Extracorporeal Shock Wave Lithotripsy Success Rate

Extracorporeal Shock Wave Lithotripsy (ESWL) is a procedure that uses shock waves to break kidney stones into smaller pieces so they can pass more easily. Its success rate varies, depending on factors like stone size, location, and composition. Many people achieve a stone-free status or pass fragments without further intervention, but some may need additional treatments.

What is Extracorporeal Shock Wave Lithotripsy Success Rate?

Extracorporeal Shock Wave Lithotripsy (ESWL) success rate refers to how effectively the procedure breaks kidney stones and allows them to pass from the body. Success is often measured by whether a person becomes "stone-free" or if remaining stone fragments are small enough to pass without causing symptoms or needing further treatment. This rate is influenced by several individual factors.

Extracorporeal Shock Wave Lithotripsy (ESWL) is a non-invasive treatment for kidney stones. It uses high-energy sound waves, called shock waves, generated outside the body to target and break up stones. These shock waves travel through the skin and body tissues until they hit the denser kidney stone, causing it to fragment into smaller pieces. The primary goal of ESWL is to reduce the stone to fragments small enough to pass naturally through the urinary tract. Success is typically defined as being stone-free, meaning no detectable stone fragments remain, or having only very small, clinically insignificant fragments that are unlikely to cause future problems. Clinicians often assess success using imaging tests like X-rays or CT scans weeks or months after the procedure. The success rate is not a single, fixed number because it depends heavily on the characteristics of the stone and the individual's anatomy. For instance, smaller stones generally have a higher success rate than larger ones. The location of the stone within the kidney or ureter also plays a significant role in how effectively the shock waves can reach and break it.

Why it's done

Extracorporeal Shock Wave Lithotripsy (ESWL) is performed to treat kidney stones that are causing symptoms or have the potential to cause complications. These stones might be too large to pass on their own, causing pain, blocking urine flow, or leading to infections. ESWL offers a less invasive alternative to surgery for many people.

ESWL is typically recommended for kidney stones that are causing significant pain, recurrent urinary tract infections, or obstruction of the urinary tract. Stones that are too large to pass naturally, usually those greater than 5 millimeters (about 0.2 inches) in diameter, are often candidates for ESWL. It is also considered for stones that have not passed after a reasonable period of observation. This procedure is a preferred option for many people because it avoids incisions and general anesthesia in some cases, leading to a quicker recovery compared to open surgery. It aims to prevent further complications such as kidney damage from prolonged obstruction or severe infections. Your doctor will assess your specific situation, including stone size, location, and overall health, to determine if ESWL is the most suitable treatment. While ESWL is effective for many stones, it may not be appropriate for all. For example, very large stones, certain types of hard stones, or stones in difficult-to-reach locations might require different treatments. Your healthcare provider will discuss all available options and help you make an informed decision.

How to prepare

Preparing for Extracorporeal Shock Wave Lithotripsy (ESWL) involves several steps to ensure your safety and the procedure's effectiveness. You will typically need to stop taking certain medications, especially blood thinners, a week or more beforehand. Fasting for several hours before the procedure is also usually required, and your doctor will provide specific instructions.

Before your ESWL procedure, your healthcare team will provide detailed instructions. It is crucial to follow these instructions carefully. You will likely need to undergo a physical exam, blood tests, and urine tests to ensure you are healthy enough for the procedure and to check for any infections. Imaging tests, such as X-rays or CT scans, will also be performed to pinpoint the exact location, size, and number of your kidney stones. One of the most important preparation steps involves reviewing your medications with your doctor. You will typically be asked to stop taking blood-thinning medications, such as aspirin, ibuprofen, warfarin (Coumadin), or clopidogrel (Plavix), for about 7 to 10 days before the procedure. This helps reduce the risk of bleeding. Always consult your doctor before stopping any prescribed medication. You will also be instructed not to eat or drink anything for several hours before the procedure, usually starting the night before. This is important if you will receive sedation or anesthesia. Arrange for someone to drive you home after the procedure, as you may feel drowsy from the medication. Discuss any questions or concerns you have with your medical team before the day of your ESWL.

What happens during

During Extracorporeal Shock Wave Lithotripsy (ESWL), you will lie on a padded table while a machine delivers shock waves to your kidney stone. You will receive medication to help you relax or sleep, and to manage any discomfort. The medical team uses X-rays or ultrasound to precisely target the stone, and the procedure typically lasts about 45 to 60 minutes.

When you arrive for your ESWL procedure, you will change into a hospital gown. An intravenous (IV) line will be inserted into your arm to administer fluids and medication. You will receive sedation or light anesthesia to help you relax and minimize any pain or discomfort from the shock waves. In some cases, a regional anesthetic may be used to numb the area. You will then be positioned on a special table, often on your back or side, with a water-filled cushion placed against your abdomen or back. This cushion helps transmit the shock waves. The lithotripter machine, which generates the shock waves, will be carefully aligned. The medical team will use real-time imaging, such as fluoroscopy (a type of X-ray) or ultrasound, to precisely locate your kidney stone and aim the shock waves. Once the stone is targeted, the shock waves are delivered in a series of pulses. You might hear a clicking sound and feel a tapping sensation or mild discomfort with each pulse. The number of shock waves delivered can vary but typically ranges from 1,000 to 3,000. The entire procedure usually takes about 45 to 60 minutes, after which you will be moved to a recovery area for observation.

Recovery & timeline

Recovery from Extracorporeal Shock Wave Lithotripsy (ESWL) is generally quick, allowing most people to go home the same day. You may experience some pain, bruising, or blood in your urine for a few days. Passing stone fragments can take days to weeks, and your doctor will schedule follow-up appointments to monitor your progress and ensure all fragments have passed.

After ESWL, you will spend an hour or two in a recovery room while the effects of sedation wear off. You may feel some mild pain or discomfort in your back or side where the shock waves were delivered. It is common to see blood in your urine for several days after the procedure, which is usually harmless. Bruising on the skin at the treatment site is also possible. Most people can resume light activities within a day or two, but strenuous exercise should be avoided for at least a week. It is important to drink plenty of water to help flush out the stone fragments. You will likely pass these fragments in your urine over the next few days to several weeks. This process can sometimes cause colicky pain, similar to kidney stone pain, as the fragments move through the urinary tract. Your doctor may prescribe pain medication to help manage this discomfort. Your doctor will schedule follow-up appointments, often within a few weeks or months, to check for remaining stone fragments. This typically involves imaging tests like X-rays or ultrasound. If significant fragments remain, further ESWL treatments or other procedures may be necessary. Complete recovery and confirmation of stone clearance can take several weeks to a few months.

Risks & side effects

While Extracorporeal Shock Wave Lithotripsy (ESWL) is generally safe, it carries some potential risks and side effects. Common temporary effects include blood in the urine, bruising, and pain as stone fragments pass. More serious, though rare, risks can include infection, kidney damage, bleeding around the kidney, or incomplete stone clearance requiring additional procedures.

The most common side effects after ESWL are temporary. You may notice blood in your urine for several days, which is normal as the body clears small blood vessels damaged by the shock waves. Bruising on the skin where the shock waves entered the body is also common. Many people experience pain or discomfort in the back or side, similar to kidney stone pain, as the broken stone fragments pass through the urinary tract. Less common but more serious risks include urinary tract infection, which may require antibiotics. There is a small risk of kidney damage, such as a temporary decrease in kidney function or, rarely, a collection of blood around the kidney (hematoma). In some cases, stone fragments may get stuck in the ureter, blocking urine flow and causing severe pain, a condition known as a "steinstrasse" (stone street). This may require an additional procedure, such as ureteroscopy, to remove the fragments. ESWL may not break all stones completely, or some fragments may be too large to pass. This can lead to the need for repeat ESWL treatments or other interventions. Your doctor will discuss these potential risks with you before the procedure and monitor you closely afterward to address any complications promptly. People with certain medical conditions, such as bleeding disorders or pregnancy, may not be suitable candidates for ESWL due to increased risks.

Success rate

The success rate of Extracorporeal Shock Wave Lithotripsy (ESWL) varies widely, typically ranging from about 50% to 90%, depending on several factors. Smaller stones, generally less than 10 millimeters (0.4 inches), and those located in the upper part of the kidney tend to have higher success rates. Larger or harder stones may require multiple treatments or alternative procedures.

The success of ESWL is often measured by the "stone-free rate," which is the percentage of people who have no detectable stone fragments after the procedure. This rate can range significantly, with studies reporting success rates anywhere from 50% to 90%. Factors that influence this rate include the size, location, and composition of the kidney stone, as well as the patient's body mass index (BMI) and kidney anatomy. Smaller stones generally respond better to ESWL. For instance, stones less than 10 millimeters (about 0.4 inches) in diameter often have a higher stone-free rate compared to larger stones. Stones located in the upper and middle parts of the kidney also tend to have better outcomes than those in the lower pole of the kidney, where gravity can make it harder for fragments to pass. The type of stone, such as calcium oxalate dihydrate, may be easier to break than harder stones like cystine or certain calcium oxalate monohydrate stones. Many people may require more than one ESWL session to achieve a stone-free status, especially for larger or more complex stones. Even if a person is not completely stone-free, ESWL is often considered successful if the remaining fragments are small enough to pass without symptoms or further intervention. Your doctor will evaluate your specific situation and discuss the expected success rate based on your individual stone characteristics.

Frequently asked questions

How long does it take to pass stone fragments after ESWL?

After ESWL, it can take anywhere from a few days to several weeks for all the stone fragments to pass through your urine. Drinking plenty of water can help speed up this process. Your doctor will monitor your progress with follow-up imaging.

Is ESWL painful?

During ESWL, you will receive medication for relaxation or light anesthesia, so you should not feel significant pain. Afterward, you might experience mild discomfort or pain similar to kidney stone pain as the fragments pass, which can be managed with prescribed pain relievers.

Can ESWL be used for all types of kidney stones?

ESWL is effective for many types of kidney stones, especially smaller ones. However, it may be less effective for very large stones, very hard stones (like cystine stones), or stones located in difficult-to-reach areas. Your doctor will determine if ESWL is suitable for your specific stone.

What happens if ESWL doesn't work?

If ESWL does not successfully break up your kidney stone or if fragments do not pass, your doctor may recommend additional treatments. These could include another ESWL session, ureteroscopy (a procedure using a thin scope), or percutaneous nephrolithotomy (a surgical procedure for larger stones).

How many ESWL treatments can I have?

The number of ESWL treatments you can have depends on various factors, including the stone's response, your kidney health, and overall health. Your doctor will assess your situation and discuss the risks and benefits of repeat procedures versus alternative treatments.

Will I need to change my diet after ESWL?

While ESWL treats existing stones, your doctor might recommend dietary changes to help prevent new stones from forming. These recommendations depend on the type of stone you had and may include increasing fluid intake, reducing sodium, or modifying intake of certain foods. Always consult your doctor for personalized advice.

Sources

• MedlinePlus — Extracorporeal Shock Wave Lithotripsy Success Rate
• Mayo Clinic — Extracorporeal Shock Wave Lithotripsy Success Rate
• Cochrane Library — Extracorporeal Shock Wave Lithotripsy Success Rate