Extracoporeal Shock Wave Lithotripsy (ESWL)
Indications For the Treatment of Kidney Stones
Not all kidney stones need treatment. If a stone is causing no symptoms, is not having any effect on the urinary tract, and is not likely to cause problems in the future, it may be left untreated and followed for future changes. If a stone is causing no symptoms and is small enough to probably pass spontaneously if it moves, it may be safely observed and not treated. Most stones measuring 5 millimeters (1/5th inch) or less fit in this category. If a stone is causing symptoms but is small enough to probably pass soon, conservative observation is indicated.
.If a small stone is causing symptoms and is not making progress toward passing over a period of time, treatment is indicated.
.Stones in the urinary tract causing pain, obstruction, infection, or visible blood in the urine should be treated (unless the stone will pass spontaneously soon). If a stone is being followed conservatively for growth, and the size reaches 5 millimeters or greater, treatment is indicated. Some jobs require the worker to be free of stones (e.g., airline pilots), and some people travel to or live in remote areas where there is scarce medical care. Stones in these patients should be treated.
Contraindications to Lithotripsy.
There are several reasons why lithotripsy may not be safe or indicated.
• It is not safe to the fetus to treat a pregnant woman.
• Patient size and stone location affect whether or not a stone can be treated by lithotripsy. Some patients may be too large to be effectively treated.
• Stones must be within range and visible for successful ESWL.
• Blood clotting must be normal at the time of treatment.
• Please carefully read the medication and dietary supplement list here. Please review any intake with your referring physician.
Conservative Treatment This involves following the patient at periodic intervals with a progress history, physical, urinalysis, and imaging study.
Endoscopic Treatment This involves the passage of a ureteroscope through the bladder into the ureter until the stone is in view. The stone can then be broken into small pieces or removed intact with special instruments. Energy sources used to break up the stone include laser, ultrasound, mechanical, and electrohydrolic energy. New energy sources are constantly being developed.
Percutaneous Lithotripsy Under anesthesia, a scope is passed through the side, under the ribs, into the kidney. The stone is fragmented under direct vision by various energy sources. This is the preferred treatment for many very large stones.
Extracoporeal Shock Wave Lithotripsy (ESWL)
This treatment involves the creation of a shock wave by a special machine called a lithotripter. The shock wave is focused on the stone, passing harmlessly through body tissue until it hits the stone, causing fragmentation. The goal is to create small enough fragments that can be passed spontaneously. How well the stone breaks up depends upon the location, size, and density (hardness) of the stone. With some stones, there is a higher ESWL success rate if it can be moved from one location to another. This procedure is called a stone dislodgement and is generally done under anesthesia just prior to lithotripsy. Lithotripsy is the only noninvasive method of treating kidney stones.
This treatment involves making an incision into the body, opening the urinary tract, and removing the stone. This is a very reliable method of stone treatment but is the most invasive and involves the longest recovery time. Inpatient hospitalization is usually required for several days, and the patient may not be able to return to work for several weeks.
Some stones may require more than one type of treatment. Common combinations include percutaneous treatment followed by shock wave lithotripsy for any retained fragments. Shock wave lithotripsy or percutaneous nephrostolithotomy can be followed by ureteroscopic removal of a stone fragment that has moved from the upper urinary tract into the lower ureter where it can be reached by a ureterscope and further fragmented.
A note on the use of stents prior to ESWL
There are times when it is necessary to insert a hollow plastic tube or J-J stent into the urinary tract prior to lithotripsy. One end of the stent coils in the kidney, and the other coils in the urinary bladder. If the urologist at the Center inserts a J-J stent, the patient and the referring urologist will be informed of its placement. It is absolutely mandatory that this stent be removed by the referring urologist. Stents that are allowed to remain in place for an extended period can become covered with calcium and require other surgical procedures to remove them. Sometimes the urologist inserting the stent will choose to leave a string on the stent leading outside the body. This makes it easier to remove at a later time by the referring urologist.
Surgery - Preoperative
Once a patient has been diagnosed with a kidney stone, there is a process to be followed to determine what treatment is best. If a doctor feels that surgical treatment is probably necessary, they are asked to send to the Center xrays or imaging studies from the patient, a medical history and physical exam, insurance information; and patient information including name, address, and telephone number so the patient can be contacted. The Center then reviews the medical information, verifies the insurance coverage, and the urologists at the Center review the case and studies making a recommendation as to the best treatment. We do have a procedure for handling cases where there is no insurance coverage.
There is a mandatory second opinion to verify the proposed treatment. If the case is to be treated at the Center, the case is then scheduled with the patient and referring doctor's office. Once scheduled, the patient is given specific instructions as to diet, when to stop eating and drinking, and what medications to take and what not to take. (See the restricted Medication list) The patient is told when to appear at the Center for treatment. If these instructions are not followed, the case may be cancelled. The patient and referring urologist are also told what laboratory tests are necessary before treatment. Depending upon the patient's medical condition the tests required may be minimal or extensive and may include blood tests, urine tests, x-rays, and cardiograms. These tests should be done 1-2 weeks before surgery and should be sent to the Center. Our staff reviews all the information 1-2 days before treatment to insure that treatment will be safe.
Surgery - Perioperative
The patient is asked to arrive at the Center 1 to 1-1/2 hours before surgery is to start. The patient is prepared for surgery, an IV is started, and informed consents are done by the treating anesthesiologist, urologist, and nurse. Postoperative instructions are given. Each treatment takes an average of 1 to 1-1/2 hours. The patient must recover from the procedure in the recovery room before discharge. Total time at the Center is usually 4-5 hours. The patient must arrange to have a responsible adult transport them at discharge. No patient is allowed to leave alone.
Surgery - Postoperative
After discharge, the patient's referring urologist resumes the patient's care. Usually, normal diet, normal physical activity, normal sexual activity can be resumed 24 hours after surgery. If the patient has questions or problems, they are to call the referring urologist. All patients are asked to see the referring urologist one to two weeks after surgery. The followup visit is extremely important to determine if the procedure was successful and to check for any problems. More than one postoperative visit may be necessary.
The postoperative visit is a good time to talk with the urologist about how to prevent future stones. The referring urologist is required to send a report back to the Center giving the outcome of treatment. If a stent is present at discharge, this must be removed in a timely fashion, usually within 4-6 weeks of being put in. If not removed, severe complications can occur, including the rapid formation of new stones. If the patient is a "stone former," it is advisable to see the urologist every year in the future to check for the silent formation of new stones.
Medications to Avoid Before Lithotripsy
To minimize the risk of bleeding after lithotripsy, blood clotting must be normal before treatment. There are a number of medications, including commonly taken dietary supplements, that interfere with blood clotting. These medications must be stopped for some time before treatment. The Kidney Stone Center must know all the medications you are taking, including any vitamins or dietary supplements, and will advise you on what to stop, and for how long. For questions about specific medications, please contact us.
Kidney Stone Prevention
Long term urinary stone management begins with prevention, and prevention typically entails minor lifestyle and dietary changes. As with any preventable medical condition, treatment should be viewed as a measure of last resort.
Diagonistic Testing Diagonistic laboratory procedures can be useful in formulating specific dietary suggestions as well as indicating appropriate medications and other courses of action. Some of these are described here.
Analysis of the passed stone material will identify kidney stone type as one of the following:
• calcium oxalate (most common)
• uric acid (usually not visible by X-ray)
• struvite (usually associated with infection)
• cystine (very hard and difficult to fragment)
Twenty-four hour urine collection is employed to measure total volume, levels of calcium, oxalate, uric acid, citrate, magnesium, sodium, phosphate, and pH.
Blood testing provides measurement of serum calcium, uric acid, phosphate, potassium, chloride, bicarbonate, albumin, and creatinine levels. Elevated serum calcium may signal parathyroid dysfunction and require serum parathyroid hormone level.
General Guidelines One should typically maintain a 24 hour urine volume of at least 2 quarts. This may require drinking up to 3 to 3-1/2 quarts of fluids per day. High urine flow helps prevent stones by washing harmful crystals from the urinary system.
Low protein, low salt, and no added dietary calcium may also lessen the likelihood of stones. This means cutting back on meat, fish, and chicken. Diets low in salt may help decrease urinary calcium excretion. There may be benefits from avoiding grapefruit juice and large portions of high oxalate foods such as spinach, sweet potatoes, rhubarb, okra, beets, beet greens, and refried beans.
Specific Therapy and Medication Treatment for calcium stones with a thiazide diuretic will decrease urinary calcium excretion. Low potsassium associated with taking thiazides is treated by adding potassium dietary supplement.
Treatment for uric acid stones also calls for low protein diet to reduce purines and urinary uric acid. Maintaining an alkaline urine is mandatory. Allopurinol may be added to correct high urinary uric acid.
Treatment for cystine stones requires keeping urine output at 2 to 3 quarts daily. Decreasing dietary protein and salt is advised. Cystine crystal formation is inhibited in alkaline urine. Potassium citrate may be added for alkalinization.
Treatment for struvite stones requires keeping the urine bacteria free. Long term antibiotics may be necessary to achieve this.