Table of Contents
Definition of Extracorporeal Shock Wave Lithotripsy (ESWL)
ESWL – a therapeutic procedure in which a machine called a lithotriptor generates shock waves that cause calcifications within the urinary tract, commonly called kidney stones (NEPHROLITHIASIS) or bladder stones (UROLITHIASIS), to break apart into smaller fragments the URINE can carry out of the body.
Lithotripsy became available in 1980 and has evolved into the current treatment of choice for stones smaller than 2 centimeters (about 0.75 inch) in diameter that form in the KIDNEYS, URETER, and BLADDER.
ESWL is sometimes effective for gallstones (cholelithiasis) as well. Today there are several types of lithotriptors, each of which uses a different energy source though all apply the same basic approach which is to focus a pulse of intense energy (the shock wave) at the stone.
Women who are or could be pregnant should not undergo ESWL.
Typically preparation requires having nothing to eat or drink for six hours before the scheduled time of the procedure. The urologist or nephrologist may recommend stopping routine use of NONSTEROIDAL ANTI-INFLAMMATORY DRUGS (NSAIDS), aspirin, and anticoagulation medications for 7 to 10 days before the scheduled ESWL to reduce the risk of bleeding during or after the procedure, as these medications interfere with PLATELET AGGREGATION and prolong the length of time a BLOOD clot takes to form.
ESWL takes about an hour to perform, with about two hours in the recovery room afterward. The person undergoing ESWL treatment will need someone to take him or her to and from the treatment center.
The urologist or radiologist generally gives the person an anesthetic or sedative for comfort before the ESWL begins. The pressure of the shock waves coming in contact with the stones can be uncomfortable. The lithotriptor integrates FLUOROSCOPY or ULTRASOUND to pinpoint the location of the targeted stone and can target several stones in one ESWL session.
The person wears a hospital gown and lies on a cushioned table. The ESWL technician positions the lithotriptor over the person to deliver the shock waves, with continual monitoring and adjustment to maintain accurate focus. The radiologist or urologist makes sure the person has adequate ANESTHESIA or SEDATION to remain comfortable for the duration of the procedure.
Risks and Complications
The most common risk associated with ESWL is bleeding from the tissues around the site of the stone, resulting in HEMATURIA (bloody urine) and some discomfort. Many people experience discomfort for up to several days after the ESWL, for which the urologist prescribes ANALGESIC MEDICATIONS (pain relief). Most people should plan on taking it easy for a few days after ESWL.
It may take days to weeks for all of the fragments to pass, and larger fragments may cause pain when they pass. Sometimes fragments of the stone cluster in the ureter or URETHRA, temporarily blocking the flow of urine and causing considerable PAIN. Generally movement (such as walking) and drinking lots of fluids help flush these clusters from the body, with appropriate analgesic medication to mitigate the pain. Some people require several ESWL sessions to completely disperse all of the stones and fragments.
Outlook and Lifestyle Modifications
Once the stone breaks apart and the fragments pass from the body in the urine, no further treatment for the stone is necessary. The urologist or nephrologist may recommend dietary changes, increased physical activity, increased water consumption, and sometimes medications to help prevent new stones from forming. Such factors depend on the stone’s content and the person’s medical history, including other health conditions. Both kidney stones and bladder stones tend to recur.