Kidney Stone Treatment: Shock Wave Lithotripsy
What is shock wave lithotripsy?
Shock Wave Lithotripsy (SWL) is the most common treatment for kidney stones in the U.S. Shock waves from outside the body are targeted at a kidney stone causing the stone to fragment. The stones are broken into tiny pieces to allow them to pass. lt is sometimes called ESWL: Extracorporeal Shock Wave Lithotripsy.
These are what the words mean:
So, SWL describes a nonsurgical technique for treating stones in the kidney or ureter (the tube going from the kidney to the bladder) using high-energy shock waves. Stones are broken into "stone dust" or fragments that are small enough to pass in urine. lf large pieces remain, another form of lithotripsy can be performed.
When can SWL be used?
SWL works better with some stones than others. The size and shape of stone, where it is lodged in your urinary tract, your health, and your kidneys' health will be part of the decision to use it. Stones that are smaller than 2 cm in diameter are the best size for SWL.
SWL is more appropriate for some people than others. Because x-rays and shock waves are needed in SWL, pregnant women with stones are not treated this way. People with bleeding disorders, infections, severe skeletal abnormalities, or who are morbidly obese also not usually good candidates for SWL. lf your kidneys have other abnormalities, your doctor may decide you should have a different treatment. lf you have a cardiac pacemaker, a cardiologist will decide if you can have SWL.
Is it urgent that the patient be treated with a procedure like this?
lf the stone does not pass on its own, it will require treatment. lf you have an infection, severe pain, or if your kidney function is threatened, your doctors will act quickly. lf you only have one kidney or have had a kidney transplant, your stone will be treated more quickly. lf you have obstruction of the ureter or stones in both kidneys, your doctors will not wait to treat you.
What does the treatment involve?
You will be positioned on an operating table. Soft, gel-filled cushions will be placed on your abdomen and behind your kidney. The body is positioned so that the stone can be targeted precisely with the shock wave. About 2500-3000 shock waves are needed to crush the stone. The complete treatment takes about 30 minutes. There is a limit of 3000 shocks per treatment to prevent micro damage to the treated kidney. Often times one SWL treatment is all that is needed to treat a stone completely. But if the stone is large or extremely hard it may require further treatments.
Sometimes, doctors insert a tube via the bladder and thread it up to the kidney just prior to SWL. These tubes (called stents) are used when the ureter is blocked, when there is a risk of infection and in patients with intolerable pain or reduced kidney function.
After the procedure, you will usually stay for about an hour then be allowed to return home. You will be asked to drink plenty of liquid, strain your urine through a filter to capture the stone pieces for testing, and you may need to take antibiotics and pain meds. Some studies have reported stones may come out better if certain medications called calcium antagonists or alpha-blockers are used after SWL.
These meds, such as Flomax (Tamsulosin) or Rapaflo (Silodosin) relax the smooth muscle of the ureter, decreasing spasm, and allows a stone to pass much easier.
Does the patient need anesthesia?
Yes, even though there is no incision, it can be uncomfortable. Regional or general anesthesia is used to help the patient remain still, reduce any discomfort, and improves the breaking of the stone.
Does the patient need to be hospitalized?
Not usually. In most cases, lithotripsy is done on an outpatient basis.
What can the patient expect after treatment?
The recovery time is usually fairly brief. After treatment, the patient can get up to walk almost at once, Many people can fully resume daily activities within one to two days. Special diets are not required, but drinking plenty of water helps the stone fragments pass. For several weeks, you may pass stone fragments.
What will happen after I leave the surgical center?
After treatment, you will have blood in your urine and possibly abdominal pain or aching for several days. Other people experience a cramping pain as shattered stone fragments make their way out of the body. Oral pain medication and drinking lots of water will help relieve symptoms.
Sometimes, the stone is not completely broken up, or big pieces remain and additional treatments may be needed.
In an extremely rare instance, a more serious problem can occur, such as bleeding near the kidney or pieces of the stone blocking the flow of urine.
Call your doctor if you feel the strong need to urinate even after you empty your bladder or if you are in extreme pain even when taking your pain medicine.
What other treatment choices for kidney stones are available?
Drug treatment is being studied with such drugs as such as calcium channel blockers (nifedipine), steroids and alpha-adrenergic blockers. The idea is that the stone might be dissolved with medication. Other drugs such as K-citrate, thiazides or allopurinol are prescribed to prevent new stones from developing. Most doctors agree that more medical trials are needed.
When SWL is not appropriate or doesn't work, some people will need ureteroscopy, a technique that goes through the bladder to reach the stone or percutaneous nephrolithotomy, a technique that goes through a small incision created in your back. Some people, in extremely rare cases, even need open surgery, a technique that involves a larger incision in your abdomen. The medical terms for kidney stone surgery with an incision are ureterolithotomy or nephrolithotomy.
How successful is shock wave lithotripsy?ln those patients who are thought to be good candidates for this treatment, some 50-75% are found to be free of stones within three months of SWL treatment. The highest success rates seem to be in those patients with smaller stones, less than 1 cm.
After treatment, some patients may still have stone fragments that are too large to be passed. These can be treated again if necessary with shock waves or with another treatment.
What about stones in the ureter?
Most small ureteral stones, less than 1-5 mm in diameter, will pass on their own. lf they don't pass, then lithotripsy can be performed. Ureteral stones that occur near the kidney are usually treated by SWL. Ureteral stones that occur lower, near the bladder, may also be treated with SWL, but they often require ureteroscopy.
Shock Wave Lithotripsy (SWL) is the most common treatment for kidney stones in the U.S. Shock waves from outside the body are targeted at a kidney stone causing the stone to fragment. The stones are broken into tiny pieces to allow them to pass. lt is sometimes called ESWL: Extracorporeal Shock Wave Lithotripsy.
These are what the words mean:
- extracorporeal: from outside the body
- shock waves: pressure waves
- lithotripsy (the Greek roots of this word are "litho" meaning stone, "tripsy" meaning crushed)
So, SWL describes a nonsurgical technique for treating stones in the kidney or ureter (the tube going from the kidney to the bladder) using high-energy shock waves. Stones are broken into "stone dust" or fragments that are small enough to pass in urine. lf large pieces remain, another form of lithotripsy can be performed.
When can SWL be used?
SWL works better with some stones than others. The size and shape of stone, where it is lodged in your urinary tract, your health, and your kidneys' health will be part of the decision to use it. Stones that are smaller than 2 cm in diameter are the best size for SWL.
SWL is more appropriate for some people than others. Because x-rays and shock waves are needed in SWL, pregnant women with stones are not treated this way. People with bleeding disorders, infections, severe skeletal abnormalities, or who are morbidly obese also not usually good candidates for SWL. lf your kidneys have other abnormalities, your doctor may decide you should have a different treatment. lf you have a cardiac pacemaker, a cardiologist will decide if you can have SWL.
Is it urgent that the patient be treated with a procedure like this?
lf the stone does not pass on its own, it will require treatment. lf you have an infection, severe pain, or if your kidney function is threatened, your doctors will act quickly. lf you only have one kidney or have had a kidney transplant, your stone will be treated more quickly. lf you have obstruction of the ureter or stones in both kidneys, your doctors will not wait to treat you.
What does the treatment involve?
You will be positioned on an operating table. Soft, gel-filled cushions will be placed on your abdomen and behind your kidney. The body is positioned so that the stone can be targeted precisely with the shock wave. About 2500-3000 shock waves are needed to crush the stone. The complete treatment takes about 30 minutes. There is a limit of 3000 shocks per treatment to prevent micro damage to the treated kidney. Often times one SWL treatment is all that is needed to treat a stone completely. But if the stone is large or extremely hard it may require further treatments.
Sometimes, doctors insert a tube via the bladder and thread it up to the kidney just prior to SWL. These tubes (called stents) are used when the ureter is blocked, when there is a risk of infection and in patients with intolerable pain or reduced kidney function.
After the procedure, you will usually stay for about an hour then be allowed to return home. You will be asked to drink plenty of liquid, strain your urine through a filter to capture the stone pieces for testing, and you may need to take antibiotics and pain meds. Some studies have reported stones may come out better if certain medications called calcium antagonists or alpha-blockers are used after SWL.
These meds, such as Flomax (Tamsulosin) or Rapaflo (Silodosin) relax the smooth muscle of the ureter, decreasing spasm, and allows a stone to pass much easier.
Does the patient need anesthesia?
Yes, even though there is no incision, it can be uncomfortable. Regional or general anesthesia is used to help the patient remain still, reduce any discomfort, and improves the breaking of the stone.
Does the patient need to be hospitalized?
Not usually. In most cases, lithotripsy is done on an outpatient basis.
What can the patient expect after treatment?
The recovery time is usually fairly brief. After treatment, the patient can get up to walk almost at once, Many people can fully resume daily activities within one to two days. Special diets are not required, but drinking plenty of water helps the stone fragments pass. For several weeks, you may pass stone fragments.
What will happen after I leave the surgical center?
After treatment, you will have blood in your urine and possibly abdominal pain or aching for several days. Other people experience a cramping pain as shattered stone fragments make their way out of the body. Oral pain medication and drinking lots of water will help relieve symptoms.
Sometimes, the stone is not completely broken up, or big pieces remain and additional treatments may be needed.
In an extremely rare instance, a more serious problem can occur, such as bleeding near the kidney or pieces of the stone blocking the flow of urine.
Call your doctor if you feel the strong need to urinate even after you empty your bladder or if you are in extreme pain even when taking your pain medicine.
What other treatment choices for kidney stones are available?
Drug treatment is being studied with such drugs as such as calcium channel blockers (nifedipine), steroids and alpha-adrenergic blockers. The idea is that the stone might be dissolved with medication. Other drugs such as K-citrate, thiazides or allopurinol are prescribed to prevent new stones from developing. Most doctors agree that more medical trials are needed.
When SWL is not appropriate or doesn't work, some people will need ureteroscopy, a technique that goes through the bladder to reach the stone or percutaneous nephrolithotomy, a technique that goes through a small incision created in your back. Some people, in extremely rare cases, even need open surgery, a technique that involves a larger incision in your abdomen. The medical terms for kidney stone surgery with an incision are ureterolithotomy or nephrolithotomy.
How successful is shock wave lithotripsy?ln those patients who are thought to be good candidates for this treatment, some 50-75% are found to be free of stones within three months of SWL treatment. The highest success rates seem to be in those patients with smaller stones, less than 1 cm.
After treatment, some patients may still have stone fragments that are too large to be passed. These can be treated again if necessary with shock waves or with another treatment.
What about stones in the ureter?
Most small ureteral stones, less than 1-5 mm in diameter, will pass on their own. lf they don't pass, then lithotripsy can be performed. Ureteral stones that occur near the kidney are usually treated by SWL. Ureteral stones that occur lower, near the bladder, may also be treated with SWL, but they often require ureteroscopy.
Ureteroscopy
|
What is ureteroscopy?
It is a procedure in which a small scope is inserted into the bladder and ureter and it is used to diagnose and treat a variety of problems in the urinary tract. For ureteral stones, it allows the urologist to actually look into the ureter, find the stone and remove it. The surgeon passes a tiny wire basket into the lower ureter via the bladder, grabs the stone and pulls the stone free. This is an outpatient procedure with or without a stent inserted (a tube that is placed in the ureter to hold it open). What is a stent? Ureteral stents are soft, hollow, plastic tubes placed temporarily into the ureter to allow drainage around a stone or or to speed healing after a stone surgery. When are they needed? Stents are used for various reasons in patients with kidney stones. They may be placed in patients to help reduce pain from a stone, when infection is present to allow drainage, or when a stone is preventing a kidney from working adequately. Stents are also commonly placed after surgeries for stones, as in ureteroscopy, to allow healing and prevent swelling of the ureter. How is a stent placed? Stents are placed during surgery by sliding them over a soft “guidewire” which is placed up the ureter, which is the tube draining the kidney. How is a stent removed? Stents can be removed in two different ways. Sometimes, a string is left attached to the end of the stent. This string is allowed to come out of the patient’s urethra, the tube where he or she urinates. The string can be used to pull on the stent and remove it. In cases where a string is not left attached, a small camera called a cystoscope is inserted into the patient’s urethra after numbing medication has usually been administered. The cystoscope is then advanced into the bladder and the stent is grasped with an instrument to be removed. How long can a stent stay in? In general, most stents are left in for a very short time. But if they do need to be left in they should only remain in for no longer than 3 or so months. If a stent is left in too long, it can form stones directly on it, making removal difficult. What are the symptoms of having a stent? While some patients with stents have minimal discomfort related to them, other patients will report symptoms that can range from being annoying to being severe enough that the stent has to be removed. These symptoms can include:
Is there anything that can help reduce the discomfort of a stent? Different medications may be given to help reduce the discomfort of a stent. The most effective appears to be those from the alpha blocker class of medications including tamsulosin (Flomax) and Alfuzosin (Uroxatral). Traditional pain medications are also less successful at reducing stent discomfort. Hasn’t anyone come up with a better stent? Research into improving stent designs will hopefully reduce the discomfort associated with them. Innovative stent designs currently being tested include stents embedded with medications to reduce discomfort and stents that dissolve by themselves. |
|