Ureterorenoscopy (URS) for kidney and ureteral stones

URS is the method of choice for stones located in the ureter. Likewise, stones located in the branched renal caliceal system and not exceeding 1-2 cm in size can be treated using a flexible instrument.

For larger stones, a Mini-PCNL is recommended.

The duration of a URS depends on many factors, such as size, location, and quantity of the stones. Individual anatomy and stone composition can also affect the duration of the procedure. Surgery for a small ureteral stone may take as little as 15 minutes. Removing a large stone in a difficult-to-reach renal calice can take 90 minutes or more.

The stones are accessed with the ureterorenoscope, a very thin and long instrument. This is inserted into the bladder via the urethra. Once inside, either the left or right ureteral orifice is chosen and then the instrument is pushed through the ureter into the kidney. Flexible instruments can even “look around the corner” so that even the further corners of the branched renal caliceal system can be examined. Thus, access to the stones is gently done in a natural, minimally invasive way.

If the stones would not fit through the ureter as a whole, they might first need to be crushed, though this depends on their size. This is done by means of a laser. The fragments are usually retrieved by a tool made of fine wires known as a basket, which “catches” the stones.

After all the stones are removed, it may be necessary to insert a double-j stent. This ensure the free flow of urine after the operation.

A double-j stent is a soft, thin plastic catheter that extends from the kidney through the ureter into the bladder. In this way, it “splints” the ureter and ensures the unobstructed flow of urine. The name comes from the fact that the tube curls in a J-shape in both the kidney and the bladder to prevent it from slipping. It is also known as a pigtail or ureteral stent.

The placement of a double-j stent is always necessary when an obstruction in the ureter needs to be bridged to ensure the free flow of urine. This is typically the case when a stone is stuck in the ureter. This causes urinary retention, which manifests itself as renal colic and can be very painful. Immediate surgical removal of ureteral stones is not always the best course of action as the ureter is very delicate. In this case, a double-j stent must be inserted before the stone is removed by means of URS. On the one hand, the double-j stent defuses the acute situation and on the other hand, it ensures that the ureter is relaxed. Stone removal can then be delayed by a few days.

After stone removal by means of URS, swelling of the ureter can occur, which can in turn cause urinary retention. Therefore, it is often necessary to insert a double-j stent during the operation as a precautionary measure to prevent pain after the operation.

A double-j stent is typically inserted while the patient is under short anaesthesia. This is done via a cystoscopy. In the bladder, the orifice of the ureter is located, and double-j stent is pushed up past the stone, into the renal pelvis.

Double-j stent removal is performed by means of a 1-2 minute cystoscopy under local anaesthesia as an outpatient procedure.

The most common risk of URS is a feverish infection in about 5-10% of cases, which requires antibiotic treatment. Other complications such as severe ureteral injuries are rare. This will be discussed in detail in the conversation prior to the procedure.

The URS is performed on the day of inpatient admission. After the operation, a bladder catheter is inserted for one night. The patient is usually discharged the day after the procedure. Pain after the URS is not expected. However, if a ureteral stent is inserted, it may cause some discomfort such as feelings of urgency or pain in the side during urination. If necessary, pain medication can also be given. A certain amount of blood in the urine is also possible and is not cause for concern.

An outpatient check-up is recommended about one week after discharge from inpatient treatment. If a double-j stent was placed, it must be removed in any case.

With the URS, a stone-free rate of about 90% can be achieved. As a rule, only one surgical operation is required for this.