Kidney stones are a common, painful medical problem, and lithotripsy is a standard treatment used by urologists. This procedure breaks up stones so the fragments can pass naturally through the urinary tract. Patients often ask whether a ureteral stent will be required afterward, and for how long. The decision to place a stent depends on the specific procedure performed and factors unique to the patient’s anatomy and stone characteristics.
Defining Lithotripsy Procedures and Ureteral Stents
Lithotripsy breaks kidney stones into smaller pieces that can be passed from the body. The two primary methods are Extracorporeal Shock Wave Lithotripsy (ESWL) and Ureteroscopy with Laser Lithotripsy (URS). ESWL is a non-invasive technique using high-energy sound waves generated outside the body to fragment the stone. This method is often preferred for softer stones located within the kidney.
URS is a minimally invasive surgical procedure where a small, flexible scope is passed through the urethra and bladder up into the ureter. A laser is then used to break the stone into tiny pieces. URS is highly effective for stones lodged in the ureter or for larger, harder stones that do not respond well to shock waves.
A ureteral stent is a thin, flexible, hollow plastic tube temporarily placed inside the urinary tract. It runs from the kidney to the bladder, with coils at both ends to keep it secured. The stent’s primary function is to ensure urine drains freely, bypassing temporary swelling, blood clots, or stone fragments that might obstruct the ureter after the procedure. Maintaining this flow protects the kidney from pressure buildup, known as hydronephrosis.
Factors Determining Stent Requirement After Stone Treatment
The necessity of a ureteral stent is dictated by the type of lithotripsy performed and the likelihood of post-procedural complications. For ESWL, stent placement is not routine unless specific risk factors are present. Since shock wave therapy is non-invasive, the ureter is not physically manipulated, reducing the risk of immediate swelling or injury. Stents may be used before ESWL for larger stones or pre-existing obstruction to reduce the risk of “Steinstrasse.”
Steinstrasse, meaning “stone street,” occurs when numerous stone fragments line up within the ureter, creating a complete blockage. For patients with a high stone burden, a stent keeps the passageway open so fragments can pass without causing an emergency obstruction.
URS carries a higher rate of stent placement because instruments are inserted directly into the ureter. This manipulation can cause temporary swelling or irritation. Urologists often require stent placement after URS to allow the ureter’s lining to heal completely from scope or laser contact.
If the procedure causes mucosal injury or a small perforation, the stent acts as a temporary splint to ensure the tissue heals correctly and prevents the formation of a ureteral stricture. A stent is also recommended if the patient had a pre-existing infection or significant kidney swelling, as it ensures drainage of potentially infected urine.
The size and location of the stone also influence the decision after URS. Treating larger stones (typically greater than 10 mm) creates more fragments, increasing the risk of obstruction. In these cases, the stent manages the high volume of debris. If the surgeon cannot completely remove all fragments during URS, a stent assists with the passage of remaining debris while the patient recovers.
The Patient Experience: Living With and Removing the Stent
While the stent is protective, its presence causes noticeable side effects. The most common symptoms relate to bladder irritation, often feeling similar to a bladder infection. Patients frequently experience a persistent urge to urinate, increased urinary frequency, and a sensation of incomplete bladder emptying. These symptoms occur because the end of the stent rests in the bladder, rubbing against the wall and causing spasms.
Patients also commonly experience blood in their urine (hematuria), which can range from light pink to red. This is normal and often increases with physical activity as the stent shifts slightly. Another common occurrence is flank pain, particularly during or immediately after urination. This happens because bladder contraction pushes urine backward up the stent toward the kidney.
These temporary symptoms can be managed with increased fluid intake and medications prescribed by the urologist. Alpha-blockers, for example, help relax the ureter and bladder neck, reducing spasms and associated pain. The stent usually remains in place for two to six weeks, depending on the extent of ureteral trauma and stone debris.
Stent Removal Process
Stent removal is a simple, quick procedure, though it can cause patient apprehension. If the stent was left with a removal string attached, the patient may be instructed to gently pull the string at home. Otherwise, the urologist performs the removal in the office using a flexible scope called a cystoscope. The scope is inserted through the urethra, the end of the stent is grasped, and the stent is pulled out. Although the pain during removal is often reported as moderate, it is typically brief, and patients usually feel immediate relief from the stent-related side effects.