A ureteral stent is a thin, flexible tube used to manage obstructions in the urinary tract, most commonly caused by kidney stones. It ensures that urine can flow from the kidney to the bladder without interruption. By keeping the pathway open, the stent helps to relieve pressure and protect the affected kidney from potential damage.
Why a Ureteral Stent is Necessary
A kidney stone traveling down the ureter can cause a complete blockage. This obstruction leads to a buildup of urine inside the kidney, a painful condition known as hydronephrosis. The resulting swelling and high pressure within the kidney cause the severe, cramping pain often associated with kidney stones.
The ureteral stent is placed to immediately relieve this pressure and allow the kidney to drain freely. The stent also helps the ureter to heal from the trauma of the stone or a previous surgery. It passively dilates the ureter over time, which can make subsequent stone removal procedures, like ureteroscopy, easier and safer. In cases where a stone causes both a blockage and an infection, placing a stent can be a measure to drain the infected urine.
The Exact Placement of the Stent
The stent is placed entirely within the urinary tract, running the length of the ureter. The ureter is a narrow, muscular tube that transports urine from the kidney’s collecting system to the bladder.
The stent is designed with a small coil at each end to secure its position and prevent migration. The proximal coil sits securely inside the renal pelvis, the funnel-like structure within the kidney that collects urine. The distal coil rests inside the bladder.
The Stent Insertion Procedure
The placement of a ureteral stent is typically performed as an outpatient procedure under anesthesia, which may range from local to general. The surgeon begins by inserting a cystoscope, a thin, lighted telescope, through the urethra and into the bladder.
Once the scope is in the bladder, the surgeon locates the ureteral orifice. A flexible guide wire is then threaded through this opening, past the obstruction, and advanced up into the kidney. The stent is slid over this guide wire and positioned correctly under real-time X-ray guidance, known as fluoroscopy. This ensures the coils are seated properly in the kidney and the bladder before the guide wire and cystoscope are removed.
Living With and Removing the Stent
It is common to experience side effects while the stent is in place. Patients frequently report an increased urge and frequency to urinate, along with discomfort or a burning sensation. Pain in the lower abdomen, flank, or back is also common, often felt more intensely during or just after urinating. This flank pain happens because urine refluxes up the stent to the kidney when the bladder muscle contracts.
The presence of blood in the urine is another expected symptom that may fluctuate with activity levels. The stent is a temporary measure and must be removed or replaced to prevent complications such as encrustation, where mineral deposits form on the tube.
Removal is a quick procedure, typically done in the office using a cystoscope to grasp and withdraw the stent. Some stents have a removal string attached, which allows for simple removal by the doctor without the need for a scope.