March 23, 2022
Kidney stones are a common condition in the U.S. – about 1 in 10 Americans get them.
Passing a kidney stone can be quite painful. It can cause severe, sharp pain in the side and back, below the rib, pain in the lower abdomen and groin and, pain or a burning sensation while urinating.
One of the most common treatment options is extracorporeal shock wave lithotripsy, which uses shock waves to break stones into smaller fragments to make them easier to pass. This procedure must be performed in a hospital or clinic, and since it is often painful, most patients require sedation. It is mostly effective on smaller stones.
But a new technique, known as burst wave lithotripsy, may be able to break up stones of a variety of sizes in a less painful and invasive way. Initial studies have shown some promising results.
Burst wave lithotripsy, or BWL, uses focused ultrasound bursts to break up kidney stones. Researchers say it successfully fragments stones of a variety of sizes, locations and densities, breaking them into smaller, more-passable fragments within 10 minutes. The shorter procedure can be performed without sedation or anesthesia and it causes minimal tissue injury.
Kidney stones are hard deposits of minerals and salts that build up in the kidneys. They can affect any part of the urinary tract — from the kidneys to the bladder, according to the Mayo Clinic.
The most common types of stones are made of calcium, uric acid, struvite or cystine. They tend to form when urine becomes concentrated, allowing minerals to crystallize. Diet, obesity, certain medical conditions, supplements and medications have been linked to an increased risk for kidney stones.
Both men and women can have kidney stones, but they are more likely to occur in men.
Some stones can easily pass on their own, but many times medical intervention is necessary. Treatment may include medications that relax the muscles in the ureter to allow the stone to pass more easily and with less pain, and surgical procedures to remove the stone.
In a study published in The Journal of Urology, 19 patients who were undergoing a ureteroscopy, a procedure used to treat larger stones, were first treated with the BWL technology for about 10 minutes. The researchers used the ureteroscope to observe how well the ultrasound waves worked and whether there was any injury to the kidney tissue.
Overall, BWL technology completely broke up about 90% of the stone volume. Thirty-nine percent of the stones were completely fragmented; 52% were partially fragmented.
After the procedure, most of the remaining fragments were less than two millimeters, which is small enough to be passed on their own with little pain. There was little or no tissue injury among the participants.
This could be a game-changer for the management of kidney stones, a condition that often requires multiple visits to the emergency department, the use of opioids for pain management and repeated treatment even after surgery or xetracorporeal shock wave lithotripsy, researchers said.
"The ability to noninvasively break stones and expel the fragments in awake patients at first presentation in the ED or clinic has the potential to provide just-in-time treatment leading to a reduction of the overall pain, cost and resource burden associated with a stone event," the researchers wrote in their study.
Their findings confirmed the results of pre-clinical studies. Researchers are planning future studies to determine whether the technique can meet their ultimate goal of a noninvasive, 30-minute treatment without anesthesia.
The burst wave lithotripsy technology was licensed to SonoMotion which is developing a commercial version of the technology. The company is conducting its own clinical trials.