Treatment options for kidney stones

Photo of two men sitting in a park (PantherMedia / william87) Small kidney stones often pass out of the body on their own. As long as they don't cause severe pain or complications, treatment isn’t necessary. Larger kidney stones usually need to be treated. Depending on how large the kidney stones are and where they're located, they can be destroyed or removed using an endoscope (a flexible tube with a light and camera at the end of it).

Most kidney stones with a diameter of less than 5 millimeters, and about half of all stones between 5 and 10 millimeters, pass out of the body on their own. These smaller kidney stones are often flushed out in the urine after one or two weeks.

If it’s thought that a stone will probably be flushed out without any treatment, doctors generally recommend waiting. If the kidney stone causes pain as it travels through the ureter (tube that runs from a kidney to the bladder), painkillers like ibuprofen or diclofenac can provide relief.

Larger stones that cause problems will usually have to be broken up or surgically removed. That needs to be done if

  • the stone isn't passed within four weeks,
  • there are complications,
  • it causes severe colic (pain), or
  • the stone is larger than 10 millimeters in diameter.

Uric acid stones can sometimes be dissolved using medication.

Is medication effective for treating kidney stones?

Making it easier to pass the stone

Alpha blockers are believed to make it easier for the stones to pass out of the body. They relax the muscles in the lower part of the bladder. Alpha blockers are medications used to treat benign prostatic hyperplasia (BPH – an enlarged prostate). They have not been approved for the treatment of kidney stones. But particularly the alpha blocker tamsulosin is sometimes used off-label.

According to current research, alpha blockers can help pass stones. An analysis of 67 studies showed this to be true for kidney stones that are about 5 to 10 millimeters in diameter.

  • Without alpha blockers, the stones passed within four weeks in about 50 out of 100 people.
  • With alpha blockers, the stones passed within four weeks in about 73 out of 100 people.

So the treatment helped 23 out of 100 people to pass the stone.

Temporary side effects of alpha blockers include low blood pressure, dizziness, and tiredness. In one large study, 4 out of 100 people stopped their treatment early due to such side effects. In 5 out of 100 men, the drugs also temporarily caused retrograde ejaculation ("dry orgasm"). This is where no semen, or much less than usual, leaves the penis. Instead, the semen flows into the bladder.

Dissolving uric acid stones

Uric acid stones are the only type of kidney stones that can sometimes be dissolved with the help of medication. Alkaline citrate salts or sodium bicarbonate are considered for this purpose, and sometimes allopurinol. Alkaline citrate salts and sodium bicarbonate increase the pH level of the urine, and allopurinol lowers the level of uric acid. Drinking a lot of water helps to increase the effect of the medication: The more urine there is, the better the uric acids can dissolve. If you have a urinary tract infection (UTI), it isn't possible to treat the uric acid stones with medication.

If the treatment is successful, surgery isn't needed to remove the stones. But it’s not clear how effectively medication can dissolve uric acid stones. There hasn’t been any high-quality research on this.

How are kidney stones removed?

If the stones don’t pass out of the body on their own, they can be broken up with ultrasound shock waves or removed in a minor surgical procedure. The most suitable method will mainly depend on how big the stones are, where they are, and what they are made of.

Ultrasound shock wave therapy

In ultrasound shock wave therapy, sound waves are used to break up the stones. The stone fragments are then flushed away in the urine. This treatment is also referred to as extracorporeal shock wave lithotripsy (ESWL). A machine is used to send sound waves from outside of the body through the tissue to the stones. Shock wave therapy typically takes about 30 to 60 minutes when treating simple kidney stones (without complications). It can often be done without having to spend the night in hospital. The treatment outcome can be checked using ultrasound or x-ray scans.

Shock wave therapy is especially suitable for kidney stones that are smaller than 20 millimeters in diameter. If the stones are in the upper third of the ureter, they shouldn’t be any bigger than 10 millimeters, though.

Illustration: During shock wave therapy – as described in the articleDuring shock wave therapy

Removing stones through an endoscopic procedure

There are two common methods for removing stones through a surgical procedure: ureterorenoscopy (URS) and percutaneous nephrolithotripsy (PCNL or PNL).

  • Ureterorenoscopy (URS): In this method, tiny instruments are moved through the urethra (the passageway that urine flows out of) and bladder with the help of an endoscope, and pushed up into the ureter where the stone is. There the stone is either broken up mechanically or using a laser so that the pieces can be flushed out in the urine or removed using the endoscope. URS is used for stones that are bigger than 10 millimeters in diameter and are in the middle or lower third of the ureter. Kidney stones up to 20 millimeters in diameter are often removed using URS.
  • Percutaneous nephrolithotripsy (PCNL): In this method, an endoscope is moved into the renal pelvis or the kidney through a small cut made on your back. There the stones can also be either broken up mechanically or with a laser. Tiny forceps are used to remove the pieces of the kidney stones. This method is mainly used to treat kidney stones greater than 10 millimeters in diameter.

General anesthesia and a short hospital stay are necessary for both of these approaches.

Nowadays, more major surgery is only very rarely needed to remove kidney stones.

How do the advantages and disadvantages of the different treatments compare?

Various treatments can be considered for kidney stones, depending on the situation. Only the following treatments have been compared in studies, though.

Shock wave therapy and percutaneous nephrolithotripsy (PCNL) for the treatment of kidney stones

Some small studies have tested shock wave therapy and PCNL. In comparison, PCNL was more successful than shock wave therapy. The following results were observed three months after treatment:

  • 44 out of 100 people didn't have any kidney stones after having shock wave therapy.
  • 95 out of 100 people didn't have any kidney stones after having PCNL.

But the outcome of shock wave therapy depends on the size, position and composition of the kidney stones: Stones with a diameter of less than 10 millimeters are easier to break up. This is more difficult if the stones are larger or harder. Stones in the lower part of the kidney are also harder to treat with shock wave therapy.

Shock wave therapy carries the risk of leaving behind kidney stone fragments that are too big to pass through the ureter. These fragments might get stuck in the ureter on their way to the bladder. Additional treatment is then needed. To prevent this from happening, a small tube (called a ureteral stent) is sometimes temporarily placed in the ureter. The stone fragments can then flow out smoothly.

The shock waves can be painful, so painkillers are given before the treatment. They can also damage the kidney tissue, which may lead to bleeding, for example. But serious complications and long-term damage are rare.

Percutaneous nephrolithotripsy (PCNL) can also lead to bleeding. A blood transfusion may then be needed sometimes. Fever and wound infections might also occur after this operation. In rare cases, other organs may be damaged. And you have to stay in hospital for a few days too.

Because only a few small studies have compared these two treatments, there are no exact figures on the likelihood of complications. But shock wave therapy is still considered to be the more gentle treatment.

Shock wave therapy and ureterorenoscopy (URS) for the treatment of ureteral stones

Kidney stones that have traveled to a ureter are called ureteral stones. These stones are typically treated using shock wave therapy or endoscopic surgery through the bladder and ureter. Several studies have compared the rates of success for these two treatments when used to remove ureteral stones. The results show that most stones can be successfully treated using shock wave therapy. But the rate of success for ureterorenoscopy was slightly higher:

  • 78 out of 100 people who had shock wave therapy no longer had any kidney stones after the treatment.
  • 93 out of 100 people who had an endoscopic treatment no longer had any kidney stones afterwards.

So people are more likely to need further treatment after shock wave therapy.

The advantage of shock wave therapy is that it's less likely to lead to complications than URS is: Complications occurred in 19 out of 100 people who had endoscopic procedures, but only in 10 out of 100 people who had shock wave therapy.

The possible complications of ureterorenoscopy include bleeding and urinary tract infections (UTIs) like cystitis. The ureter may be damaged during the procedure as well. But serious complications are generally rare.

People who had shock wave therapy were much less likely to need supportive treatments afterwards, such as ureteral stents or a temporary artificial opening (stoma) in the kidney. But pain was more common during and after treatment. Bleeding and infections also seem to be more common following shock wave therapy.