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UPJ Obstruction • By age, and special situations

UPJ Obstruction and Kidney Stones Together: Treating Both With Pyeloplasty

In UPJ obstruction, urine pooling in the renal pelvis (stasis) makes stone formation easier — and a stone can be the first sign of the narrowing. This page explains which comes first, and how the two are treated together when both problems are present.

Who this is forChildren, adolescents, adults and families with a kidney stone found alongside hydronephrosis or UPJ obstruction
Reading≈5 min
ByProf. Dr. Ali AvanoğluUpdated
This page is part of UPJ obstruction.Read the full treatment overview on the hub page
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kidney–ureter–bladder: SFU 3 hydronephrosis, narrowing at the UPJ (red ring) · stone in the pelvis
01 · Why the narrowing causes stones, and how a stone can hide the narrowing02 · Why treating just the stone isn't enough03 · How the stone is removed during pyeloplasty04 · If there's a stone, a metabolic workup isn't skipped05 · When emergency care is needed
In brief5 madde
  • Why the narrowing causes stones, and how a stone can hide the narrowing: In UPJ obstruction (ureteropelvic junction obstruction; informally, kidney outlet narrowing), the renal pelvis can't fully empty; crystals settle out of the urine…
  • Why treating just the stone isn't enough: Stone-breaking (ESWL) or endoscopic stone removal doesn't remove the narrowing; because urine stasis in the renal pelvis continues, a stone re-forms, and broken…
  • How the stone is removed during pyeloplasty: In Anderson–Hynes (dismembered) pyeloplasty, the renal pelvis is already opened while the narrow segment is being removed; stones can be taken out directly at this…
  • If there's a stone, a metabolic workup isn't skipped: The narrowing can explain the stone, but an underlying metabolic cause (an imbalance of calcium, citrate, oxalate or uric acid in the urine) can also be present.
  • When emergency care is needed: The most serious situation in a kidney with both a stone and a narrowing is an infected obstruction: flank pain with fever, shivering and vomiting needs same-day…
01

Why the narrowing causes stones, and how a stone can hide the narrowing

In UPJ obstruction (ureteropelvic junction obstruction; informally, kidney outlet narrowing), the renal pelvis can't fully empty; crystals settle out of the urine that sits there, making stone formation easier. Adult UPJ obstruction case series report a stone occurring alongside it in roughly 15–20% of cases; it's rarer but does occur in children.

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  • In some people, a stone is the first finding: imaging shows a stone and hydronephrosis (kidney swelling) together, and the widening is attributed to the stone alone. If the widening persists after the stone passes or is broken up, that's a clue to an underlying narrowing.
  • The reverse also happens: a stone is found on a follow-up ultrasound in a child or adult with known UPJ obstruction. Hydronephrosis is a finding, not a diagnosis; when a stone and a narrowing occur together, each needs to be evaluated separately.
02

Why treating just the stone isn't enough

Stone-breaking (ESWL) or endoscopic stone removal doesn't remove the narrowing; because urine stasis in the renal pelvis continues, a stone re-forms, and broken fragments have trouble passing through the narrow junction. So in a kidney with UPJ obstruction, treating only the stone generally doesn't provide a lasting solution.

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  • Guidelines (the EAU stone disease guideline, pediatric section) recommend correcting the anatomical anomaly at the same time as the stone. For UPJ obstruction, this means removing the stones during pyeloplasty while the renal pelvis is already open.
  • The reverse is also true: the presence of a stone means the narrowing needs to be taken more seriously — a stone can worsen the obstruction, raises the risk of infection, and is counted, on its own, among the reasons for surgery in symptomatic obstruction.
03

How the stone is removed during pyeloplasty

In Anderson–Hynes (dismembered) pyeloplasty, the renal pelvis is already opened while the narrow segment is being removed; stones can be taken out directly at this stage (pyelolithotomy). For stones in the calyces (the small chambers inside the kidney), a flexible nephroscope is passed through the same opening to find and remove them.

  • Removing stones directly while the pelvis is open (pyelolithotomy)
  • Looking into the calyces through the same opening with a flexible nephroscope for calyceal stones
  • The repair is completed; a JJ stent or other drainage is placed at the surgeon's discretion
  • Any remaining fragments are monitored with ultrasound
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  • This approach can be used with open, laparoscopic, and robotic pyeloplasty alike; in laparoscopic and robotic surgery, placing the flexible nephroscope through the ports depends on center experience. Clearing every stone isn't always possible; any small remaining fragments are monitored after surgery.
  • The choice between open, laparoscopic or robotic approach is made through the joint assessment of two pediatric urology specialists, taking the stone burden and location into account as well.
04

If there's a stone, a metabolic workup isn't skipped

The narrowing can explain the stone, but an underlying metabolic cause (an imbalance of calcium, citrate, oxalate or uric acid in the urine) can also be present. Guidelines recommend a metabolic evaluation whenever a stone is present, even with a narrowing present too; this is especially important in children.

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  • This evaluation usually includes blood tests, a 24-hour urine collection, and stone analysis. Based on the results, fluid-intake and dietary recommendations, or any further treatment your doctor considers appropriate, are planned; this page does not give medicine names or doses.
  • If a stone recurs after surgery, the narrowing needs to be re-evaluated: a new stone can sometimes be the first sign that the repair isn't sufficiently open.
05

When emergency care is needed

The most serious situation in a kidney with both a stone and a narrowing is an infected obstruction: flank pain with fever, shivering and vomiting needs same-day evaluation. In this situation, drainage is established first with a JJ stent or nephrostomy, and the stone and the narrowing are addressed once the infection has cleared.

  • Fever (38 °C/100.4 °F and above) with flank pain: same day.
  • Severe pain that doesn't ease, with vomiting: come in for an ultrasound while the pain is present.
  • Visible blood in the urine, a drop in urine output: don't wait.
  • A stone and narrowing in a solitary kidney: seek care earlier for any symptom.
Related videos
Full guide (3) →
Frequently asked questions
Couldn't we break up the stone first and think about the narrowing later?
As long as the narrowing persists, the stone re-forms, and broken fragments have trouble passing through the narrow junction. Guidelines recommend correcting the anatomical problem at the same time as the stone; removing the stones while the renal pelvis is open during pyeloplasty is the accepted approach. In an emergency infection, drainage comes first.
Can both the stone and the narrowing be resolved in one operation?
In most cases, yes; stones are removed directly, or with a flexible nephroscope, while the renal pelvis is open during pyeloplasty. When stones are scattered through the calyces, clearing every single one may not be possible; remaining fragments are monitored after surgery.
If the stone is from the narrowing, is metabolic testing unnecessary?
No. The narrowing makes a stone easier to form through stasis, but an underlying metabolic tendency can be present too. Guidelines recommend a metabolic evaluation whenever a stone is present; blood tests, a 24-hour urine collection and stone analysis are planned accordingly.
Can a stone form again after surgery?
Once the narrowing is corrected and stasis is resolved, stone formation drops significantly; if a metabolic tendency is present, dietary and fluid recommendations lower the risk. If a stone recurs, how open the repair is gets re-evaluated.
Doç. Dr. Yaşar Issı's publications on this topic · 1
  1. Resorlu B, Issi Y, Onem K, et al. (2016). Management of lower pole renal stones: the devil is in the details. Annals of translational medicine. PubMed ↗
←Previous • By age, and special situationsRedo Pyeloplasty in AdultsNext • By age, and special situationsUPJ Obstruction in a Solitary Kidney→
Related pagesFull index →
Follow-up or surgery?Pain, Febrile Infection, or a StoneIn asymptomatic UPJ obstruction, the decision is usually based on numbers; once a symptom appears, the scale shifts. Recurrent flank pain, febrile urinary tract infection, and kidney stones are listed in guidelines under "symptomatic obstruction" as an indication for pyeloplasty. This page explains how each symptom feeds into the decision.After surgery and follow-upEndoscopic MethodsEndopyelotomy and balloon dilation are endoscopic methods that widen UPJ obstruction from the inside, using thin instruments passed through the urinary tract or the skin, without an incision. Because their success is lower than pyeloplasty's, they aren't for everyone — they're used in selected cases, especially adults and older children who've already had surgery.By age, and special situationsUPJ Obstruction in Adults: Symptoms, Evaluation, TreatmentUPJ obstruction in adults is most often a narrowing that has been present since childhood and only becomes symptomatic late — showing up as flank pain, recurrent infection, or a kidney stone. This page summarizes evaluation and treatment options in adults, noting that it draws on review data rather than a formal guideline.Pyeloplasty and approachesLaparoscopic Pyeloplasty: UPJ Repair Through a Closed (Keyhole) ApproachLaparoscopic pyeloplasty is the Anderson–Hynes repair for UPJ obstruction performed through several small openings, into the abdominal cavity or behind the kidney, using a camera and fine instruments. This page explains who it suits, how surgery proceeds, and its limits.
UPJ Obstruction topic clustersMain treatment page →
Basics 7Diagnosis and evaluation 6Follow-up or surgery? 7Conservative follow-up 5Pyeloplasty and approaches 7After surgery and follow-up 6By age, and special situations 7
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