Extracorporeal shock wave lithotripsy (ESWL) is a noninvasive means of treating kidney and upper ureteral stones.
The procedure uses sound shockwaves through the flank under x-ray guidance to fragment the stone and then relies on spontaneous passage of the fragments. Due to the need to target the stone, ESWL is usually reserved for patients with stones that are visible on x-ray imaging of the abdomen. All stones that are larger than 2 cm are too large to be effectively treated by ESWL. Depending on the location, ESWL is sometimes not your best option for stones that are over 1 cm.
When to ask a Urologist about ESWL
You should speak with a Urologist about ESWL if you have a stone smaller than 1-2 cm in the kidney or upper ureter (tube that drains the kidney).
Typically covered by most insurances (although coinsurance and deductibles may apply). Coverage will be verified prior to proceeding. If you do not have insurance, our office will be able to give you an out-of-pocket cost estimate.
The stone-free rate after a single ESWL procedure is around 73%, and some patients undergo ESWL more than once. An alternative surgery to treat stones called ureteroscopy has a higher stone-free rate (90%) but requires passing instruments up the ureter and often requires ureteral stenting. ESWL has less morbidity and fewer complications than ureteroscopy. Certain clinical factors, such as stone density on imaging, distance between the skin and the stone, and irregular anatomy of the urinary system, may lower the expected success rate of ESWL and lead your physician to recommend an alternative procedure.
Possible Side Effects
ESWL risks include flank pain, bleeding, incomplete stone fragmentation, and about a 5% chance of sufficient stone debris in the ureter to cause blockage postoperatively requiring a temporary stent.
Alternatives to ESWL may include surgical stone treatment with ureteroscopy or a procedure called percutaneous nephrolithotomy where the stone is accessed through a small tube passed directly through the flank and into the kidney. Asymptomatic stones in absence of renal insufficiency and recurrent infection may be observed without immediate intervention.
What to do to Prepare for Surgery
You will receive detailed instructions from the surgical schedulers regarding any necessary testing or appointments prior to surgery. In general, you should temporarily stop blood-thinning medications prior to surgery (when to stop depends on the type of blood thinner). Prescription blood-thinning medications should be stopped following clearance from the doctors that prescribed them though other medications that thin the blood including fish oil and pain relievers such as ibuprofen should be stopped as well.
On the day before surgery, you will receive a phone call alerting you to the time that you should arrive.
You should not eat or drink anything after midnight on the day of surgery, but you may take approved home medications in the morning before surgery with a small sip of water.
What to Expect after Surgery
ESWL is performed in an outpatient setting under anesthesia and typically takes around 1 hour. You may have nausea or drowsiness from anesthesia. You will likely experience pain and tenderness in your side with some skin redness or bruising. You will also likely pass blood and stone fragments in your urine. If possible, keep a stone fragment that has passed in a plastic bag and bring it with you to your follow-up appointment to be sent for mineral analysis.