A ureteral stent is a small tube placed inside the body to keep urine flowing from the kidney to the bladder. It is a very common and valuable tool in urology.
However, problems can arise when a stent remains in place longer than intended without follow-up or planned exchange. This situation is known as a forgotten ureteral stent.
This article explains, in clear language, how long different ureteral stents can stay in, why forgotten stents become a problem, what symptoms may occur, and how modern urology manages and prevents this complication, based on recent high-quality medical evidence.
What Is a Ureteral Stent, and Why Is It Put In?
A ureteral stent (often called a double-J stent) is a thin, flexible tube placed between the kidney and the bladder. The curled ends help keep it in position.
Ureteral stents are used to:
- Bypass blockage caused by kidney stones
- Protect the ureter after ureteroscopy
- Allow healing after surgery
- Relieve obstruction from scarring, inflammation, or cancer
A stent does not cure the underlying condition. It is used either as:
- A temporary measure, or
- A long-term drainage solution, depending on the clinical situation
How Long Can a Ureteral Stent Safely Stay In?
This depends on the type of stent used and the reason it was inserted.
Short-term ureteral stents
- Commonly used after stone surgery or endoscopic procedures
- Often intended to stay in place for days to weeks
- Typically removed once swelling settles and healing occurs
Long-term ureteral stents
- Used in selected patients with chronic or recurrent obstruction
- It may be intentionally exchanged at planned intervals, commonly:
- Every 6 months, or
- Up to 12 months (including yearly changes) in appropriate cases
Importantly, there is no single “danger time” after which all stents become unsafe.
The key factor is whether the stent is:
- Monitored
- Documented
- Exchanged or removed as planned
What Is a Forgotten Ureteral Stent?
A forgotten ureteral stent is one that remains inside the urinary system longer than originally intended, without appropriate follow-up, monitoring, or planned exchange.
In published studies, this typically refers to a stent:
- Left in place unintentionally, or
- Present despite missed follow-up appointments
A 2024 systematic review analysing 1,292 patients found an average forgotten stent duration of 33.5 months, with reported extremes exceeding1,292 patients found an average forgotten stent duration of 33.5 months, with reported extremes of over 30 years.
How Common Are Forgotten Ureteral Stents?
Forgotten stents are uncommon but well -recognised in urology.
- Reported rates range from 0.9% to 12%
- Around 79% were initially placed for kidney stone treatment
Although relatively infrequent, forgotten stents account for a disproportionate number of complex and high-risk procedures .
Why Do Ureteral Stents Become Forgotten?
The evidence shows this is usually due to multiple causes.
Patient-related factors (≈84%)
- Feeling well and assuming no action is needed
- Forgetting follow-up appointments
- Misunderstanding that removal or exchange is essential
System-related factors (≈25%)
- Inadequate explanation at insertion
- Lack of reminder or tracking systems
Practical factors
- Work or travel commitments
- Social or financial difficulties
Interestingly, patients who tolerate a stent well are more likely to forget it, because symptoms may be minimal .
What Happens If a Ureteral Stent Is Left in Too Long Without Follow-Up?
A ureteral stent is a foreign body. Over time, interaction with urine and bacteria can lead to complications, especially when follow-up is lost.
Potential problems include:
- Encrustation (mineral build-up on the stent)
- Stone formation
- Urinary tract infection
- Stent fracture or migration
- Obstruction of urine flow
- Kidney function deterioration
The risk increases with time, but not in a fixed or predictable way. Risk is strongly influenced by:
- Stent material
- Infection
- Stone disease
- Individual metabolic factors
- Absence of monitoring
Why Do Forgotten Stents Become Encrusted and Form Stones?
Urine naturally contains minerals. Bacteria can attach to the stent surface and form a biofilm (a thin bacterial layer).
This situation leads to:
- Changes in urine chemistry
- Gradual mineral deposition
- Progressive stone formation, especially at the kidney and bladder ends
In a large review:
- 80.8% of forgotten stents were encrusted
- 40.2% were associated with infection
A 2024 case report described a stent forgotten for 18 years, resulting in severe encrustation and a giant bladder stone, requiring multiple procedures for safe removal .
What Symptoms Can a Forgotten Ureteral Stent Cause?
Symptoms are variable and may develop slowly.
Common symptoms include:
- Flank or back pain (37%)
- Urinary frequency or urgency (33%)
- Blood in the urine (23%)
- Recurrent infections (40%)
- Fever or sepsis in severe cases
Notably, around 11% of patients are initially symptom-free, which is why forgotten stents can remain undetected for long periods .
Can a Forgotten Ureteral Stent Damage the Kidney?
Yes.
Studies show:
- Impaired kidney function in ≈25% of patients
- Much higher risk in bilateral stents or solitary kidneys
- Prolonged obstruction may cause irreversible damage
Early identification and treatment greatly reduce this risk.
How Is a Forgotten Ureteral Stent Diagnosed?
Assessment usually includes:
- CT scan (used in ~76% of cases)
- X-ray (KUB)
- Ultrasound
- Blood tests for kidney function
- Urine tests for infection
CT imaging is particularly important for assessing encrustation severity and planning safe removal.
Why Is Removing a Forgotten Ureteral Stent More Difficult?
Once encrusted, a stent cannot simply be pulled out.
Challenges include:
- Risk of breaking the stent
- Stone burden along its length
- Risk of ureteral injury
- Infection during manipulation
This is why planned, staged removal is often safer.
How Are Forgotten Ureteral Stents Removed?
Management depends on where and how severely the stent is encrusted.
Approaches may include:
- Cystoscopy
- Ureteroscopy with laser fragmentation
- Percutaneous nephrolithotomy (PCNL) for kidney involvement
- Rarely, open or laparoscopic surgery
A large review showed:
- 59% required more than one procedure
- 99% were ultimately rendered stent-free
Will More Than One Procedure Be Needed to Remove a Forgotten Stent?
Often, yes.
Staged procedures:
- Reduce operative risk
- Limit infection and bleeding
- Improve overall safety
This is considered best practice, not a complication.
Can Forgotten Ureteral Stents Be Prevented?
Yes — prevention is the most important message.
Effective measures include:
- Clear explanation at insertion
- Written follow-up plans
- Electronic stent registries
- Automated reminders
- Planned exchange schedules for long-term stents
Tracking systems have been shown to significantly reduce forgotten stents.
What Should You Do If You Think You Still Have a Ureteral Stent?
- Do not assume it has been removed
- Do not ignore mild symptoms
- Confirmation with imaging is simple and effective
Early assessment prevents complex treatment later.
Frequently Asked Questions About Forgotten Ureteral Stents
Can stents be safely left in for a year?
Yes, some long-term stents are intentionally exchanged yearly, provided there is monitoring and planning.
Is time alone the problem?
No. The key risk is loss of follow-up, not duration alone.
Can a stent be forgotten without symptoms?
Yes. About 1 in 10 patients are initially symptom-free.
Does removal always require surgery?
No. Mild cases can be managed endoscopically.
Can kidney damage be reversed?
Often, kidney damage can be reversed if it receives early treatment.
Forgotten Ureteral Stents: Key Safety Messages Every Patient Should Know
- Not all ureteral stents are the same
- Some are designed for long-term use with planned exchange
- Forgotten stents result from missed follow-up, not simply time
- Complications are preventable
- Early detection makes treatment simpler and safer
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