the needle to remove the source of blockage. Following the procedure, you are observed carefully. If there are no complications, you may be allowed to return home where you are advised to continue observing your urine output. You may experience slight pain with urination following the procedure, which can be relieved with medication that your surgeon will prescribe.
Antegrade pyelogram is not recommended for those with clotting disorders and may occasionally be associated with some risks and complications such as bleeding, clot formation, sepsis, urine-filled cysts or allergy to the contrast dye.