Understanding Ureteral Stricture and Metal Stenting
Metal stents are small, expandable tubes made of flexible, biocompatible metal alloys such as nitinol or a nickel-titanium alloy. They are inserted into the ureter to help maintain its patency when a stricture (narrowing) is present, allowing urine to flow freely from the kidney to the bladder.
What are the benefits of using metal stents compared to traditional polymer stents?
Metal stents offer several advantages over traditional polymer stents, such as:
Longer lifespan: Metal stents can remain in place for a longer duration, reducing the need for frequent replacements.
Reduced risk of encrustation and blockage: Their smooth surface makes them less prone to the buildup of mineral deposits.
Better radial force: They exert a more consistent outward pressure, effectively keeping the ureter open.
Are metal stents suitable for both benign and malignant ureteral strictures?
Yes, metal stents can be used for both benign and malignant ureteral strictures. However, the specific type of stent recommended may vary depending on the underlying cause of the stricture and individual patient factors.
What are the potential risks and complications associated with metal stents?
While generally safe, metal stents can have potential risks and complications, including:
Stent migration: The stent may move from its intended position.
Urinary tract infections (UTIs)
Obstruction: The stent itself may become blocked by blood clots or tissue growth.
Fistula formation: In rare cases, a connection may form between the ureter and other organs, such as the bowel or blood vessels.
What factors might influence the success rate of metal stents?
Several factors can influence the success rate of metal stents, including:
Length and location of the stricture: Longer strictures, especially those located in the upper ureter, may have lower success rates.
Prior radiation therapy: Radiation can cause tissue damage and fibrosis, making stent placement more challenging.
History of percutaneous nephrostomy (PCN): Patients who previously needed a PCN often have more complex strictures.
How are metal stents inserted, and what is the recovery process like?
Metal stents are typically inserted using a minimally invasive procedure called ureteroscopy. The stent is placed through the urethra and bladder into the ureter under x-ray guidance. General or spinal anesthesia is used during the procedure. Most patients go home the same day or the day after the procedure.
How long can a metal stent stay in place, and what is involved in its removal?
Metal stents can often remain in place for a year or longer, depending on the type of stent and individual patient factors. Removal typically involves a similar procedure to insertion, with the stent being retrieved through a ureteroscope.
What are the alternatives to metal stents for treating ureteral strictures?
Alternatives to metal stents include:
Repeated dilation: This involves stretching the stricture with a balloon.
Ureteral reconstruction surgery: This involves surgically removing the strictured portion of the ureter and reconnecting the healthy ends.
Percutaneous nephrostomy (PCN): This involves placing a tube through the skin into the kidney to drain urine. The treatment choice depends on the individual patient's situation and the severity of the stricture.
The above has been extracted from two studies in the BMC Urology journal. To read more, download the full papers here:
Long-Term Outcomes of Metal Stents for Benign Ureteral Strictures
The following video discusses a research paper comparing the long-term effectiveness of two types of metal stents in treating chronic benign strictures.
