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Urinary Disorders

Large Stone Fragments Left After ESWL

09/30/2010

Question:

I recently had laser litho for a stone lodged in the ureter. That proc. was successful. The Dr. thought it was also time to remove one very large stone in the rt kidney (19 mm) and 2 smaller but still large ones in the left kidney which had been tucked away in the calyxes for some time. He believed they may have been sporadically dislodged and been occasionally blocking urine output from time to time and now needed to come out. A week after the 1st procedure he did ESWL on the 3 large stones. I passed large and small fragments for days afterward (about 70 fragments - ca oxalate - mono). I felt relieved that the stones were all gone and we were going to do a new metabolic work-up (old work-up done 7 yrs ago) to see if we could get to the bottom of this 10 yr problem w/stone formation. Went back last week for one month follow-up, and he did ultra-sound and to my amazement and tremendous frustration, there was still a 12 mm fragment in the right kidney and a 6 mm and 5 mm fragment in the left kidney. I`m told to get the metabolic work-up and we`ll see what the results are.  Since the fragments are in the lower pole and more apt to stay stable there, I was told to come back in a year unless a problem pops up.

My question: is there some reason that ESWL procedure wasn`t continued/extended on the broken-up large fragments at the time of the ESWL procedure for these large stones so they could be broken up further in order to pass them (i.e., why were they left in when ESWL was at the doc`s disposal to break them up further so they would indeed pass). Thanks a ton for your insights and possibly some questions I should ask next visit.

Answer:

The issue regarding choice of therapy for kidney stones and the indications for intervention vs surveillance are complicated. I am biased with regard to treatment of large stones in the kidneys (but not biased by financial considerations that may impact judgement when the physician is an owner of the ESWL machine). That being said, I will discuss your case specifically:

Large stones in the kidney are most likely cleared completely (85%) in one treatment when percutaneous nephrostolithotomy (PCNL) is performed. This is an invasive procedure putting scope directly into the kidney. ESWL success rate decreases with increasing stone volume and with lower pole stones. The number of shocks delivered is ESWL machine dependent but, on average 2500-3000 shocks are the limit per treatment. Repeat ESWL can be done, but with lower pole stones the clearance rate is 50%. Ureteroscopy can be done for kidney stones but the success rate again is 50% for lower pole stones. Ureteroscopy is best for ureteral stones.

In your current situation, as you point out, the remaining stones may never become symptomatic and surveillance may be a reasonable choice. Movement of stones from the lower pole on plain abdominal film could be used as a guide to proceed with treatment.

Ultrasound is not specific in my experience- can detect stones but could not be relied upon to measure number or volume- either CT scan or abdominal film would be better (KUB film = kidney/ureter/bladder). Hope this is helpful.

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Response by:

James F Donovan, Jr, MD James F Donovan, Jr, MD
Professor of Surgery
Director of UC Urology
College of Medicine
University of Cincinnati