What Is the Main Idea?

Treatment of large ureter stones depends on where they are located in the ureter. In the research article “Impact of Stone Localization before Emergency Ureteral Stenting on Further Stone Treatment”, published in the journal Urologia Internationalis, the authors describe how emergency ureteral stenting can change the location of a ureter stone, potentially changing the treatment approach that will be most effective.

What Else Can You Learn?

In this blog post, ureter stones and their symptoms are discussed. Ureteral stents and the different types of treatment for large ureter stones are also discussed.

What Are Ureter Stones?

Ureter stones (also known as ureteral stones) are essentially kidney stones that have moved from the kidney into the ureter (the tube that connects the kidney to the bladder, which is about the same diameter as a small vein). The main roles of the kidneys are removing waste products from the blood by filtering it, and making urine so that the waste products can be passed out of the body (excreted). Urine contains many dissolved minerals and salts. If they are present at high levels they can start to form crystals that may clump together into hard, stone-like lumps. Some are small enough to pass along the ureter and out of the body unnoticed, but larger ones may become stuck and block the flow of urine to the bladder.

What Are the Symptoms of Ureter Stones?

If a ureter stone is small it is unlikely to cause any symptoms, but for larger kidney and ureter stones the most common symptom is pain. The pain can range from mild and dull to intense and unbearable, and can radiate to other areas. People with ureter stones may also experience a need to urinate more frequently and pain or a burning sensation when they do. There may be blood in their urine, which gives it a pinkish color, and they may experience nausea and vomiting. If a person experiences fever or chills they may have a urinary tract infection (UTI). UTIs can spread to the kidney and cause a type of sepsis called “urosepsis”. It is important that people seek prompt medical treatment if they have any of the above symptoms, but sepsis can be life-threatening and is a medical emergency.

How Are Ureter Stones Treated?

The type of treatment recommended depends on the size, location and composition of the stones. If they are small enough, they can usually be encouraged to pass out of the body by the person drinking up to 3 liters of water per day. If they are larger, they may need to be removed by surgery.

  • Extracorporeal shock wave lithotripsy (ESWL) is a treatment method that uses X-rays or ultrasound from outside the body to break down the stones into particles so that they can pass out in the urine (“lithotripsy” is derived from the Greek words meaning “breaking stones”).
  • Percutaneous nephrolithotomy tends to be used if stones are large or located where it’s difficult for them to be treated by ESWL. A thin telescopic device called a nephroscope (a type of endoscope that is specially designed for looking inside the kidney) is inserted into the kidney through a small incision in the person’s back. Once the stone is located, it is either removed or broken down.
  • Uteroscopy involves a type of endoscope called a uteroscope being passed through the urethra (the tube that your urine passes through when it leaves your bladder and passes out of the body), into your bladder and then up into your ureter. Once located, the stone is either removed or broken down using laser energy or shock waves. It can only be performed if the stone is located in the lower half of the ureter.

What Is a Ureteral Stent?

If a person’s ureter is blocked by a ureter stone their urine is unable to drain from the kidney to the bladder properly. This causes the affected kidney to fill with urine and swell, and if the stone blocks the ureter for a long period of time the kidney can become damaged. To prevent this, a ureteral stent (a thin tube that’s placed inside the ureter) can be placed with one end inside the kidney and the other directly inside the bladder so that the urine can flow from one to the other. Emergency insertion of a ureteral stent is often used if a patient is experiencing severe pain and/or has developed urosepsis. However, this can change the location of the stone that’s causing the problem, which potentially changes how it needs to be treated.

What Did This Study Show?

The authors retrospectively analyzed stone locations in 649 patients who were treated by uteroscopy by looking at their medical records. For 469 patients, the locations of the ureter stones were checked both before emergency stent insertion and uteroscopy were performed. They found that around half (45.6%) of the patients had ureter stones that were accidentally relocated after the insertion of a stent, with around one-quarter (25.4%) experiencing displacement of their stones back into the kidney. Relocation of stones that were initially in the part of the ureter that connects with the kidney (known as the “proximal” ureter) was particularly likely. The authors note that the relocation of ureter stones affects the type of surgery that is most likely to be effective, and suggest that carrying out imaging to double-check the location of stones before surgical treatment may help patients to avoid more complex stone treatment in the future.

Take-Home Message

Neither national nor European guidelines for the diagnosis and therapy of ureter stones currently recommend that imaging to determine stone location be repeated after the insertion of a ureteral stent. Decision-making regarding whether to repeat imaging or the type of surgery depends on the opinions of both the surgeon and the patient. Patients with ureter stones who receive a ureteral stent may wish to discuss repeat imaging with their medical team before a final decision is made about the type of surgery that will be performed.

Note: This post is based on an article that is not open-access; i.e., only the abstract is freely available.

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