JON MARKS, MD: Treatment is determined in a number of ways. The size of the stone and the composition of the stone influence that, but the average stone of modest size, perhaps less than 2 centimeters, less than about three quarters of an inch, those are stones that can be treated in general with shockwave lithotripsy.
PAUL MONIZ: Which is the procedure that we just saw.
JON MARKS, MD: That is correct.
PAUL MONIZ: That is the most common procedure right now?
JON MARKS, MD: It is. It's popularity has to do with the fact that apart from being effective, it is done under sedation. It requires no hospitalization. Patients can have it on one day and be back to work the following day. So it is advantageous in that respect.
PAUL MONIZ: Dr. Salant, take us through the procedure. How long does it take? What's involved?
ROBERT SALANT, MD: In general, the way the modern lithotripsies are done, a patient is placed on a special table, and using either X-rays or ultrasound, the stone is localized. That enables the surgeon to focus the shockwaves on the stone itself. The shockwaves pass harmlessly through the body and hit the stone, breaking the large stone up into smaller pieces. These fragments hopefully will be about the size of a grain of sand, perhaps a little bit bigger. These fragments can then pass easily through the body and out through the urethra.
PAUL MONIZ: Dr. Marks, maybe you can explain to our audience how the breakup actually occurs with these shockwaves. What's actually happening in there?
