Urinary stones refer to all types of stones that form within the urinary system and most commonly originate in the kidneys. Once formed in the kidney, stones may travel through the ureter, bladder, and urethra, obstructing the flow of urine and causing pain in the surrounding areas. During this process, complications such as urinary tract infection, hydronephrosis (swelling of the kidney), and even kidney failure can occur.
When urinary stones are diagnosed, extracorporeal shock wave lithotripsy (ESWL) is usually attempted first. ESWL does not require hospitalization or anesthesia, and most patients can return to their normal daily activities within about an hour after the procedure. However, not all stones can be effectively treated with ESWL. In certain situations, ureteroscopic stone removal may be a more appropriate treatment option.
One situation is when complications such as kidney failure, hydronephrosis, or urinary tract infection are present. When kidney function begins to decline, endoscopic surgery may need to be considered. ESWL works by breaking stones into fragments with shock waves so they can pass naturally through urine. However, if kidney function is already impaired, urine flow may be reduced, making natural passage of stone fragments difficult.
In cases where a urinary tract infection has developed, it is often preferable to remove the stone promptly before inflammation worsens. In such situations, ureteroscopic stone removal may be more effective than ESWL.
Another scenario involves special types of stones such as radiolucent stones, bilateral ureteral stones, or multiple stones. Radiolucent stones cannot be seen on X-ray images, which makes ESWL difficult because the procedure typically relies on X-ray imaging to guide treatment. Bilateral ureteral stones, which block both ureters simultaneously, can prevent urine from draining from both kidneys. If untreated, this can lead to acute kidney failure, making it dangerous to wait for multiple ESWL sessions.
Similarly, when several stones are present within one ureter, breaking only one stone may not resolve the problem because other stones remain and continue to obstruct urine flow. In these cases, ureteroscopic removal is often more appropriate than repeated ESWL.
Stone size is also an important factor. When stones are larger than 1 centimeter, endoscopic surgery may be a more effective initial treatment. Large stones of this size have a significantly lower chance of being completely fragmented by a single ESWL session. As a result, multiple treatment sessions may be required. Because ESWL sessions must usually be spaced five to seven days apart to allow the body to recover from the shock waves, the overall treatment period can become prolonged. During this time, the large stone may continue to block the ureter, causing persistent severe pain and progressive decline in kidney function. For this reason, stones larger than 1 centimeter are often better treated with endoscopic surgery, which can remove the stone in a single procedure.
Urinary stones can cause extremely severe pain, often described as comparable to the pain of childbirth. Therefore, if ESWL does not provide sufficient improvement, ureteroscopic stone removal—which allows the stone to be removed in a single procedure—should be considered. In recent years, advancements in surgical equipment, including rigid and flexible endoscopes, have made these procedures safer and more effective than before.