Extracorporeal Shockwave Lithotripter--ESWL Knowledge
►ESWL - Procedure
►What are the side effects of
Wave Lithotripsy (ESWL)
►Extracorporeal shock wave lithotripsy (ESWL) for kidney stones
Wave (ESWL), Ureteroscopic Laser Lithotripsy
Wave Lithotripsy:a shocking blow for kidney stones
►Extracorporeal shock wave lithotripsy (ESWL) versus percutaneous
nephrolithotomy (PCNL) or retrograde intrarenal surgery (RIRS) for kidney stones
ESWL - Procedure
Extracorporeal Shock Wave Lithotripsy (ESWL) is a well-established and most
common procedure for the treatment of urinary stones. In general, it ensures a
high success rate with low adverse effects.
The success of ESWL is dependant upon several factors such as stone location,
stone composition, stone size, patient's body characteristics and risk factors,
pain management, treatment strategies, and the shock wave parameters. The
effectiveness of the shock wave is also related to the absence of anatomical
structures within the shock wave path and the accuracy with which the stone is
located and aligned in the therapy focus of the shock wave source.
Kidney stones are usually undetected during formation. As the stone moves into
the urinary tract they are often accompanied by the following symptoms:
burning or slow urination
in the urine
nausea and/or vomitting
About 5 % of all women and 10 % of men have a kidney stone once in a life time.
Kidney stones usually appear in people between the ages of 20 每 45, and
occasionally develop in children. After the age of 50 the incidence rate
declines. Kidney stones are especially common in dry, hot countries and are seen
more often in Caucasians than people of African descent.
When the urine becomes too concentrated with impurities, small crystals may form
and develop into stones. Calcium oxalate stones are most common. They often
develop due to insufficient fluid intake. Other types of stones include calcium
phosphate, struvite, uric acid and cystine stones.
The most common causes of calculi are dehydration and poor nutrition. Certain
medications such as antacids and protein supplements have also been linked to
formation. Cystine stones are linked to heredity and although rare, have been
seen in children.
Urinary System, including kidneys, ureter and bladder
Contraindications to ESWL include:
abnormalities as indicated by abnormal prothrombin time (PT), partial
thromboplastin time (PTT), or bleeding time; patients on anticoagulants;
arterial aneurysms, bodies of vertebrae, large bony areas, arterial
calcification or hemangioma in the shockwave path;
of urinary tract distal to the stone
anomalies preventing adequate positioning
which cannot be clearly located and localized on the imaging system of the
Stones can either be localized with ultrasound or X-ray. The main benefits of
ultrasound are real time monitoring of the disintegration process and the
absence of ionizing radiation. Flouroscopic imaging usually is very fast and
precise. It visualizes areas that are not seen with ultrasound. Dornier
lithotripters are designed for dual-mode imaging offering the choice to apply
both imaging modalities simultaneously.
Stone fragmentation is primarily caused by high local tensile and shear waves
created by the focused shock waves hitting the stone. Spherical shock wave
fronts contribute to compression-induced tensile cracks or spalling at the
posterior surface of the stone. Cavitation is also important for stone
comminution. The rapid collapse of cavitation bubbles on the surface of the
stone or in liquid-filled cracks within the stone produces shock waves that
cause microfractures in the stone.
Stone fragmentation correlates quite well with the shock wave energy delivered
into the focal zone. The acoustic energy of a shock wave pulse is determined
within an area having a diameter that corresponds to the average size of urinary
stones. The effective energy contributing to stone disintegration is generally
defined as energy delivered to an area of 12 mm diameter in the focal plane. The
12-mm area corresponds to most stones indicated for ESWL monotherapy. Provided
the stone is precisely targeted, most of the effective energy contributes to
fragmentation except for the portion that does not hit the stone. The
surrounding tissue absorbs the energy that misses the stone. For larger stones,
the full effective energy is applied to the stone for fragmentation. This is
important when selecting a safe energy dose, i.e., the number of shock waves
times the effective energy, to disintegrate the stone.
The energy dose Etot (12mm) is defined as Etot(12mm) = n * Eeff(12mm) where n is
the number of applied shocks and Eeff(12mm) is the disintegration energy, i.e.
the acoustic energy per shock wave delivered to an area of 12 mm diameter in the
focal plane. The applied energy dose determines treatment success in terms of
fragmentation and side effects. Thus, the success of ESWL treatments at
different intensity levels seems to remain the same when the number of shots is
in the range receiving equivalent energy dose. The energy dose for kidney stones
typically is in the range of 100 to 200 J per treatment.
Cavitation bubbles in the shock wave path have a noticeable effect on
fragmentation efficacy. They attenuate the shock wave and fragmentation efficacy
is reduced. Studies performed in vitro suggest that the PRF influences
fragmentation efficacy due to cavitation effects. At higher PRFs shock waves
become less effective. For this reason PRF should be kept as low as possible.
Most patients only experience minimal side effects after the procedure. Side
effects may include mild discomfort in the abdominal region, along with redness
or bruising at the treatment site, and blood in the urine. Patients can return
to a normal routine within twenty-four hours of the treatment.
Even though it has not been scientifically proven, the risk of side effects from
a shock wave exposure may increase due to factors such as medication, age,
hypertension, cardiac rhythm dysfunction, vascular debility, diabetes or
obesity. Tender vessels in the renal parenchyma are particularly endangered, and
high shock wave intensities can lead to a serious hematoma if the patient
presents a combination of these risk factors. Clinically relevant perirenal
hematomas are observed within 1 - 3% after ESWL as confirmed by ultrasound
imaging, and most are treated conservatively.
Open surgical treatment 每 With the invention of ESWL, open surgical procedures
on the kidney are rare. There are, however, specific indications, which make
open surgery necessary.
• Failure less invasive treatments due to size, composition and location of the
• Certain anatomic abnormalities of the urinary tract
Minimally Invasive Treatments 每 Ureteroscopy (URS) can be performed to remove
stones located in the lower part of the ureter. During this procedure, an
ureteroscope is inserted through the urethra to gain access to the stone. Once
the stone is located, it is either removed by means of a specialized basket or
by laser lithotripsy. The advantage of Holmium laser lithotripsy over other
endoscopic treatments is decreased stone movement and decreased bleeding during
Percutaneous Nephrolithotomy (PCNL) 每 This method is often used for calculi
larger than 2 centimeters in size or for hard stones. General anesthesia is
required. A small incision is made in the back and a nephroscope is passed
directly into the kidney. Direct fragmentation of the stone is performed using
an ultrasonic, electrohydraulic, or laser device through the nephroscope under
direct vision. This treatment can also be performed using the Dornier Medilas
Conservative treatment 每 Diet, hydration, medications or a combination of these
treatments may assist the natural passing of the calculi. The conservative
treatment is only successful for stones smaller than 5 mm in diameter. The
effectiveness of medications is dependent on the composition of the stone.
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Overview of ESWL
Extracorporeal shock wave lithotripsy (ESWL) uses sound waves or shock waves to
break stones into small fragments that can pass spontaneously. It is performed
usually as an outpatient procedure whilst awake or sometimes with sedation.
Usually, you can go home immediately after, although it may need to be repeated.
What are the reasons for having ESWL?
Usually, there is a stone present within the kidney or upper part of the ureter
that will not pass by itself. The stone may sometimes cause pain or sometimes no
pain at all, although it may impede the passage of urine from the kidney down to
the bladder. Usually, the stone will be less than 2 cm in size, although
sometimes larger. Stones present in the ureter may be treated where they are or
sometimes pushed up into the kidney before treatment. To do this, a procedure
under general anaesthetic would normally be required before the ESWL itself.
What are the advantages of ESWL?
There are several advantages of ESWL over other treatments for stones. These
procedure that takes 1 hour
cutting or invasion of the body at all
risk of infection from hospital bacteria
What are the risks of ESWL?
About 1 in 10 people experience a problem. The main risks are:
treatment does not break the stone
as fragments of stone pass down the ureter
urine flow if stone fragments cannot pass down the ureter
around the outside of the kidney
What are the alternatives to ESWL?
Depending on the qualities of the stone and the individual with the stone, it
may be possible to consider:
waiting (i.e. waiting for the stone to pass by itself)
or uretero-renoscopy: a procedure under general anaesthetic to find and break
the stone by passing a telescope through the water pipe ('urethra'), bladder and
up the ureter to the kidney. Usually, a day in hospital is required.
a procedure under general anaesthetic to remove the stone by placing a tube
directly through to the kidney. Usually, several days in hospital are required.
It is more likely to be successful than ESWL for stones in the kidney.
removal: under general anaesthetic, an incision to remove the stone either
directly or through telescopes (laparoscopes). Usually, a few days in hospital
are required. It is more likely to be successful than ESWL, but is quite
Can everyone with a stone have ESWL?
ESWL may not be possible for patients with the following characteristics
over 300 lbs (136 kg),
pacemakers should be evaluated by a cardiologist familiar with ESWL. A
cardiologist may need to be present during the ESWL procedure in the event the
pacemaker needs to be overridden.
What do you have to do before ESWL treatment?
You will usually be asked eat a light breakfast or lunch before the procedure.
If you take regular medicines, you should ask your doctor if they are safe to
take before the procedure. For instance, you may be asked to stop taking aspirin
or clopidogrel, and other drugs (e.g. warfarin) that interfere with blood
clotting several days before.
On the day of the procedure, you should wear comfortable clothes that are easy
to remove, as you will have to change into a surgical gown.
Someone should be available to drive you home in case you have received
medication that has made you feel drowsy or if you have pain afterwards.
How is ESWL performed?
When you arrive, you may need to change into different clothes. Sometimes, it is
necessary to have another x-ray before treatment. After you enter the room with
the ESWL machine, you will be asked to lie down on the treatment table. If the
stone is in the kidney, you are usually asked to lie face down, but if the stone
is in the ureters, you will probably be asked to lie on your back. Once you are
comfortable on the treatment table, the stone will be located either by X-ray or
ultrasound. During this time, it is important to stay as possible during this
time. This is important so that the shock waves can be accurately focused on the
stone. Movement and deep breathing will make it difficult for the shock waves to
hit the stone. Before we put the Lithotripter treatment head (a cushion with
water inside) to your back/front we will put. Some ultrasound jelly is applied
to the skin and then a cushion containing water is positioned to allow the shock
waves to be delivered to the stone. The jelly is water-based and will wash off.
The treatment usually lasts between 20 and 40 minutes; you will hear a
※clicking§ noise and feel something like a ※flicking§ on your back/front. Some
people have said that it feels a bit like a small electric shock. The power or
intensity may increase during the procedure so that the stone can be completely
broken. It may feel uncomfortable but should be bearable and additional pain
killers can be given.
What to expect after ESWL?
After passing urine, it should be possible to go home. Someone may need to drive
you home. In some cases, it may be necessary to take antibiotics for a few days.
You should large volumes of water to increase urine flow and help flush stone
You should be able to resume normal activities the day after treatment.
You may see blood in your urine after the treatment. This is not important,
unless the urine is completely opaque because of blood. A bruise may appear on
the back where the treatment head was placed Small fragments of stone may pass
giving pain sometimes as bad as renal colic.
When should I contact a doctor?
If you have the following, you should contact a doctor:
you cannot pass urine or if you find it difficult to pass urine
pain in the back or surrounding area
How often does ESWL need to be repeated?
Often only 1 treatment is required, but large stones in difficult locations may
require multiple treatments over weekly or more intervals.
What happens if ESWL doesn't work?
One of the alternative options listed above may be needed i.e. either
uretero-renoscopy or PCNL.
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Extracorporeal Shock Wave (ESWL), Ureteroscopic Laser Lithotripsy
Kidney Stone Removal
Methods and TechniquesLithotripsy (stone crushing) is the kidney stone removal
method where the stone is fragmented either by energy applied from outside the
body (shock wave in ESWL) or from within in ureteroscopic methods (laser
lithotripsy). These methods will only be considered if other forms of treatment
like kidney stone medication has been ineffective or if the stone is causing an
obstruction or severe kidney stone pain.
Extracorporeal Shockwave Lithotripsy (ESWL)
This is an outpatient procedure and overnight hospitalization is not necessary
unless there are complications or other risk factors present. Extracorporeal
(outside-body) means that no device will have to be inserted into the urinary
tract, except if a ureteral stent is necessary.
Local anesthesia and intravenous (IV) sedation is commonly used. General
anesthesia (GA) may be administered in certain cases. Fasting for up to 8 hours
before general anesthesia is recommended while a 4 hour fast may be sufficient
for IV sedation.
The patient lies down on a water filled cushion on the lithotripter table. With
older machines, the patient may need to be partially submerged in water.
The location of the stone is isolated by the use of an ultrasound or
fluoroscopy. This also assists with tracking the movement of the stone(s) during
High energy shockwaves are generated outside the body by a machine known as a
lithotripter and applied over the target area. These shockwaves will not damage
other organs and tissue in the body.
A ureteral stent, which is a thin plastic tube inserted through the urethra,
into the bladder and up into the ureter, may be necessary to allow for the
stones to pass out more easily.
The entire procedure may last for up to an hour or even two although the
lithotripsy part may only take 20 to 30 minutes.
Ureteroscopic LithotripsyThis is also known as endoscopic or intracorporeal
(inside-body) lithotripsy. This is an outpatient procedure as well but due to
the use of general anesthesia, the presence of any risk factors or complications
that may arise during or after the procedure, hospitalization may be necessary.
If You Are Suffering From Bad
Breath, You May Have Tonsil Stones!
This procedure is conducted under general anasthesia (GA).
A thin flexible (sometimes rigid) tube-like viewing device, known as a
ureteroscope, is passed up the urethra, into the bladder and up the into the
ureter along with a guiding wire. This will allow the urologist to actually see
the stone in the ureter.
Small stones can be grasped with a wire prong grasper or basket. Larger stones
will need to be fragmented and sometimes a special type of basket is inserted to
prevent the stone from moving higher up the ureter.
A laser fiber is inserted up the ureter which delivers the laser energy to the
stone. The laser machine itself does not enter the body. Laser lithotripsy is
preferred over other forms of intracorporeal lithotripsy like pneumatic
mechanical or electrohydraulic devices.
A ureteral stent is inserted for drainage.
The procedure may last for approximately 90 minutes but can extend for up to 3
If none of these methods are effective or viable, percutaneous nephrolithotomy
or open surgery may be considered.
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Extracorporeal Shock Wave Lithotripsy:a shocking blow for kidney stones
Extracorporeal Shock Wave
Lithotripsy (ESWL) is the medical procedure by which acoustic shock waves,
generated outside the body, are focused onto a kidney stone in the kidney or
ureter causing the stone to fragment. The technique has been used in hospitals
since 1980; currently more than 2000 lithotripters are in operation around the
world and over five million treatments have been carried out. Approximately 70%
of patients with stones can be treated with ESWL alone. A further 25% of
patients receive ESWL in conjunction with some other procedure - avoiding the
need for open surgery in 95% of cases of kidney stones.
Despite the success of ESWL there is no agreement in the community as to the
mechanism by which the stone fails. Furthermore there is evidence that the shock
wave leads to permanent damage to healthy tissue in the kidney. The significance
of the injury is also debated.
The two major hypotheses for stone comminution are spallation and cavitation.
Spallation refers to large tensile stress that the stone leading to stone
failure probably by fatigue. Cavitation occurs when the tensile stress of the
shock wave is strong enough to make fluid rip apart. The nature of the shock
wave in lithotripsy leads to a dramatic growth of the bubble followed by a
subsequently violent collapse. The collapse leads to an probably surface
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Extracorporeal shock wave
Extracorporeal shock wave
lithotripsy (ESWL) is the non-invasive treatment of kidney stones (urinary
calculosis) and biliary calculi (stones in the gallbladder or in the liver)
using an acoustic pulse. Lithotripsy and the lithotriptor were developed in the
early 1980s in Germany by Dornier Medizintechnik GmbH (now known as 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 calculosis.
It is estimated that more than one million patients are treated annually with
ESWL in the USA alone.
How it works
The lithotriptor attempts to break up the stone with minimal collateral damage
by using an externally-applied, focused, high-intensity acoustic pulse. The
sedated or anesthesized patient lies down in the apparatus' bed, with the back
supported by a water-filled coupling device placed at the level of kidneys. A
fluoroscopic x-ray imaging system or an ultrasound imaging system is used to
locate the stone and aim the treatment. The lithotriptor has a half
ellipsoid-shaped piece that opens toward the patient. The acoustic pulse is
generated at the ellipsoidal focal point that is furthest from the patient and
the stone positioned at the opposite focal point receives the focused shock
wave. The treatment usually starts at the equipment's lowest power level, with a
long gap between pulses, in order to accustom the patient to the sensation. The
frequency of pulses and the power level are then gradually increased, so as to
break up the stone more effectively. The final power level usually depends on
the patient's pain threshold. If the stone is positioned near a bone (usually a
rib in the case of kidney stones), this treatment may be more uncomfortable
because the shock waves can cause a mild resonance in the bone which can be felt
by the patient. The sensation of the treatment is likened to an elastic band
twanging off the skin. Alternately the patient may be sedated during the
procedure. This allows the power levels to be brought up more quickly and a much
higher pulse frequency, often up to 120 shocks per minute.
The successive shock wave pressure pulses result in direct shearing forces, as
well as cavitation bubbles surrounding the stone, which fragment the stones into
smaller pieces that then can easily pass through the ureters or the cystic duct.
The process takes about an hour. A ureteral stent (a kind of expandable hollow
tube) may be used at the discretion of the urologist. The stent allows for
easier passage of the stone by relieving obstruction and through passive
dilatation of the ureter.
Some of the passed fragments of a 1-cm calcium oxalate stone that was smashed
using lithotripsy.Extracorporeal lithotripsy works best with stones between 4 mm
and 2 cm in diameter that are still located in the kidney. It can be used to
break up stones which are located in a ureter too, but with less success.
The patients undergoing this procedure can, in some cases, see for themselves
the progress of their treatment. If allowed to view the ultrasound or x-ray
monitor, they may be able to see their stones change from a distinct bright
point (or dark spot depending on whether the fluoro unit is set up in native or
bones white) to a fuzzy cloud as the stone is disintegrated into a fine powder.
ESWL is the least invasive of the commonplace modalities for definitive stone
treatment, but provides a lower stone-free rate than other more invasive
treatment methods, such as ureteroscopic manipulation with laser lithotripsy or
percutaneous nephrolithotomy (PCNL). The passage of stone fragments may take a
few days or a week and may cause mild pain. Patients may be instructed to drink
as much water as practical during this time. Patients are also advised to void
through a stonescreen in order to capture stone fragments for analysis.
ESWL is not without risks. The shock waves themselves, as well as cavitation
bubbles formed by the agitation of the urine medium, can lead to capillary
damage, renal parenchymal or subcapsular hemorrhage. This can lead to long-term
consequences such as renal failure and hypertension. Overall complication rates
of ESWL range from 5每20%.
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Wave Lithotripsy (ESWL)
Shock wave lithotripsy, or
ESWL, is an outpatient procedure. It is usually performed under general
anesthesia and takes about an hour.
First, the kidney stone is located by x-rays. Then, the doctor directs
high-intensity sound waves at the stone. The goal is to break the stone into
tiny fragments (about the size of grains of sand) so they may then flush out of
the body with the urine. The major advantage of ESWL is that it doesn't require
During ESWL, it is possible that some stones may not break or may break into
large pieces that are difficult to pass. There is a limit to the number of shock
waves that can be safely administered in a single treatment session.
While many ESWL patients are free from stones three months after the procedure,
some require additional treatments.
If you need a stent
A ureteral stent may be inserted at the time of treatment if your doctor is
concerned that stone fragments will block your ureter. Stents are most commonly
used for patients with ureteral stones, large stones (usually greater than 15
mm), particularly dense stones or those with a history of urinary tract
infections. Stents are usually removed in the urologist's office, after x-rays
indicate that there is no longer a risk of obstructing fragments.
ESWL may be a good option for:
Stones that can be seen on an x-ray (are radio-opaque)
Kidney stones less than 20 mm
Ureteral stones less than 10 mm
ESWL may not be a good option for:
Stones that are difficult to see on an x-ray
Stones in the bottom part of the kidney (lower pole stones)
Mid ureteral stones - Treating stones in the region of the ureter overlying the
bony pelvis is not recommended because bone blocks shockwaves and makes it
difficult to find the stone.
Distal ureteral stones - These stones are often better treated by ureteroscopy
Chronic infection - The only way to stop chronic infection associated with
kidney stones is to completely remove the stones. ESWL tends to leave small
Obstruction distal to stone - if the ureter is blocked by scarring or some other
proces, the stone fragments are unlikely to pass.
Patients on blood thinners - ESWL treatment carries a risk of bleeding from the
Obesity - Stones can be difficult to see in heavier patients. Most ESWL units
cannot support a patient heavier than 350 pounds.
Patients who require complete stone clearance - It may take up to three months
for all fragments to clear after ESWL and that time period may be unacceptable
for some patients.
Success rate of ESWL
As with any medical procedure, your doctor can't guarantee success. To give our
patients the best chance at getting rid of stones, we select patients who are
most likely to succeed before recommending ESWL.
Much of the research evaluating the effectiveness of ESWL was completed before
CT scans were commonly used for stone disease. Therefore, it is difficult to
compare older research with current research.
Older research - Using plain x-rays, patients with fragments less than 4 mm in
size were generally considered to have had a successful treatment. Using this
criteria, "successful treatment" occurs for 70 - 80% of ureteral stones and 60 -
80% of kidney stones.
Current research - A more recent study used CT scans to look for fragments in
patients with lower pole stones less than 1 cm who had undergone ESWL treatment.
Researchers found that less than 30% of patients had completely successful
treatment. Find out about ESWL research in the news.
How will I feel after ESWL?
Most patients experience discomfort for a day or two after ESWL. Generally, the
discomfort is at its worst the evening after surgery and then gradually lessens.
It is normal to see small amounts of blood in the urine for up to a month after
surgery. As with any procedure requiring general anesthesia, many patients also
find that they are more tired for up to a month after the procedure.
While most patients who undergo ESWL don't have complications, it's important to
report any of the following to your doctor:
Increasing pain - May be sign of an obstruction caused by kidney stones or
Heavy bleeding or blood clots - May be a sign of kidney injury
Fever - May indicate a serious kidney infection
Feeling unwell - It is normal to feel tired but it is not normal to feel sick
What follow-up is required after ESWL?
If you have a stent, your urologist will want to see you one week after the
procedure. An x-ray will be taken to see if the stone has cleared. If so, the
stent can be removed. If the stone fragments haven't cleared, x-rays may be
repeated every one to two weeks.
If you don't have a stent, an x-ray will be performed one month after the
procedure to see if the stone fragments have cleared.
In either case, if large stone fragments remain, further treatment with ESWL or
ureteroscopy may be recommended.
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Extracorporeal shock wave lithotripsy (ESWL) for kidney stones
Extracorporeal shock wave
lithotripsy (ESWL) uses shock waves to break a kidney stone into small pieces
that can more easily travel through the urinary tract and pass from the body.
You lie on a water-filled cushion, and the surgeon uses X-rays or ultrasound
tests to precisely locate the stone. High-energy sound waves pass through your
body without injuring it and break the stone into small pieces. These small
pieces move through the urinary tract and out of the body more easily than a
The process takes about an hour.
You may receive sedatives or local anesthesia.
Your surgeon may use a stent when your stones are larger than 2.5cm. A stent is
a small, short tube of flexible plastic mesh that holds the ureter open. This
helps the small stone pieces to pass without blocking the ureter.
What To Expect After Treatment
ESWL is usually an outpatient procedure. You go home after the treatment and do
not have to spend a night in the hospital.
It may take a few days or weeks for all the stone fragments to pass from your
body. You may have mild pain as the small fragments pass through the urinary
Why It Is Done
ESWL may be used on people with a kidney stone that is causing pain or blocking
the urine flow. Stones that are between 4mm and 2cm in diameter are most likely
to be treated with ESWL.
ESWL may work best for kidney stones in the kidney, not in the ureter. It may be
harder for ESWL to break up a stone that has moved into the ureter, although
this is still possible. Your surgeon may try to push the stone back into the
kidney with a small instrument (ureteroscope) and then use ESWL.
ESWL is usually not used if you:
Are pregnant. The sound waves and X-rays may be harmful to the fetus.
Have a bleeding disorder.
Have a kidney infection, urinary tract infection, or kidney cancer.
Have kidneys with abnormal structure or function.
How Well It Works
After ESWL, stone fragments usually pass in the urine for a few days and cause
mild pain. If you have a larger stone, you may need more ESWL or other
ESWL machines can be low-energy or high-energy. Low-energy machines cause less
discomfort, but you may need more treatments before the stone is broken into
pieces small enough to pass.
For 9 out of every 10 patients who have kidney stones smaller than 10mm-either
in the kidney or in the ureter-ESWL gets rid of all of the stone or leaves only
small fragments that don't cause any symptoms.1
ESWL does not replace the need for the preventive treatment of kidney stones,
such as drinking enough fluids so that you don't get dehydrated.
Complications of ESWL include:
Pain caused by the passage of stone fragments.
Blocked urine flow as a result of stone fragments becoming stuck in the urinary
tract. The fragments may then need to be removed with a ureteroscope.
Urinary tract infection.
Bleeding around the outside of the kidney.
What To Think About
ESWL does not successfully treat cystine kidney stones. These stones do not
break up easily.
ESWL is a safe procedure and may be used on children and on individuals with
only one working kidney. ESWL should not be used if you have a pacemaker unless
a cardiologist has determined it is safe.
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Extracorporeal shock wave lithotripsy (ESWL) versus percutaneous
nephrolithotomy (PCNL) or retrograde intrarenal surgery (RIRS) for kidney
BACKGROUND: Stones in the
urinary tract are a common medical problem in the general population. At
present, the great expansion in minimally invasive techniques has led to the
decrease in open surgery. Extracorporeal shock wave lithotripsy (ESWL) has been
introduced as an alternative approach which disintegrates stones in the kidney
and upper urinary tract through the use of shock waves. Nevertheless, as there
are limitations with the success rate in ESWL, other minimally invasive
modalities for kidney stones such as percutaneous nephrolithotomy (PCNL) and
retrograde intrarenal surgery (RIRS) are also widely applied. OBJECTIVES: To
evaluate the effectiveness and complications of ESWL compared with PCNL or RIRS
for managing kidney stones. SEARCH STRATEGY: We searched the Cochrane Central
Register of Controlled Trials (CENTRAL in The Cochrane Library), MEDLINE, EMBASE
and reference lists of articles without language restriction. SELECTION
CRITERIA: Randomised controlled trials (RCTs) assessing the use of ESWL compared
to PCNL or RIRS for kidney stone management. DATA COLLECTION AND ANALYSIS: Two
authors independently assessed all the studies for inclusion. Statistical
analyses were performed using the random effects model and the results expressed
as risk ratio (RR) for dichotomous outcomes or mean difference (MD) for
continuous data with 95% confidence intervals (CI). MAIN RESULTS: Three studies
(214 patients) were included, however results could not be pooled. Two RCTs
compared ESWL to PCNL. The success rate at three months for lower pole kidney
stones was statistically higher for PCNL (RR 0.39, 95% CI 0.27 to 0.56).
Re-treatment (RR 1.81, 95% CI 0.66 to 4.99) and using auxiliary procedures (RR
9.06, 95% CI 1.20 to 68.64) after PCNL were less compared to ESWL. The
efficiency quotient (EQ) in PCNL was higher than ESWL. Hospital stay (MD -3.30
days, 95% CI -5.45 to -1.15), duration of treatment (MD -36.00 minutes, 95% CI
-54.10 to -17.90) and complications were less for ESWL. One RCT compared ESWL
versus RIRS for lower pole kidney stones. The success rate was not significantly
different at the end of the third month (RR 0.91, 95% CI 0.64 to 1.30). AUTHORS'
CONCLUSIONS: Results from three small studies, with low methodological quality,
indicated ESWL is less effective for lower pole kidney stones than PCNL but not
significantly different from RIRS. Hospital stay and duration of treatment was
less with ESWL. More RCTs are required to investigate the effectiveness and
complications of ESWL for kidney stones compared to PCNL or RIRS.
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What are the side effects of
ESWL has a few side
effects, which may include the following:
most common side effect is pain caused by passing of fragments through the
if stone is not fragmented using correct parameters of shockwave pressure etc.
Large fragments can be formed and block the urinary tract. Thereafter blocking
the urine flow. Such blocked fragments need to be removed with a ureteroscope.
in the Urinary tract.
around the outside of the kidney.
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