URS stands for ureteroscopy, a minimally invasive procedure where a urologist passes a thin, camera-equipped scope through your urinary tract to diagnose or treat problems in the ureter or kidney. No incisions are needed. The most common reason for a URS is to find and break up kidney or ureteral stones, though it’s also used to biopsy tumors, investigate unexplained bleeding, and remove foreign bodies like migrated stents.
How Ureteroscopy Works
The procedure is performed under general anesthesia, so you’re asleep throughout. Your urologist inserts the scope through your urethra and bladder, then advances it up into the ureter, the narrow tube connecting your kidney to your bladder. A tiny camera on the tip gives a live view of the inside of your urinary tract. If a stone is found, a laser fiber is threaded through the scope and used to break the stone into fragments. Those fragments are then collected with a small wire basket.
At the end of the procedure, most patients receive a ureteral stent, a thin flexible tube left inside the ureter to keep it open while swelling goes down. This stent is temporary and typically stays in place for about 3 to 14 days, depending on how complex the procedure was and how much the ureter was irritated. Your urologist removes it at a follow-up visit.
Rigid vs. Flexible Scopes
There are two main types of ureteroscopes, and which one your surgeon uses depends on where the problem is located.
- Semirigid ureteroscopes are straight instruments that provide excellent visibility and work well for stones in the lower and mid-ureter. They allow faster procedures and high stone clearance rates for stones in those locations.
- Flexible ureteroscopes can bend and navigate curves, making them essential for reaching stones in the upper ureter or inside the kidney itself. The European Association of Urology recommends flexible URS for upper ureteral stones because the scope can follow fragments if they drift back toward the kidney during treatment.
Semirigid scopes can use several energy sources to break stones, including pneumatic (ballistic) devices. Flexible scopes rely exclusively on laser energy, since the fiber needs to bend with the instrument.
Laser Technology for Stone Treatment
The standard laser for ureteroscopy has long been the holmium laser, which fragments stones effectively across a wide range of sizes and compositions. A newer option, the thulium fiber laser, is gaining traction because of its speed. In a head-to-head trial, thulium fiber laser procedures averaged about 18.5 minutes of operating time compared to 31.6 minutes for holmium, and the actual lasering time was roughly half: 7.4 minutes versus 14.8 minutes. The thulium laser also broke stone material about three times faster and caused less stone “kickback” (retropulsion), which is when the laser pushes the stone away instead of fragmenting it.
The trade-off is visibility. The holmium laser kept a clear surgical field in over 93% of cases, while the thulium laser produced more debris that clouded the view in about 23% of cases. Both lasers had similar complication profiles.
Success Rates
How well ureteroscopy clears stones depends heavily on where the stone sits and how big it is. Real-world data from a large surgical collaborative found that about 73% of patients with ureteral stones were completely stone-free after the procedure, compared to about 50% for kidney stones. Stones in the lower pole of the kidney, larger stones, and multiple stones were all harder to clear completely.
Those numbers are lower than what specialized centers often report, partly because they use a strict “zero fragment” definition of success. Even when small fragments remain, many are tiny enough to pass on their own over time. Your surgeon’s experience also matters: adjusted stone-free rates varied from 26% to 72% for kidney stones and from 52% to 90% for ureteral stones across different surgeons in the same collaborative.
Risks and Complications
Ureteroscopy is generally safe, but it carries a risk of infection ranging from about 2% to 20% across studies. Most infections are urinary tract infections that respond to antibiotics, though in rare cases the infection can spread to the bloodstream (urosepsis), which is more serious. One factor that raises infection risk is the ureteral stent itself: bacteria colonize stents in 42% to 90% of patients, which is one reason surgeons try to keep stent time as short as possible.
Other potential complications include temporary blood in the urine, ureteral swelling, and, rarely, ureteral injury or scarring (stricture). Serious injuries like ureteral perforation or avulsion are uncommon with modern instruments and techniques.
What the Stent Feels Like
The ureteral stent is often the most uncomfortable part of the experience. It can cause a frequent urge to urinate, a burning sensation when you pee, and flank discomfort, especially during physical activity. The type of discomfort varies depending on how long the stent stays in. Patients whose stents are removed within five days tend to experience more flank pain and blood in the urine, likely because healing isn’t quite complete. Patients who keep stents for six days or longer report higher rates of fever and painful urination, likely from bacterial colonization of the stent over time.
Current guidelines from the American Urological Association suggest 3 to 7 days as the sweet spot for most patients, while European guidelines allow up to 14 days for more complex cases. Your urologist will weigh factors like how much swelling occurred during surgery and how large the stone burden was.
Recovery Timeline
Most people can eat and drink normally right after the procedure. The key instruction is to drink plenty of water, aiming for two to three liters a day, to flush out any remaining stone fragments and keep the stent from getting blocked.
You can typically return to work within 7 to 10 days if your job isn’t physically demanding. Driving is usually safe after about two weeks, once you’re off pain medication and feel comfortable. During recovery, avoid heavy lifting, intense exercise, and contact sports. The stent can shift with vigorous movement, and straining increases discomfort. Once the stent is removed, most patients notice a significant improvement in comfort within a day or two.
Beyond Stones: Other Uses for URS
While stone treatment accounts for most ureteroscopies, the procedure has several other applications. Urologists use it to biopsy or perform laser ablation of upper urinary tract tumors, investigate unexplained blood in the urine, evaluate and treat ureteral narrowing (strictures), and diagnose fistulas, particularly connections between the ureter and vagina. It’s also the go-to method for retrieving broken or migrated stent fragments that can’t pass on their own. In each of these situations, the ability to look directly inside the ureter and kidney with a camera, and to pass instruments through the scope, makes URS a versatile tool that often avoids the need for open surgery.