Extracorporeal lithotripsy (ESWL)
When is this procedure indicated?
According to European Association of Urology (EAU) guidelines, extracorporeal lithotripsy may be offered as a first-choice treatment in ureteral stones up to 5 mm and kidney stones up to 2 cm. However, there are factors that make the success of extracorporeal lithotripsy unlikely, such as the presence of a very hard stone (Hounsfield Unit > 1000), a distance between the skin and the stone > 15 cm, an anatomy of the kidney not conducive to spontaneous expulsion of residual fragments (e.g., a wide pelvic-infundibular angle, a narrow infudibulum, a long goblet), incorrect use of the lithotripter. Each of these factors significantly influences the need for a new session and the likelihood of achieving complete remediation, so each case must be evaluated individually to plan the best treatment for the patient.
How is it performed?
Extra-corporeal Shock Wave Lythotripsy (ESWL) is a non-invasive procedure reserved for the treatment of renal and ureteral calculosis. It uses an instrument, the lithotripter, which emits high-energy acoustic shock waves that pass through the tissues from the outside to the inside of the body. These shock waves, focusing on the calculus, allow the fragmentation of the same into small fragments susceptible to spontaneous expulsion with urine. This procedure, generally well tolerated by patients, does not require any type of sedation and/or analgesia.
In order to achieve optimal calculation fragmentation, more than a single session may be required. There is no clear consensus on how many sessions and how much interval should elapse between the sessions. The optimal frequency of shock wave emission to achieve good lithotripsy is 1/1.5 Hertz.
The procedure, with an average duration of 30 minutes, is normally performed in day hospital, only in case of complications it may be necessary to move to an ordinary hospitalization.
Complications related to extracorporeal lithotripsy may include:
- Generation of residual fragments that stack along the ureter (Steinstrasse) (4-7%);
- Regrowth of residual fragments (21-59%);
- Renal colic (2-4%);
- Bacteriuria (7.7-23%);
- Sepsis (1-2.7%);
- Symptomatic renal hematoma (<1%);
- Asymptomatic renal hematoma (4-19%).
There are some studies showing relation of the onset of diabetes mellitus and hypertension after ESWL treatment, however, a cause-and-effect relationship has never been unequivocally demonstrated.