Extracorporeal Shock Wave Lithotripsy (ESWL)

Noninvasive Kidney Stone Treatment

Extracorporeal Shock Wave Lithotripsy, or ESWL, has revolutionized kidney stone treatment since its introduction in the mid-1980s. Today, it’s the most employed kidney stone treatment in the United States and represents a first-line, noninvasive treatment for symptomatic kidney stones.

To understand the benefits of ESWL, we must discuss the nature of kidney stones. Kidney stones come in various shapes, sizes, and compositions, the most common of which is a calcium-based accumulation. Kidney stones can occur within the kidney or in the ureter, which delivers urine from the kidney to the bladder. Most kidney stones are asymptomatic, but when they block the outflow of urine, they can cause kidney swelling and extreme pain.

The inspiration For ESWL was derived from aeronautical science, where the shock wave at the leading edge of airplane wings was studied at high speed. In short, ESWL’s shock wave (electromagnetic, as in our Dornier device) is focused and directed at the stone. Various physical forces are optimized to induce fragmentation, reduce larger stones, and allow for passage in the urine. Refinements over the last 30 years allow the current generation of lithotripters to precisely focus the shock wave energy and minimize unintended injury to nearby structures.

ESWL is an excellent option for smaller and softer kidney stones. While it can be used for stones within the kidney or the ureter, it is most often performed for those within the kidney. As mentioned above, ESWL is a non-invasive procedure, performed entirely outside the body.

How ESL is Performed

ESWL is performed in a hospital setting with patients under anesthesia. Not only does this eliminate the discomfort associated with the procedure, but since precise shock wave delivery is paramount, patient movement (a possibility under twilight anesthesia) compromises overall success and can cause collateral damage. The lithotripter has a few different components. First is the shockwave generator or head, which is placed in the approximate location of the kidney. Fluoroscopy (continuous X-ray) or ultrasound guidance systems are also connected to the machine, allowing for precise stone targeting.

Like a video game, the urologist trains crosshairs on the kidney stone, which is visualized using the urologist’s preferred guidance system. At this point, shockwaves are deployed and concentrated at the kidney stone. The machine emits a light pop for each shockwave delivery, and a course of treatment may include up to 2500 or more of these pulses. As the urologist oversees the procedure, adjustments can be made based on what they visualize on the ultrasound/x-ray. Eventually, the kidney stones are reduced to smaller pieces, most of which can be passed through the urinary system over time.

The Benefits of ESWL

The benefits of ESWLR are significant in that patients do not have to undergo any surgical or invasive procedure to manage their kidney stones. Indeed, many patients find ESWL their preferred method of treating a stone because of its ease and minimal downtime post-procedure. While it may not render the patient 100% stone-free, it is suitable for and very successful in qualifying patients.

Risks and Considerations of ESWL

The risks of ESWL are few, and most are mild. Because there is no surgical entry or insertion into the urinary tract, the risk of infection and damage to urinary structures is low. However:

Some patients may experience blood in the urine or hematuria for several days after the procedure.
Because we do not know the composition of the stone beforehand, ESWL is almost always performed on calcium-based stones that show on X-ray. Uric acid, struvite, and cystic stones may require alternate modalities.
The shockwaves may not completely pulverize the stone, requiring a follow-up procedure or potentially causing a smaller piece to lodge in the ureter and cause additional symptoms. These stone fragments may also grow over time.

Fortunately, having ESWL does not preclude a follow-up procedure like ureteroscopy with laser lithotripsy for more stubborn stones.

What You Need to Know about ESWL

Large stones (greater than 1 cm), especially more problematic stones, may require multiple sessions. This is because the energy needed for these stones surpasses the amount the body can tolerate in a single session.
Large and difficult-to-break stones may be more expediently treated by surgical stone removal, known as Percutaneous Nephrolithotomy (PCNL). In this procedure, an endoscopic port is introduced via the flank, allowing for direct visualization, stone fragmentation, and removal.
Stones located in the lower ureter may also be treated via mini endoscopes through the urethra for direct basket removal or laser lithotripsy with a high success rate.

Early management of kidney stones is crucial to effective treatment and avoidance of urinary issues, including kidney failure. Be sure to contact a urologist, such as those at Georgia Urology, to get an appointment for treatment and relieve the significant pain associated with stones. Our stone hotline is available 24 hours a day for appointments, and we can often see stone patients on the same day or the next business day.