A kidney stone, also known as a renal calculus (from the Latin rēnēs, “kidneys,” and calculus, “pebble”), is a solid concretion or crystal aggregation formed in the kidneys from dietary minerals in the urine.
Urinary stones are typically classified by their location in the kidney (nephrolithiasis), ureter (ureterolithiasis), or bladder (cystolithiasis), or by their chemical composition (calcium-containing, struvite, uric acid, or other compounds). About 80% of those with kidney stones are men.
Renal calculi are formed when the urine is supersaturated with salt and minerals such as calcium oxalate, struvite (ammonium magnesium phosphate), uric acid and cystine. 60-80% of stones contain calcium. They vary considerably in size from small ‘gravel-like’ stones, to large staghorn calculi.
Retrograde Pyelogram is a urologic procedure where the physician injects contrast into the ureter in order to visualize the ureter and kidney. The flow of contrast (up from the bladder to the kidney) is opposite the usual flow of urine, hence the retrograde name.
Reasons for performing a retrograde pyelogram include identification of filling defects (e.g. stones or tumors), as an adjunct during the placement of ureteral stents or ureteroscopy, or to delineate renal anatomy in preparation for surgery.
Percutaneous nephrolithotomy (PCNL) is a surgical procedure to remove stones from the kidney by a small puncture wound (up to about 1 cm) through the skin. It is most suitable to remove stones of more than 2 cm in size and which are present near the pelvic region. It is usually done under general anesthesia or spinal anesthesia.
An intravenous pyelogram or IVP for short is a radiological procedure used to visualize abnormalities of the urinary system, including the kidneys,ureters, and bladder.