Extracorporeal Shock Wave Lithotripsy (ESWL) utilizes shock wave energy generated outside the body (extracorporeal) to fragment stones within the urinary tract. The word lithotripsy comes from the Greek words “lithos” for stone and “tripsy” meaning to crush.
ESWL technology was developed in Germany by Dr.’s Christian Chaussy and Egbert Schmeidt in conjunction with the German aerospace company Dornier. It gained FDA approval in the United States in the mid-1980’s.
The original lithotripsy machines were commonly referred to as “stone baths” because the patient was placed on a supportive frame called a gantry and partially immersed in a tub of water which had been deionized to eliminate air bubbles. The gantry was positioned such that the patient’s stone was within the crosshairs of an aiming system (at the so-called F2 focal point) and electromechanical shock waves generated under water at the F1 point by a spark gap generator traveled through the body to fragment the stone. Ultrasound or fluoroscopy is utilized during the treatment to monitor the fragmentation process. Once the stone or stones have been fragmented, the particles flush through the urinary tract and are eliminated.
Lithotripsy technology has advanced through several generations of machines in the ensuing 25 years and modern devices have eliminated the need for a tub of water. The newest lithotripters are portable and can therefore be transported easily from one facility to another.
Stones in the kidney are most commonly treated with ESWL but stones in the ureter can be treated as well. Large kidney stones or very dense stones in the kidney sometimes require a different technique called percutaneous nephrolithotomy in which the surgeon gains access to the kidney through a puncture in the flank which is dilated to accommodate a scope called a nephroscope. A laser fiber or ultrasound probe is passed through the scope and the stone is fragmented and the particles evacuated under direct vision.
An alternative form of treatment for stones in the ureter is ureteroscopy and laser lithotripsy. This form of therapy utilizes a very small scope called a ureteroscope to visualize the stone. A small fiber connected to a laser generator is passed through the scope and placed against the stone. Impulses of laser energy are then used to fragment the stone.
At Texas Urology Specialists-Memorial Urology Associates, we provide all available stone treatment technology to our patients in multiple locations throughout the Houston area.