Wednesday, 20 March 2013
LITHOTRIPSY: NON INVASIVE TREATMENT OF KIDNEY
Extracorporeal Shock Wave Lithotripsy (ESWL) is the non-invasive treatment of kidney stones. The lithotriptor was developed in the early 1980s in Germany by Dornier MedTech Systems GmbH, and came into widespread use with the introduction of the HM-3 lithotriptor in 1983. Within a few years, ESWL became a standard treatment of urinary tract calculi.
EWL using an externally-applied, focused, high-intensity acoustic pulse (shock wave) which pass through the body. When the wave encounters the calculus, the pressure causes the stone to be stressed, then fractured into small fragments that can pass spontaneously and eventually disintegrated. Ultrasound or fluoroscopic x-ray system is used to direct the focus of the waves precisely on the stone. The shock waves are able to break up the stones with less risk of damage to any of the surrounding tissue than an open surgical procedure. It is performed as an outpatient procedure, requiring sedation on some occasions. The patient is fit for discharge immediately after the procedure.
Why have ESWL?
The procedure is performed as an outpatient procedure with the patient able to return to their normal daily activity almost immediately. It is non invasive with no cutting to the body required. Analgesic requirement is minimal with reasonable stone clearance rate.
What are the risks of ESWL?
During the procedure, some patients may experience pain severe enough to require analgesia. The treatment may not break the stone. Occasional patients report transient passage of blood following ESWL. Very rarely stone fragments pass down the ureter and obstruct the kidney. There is a small risk of developing a urine infection.
Are there any alternatives to ESWL?
There are a number of factors which must be taken into consideration before offering alternative treatments. These will be discussed with you by your urologist and include Medical expulsive therapy / watchful waiting, PCNL, Ureteroscopy or surgical removal.
Can ESWL be used for all patients with stones?
ESWL is contraindicated in patients with:
# Acute urinary tract infection or urosepsis
# Uncorrected bleeding disorders or coagulopathies
# Uncorrected obstruction distal to the stone
# Body habitus: Morbid obesity and orthopaedic or spinal deformities may complicate or prevent proper positioning.
# Cardiac pacemakers are also not contraindicated, although seeking assistance from a cardiologist for possible changes to pacemaker settings would be prudent.
Any precautions before ESWL treatment?
You should check with your urologist about what medication you need to stop. If you are on Aspirin, Clopidogrel or warfarin, these will need to be stopped at least 10 days before your treatment.
How is ESWL performed?
You will be asked to lie on your back and the treatment begins once you are in a comfortable position on the treatment table. The stone will be located either by fluoroscopy or ultrasound. It is important to remain still during the procedure to ensure accurate delivery of shock waves onto the stone. You will hear and feel a flicking noise during the procedure. Treatment lasts approximately 45 minutes. On some rare occasions, analgesia may be required. Treatment might need to be repeated for large or hard stones.
What to expect post ESWL?
You might notice blood in the urine following the procedure, however, this is transient. Stone fragments can sometimes be seen in the urine. It is essential to consume large volumes of water to increase urine flow and help flush stone fragments through.
If the blood in the urine does not clear after a few days or should your pain fail to settle with analgesia or should you develop fever you should contact your urologist.