Ask us: Do I need to treat my 3mm stone?

In our “Ask a kidney stone doctor” section, we field questions from stone formers or their family members. Today’s question is about small non-symptomatic kidney stones. See other questions and answers or ask your own question here.


July 22, 2011

Question from Minnesota:

I have a 3mm to 4mm stone in my right kidney, which has been there since 2003.  It originally was very high up in the kidney, but moved to the lower part of the kidney in 2006. I just had another CT done, and it is still in the same place and the same size.  Because the stone is in the lower part of the kidney versus the higher part, is it less likely to pass, because it would have to go up to get into the ureter versus down? Because I’ve had this stone so long with no changes, what are the chances that it will just continue to sit there and never pass?  It has caused me no pain other than occasional blood in my urine. I was told by my doc that I could wait and watch the 3-4mm stone in my right kidney or proceed with ureteroscopy to remove it. It’s been sitting there since 2003 without giving me any discomfort. How painful is having a stent put in to promote healing after the ureteroscopy and is it really necessary?


Many patients are found with small stones and it can be confusing deciding on whether to proceed with treatment or to continue observing the stone(s). Several factors need to be considered to help make a decision:

1)    Size: Stones that are smaller than 5mm are more likely to be able to pass successfully without requiring surgery. When a stone is larger (>6mm) and unlikely to pass successfully, it may make more sense to intervene. In your case, the stone is small and if it were to start moving down the ureter, it would have a good chance of passing spontaneously. However, successful passage does not mean non-painful passage as even small stones can cause significant discomfort when they move down the ureter. Because of this, patients who have already experienced a stone episode in the past are usually more motivated to have an early intervention so that they can avoid another stone passage episode.

2)    Stability: Stones that are growing are more likely to lead to problems while stones that stay the same size are less likely to become symptomatic. As your stone is stable over 8 years, one could argue to continue to watch it.

3)    Location: Stones that are not obstructing, like yours, are generally asymptomatic. Stones that are floating in the renal pelvis or ureter are more likely to cause obstruction and more likely to require intervention. Stone fragments in the lower pole are generally felt to be less likely to pass. However, in addition to whether the stone is in the upper pole, middle-pole, or lower pole of the kidney, researchers have focused on the “calyceal anatomy” which can be though of as the length of the “tunnel” and the angle of the “tunnel” that the stone would have to travel to end up in the center part of the kidney where it could start making its way down the ureter.

4)    Symptoms: Stones that cause symptoms such as pain, recurrent infections, or significant bleeding would be more likely to require intervention than stones that are causing minimal symptoms.

5)    Other things to consider: Certain individuals will be advised to have their stone treated even if it is small and asymptomatic. This includes pilots, who would put themselves and their passengers at risk if they were to experience a stone passage episode while flying, and travelers to remote locations, where modern medical facilities may not be available if they were to suffer a stone attack.

The short answer as to how likely your stone is to remain there without causing problems is 80% over the next 3-10 years. Another way of looking at this is that 20%, or 1 out of 5 patients in your situation will experience a stone passage episode over the next 3-10 years while 4 out of 5 will do fine without experiencing problems. Here’s the long answer: Based on a study of 5,047 adults who underwent CT colonography screening, asymptomatic stones, such as yours, are found in 8% of American adults. In that study, the average stone size was 3mm. Over 10 years, 20.5% of patients with stones, or 1 out of 5, developed a symptomatic “stone episode” requiring intervention. Alternatively, 4 out of 5 patients did fine without experiencing a stone episode. This rate of 20% of small stones requiring treatment when observed is remarkably consistent with multiple other studies where patients with small stones were observed.

Finally, as to your question about ureteral stents, stents are often required after ureteroscopy surgery because of the ureter’s tendency to swell temporarily and become blocked after this type of surgery. This swelling can cause pain similar to a stone episode. We’ve found that this is more likely to occur in patients who have not had prior ureteroscopy surgery. Note though that this is a “surgeon’s preference” as some urologists will be more likely to perform ureteroscopy without leaving a stent. Stent pain can be mild or can be very uncomfortable. While some patients do not even realize a stent is there, most can’t wait to have them removed and some patients will say that the stent was worse than their stone. One way to potentially avoid a stent is to consider shockwave lithotripsy (ESWL) if the stone is easily visible on a plain x-ray.

About Dr. Mike Nguyen

Mike M Nguyen, MD, MPH, is a urologist and an Associate Professor of Clinical Urology at the Keck School of Medicine of USC in Los Angeles, CA. He specializes in the treatment of kidney stones with both surgery and dietary prevention and the in the treatment of kidney and prostate cancer using the latest robotic surgical approaches. He sees patients at clinics located in Los Angeles, Pasadena, and La Canada, CA. He is the founder of the website.
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16 Responses to Ask us: Do I need to treat my 3mm stone?

  1. Md. Hasan says:

    IT has been seen 4mm stone like echogenic foci in right kidney. It gives me severe pain.
    Dr. prescribe me Rowatinex but my pain remain still same after taking 4 month of medicine. What can i do now ?

  2. rongul pitroda says:

    sir i have 6mm long stone in my right kidney at right VJU and dense is 735 HU,pls give me suggestion about treatment

  3. Hi’ I have 3to 4 mm stone in upper & middle pole of my right kidney & not passing my urinare which is causing me pain often so what should I do. Do I have to go for a surgery r shock wave treatment

  4. mayur kamble says:

    i have 3..4mm stone in right kidney what shoul i do plzz reply me…

  5. B.K.Joseph says:

    I have 4.1mm calculi at upper pole of my Rt. kidney and often crating trouble by severe pain and does not pass through the urine. Please advise ???

  6. prince says:

    i have two 3mm stone in right kidney and one 3mm stone in left kidney what should i do plzz rply me

  7. prince says:

    i have 2 ..3mm stone in right kidney and 1 ..3mm stone in left kidney what should i do plzz rply me..

  8. ajaz says:

    I have 6-7mm stone in lower pole of the left kidney for the last one year, is there any chance that it will pass by itself using lot of fluids.

  9. Pradeep says:

    I have stone measuring 6mm in ureter. It is at the same position for past 1 month. I have no problem while passing urine. DO I need to do treatment fro this stone or will it pass if I drink lots of water ?

  10. Barbara says:

    This is the test result from a CT scan. I am having lot of pain and there is always blood in my urine when I go to the doctor not that I can see it with my naked eye. Should I see a urogolist and have this removed.

    Abdomen:There is a 7 x 8 mm calculus in the midpole of the right kidney,previously measuring 6 x 5 mm. No left renal calculus isidentified. No hydronephrosis or hydroureter. Stable calcifiedphleboliths in the bilateral pelvis. No distal ureteral calculusis identified. No new perinephric fat stranding.

  11. Marie Pavese,M.D. says:

    I enjoyed reading your article on asymptomatic kidney stones.
    If you had a patient with an asymptomatic 9mm calculus in the right lower pole unchanged much significantly in size and postition since 2004 would you continue to observe, do nothing ? There was intially lithotripsy done for a 1.2 cm stone in this location in 12/9/03 and a second 12/27/03 with shrinkage of this stone down to 7.4mm by 2/5/05. The patient who is a physician, began HCTZ for the etiology of stone formation of secondary hyperparathyroidism to reduce stone formation progression by reaborbing calcium from the urine, and urocit K 10 meq and drinking lemonade. Serial KUB’s over time showed growth to 8mm in 2007 and 9mm in 2008 but same position then. It remains asymptomatic . Would you continue to observe? Would you keep doing KUB’s and exposing pt to radiation and if so how frequently or just do a radiological test if and when any symptoms resume?

    In as much as the removal of the stone in 2004 from lithotripsy only resulted in a 4.6mm reduction in size after two back to back lithotripsies , and the stone now has grown 1.6 mm in 7 yrs on meds, would you say that this is insignifant changes to worry about?

    • says:

      It really is up to the patient regarding whether to treat this stone. At 9mm, it is unlikely to pass on its own and may continue to increase in size over time. The advantage of treating the stone earlier is that shockwave lithotripsy or ureteroscopy with laser lithotripsy are more likely to be successful when stones are smaller. Between the two, ureteroscopy with laser lithotripsy will have a higher chance of completely eradicating the stone but causes more discomfort than shockwave lithotripsy. Alternatively, the advantage of waiting is that the stone is currently asymptomatic and can be tracked using annual low radiation KUBs which are relatively low risk. Observing until symptoms occur or the stone gets larger is also a reasonable option.

      • Marie Pavese,M.D. says:

        the literature says that the lower pole kidney stones have less of a chance of passing due to this anatomical location. the question is what to do with lower pole asymptomatic poles since they are less likely to pass even with procedures.Of course the 9mm lower pole ones won’t pass spontaneously but maybe neither the 3-4 mm lower pole ones either simply due to the lower pole location.
        WHAT is reasonable and customary to do for lower pole stones especially those that remain always and for years ,asymptomatic??

      • Marie Pavese,M.D. says:

        when you say observing if pain or if the stone gets larger, if the stone always in the same lower kidney pole and remains asymptomatic, non-obstructing, no changes in signs,no decrease in renal function or anything else, goes from 7.4 to 9mm in 7 yrs and then increases a mm or so, and still without pain or any other symptoms in 10 yrs, then how oftern should you decrease the frequency of testing and films?

        • says:

          That’s up to the patient and treating physician. A typical followup schedule would be a single abdominal (KUB) film and followup visit once a year. A single KUB film delivers a relatively low amount of radiation. If a stone remains stable and asymptomatic, some patients may decide on less frequent imaging – once every two years or whatever they and their physician are comfortable with.

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