Kidney Stones - Prevention

Other Treatments

Surgery is usually needed if the stone is too large to pass on its own, if there are signs that the stone is growing, if the stone is blocking the urine flow, or if it is causing a urinary tract infection or kidney damage.

Today, treatments for stones are much less invasive than in the past. Major surgery is performed in less than 2% of patients.

Stone removal procedures:

• Extracorporeal shock wave lithotripsy (SWL) is used for small stones (smaller than 2 centimeters, or about three-quarters of an inch) that occur in the upper part of the ureter and do not pass on their own. Lithotripsy might even be safe and effective for patients whose stones are associated with malformed kidneys, although such patients are at higher risk for stone recurrence and should be carefully monitored. SWL takes less time to perform and requires a shorter hospital stay than percutaneous nephrolithotomy.
• Ureteroscopy. For stones in the lower urinary tract, ureteroscopy is generally the best procedure, although lithotripsy is also usually feasible and patients ordinarily prefer it.
• Percutaneous nephrolithotomy (PCNL). PCNL can be used for large stones in the upper urinary tract, when SWL or ureteroscopy fails, for kidney transplant patients, or when the kidneys or surrounding areas are malformed. PCNL is the preferred procedure for drug-resistant cystine stones, which are usually also resistant to shock wave therapy.
• Standard open surgery (nephrolithotomy) may be required if these procedures fail or are not appropriate, or in special cases, such as when the patient is very obese.

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Most procedures are more effective for calcium and uric acid stones and less effective for struvite and cystine stones, although new techniques may be improving their effectiveness on all stones.

Extracorporeal Shock Wave Lithotripsy

Extracorporeal shock wave lithotripsy (SWL) is a technique that uses sound waves (ultrasound) to break up simple stones in the kidney or upper urinary tract. ("Extracorporeal" means "outside the body," and "lithotripsy" means stone-breaking.) SWL is not used for cystine stones. The procedure generally does not work for stones larger than 3 centimeters in diameter (which is slightly over an inch). There are several variations of SWL. The following is a typical procedure:

• SWL procedures can often be done on an outpatient basis.
• The patient is positioned in a water bath. (In some procedures the patient lies on a soft cushion.)
• The procedure uses ultrasound to generate shock waves that travel through the skin and body tissues until they hit the dense stones. (The doctor pinpoints the stone during treatment by using x-rays or ultrasound.)
• The shock waves crush the stones into tiny sand-like pieces that usually pass easily through the urinary tract.