Pyeloplasty
Surgery that cuts out a narrowed spot where the kidney drains into the ureter and sews a wide new funnel, so urine flows freely again.
Also called robotic pyeloplasty, dismembered pyeloplasty, Anderson-Hynes pyeloplasty, laparoscopic pyeloplasty, UPJ obstruction repair, UPJO surgery, ureteropelvic junction obstruction, kidney blockage surgery
- Where
- Hospital operating room
- Anesthesia
- General anesthesia (you are fully asleep)
- Time in the room
- About 2 to 3 hours
- Hospital stay
- Usually 1 night
- Going home with
- An internal ureteral stent for about 4 to 6 weeks
- Back to normal
- About 2 to 3 weeks, though the stent can be bothersome until it is out
- Back to work
- Desk work in 1 to 2 weeks; physical work in about 4 to 6 weeks
Overview
Urine made in the kidney collects in a funnel called the renal pelvis, then drains through a narrow tube, the ureter, to the bladder. The spot where the funnel meets the ureter is called the ureteropelvic junction, or UPJ. If this spot is too narrow, urine backs up and the kidney swells, a condition called hydronephrosis. This is called UPJ obstruction.
Many people are born with a narrow UPJ and some are not found until adulthood, often because of episodes of side or back pain, especially after drinking a lot of fluid, coffee or alcohol. In some adults, an extra blood vessel to the lower part of the kidney crosses over the UPJ and presses on it, often in roughly a third to a half of adults with UPJ obstruction.
A pyeloplasty fixes the blockage. In the most common version, the dismembered pyeloplasty, the surgeon cuts out the narrow segment, moves the ureter in front of any crossing vessel, and sews the ureter to the funnel in a wide, smooth, downward-draining shape. A thin tube called a stent is left inside for a few weeks while it heals. With the robotic approach, this is done through small keyhole cuts, and success rates are over 90 in 100.
Not every swollen kidney needs surgery. Some mild cases are stable and only need watching. Your urologist decides based on your symptoms and on a nuclear scan, called a diuretic renogram, that shows how well the kidney drains and how much work it does.
The parts of your body involved
Each kidney makes urine, which gathers in small cups called calyces and flows into the renal pelvis, a funnel inside and just outside the kidney. The funnel narrows into the ureter, a tube about as wide as a drinking straw that runs down to the bladder. The narrowing point is the UPJ. If it is too tight, or a blood vessel presses on it, urine drains slowly, the funnel and cups stretch, and over time the kidney can lose function or become infected.
- Renal pelvis
The urine-collecting funnel. It balloons out when drainage is blocked.
- UPJ
Where the funnel meets the ureter. This is the narrowed spot that is fixed.
- Ureter
The tube from the kidney to the bladder.
- Crossing vessel
An extra artery or vein to the lower kidney that can press on the UPJ. It is kept, because it feeds part of the kidney.
- Calyces
The small cups that drain into the funnel. They stretch when urine backs up.
Why it’s done
The goals are to relieve pain, protect the kidney, and stop infections or stones caused by poor drainage.
- Pain
Episodes of side or back pain from the kidney stretching, often after drinking a lot.
- Falling kidney function
A renogram showing the blocked kidney doing less of its share over time.
- Infections
Urine that sits in a swollen kidney can become infected.
- Stones
Slow drainage makes stones more likely. They can sometimes be removed during the same operation.
- Poor drainage on a renogram
Clear blockage on the scan, especially with symptoms, usually means surgery helps.
Other options
- Watching
Mild swelling with good kidney function and no symptoms can be watched with ultrasound and repeat renograms.
- A stent or nephrostomy tube
A tube inside the ureter, or through the back into the kidney, relieves the blockage temporarily. It is a short-term fix, used before surgery or if surgery is not possible.
- Endopyelotomy
Cutting the narrow spot from the inside with a scope and laser. It avoids cuts on the belly but works less often than pyeloplasty, especially when a crossing vessel is present.
- Open pyeloplasty
The same repair through a small cut on the side. Still common in babies and young children, and sometimes used for repeat repairs.
- Removing the kidney
If the blocked kidney does very little work, usually under about 10 to 15 percent of total function, removing it may be simpler than repairing it.
Getting ready
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Weeks before
The week before
The day before
The morning of surgery
In the operating room, step by step
Press play or pick a step. Each drawing shows what your surgeon is doing at that moment. Your team may do some steps differently.
1. Going to sleep and positioning
You fall fully asleep and a breathing tube is placed. You are turned onto your side, with the blocked kidney up. A catheter is placed in your bladder.
More detail
Some surgeons first look into the bladder with a scope, with your legs in supports, to take an X-ray picture of the ureter or to place the stent from below before turning you on your side. Others place the stent from above during the repair.
The surgeon sits at a console a few steps from you and moves every instrument with hand controls and foot pedals. The robot cannot move on its own or make decisions.
A camera on one arm gives the surgeon a bright, three-dimensional picture magnified about ten times, which helps them see small nerves and vessels.
The instruments are about the width of a pencil and bend like a wrist inside your body, so the surgeon can stitch and dissect through small openings.
A bedside assistant and a scrub nurse stay at the table, and the anesthesia team watches your breathing and blood pressure throughout. Most U.S. hospitals use the da Vinci system made by Intuitive.
After the operation
In the hospital
- Waking up
You wake with an IV and a bladder catheter, and sometimes a drain.
- Why the catheter
The bladder catheter keeps the bladder empty so urine does not push back up through the stent into the fresh repair. It usually comes out the next day.
- Pain control
Acetaminophen and other non-opioid medicines, with small amounts of opioid medicine if needed.
- Walking and eating
Walking the same evening or next morning and eating as you feel ready.
- Going home
Most people go home after 1 night.
At home
- Living with the stent
Most people feel the stent: a frequent, urgent need to urinate, burning, blood in the urine, and an ache in the side, especially at the end of urinating. This is expected and goes away when the stent is removed.
- Medicines for stent symptoms
Your team may prescribe tamsulosin, which relaxes the ureter, or a bladder-calming medicine to ease stent discomfort.
- Pain
Acetaminophen on a schedule; the stronger pill only if needed.
- Fluids
Drink enough to keep your urine light yellow to pink. It is normal to see more blood after activity.
- Incisions
Shower after 24 to 48 hours. Avoid baths and swimming for about 2 weeks.
- Activity and lifting
Walk daily. Avoid lifting more than about 10 to 15 pounds (5 to 7 kilograms) and hard exercise for about 4 weeks, or until the stent is out.
- Driving
Not while taking opioid pain medicine. Most people drive in about 1 week.
- Sex and work
Sex when comfortable; the stent may make it a little uncomfortable. Desk work in 1 to 2 weeks.
- Stent removal visit
Keep your appointment to remove the stent, usually 4 to 6 weeks after surgery. A stent left in too long can become blocked or crusted.
Recovery timeline
- Day of surgerySurgery
You wake with a catheter and start walking.
- Day 1Home
The catheter comes out and most people go home.
- Weeks 1 to 2Recovering with a stent
Incision soreness fades, but stent symptoms often continue.
- Weeks 4 to 6Stent removal
The stent is removed in the office with a thin scope, after numbing jelly, in a few minutes.
- 6 to 12 weeks after stent removalFirst drainage test
An ultrasound and often a repeat renogram check that the kidney drains well.
- About 1 yearLong-term check
Another ultrasound or renogram. The kidney may stay somewhat wide even when it drains well; drainage and symptoms are what matter.
What it feels like
Most people recover from the surgery itself quickly. The stent is often the main complaint, and the day it comes out is a big relief.
Waking up
Grogginess, sore keyhole cuts, and shoulder-tip pain from the gas.
What helpsWalk early and often; it helps the gas pain fade within a day or two.
Living with the stent
A constant urge to urinate, burning, pink urine, and a twinge or ache in the side when you urinate. Some people find it more annoying than the surgery.
What helpsAsk about tamsulosin or a bladder-calming medicine. Drink steadily, and remember it is temporary.
The stent removal
Nervousness beforehand, then a brief pressure or pinch as the stent slides out. Some people get a strong ache in the side for a few hours afterward.
What helpsTake acetaminophen beforehand if your team allows, drink fluids afterward, and rest that evening.
Weeks later
Relief as the old pain episodes stop. Some people stay on edge for a while, waiting for the pain to come back.
What helpsThe follow-up scan gives a clear answer. Most people never have the old pain again.
When the scan still shows a wide kidney
Worry that the operation did not work.
What helpsA stretched kidney often stays somewhat wide after a successful repair. What matters is that the scan shows good drainage and your symptoms are gone.
How well it works
Success means urine drains freely, the pain episodes stop, and the kidney's function stays stable or improves.
- High success rate
Robotic and laparoscopic pyeloplasty succeed in more than 90 in 100 people.
- Drainage on the renogram
Follow-up renograms show urine leaving the kidney promptly after the water pill.
- Symptoms
Pain episodes usually stop entirely.
- Kidney function
Split function usually stays stable. It may improve a little in some people.
- If narrowing returns
Uncommon, and usually within the first year or two. It can be treated with a scope procedure or a repeat repair.
Risks
Every operation has risks. These are the ones people ask about most, with honest odds where good numbers exist. Your surgeon’s own results matter more than averages.
Common
Urgency, frequency, burning, blood in the urine, and side pain while the stent is in. Most people have at least some.
Soreness at the cuts for 1 to 2 weeks.
Common while the stent is in.
Less common
Treated with antibiotics.
A small leak from the repair usually heals with the stent and catheter left in longer.
The repair scars down again and blocks.
The stent can move or become blocked and need replacing.
Rare
Rare.
Rare. Most are repaired during surgery.
A clot in a leg vein that can travel to the lungs.
Very rare.
Call your care team or go to the emergency room if
- Fever of 101°F (38.3°C) or higher, or shaking chills (a stent plus infection can become serious quickly)
- Severe side pain that does not ease with your medicine
- Thick red urine with clots, or unable to urinate
- Fluid leaking from a cut, or a swollen, tense belly
- Vomiting that will not stop
- Pain, swelling or redness in one calf, or chest pain or trouble breathing (call 911)
- The stent string, if you have one, has come out early, or you see the stent itself
Questions to ask your surgeon
- How sure are we that the junction is blocked, and what did the renogram show?
- How much work does the blocked kidney do?
- Is there a crossing vessel?
- Will you do a dismembered repair?
- How many pyeloplasties do you do each year?
- Will I have a stent, and when will it come out?
- What can I take for stent discomfort?
- Will I have a drain or a catheter?
- What tests will show the repair worked, and when?
- What happens if the narrowing comes back?
Words you may hear
- Pneumoperitoneum
- The gas-filled belly that makes keyhole surgery possible. Carbon dioxide is pumped in through a thin needle or the first port until the belly wall lifts like a tent (usually at a pressure of 12 to 15 mmHg), giving the camera and instruments room to work. The gas is let out at the end, and the little that remains is absorbed and breathed out over a day or two; it can cause shoulder-tip ache in the meantime.
- Ureteropelvic junction (UPJ)
- Where the kidney's collecting funnel meets the ureter.
- UPJ obstruction
- A blockage at the UPJ that slows urine drainage from the kidney.
- Hydronephrosis
- Swelling of the kidney's drainage system from urine backing up.
- Renal pelvis
- The funnel that collects urine from the kidney.
- Crossing vessel
- An extra blood vessel to the lower kidney that crosses and can press on the UPJ.
- Dismembered pyeloplasty
- A repair where the narrow segment is cut out and the ureter is rejoined to the funnel.
- Double-J stent
- A thin, soft tube with a curl at each end, placed inside the ureter from the kidney to the bladder.
- Diuretic renogram
- A nuclear medicine scan with a water pill that shows how well each kidney drains and works.
- Split function
- The share of total kidney work done by each kidney.
- Endopyelotomy
- Cutting the narrowed junction from inside with a scope.
Common questions
Was I born with this?
Many people were. A narrow junction can be present from birth and cause no trouble until later. In some adults, a crossing blood vessel or scarring from stones or past surgery causes the narrowing.
Why do I need a stent?
The stent holds the new join open and drains urine while the stitches heal, which lowers the chance of a leak or early scarring.
How is the stent removed?
Usually in the office, with numbing jelly and a thin flexible scope passed into the bladder. The stent is grasped and pulled out in a few minutes.
Will my kidney go back to normal size?
It often stays somewhat wide, like a stretched balloon. What matters is that it drains well and your pain is gone.
Can this be done in children?
Yes. Pyeloplasty is one of the most common kidney operations in children, often done open through a small cut in babies and robotically in older children.
Sources this page draws on
- Urology Care Foundation, Ureteropelvic Junction (UPJ) Obstruction
- European Association of Urology, EAU Guidelines on Paediatric Urology (UPJ obstruction)
- European Urology, Robot-assisted and laparoscopic repair of ureteropelvic junction obstruction: a systematic review and meta-analysis (Autorino et al.)
- Elsevier, Campbell-Walsh-Wein Urology, chapter on surgery of the ureteropelvic junction
Written November 2026. This page explains what usually happens. It is not medical advice and does not replace a conversation with your own surgeon, whose plan for you comes first.