Lithotripsy

Lithotripsy

Lithotripsy, a greek word that means "stone crushing", is a technique that uses focused energy waves to break apart kidney stones without damaging nearby tissue. Lithotripsy utilizes a medical device called a lithotripter to generate energy in a targeted manner to disintegrate kidney stones so that they can pass easily out of the body.

Origin

A German company called Dornier originally developed this technology for medical use in the 1970s and 1980s. The first lithotripter, the Dornier HM3, was commercially sold for the first time in 1983. In 1984, the U.S. Food and Drug Administration approved lithotripsy for shockwave fragmentation of kidney stones.

Types of Lithotripsy

It is estimated that more than 1 million patients are treated each year with shockwave lithotripsy. It has been shown that shockwaves can be generated and focused against kidney stones using many different methods including electromagnetic induction, microexplosions, focused laser and piezoelectric crystals. Lithotripsy techniques are available that generate energy waves from inside the body (intracorporeal) and outside the body (extracorporeal). The extracorporeal technique is most commonly used in clinical practice.

More Information

Extracorporeal Shockwave Lithotripsy (ESWL)

ESWL specifically refers to the non-invasive treatment of stones that are in your kidney. It is a safe, commonly used procedure that can be used on children and patients with only one working kidney. It works best for stones that are in the kidney.

If your stone is not in the kidney and has instead traveled down the ureter, ESWL is not the ideal treatment. One option is for your urologist to use a ureteroscope (link) to push the stone back into the kidney and then use ESWL.

Alternatively, an intracorporeal approach may also be used for stones in the ureter. Stones in the kidney that range in size from 4 mm to 2 cm and are not completely blocking the ureter or kidney are the best candidates for ESWL.

You may not be good candidate for ESWL if you meet any of the following criteria:

  • You are pregnant
  • You have an anatomically abnormal kidney
  • Your kidneys are not working properly
  • You have a urinary tract cancer or kidney cancer
  • You have a bleeding disorder
  • You have a cystine stone

If you are to undergo ESWL, an anesthesiologist will sedate you. The procedure is usually outpatient, meaning that you can go home the same day as the procedure. The basic principle of ESWL is that weak shockwaves are generated outside your body, are transmitted through your body, and focused to break apart your stone.

There are three categories of shockwave generators:

  • Electrohydraulic or spark gap
  • Electromagnetic
  • Piezoelectric

Each of these generators produces shockwaves of different shapes that focus in different ways. They each have specific advantages, but all are effective in breaking apart stones.

Stone Location
The first step of the procedure is to determine the exact location of your stone(s). Depending on the lithotripter, this is done using ultrasound, fluoroscopy, or a combination of both. Once the stone is localized, the lithotripter head is aimed so that the focus point of the shockwaves is right on the stone.

Lithotripsy | Treatment

Next, the treatment is started. Depending on whether you are sedated or anesthetized, the power level and frequency of pulses are brought up slowly or more rapidly. The shock waves pulses create several different types of forces on the stone that combine to fragment it. The procedure usually takes an hour, but can go longer depending on the stone being fragmented. The picture on this page shows a visualization of the shockwaves converging on a kidney stone.

Post Treatment

After the treatment, a stent may be placed to expand your ureter and make it easier for the newly fragmented stone to pass out of your body. It may take up to a week for the fragments to pass, and they may cause some mild pain and blood in the urine when they are passed. Your doctor may encourage you to drink as much water as you can to help pass the pieces, or void through a screen to capture the pieces for analysis.

There can be complications as a result of ESWL. These include damage to nearby blood vessels and kidney tissue, which in rare cases can impair function of your kidneys. The risks of the procedure should and will be discussed in detail by your urologist.

Intracorporeal Lithotripsy

Advances in ureteroscopy have allowed better access through the ureter for kidney stone treatment. Most stones in the upper urinary tract can be treated with ESWL. However, certain stones are poor candidates for ESWL, as mentioned above, and require intracorporeal treatment.

For small stones, an endoscopic basket or grasping device can be used to remove a stone. However, larger stones require some fragmentation before they can be safely removed. To accomplish this, four techniques can be used for intracorporeal lithotripsy.

Laser Lithotripsy
Laser lithotripsy uses a holmium:YAG laser to vaporize kidney stones. This technique can fragment all types of kidney stones, and represents the most effective, safest, and most versatile intracorporeal technique available to urologists today. As with all intracorporeal techniques, a ureteroscope is first placed. Then, fibers of different sizes can be placed through the endoscope to reach the stone. Large fiber cores are used for the ureter and bladder, while small core fibers can be used to reach the kidneys.
Electrohydraulic Lithotripsy
Electrohydraulic lithotripsy (EHL) uses two electrodes to produce a spark that creates a shockwave to break apart the stone. EHL uses small, flexible probes that can reach stones throughout the entire upper urinary tract. Its disadvantages are its potential for damaging adjacent tissue, producing large fragments, and occasionally failing to fragment the hardest calculi, including calcium oxalate.
Ballistic Lithotripsy
Ballistic lithotripsy uses a small endoscopic jackhammer to generate energy that uniquely targets inflexible stones. This technique is efficient, very safe, and especially good for large, hard stones. The main disadvantage of this technique is that it requires a rigid lithotriper and a straight ureteroscope.
Ultrasonic Lithotripsy
Ultrasonic lithotripsy was the first intracorporeal technique. Like the ballistic technique, it requires a rigid endoscope. Ultrasound waves are generated by electrical stimulation of a plate inside the ultrasound probe. This technique is more commonly used percutaneously (through the skin) as opposed to through a ureteroscope.

Types of Lithotripsy

It is estimated that more than 1 million patients are treated each year with shockwave lithotripsy. It has been shown that shockwaves can be generated and focused against kidney stones using many different methods including electromagnetic induction, microexplosions, focused laser and piezoelectric crystals. Lithotripsy techniques are available that generate energy waves from inside the body (intracorporeal) and outside the body (extracorporeal). The extracorporeal technique is most commonly used in clinical practice.

More Information

Extracorporeal Shockwave Lithotripsy (ESWL)

ESWL specifically refers to the non-invasive treatment of stones that are in your kidney. It is a safe, commonly used procedure that can be used on children and patients with only one working kidney. It works best for stones that are in the kidney.

If your stone is not in the kidney and has instead traveled down the ureter, ESWL is not the ideal treatment. One option is for your urologist to use a ureteroscope (link) to push the stone back into the kidney and then use ESWL.

Alternatively, an intracorporeal approach may also be used for stones in the ureter. Stones in the kidney that range in size from 4 mm to 2 cm and are not completely blocking the ureter or kidney are the best candidates for ESWL.

You may not be good candidate for ESWL if you meet any of the following criteria:

  • You are pregnant
  • You have an anatomically abnormal kidney
  • Your kidneys are not working properly
  • You have a urinary tract cancer or kidney cancer
  • You have a bleeding disorder
  • You have a cystine stone

If you are to undergo ESWL, an anesthesiologist will sedate you. The procedure is usually outpatient, meaning that you can go home the same day as the procedure. The basic principle of ESWL is that weak shockwaves are generated outside your body, are transmitted through your body, and focused to break apart your stone.

There are three categories of shockwave generators:

  • Electrohydraulic or spark gap
  • Electromagnetic
  • Piezoelectric

Each of these generators produces shockwaves of different shapes that focus in different ways. They each have specific advantages, but all are effective in breaking apart stones.

Stone Location
The first step of the procedure is to determine the exact location of your stone(s). Depending on the lithotripter, this is done using ultrasound, fluoroscopy, or a combination of both. Once the stone is localized, the lithotripter head is aimed so that the focus point of the shockwaves is right on the stone.

Lithotripsy | Treatment

Next, the treatment is started. Depending on whether you are sedated or anesthetized, the power level and frequency of pulses are brought up slowly or more rapidly. The shock waves pulses create several different types of forces on the stone that combine to fragment it. The procedure usually takes an hour, but can go longer depending on the stone being fragmented. The picture on this page shows a visualization of the shockwaves converging on a kidney stone.

Post Treatment

After the treatment, a stent may be placed to expand your ureter and make it easier for the newly fragmented stone to pass out of your body. It may take up to a week for the fragments to pass, and they may cause some mild pain and blood in the urine when they are passed. Your doctor may encourage you to drink as much water as you can to help pass the pieces, or void through a screen to capture the pieces for analysis.

There can be complications as a result of ESWL. These include damage to nearby blood vessels and kidney tissue, which in rare cases can impair function of your kidneys. The risks of the procedure should and will be discussed in detail by your urologist.

Intracorporeal Lithotripsy

Advances in ureteroscopy have allowed better access through the ureter for kidney stone treatment. Most stones in the upper urinary tract can be treated with ESWL. However, certain stones are poor candidates for ESWL, as mentioned above, and require intracorporeal treatment.

For small stones, an endoscopic basket or grasping device can be used to remove a stone. However, larger stones require some fragmentation before they can be safely removed. To accomplish this, four techniques can be used for intracorporeal lithotripsy.

Laser Lithotripsy
Laser lithotripsy uses a holmium:YAG laser to vaporize kidney stones. This technique can fragment all types of kidney stones, and represents the most effective, safest, and most versatile intracorporeal technique available to urologists today. As with all intracorporeal techniques, a ureteroscope is first placed. Then, fibers of different sizes can be placed through the endoscope to reach the stone. Large fiber cores are used for the ureter and bladder, while small core fibers can be used to reach the kidneys.
Electrohydraulic Lithotripsy
Electrohydraulic lithotripsy (EHL) uses two electrodes to produce a spark that creates a shockwave to break apart the stone. EHL uses small, flexible probes that can reach stones throughout the entire upper urinary tract. Its disadvantages are its potential for damaging adjacent tissue, producing large fragments, and occasionally failing to fragment the hardest calculi, including calcium oxalate.
Ballistic Lithotripsy
Ballistic lithotripsy uses a small endoscopic jackhammer to generate energy that uniquely targets inflexible stones. This technique is efficient, very safe, and especially good for large, hard stones. The main disadvantage of this technique is that it requires a rigid lithotriper and a straight ureteroscope.
Ultrasonic Lithotripsy
Ultrasonic lithotripsy was the first intracorporeal technique. Like the ballistic technique, it requires a rigid endoscope. Ultrasound waves are generated by electrical stimulation of a plate inside the ultrasound probe. This technique is more commonly used percutaneously (through the skin) as opposed to through a ureteroscope.