Urology · Kidney stones
Been told your kidney stone needs surgery?
Many stones never need an operation. Of those that do, the right operation depends on two things: how big the stone is and where it sits. Here is what the European and American urology guidelines actually say — and what a patient travelling from abroad has to arrange before booking anything.
The short answer
- Small stones often pass by themselves. Ureteral stones of 5–10 mm pass without surgery in roughly 25–53% of cases.
- Size decides the operation. Under 10 mm: shock wave therapy or flexible endoscopy. 10–20 mm: either. Over 20 mm: keyhole surgery through the back (PCNL).
- A blocked, infected kidney is an emergency — it is treated where you are, not on a planned trip abroad.
- The stent is the part patients are least told about. If you fly home with one, removal must be arranged before you leave.
When a stone does not need surgery
If the stone is small, the kidney is not blocked, there is no infection and the pain is controllable, waiting is a legitimate treatment. The guidelines support observation with pain relief, and in selected patients a medicine that relaxes the ureter (an alpha-blocker) to help the stone pass.
That medicine is not magic, but it is real: in pooled analyses patients given an alpha-blocker were about 50% more likely to pass the stone than those who were not (risk ratio 1.54, 95% CI 1.29–1.85). The benefit is clearest for stones in the lower ureter larger than 5 mm.
- Fever or chills with the pain — an infected, blocked kidney can become life-threatening within hours
- Pain that does not respond to painkillers
- Vomiting that prevents you from drinking
- Kidney function that is getting worse, or only one working kidney
The guidelines are explicit that conservative treatment is stopped if any of these appear.
When surgery is the right answer
- The stone is too large to pass — as a rule of thumb, above 10 mm the odds fall sharply
- It is blocking the kidney, or the kidney is already losing function
- There is infection behind the blockage
- The stone has not moved after a reasonable trial of waiting
- You have one kidney, or stones in both
- Your job or your country makes an unplanned emergency unacceptable — for example, pilots and seafarers are often treated rather than watched
Which operation, and why
| Stone | Usual first choice | What it involves |
|---|---|---|
| Under 10 mm, in the kidney | Shock wave therapy (SWL) or flexible endoscopy (RIRS) | SWL: no cut, sound waves break the stone; fragments still have to pass. RIRS: a fine scope through the natural passage, laser breaks the stone |
| 10–20 mm | SWL, RIRS or keyhole surgery — the team chooses | Stone hardness, kidney anatomy and your preference all count here |
| Over 20 mm | PCNL (keyhole through the back) | A small tract into the kidney; the most effective option for large stones, and the one with the highest complication rate |
| Staghorn stones (filling the collecting system) | PCNL, sometimes combined with RIRS | Often more than one session; clearing the whole stone matters more than speed |
No method clears every stone in one go. Asking a centre for its stone-free rate for stones like yours — and how often a second session is needed — tells you more than any headline figure.
The stent: the part nobody explains
After endoscopic stone surgery a soft plastic tube (a JJ stent) is often left between the kidney and the bladder so that swelling does not block urine flow. It is normal, it is temporary, and it can be uncomfortable: urgency, blood in the urine and flank discomfort when passing water are common.
There is no single agreed removal day. Evidence suggests removing it very early (four days or less, in patients who had no stent before surgery) is linked to more emergency visits, while leaving it in longer makes symptoms worse without improving how much stone is cleared. In practice most teams remove it within one to two weeks.
If you are travelling home with a stent, removal must be arranged before you fly. A stent forgotten in place for months can encrust and become a serious problem. Ask for the removal date in writing, and for a report your own urologist can act on.
What a patient coming from abroad has to arrange
- A recent CT scan. Treatment planning depends on stone size, position and density. A scan older than a few months may no longer describe your stone.
- Stone analysis afterwards. What the stone is made of decides how you prevent the next one. Ask for the fragments to be sent for analysis and for the result to be given to you.
- Follow-up at home. Stone disease is a recurring condition, not a one-off event. Blood and urine tests, and for repeat stone formers a 24-hour urine collection, are done where you live.
- A clear plan for the stent, as above.
"The laser dissolves the stone and it is over."
The laser breaks the stone into fragments; those fragments still have to leave the body, and not every operation clears everything. A second session is sometimes planned from the start. A centre that promises a guaranteed single-session cure is promising something the evidence does not support.
Medically reviewed by Assoc. Prof. Dr. Bekir Voyvoda
Urologist at Florence Nightingale Hospital, Istanbul; Associate Professor since 2025. This guide was prepared by the BookingHospital medical team from the current European (EAU 2025) and American (AUA 2025) stone guidelines, and reviewed for surgical accuracy. Treatment for each patient is planned by the operating urologist after their own imaging is assessed.
Send your scan and we will tell you what is realistic
Send your CT report and recent blood and urine tests. A physician will review them and tell you which treatments are reasonable for your stone — including when waiting is the better answer.
Medical disclaimer. This article is general information based on published international guidelines. It is not personal medical advice, it does not establish a doctor–patient relationship, and it cannot replace assessment by the physician treating you. Fever with flank pain needs urgent medical attention where you are.
References
- European Association of Urology. EAU Guidelines on the Diagnosis and Treatment of Urolithiasis. European Urology 2025.
- American Urological Association. Surgical Management of Kidney and Ureteral Stones: AUA Guideline, 2025.
- Campschroer T, et al. Alpha-blockers as medical expulsive therapy for ureteral stones. Cochrane Database of Systematic Reviews.