ESWL or Extracorporeal Shock Wave Lithotripsy is a non surgical technique used to break kidney stones that uses sound waves to create cracks within the stone and break it into pieces from outside the body using a high voltage sound generated by a spark plug. This procedure does not involve any anaesthesia, pain, bleeding or cut.
Who is the Best Candidate for Lithotripsy
Lithotripsy is offered to patients with stones less than 2 centimeters located either in the kidneys or the upper part of the urinary pipe called the ureter. The body weight and the hardness of the stone directly make an impact on the results of the lithotripsy. Ideally the stone hounsfield unit which correlates well with the stone composition should be less than 1000 and the skin to stone distance should be less than 10 centimetres.
Once you are advised lithotripsy you have to get admitted on the day planned. You are made to change into a patient gown and shifted to the lithotripsy suite. If required an intravenous line is established to administer pain killer injection. You are made to lie on the lithotripsy table and a conducting gel is applied on the back of the affected side. The lithotripsy head is brought in contact with the skin. The stone is then focussed and fine adjustments are made to your position to achieve precise focus of the sound waves under X Ray monitoring. The generator is then switched on to produce high energy sound waves which can be heard as a loud sound. Based on tolerance the energy is stepped up slowly and slowly till the desired number of shockwaves have been delivered.
The location of the stone and focus are rechecked from time to time. Once the procedure is completed you are shifted back to the room and discharged after having passed urine.
Preparing for the Procedure
As such no specific preoperative preparation is needed. You may be prescribed medicines to reduce gas in your abdomen so that the stone is seen clearly on the X ray and can be precisely focussed. You must ensure that you have a regular motion especially on the day of the procedure to reduce fecal loading of the large intestine.
Procedure Timeline (In Minutes):
00:00 Hrs – Admission
00:30 Hrs- Completion of consent and changing into patient gown
01:00 Hrs- Shifting to the lithotripsy suite
01:10 Hrs – Establishment of intravenous line (optional) and counselling
01:20 Hrs – Focussing of the stone and fine correction of posture
02:00 Hrs – Completion of Lithotripsy Procedure
02:20 Hrs- Shifting back to the room
03:00 Hrs- completion of discharge and explanation of medications
Sucess rate of Lithotripsy is 90%
When chosen for the right stone in the right patient the success rate of lithotripsy is about 80-90%. However to achieve this rate 2 to 3 sessions are needed as the stone does not break completely in just one sitting especially when it is hard.
Duration: The procedure takes 60 minutes and stay in the hospital is for a total of 2-4 hours
Complications: Since the procedure uses high energy shockwaves the procedure can lead to small regions of bleeding in and around the kidneys. There may be a risk of infection due to bacteria being released from the broken stones. If the fragments that form are too large to pass through they may get stuck in the passage of urine leading to recurrence of symptoms and the need of repeat lithotripsy or any other endoscopic procedure. There can also be some bruising of the skin.
Some studies related the procedure to subsequent development of hypertension and diabetes but the scientific evidence is weak to support it strongly.
Other Techniques: In conditions where a lithotripsy is offered, the usual other options are percutaneous nephrolithotripsy (PCNL), in which the stone is removed using a small puncture into the kidney from the back side or Retrograde Intrarenal Surgery (RIRS). In RIRS a flexible scope is passed from the ureter into the kidney and the stone is fragment using laser energy and extracted piece by piece. Both PCNL and RIRS are invasive procedures that require additional procedures like DJ stunting and DJ stent removal along with 2-3 days of hospital stay.
Usual course after Lithotripsy
After you have been shifted to your room you are free to walk around and eat anything you like. If you have any minor pain or discomfort, the nursing staff will provide you with pain killers to be taken on SOS basis. You will be required to drink plenty of fluids so that fragments of stones can pass.
You may encounter some bleeding in urine which will clear on its own an occasionally if a fragment is stuck in the urinary passage it may lead to acute colic. you will be provided with instructions as to how to seek medical support if the pain occurs.
Usually the stone fragments pass on their own starting from the day of lithtripsy itself. Most of the fragments usually pass out without any pain however if they are larger pieces then the patient may encounter some pain.
After a week of the procedure, an X ray of the KUB region is repeated to document whether the stone has been fragmented. If there are large residual fragments, a second sitting of the procedure is planned.
Salient Points of Lithotripsy | ESWL
- Lithotripsy uses highly focussed sound waves to break stones.
- The procedure is painless and one session lasts for about 45 minutes
- In this process there is no cut or bleeding
- This procedure can be performed even on a daycare basis.
- We perform lithotripsy on the electrohydraulic lithotripter situated at Urocentre.
- Breakage of stones depends on a lot of factors like Size of stone, Body fat distribution, Composition of the stone, age of the stone, patient compliance etc.
- Most large stones require 2 to 3 sittings for adequate breakage
- Stones are reduced to small fragments after ESWL which usually pass out on their own but sometimes involve auxiliary procedures like Ureteroscopy and stenting.
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