Kidney stones are hard deposits that can form inside the kidneys, made from salts and minerals found in urine. While some stones remain small and pass unnoticed, others can grow larger, blocking the ureters, the narrow tubes carrying urine from the kidneys to the bladder. This blockage can lead to pain, kidney swelling (hydronephrosis), and complications like infection or kidney damage.
Understanding Ureteral Stents
A ureteral stent is a thin, flexible tube placed inside the ureter. These tubes, made of silicone or polyurethane, help maintain an open pathway for urine to flow from the kidney to the bladder. Most ureteral stents, often called double-J or pigtail stents, have a coil or curl at both ends. One coil sits in the kidney and the other in the bladder, which helps to keep the stent securely in place.
How Stents Facilitate Urine Flow
Ureteral stents work in several ways to restore and maintain proper urine flow. The hollow design of the stent allows urine to bypass an obstructing kidney stone, flowing through and around the stone. This action directly relieves the blockage and reduces pressure buildup in the kidney. Over time, the stent can gently widen the ureter, a process known as passive dilation, which can help smaller stones pass more easily or prepare the ureter for future stone removal procedures.
The stent also helps reduce ureteral spasms, which contribute to the severe pain associated with kidney stones. By providing a smooth channel, the stent helps to minimize muscle contractions in the ureter. Additionally, the stent ensures continuous drainage of urine from the kidney to the bladder, preventing urine accumulation that can lead to kidney swelling (hydronephrosis) and infection. This continuous drainage is important in safeguarding kidney function when a stone causes an obstruction.
When Stents Are Used for Kidney Stones
Ureteral stents are used in various scenarios during kidney stone management. They are placed for immediate relief of acute obstruction caused by a blocking stone, especially when accompanied by severe pain, kidney swelling, or infection. The stent helps to drain infected urine and stabilize the patient’s condition before definitive stone treatment.
Stents also serve a preparatory role before stone removal procedures, such as ureteroscopy or extracorporeal shockwave lithotripsy (ESWL). They can help to dilate the ureter, making it easier for instruments to access the stone or for stone fragments to pass after treatment. Following stone removal procedures, stents are inserted to ensure proper drainage, prevent swelling of the ureter, and allow the urinary tract to heal. A stent may also be placed to facilitate the spontaneous passage of smaller stones by keeping the ureter open and reducing spasms.
What to Expect with a Ureteral Stent
Ureteral stent placement is typically performed as an outpatient procedure under general anesthesia. A urologist uses a cystoscope, a thin instrument with a camera, inserted through the urethra into the bladder, to guide a wire into the ureter. The stent is then threaded over this wire into position, with its coiled ends resting in the kidney and bladder.
Patients commonly experience symptoms while a stent is in place. These can include frequent urination, a sudden urge to urinate, and discomfort or pain in the bladder, lower abdomen, or flank area, which may worsen during urination. Blood in the urine, appearing pink or reddish, is also a common and normal observation. Over-the-counter pain relievers and prescribed medications, such as alpha-blockers, can help manage discomfort and bladder spasms.
Individuals can resume light daily activities within a day or two after stent placement. Maintaining good hydration by drinking plenty of fluids is recommended to help flush the system and reduce irritation. Strenuous activities, heavy lifting, and sexual intercourse may be advised against to minimize discomfort or potential complications. Stent removal is usually a quick, in-office procedure, performed using a cystoscope after numbing gel is applied. If a string is attached to the stent, patients may be given instructions to remove it themselves at home.