A noninvasive procedure for removing kidney stones
Saint Peter’s University Hospital offers extracorporeal shock wave lithotripsy (ESWL), a non-invasive procedure used to “fix” kidney stones. Dr. Steven Richards, a urologist with Saint Peter’s, says lithotripsy is an outpatient procedure that is highly effective for most patients.
“Lithotripsy uses shock waves to break up the stone non-invasively,” he explains. “We use a fluoroscope to locate the stone, then pulverize it with focused shock waves. The tiny, sandlike particles that result can then be eliminated through the urinary tract. It is successful for about 85 percent of our patients.”
The Kidney’s Job, and How Lithotripsy Works
The kidney’s job is to filter waste products from the blood so they can be diluted in the urine and eliminated from the body. Kidney stones develop when waste products do not dissolve, forming crystals that can build up and develop into stones. The stones can become lodged in the kidney or urinary tract, blocking the flow of urine and causing considerable pain. Medication can dissolve certain types of stones, but in many cases more aggressive treatment is necessary.
Lithotripsy uses a device called a lithotripter to break up kidney stones. An electrode embedded in a round, water-filled pad is placed over the area where the stone is lodged. A fluoroscope, an X-ray that provides continuous “live” pictures rather than “snapshots,” guides the medical team as they aim the electrode at the stone. Like a pebble dropped in water, the electrode emits highly focused shock waves through the body to the stone, then the energy is dissipated through the water pad. This lessens the impact of the shock waves on the kidney.
“Lithotripsy is very precise,” said Mala Parikh, a radiology technologist who operates the lithotripter at Saint Peter’s. “It delivers 3,000 shock waves per treatment, and about 80 percent of those shock waves directly hit the stone.” Mala said the treatment team consists of a radiology technician, a supervising urologist and an anesthesiologist, who makes sure the patient is comfortably sedated during the session. The patient lies supine or prone, depending on whether the stone is lodged in the kidney, the ureter or the bladder, and the pad is placed over the stone. Treatment takes between 30 and 45 minutes.