Lithotripsy | Types

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.

As mentioned in the kidney stone page, the decision as to which technique will be used depends on the following factors:

  • Stone location
  • Number of and sizes of stones
  • Stone composition
  • How long the stone has been present and causing symptoms
  • Pain caused by the stone
  • Whether or not there is infection
  • Patient expectation and desire
  • Patient anatomy

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.