ESWL (Extracorporeal Shock Wave Lithotripsy)
What is Extracorporeal Shock Wave Lithotripsy?
Extracorporeal Shock Wave Treatment:Extracorporeal means from outside the body. Lithotripsy can be broken down into its Greek roots, litho meaning stone, and tripsy meaning to break down. ESWL or Extracorporeal shock wave lithotripsy is a medical procedure involving the breakdown of hardened masses such as kidney stones, gallstones, or other calculus into smaller particles. ESWL or Extracorporeal shock wave lithotripsy is the most common treatment for kidney stones in the United States.
Alternatives to ESWL?
There are two other minimally invasive surgical techniques that can be used to remove a stone. Aside from ESWL, there is Percutaneous nephrolithotomy (PNL), as well as rigid and flexible ureteroscopy. PNL is used for larger stones while ESWL is used for stones smaller than 2cm. The choice of intervention for stones that are unlikely to pass spontaneously varies with the location and size of the stone. Both ESWL and ureteroscopy are viable options for managing ureteral calculi (aka renal stones). ESWL is the treatment of choice for most small renal calculi, while PNL is the preferred method of stone removal for larger renal stones, including staghorn calculi.
Ureteroscopy continues to be the treatment of choice for the majority of middle and distal ureteral stones but also can be used to manage proximal ureteral and intra-renal calculi. Ureteroscopic access is frequently useful for the management of ureteral calculi where ESWL failed.
- Complex calculi
- Large or hard calculi (cystine, calcium oxalate monohydrate)
- Stones located in a calyceal diverticulum
- Stones located in the lower pole calyx or middle or lower ureter
- Most small renal and ureteral calculi (<2cm)
- ESWL is most effective for stones in the renal pelvis and upper ureter
About the Procedure:
- ESWL employs high-energy shock waves produced by an electrical discharge, which ultimately fragments the stone.
- The shock waves are transmitted through water and directly focused onto a renal/ureteral stone with the aid of biplanar fluoroscopy.
- The change in tissue density between the soft renal tissue and the hard stone causes a release of energy at the stone surface.
- This energy fragments the stone.
- Incomplete stone fragmentation
- Renal parenchymal injury
- Declining GFR (Glomerular Filtration Rate)
Summary / Recommendations:
- ESWL is the most common treatment for renal stones that are small and in uncomplicated locations because of its general safety and reduced hospitalization time
- Repeated Extracorporeal shock wave lithotripsy for the same stone is unlikely to be successful. If ESWL fails to work the first time,
alternatemethods should be considered.
- After the procedure, the main consideration should be to prevent new stone formation. This is typically carried out via pharmacological measures.