A kidney stent, more accurately called a ureteral stent, is a thin, flexible tube temporarily placed inside the ureter, the tube connecting the kidney to the bladder. This device ensures a clear pathway for urine flow. When a blockage occurs, urine can back up, causing the kidney to swell (hydronephrosis), which can lead to damage if not treated promptly. The stent acts as an internal bypass, maintaining drainage until the underlying problem is resolved.
Defining the Device and its Purpose
This specialized device is typically a hollow tube made from flexible plastic materials like silicone or polyurethane. In adults, it measures between 22 and 30 centimeters in length, with the diameter selected based on the patient’s anatomy. The stent is uniquely designed with curled ends, often called “pigtails” or a “double-J” shape, which help anchor it in place. One curled end sits securely within the kidney, and the other is positioned inside the bladder, preventing migration.
The primary purpose of the ureteral stent is to relieve or prevent an obstruction. Blockages most commonly arise from kidney stones, which can impede urine flow. Other conditions necessitating placement include ureteral strictures (abnormal narrowings) or external compression from a tumor. Stents are also often placed following ureteral surgery to allow inflamed tissue to heal without collapsing or forming scar tissue. By holding the ureter open, the stent ensures continuous drainage and reduces the risk of infection or permanent kidney damage.
The Insertion Process
Stent placement is a common, minimally invasive procedure most frequently performed using retrograde insertion. This approach involves a cystoscope, a thin, flexible instrument equipped with a camera. The urologist inserts the cystoscope through the urethra and advances it into the bladder.
Once the ureter opening is located, the stent is guided upward into the ureter and kidney, often assisted by a wire and X-ray guidance. The procedure is typically performed under sedation or general anesthesia and usually takes less than 30 minutes. A less common method, called antegrade or percutaneous insertion, involves placing the stent through a small incision in the patient’s back directly into the kidney for complex cases.
Living with a Kidney Stent
While highly effective, the presence of the stent can cause expected side effects known as stent-related symptoms. Many patients experience discomfort or a dull ache in the flank or groin area. This pain often intensifies during urination because bladder muscle contraction can push urine backward up the stent toward the kidney.
Bladder irritation is also common, leading to increased urinary frequency and urgency. It is normal to observe blood in the urine (hematuria), which can range from light pink to reddish. Patients are encouraged to maintain high fluid intake, which helps flush the urinary system and may reduce bleeding. Most daily activities can be maintained, but heavy lifting or strenuous exercise may increase discomfort or bleeding.
Patients must monitor for warning signs indicating a complication requiring immediate medical attention. These include an inability to urinate, a fever accompanied by chills, or severe pain not relieved by prescribed medication. These symptoms suggest an infection or a blockage of the stent itself.
When and How the Stent is Removed
Ureteral stents are typically temporary devices and must be removed or exchanged within a specific timeframe to prevent complications. The duration varies based on the underlying condition; stents are often removed within a few days to a few weeks after a kidney stone procedure. If the stent is needed for chronic conditions, such as external compression from a tumor, it requires replacement every three to six months to avoid encrustation (mineral deposits building up on the device).
The removal procedure is generally quick and performed in a doctor’s office or outpatient setting. The most common technique is removal via flexible cystoscopy, where a urologist inserts a small camera through the urethra to visualize the stent’s coiled end in the bladder. A small grasper is then passed through the cystoscope to gently pull the stent out. For short-term placement, the stent may have a removal string attached that extends out of the urethra, allowing for simpler retrieval by the healthcare provider or the patient at home.