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Identifying Kidney Stones

There are several types of kidney stones. Your kidney stone’s size and shape determine whether it is likely to pass by itself. Knowing a stone’s composition helps your doctor find its cause. Then he or she can suggest the best treatment.


A stone may be as small as a grain of sand. Or it may be as large as a golf ball. Small stones may pass out of the body when you urinate.


Small smooth, round stones may pass easily. Jagged-edged stones often lodge inside the kidney or ureter. Staghorn stones can fill the entire kidney.


Most stones are calcium oxalate, a hard compound. Stones made of cystine or uric acid, or caused by infection, are less dense. Stones often contain more than one chemical.


Your kidneys filter your blood and release chemicals into the urine. If certain chemicals build up in the kidneys, they can form a stone.

Treating Your Stones

You and your doctor will work together to form a treatment plan. Your doctor may suggest that you let your stone pass naturally. Or you may manage it with medications. SWL(shock wave lithotripsy) or surgery may also help. And you will be told how you can help prevent kidney stones in the future.

Shock Wave Lithotripsy

Passing a kidney stone can be very painful. Shockwave lithotripsyis the fragmentation of kidney stones (typically stones located in the kidney and/or upper ureter) by the administration of shockwaves generated outside of the body.   The electrical discharge of energy in a special machine generates these high energy amplitudes, or shockwaves.  These shockwaves, which behave like acoustic waves, are then focused upon a patient’s stone(s).   Shock wave lithotripsy is a treatment that helps by breaking the kidney stone into smaller pieces that are easier to pass through the urinary system. This treatment is also called extracorporeal shock wave lithotripsy (ESWL).Lithotripsy takes about an hour. It’s done in a hospital, lithotripsy center, or mobile lithotripsy van.

Shockwave lithotripsy is generally used for stones higher up (in the kidney or first part of the ureter) in the urinary system.   Sometimes, stones that were higher up in the urinary system can move lower down into the lower ureter on the day of treatment.  Should this happen, the surgeon may elect to perform an ureteroscopy with laser lithotripsy as opposed to a shockwave lithotripsy to treat that stone.  You will likely go home the same day.

Pre-Shockwave Lithotripsy Information

  • There are some steps that need to be performed in order to maximize the chance for a successful and safe procedure.

  • Shockwave lithotripsy is absolutely contraindicatedin any patient with any type of inherent or drug-induced bleeding disorder.   Therefore, it is imperative that a patient not have taken/received any aspirin, ibuprofen, Motrin, Advil, Toradol/Ketorolac, Coumadin/Warfarin or any other type of blood thinning products for at least 7 days prior to the procedure. If you are taking or have recently been taking any of these types of medications be sure to inform your urologist.  Shockwave lithotripsy is also contraindicated in any pregnant patients.  Therefore, on the day of treatment, if you are a woman of childbearing age, a pregnancy test will be performed.  If there is any chance that you think you might be pregnant, please inform your physician/physician's nurse immediately.  Finally, shockwave lithotripsy is also contraindicated in any patient with a urinary tract infection.  Therefore, if your physician feels you might have a urinary tract infection, he/she may delay the surgery until they feel comfortable there is no infection.

  • Like with any surgery, sometimes blood work and an EKG is needed prior to proceeding with surgery.   Your urologist/urologist nurse will let you know if they feel blood work and/or an EKG are needed.

  • One of the most important parts about shockwave lithotripsy is being able to focus the acoustic waves directly onto the stone(s). To be able to focus/target these waves accurately, the stone must be clearly visible on plain film x-rays.   Sometimes stool and/or intestinal gas can obscure the stone(s) on x-rays.  To maximize the chance of being able to see the stone, it is best, time permitting, that a patient performs a bowel prep the day prior to surgery.

Bowel Preparation

  • A typical bowel preparation for shockwave lithotripsy involves a CLEAR LIQUID DIET THE ENTIRE DAY PRIOR TO THE PROCEDURE, NO SOLID FOOD THE DAY PRIOR TO THE PROCEDURE.  Starting around 11a.m., take two 5mg bisacodyl tablets.  Take these tablets with at least 8 ounces (240ml) of water.  Even more water would be better.  Generally, you will have a bowel movement within 6-12 hours.  The bowel preparation may lead to mild dehydration, so be sure to drink plenty of fluids.  And remember, unless specifically instructed otherwise, DO NOT EAT OR DRINK ANYTHING AFTER MIDNIGHT on the day before surgery.

  • Some patients, who may have more problems with constipation, may be asked to take one bottle (8oz) of magnesium citrate, instead ofthe two 5mg bisacodyl tablets.  Your urologist/urologist nurse will inform you, if your urologist feels you may be better suited by taking the magnesium citrate instead of the two bisacodyl tablets.

During the Procedure

  • You receive medication to prevent pain and help you relax or sleep during lithotripsy. Once this takes effect, the procedure will start.

  • A stent (flexible tube with holes in it) may be placed into your ureter (the tube that connects the kidney and the bladder). This helps keep urine flowing from the kidney.

  • Your healthcare provider then uses x-ray or ultrasound to find the exact location of the kidney stone.

  • Sound waves are aimed at the stone and sent at high speed. If you’re awake, you may feel a tapping as they pass through your body.

Energy waves strike the stone, which begins to crack.

The stone crumbles into tiny pieces.

After the Procedure

  • You’ll be monitored in a recovery room for about 1–3 hours. Antibiotics and pain medication may be prescribed before you leave.

  • After shockwave lithotripsy, it is not uncommon to experience bruising of the skin and blood in the urine. This is a normal response. Rarely, the blood in the urine can be in the amount were it forms clots and difficulty voiding. You should inform your urologist immediately if at any point after the surgery you feel you cannot urinate. You should refrain from any exercise, strenuous activity or heavy lifting until after your urine is clear (free of blood) for 24 hours. Rarely, shockwave lithotripsy can lead to significant bleeding within the kidney or around the kidney. This may or may not be associated with significant blood in the urine. Severe back pain not readily controlled with pain pills, dizzyness/lightheadness, feeling overwhelming tired or being significantly pale, should prompt you to contact your urologist immediately.

  • Sometimes, a ureteral stent is placed to help prevent the passing kidney stones from blocking the kidney and causing severe pain.  When the kidney is blocked, severe back pain with radiation to the front can develop.  This pain is called renal colic.  Ureteral stents are oftentimes placed for larger stones, to help prevent the stone pieces generated from the fragmentation from blocking the kidney as they pass down the ureter.  Unfortunately ureteral stents themselves can cause some discomfort.  The stents can cause urinary frequency and urgency.  In addition, they can typically cause discomfort in the mid back/kidney area with urination.  Ureteral stents usually are removed within a couple of weeks after placement. Stents should be removed (or sometimes exchanged) within 2 months, or they may become calcified themselves – a difficult problem to correct.

  • You’ll have a follow-up visit in a few weeks. If you received a stent, it will be removed. Your doctor will also check for pieces of stone. If large pieces remain, you may need a second lithotripsy or another procedure.


Possible Risks and Complications

  • Infection

  • Bleeding in the kidney

  • Bruising of the kidney or skin

  • Obstruction (blockage) of the ureter

  • Failure to break up the stone (other procedures may be needed)

Passing the Stone

It can take a day to several weeks for the pieces of stone to leave your body. Drink plenty of liquids to help flush your system. During this time:

  • Your urine may be cloudy or slightly bloody. You may even see small pieces of stone.

  • You may have a slight fever and some pain. Take prescribed or over-the-counter pain medication as instructed by your healthcare provider.

  • You may be asked to strain your urine to collect some stone particles. You should bring these fragments with you to your follow-up appointment.  These pieces can be sent to the lab to determine what type of stone you have formed. Of course, if your doctor already knows what type of stones you form from previous stone analysis, he/she may not need you to collect your stone fragments.

  • Fragmented stones can have trouble passing through the narrowest part of the ureter. This is located as the ureter enters the bladder.   If stones get stuck in this part of the ureter, you may experience renal colic (“kidney stone pain”) and urinary frequency and urgency.  Infrequently, your urologist may have to perform surgery to remove these stone pieces and/or place a ureteral stent if no stent was placed previously.  However, usually these stone pieces will pass.  Sometimes a medication such as Flomax can help pass ureteral stone pieces. Your urologist does/doesnot think Flomax may help you. (Flomax is a medication designed to help men with prostate problems urinate. It works by relaxing the muscle around the prostate. It has also been shown to relax the muscles around the ureter and help ureteral stones pass.)

  • Inversion therapy: Stones located in different parts of the kidney drain differently. Stone fragments in the upper part of the kidney generally drain better. Stones in the lower (more dependent) part of the kidney do not drain as well. For stones in the lower part of the kidney, inversion therapy has been demonstrated to help pass stone fragments. Inversion therapy helps by moving the stone fragments out of the lower pole of the kidney, and into the renal pelvis where they have a greater chance of passing down the ureter. Inversion therapy involves drinking about 20 oz of water and then 15 minutes later, trying to maintain a head down position for a couple of minutes. A head down position is any position where the head is lower then the hips. One easy way to accomplish this is to lie on a bed with only your legs and hips on the bed. Then, you bend forward at the waist with the remainder of your body (the head, chest, stomach) lying off the edge of the bed and down towards the floor. Imagine lying on your bed and trying to find some shoes you have left underneath your bed. If you have lower pole stone fragments you should try to perform inversion therapy twice a day if possible.   In addition, percussion therapy can also help remove/drain lower pole stone fragments.  Percussion therapy involves having someone gentle hit you in the mid back area on the side of your treatment when you are in the inversion position.  Your urologist may or may not think inversion and percussion therapies may help you pass stone fragments.

Call Your Doctor If You Have:

  • Fever over 100.4°F

  • Heavy bleeding

  • Pain that doesn’t go away with medication

  • Upset stomach and vomiting

  • Problems urinating


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