Urine is filtered from blood by glomerulus , basic filtrering unit of kidney.The calyces, renal pelvis form the drainage tubes. The calyces are divided into upper, middle and lower parts. Stone are formed at the calyceal level and it may increase in size, and or move down to ureter via renal pelvis. If it can reach the bladder it is usually passed out in the urine. Sometimes it can get stuck within the renal calyces, renal pelvis, ureter or urethra
The tip of the flexible ureteroscope can bend both up and down in a single plane and allows easy access to the calyceal system which is not possible with rigid scope.There is a channel in the center of scope through laser fibre for breaking the stone, baskets and similar retrival devices can be passed. Current flexible ureteroscope are small in diameter, better optics and capable of visualising the calyces in 94 to 100 % of cases. Laser can break stones of very hard nature as well
Ureteroscopy is one of the common procedures used to treat kidney stones. It is also used to diagnose and treat a variety of conditions such as polyps or cancer in the urinary tract. Cancers can also be treated in the early stages with laser .
It takes about one hour to complete the procedure, which may or may not require an overnight stay. A self retaining tube , one end of which will fold itself in the kidney and the other end will coil itself in the bladder called ureteric stent will be placed . This allows stone fragments to pass down the ureter in to the bladder and then patients passes stone fragments in the urine It also relieves obstruction to the urine flow. A repeat Scan or xray will assess completeness of stone clearance.The stent is removed 2 to 4 weeks later as a day case procedure