Extra-Corporeal Shock Wave Lithotripsy (ESWL)

ESWL is a non-invasive treatment for kidney stones. A sound wave is focused on your kidney using x-ray or ultrasound guidance. The shock waves are transmitted across a rubber pad placed on your skin overlying the kidney. Following treatment sand-like fragments from the shattered stone pass out of the body in the urine over a several week period.

ESWL is most suited for stones less than 2cm in diameter located within the kidney. Very small stones are not treated with ESWL as they will not be visible on the imaging equipment used to guide the shock waves. Stones located within the ureter or bladder are not treated with ESWL due to adjacent vertebral and pelvic bones shielding the stone from the shockwaves. ESWL is not safe during pregnancy.

Stones which cannot be treated with ESWL can be treated with other techniques such as ureteroscopy and percutaneous stone removal.


ESWL is performed under a general anaesthetic on the lithotripsy bus. The lithotripsy bus operates from many hospitals throughout New Zealand. It is a specialized bus equipped with an operating room, anaesthetic equipment, x-ray and ultrasound equipment. The bus is staffed by the local urologist, anaesthetist and nursing staff plus specialized radiographers . The bus visits Wellington every five weeks. ESWL takes approximately 1 hour. During the procedure the urologist and anaesthetist will constantly monitor you.


Aspirin, clopidogrel, dabigatran, warfarin and any other blood thinning medications will need to be stopped prior to surgery. We will advise you on the timing of when to stop and re-start these medications.

A urine sample needs to be provided to the laboratory 1 week prior to surgery.


Following ESWL you will be transferred to the hospitals recovery room then from there back to the ward. You will be able to head home on the day of the procedure. There will be bruising of your flank where the shock waves have entered your body. It is normal for blood to be present in the urine for several days after the procedure.


Urinary infection

Antibiotics are given prior to ESWL to reduce infection risk however infection is still possible so If you experience a fever or urinary symptoms suggestive of an infection then please contact Rod Studd.


Stone fragments may cause pain as they pass through the urinary tract. Larger fragments may become lodged in the ureter. If your pain becomes severe despite oral painkillers or you develop a fever then contact Rod Studd. A stone blocking the ureter may need to be treated by insertion of a temporary ureteric stent.

Internal injury

Injury to the kidney, spleen or other adjacent organs is possible however is very rare. Patients with bleeding disorders should not have lithotripsy.

Return to Work

You must not drive a vehicle or operate any machinery for 24 hours following a general anaesthetic. Most people could return to a sedentary type job within five days. Heavy lifting needs to be avoided for three weeks.

Follow-up after Surgery

An appointment will be made for three months post ESWL. Prior to this an x-ray of the kidney will be performed to assess for the presence of residual stone fragments.