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Prof. Dr. Ali Avanoğlu
UPJ Obstruction • By age, and special situations

Pyeloplasty in Infants and Older Children: Which Approach, at What Age?

The decision for pyeloplasty in an infant is made based on the kidney's course, not age; the approach is chosen based on the baby's size and the center's experience. This page addresses "at how many months" and "open or minimally invasive" separately for infants and older children.

Who this is forFamilies whose infant or child has been recommended pyeloplasty and who are unsure about approach and timing
Reading≈5 min
ByProf. Dr. Ali AvanoğluUpdated
This page is part of UPJ obstruction.Read the full treatment overview on the hub page
OPEN · single incision3–5 cm incisionMOST COMMON IN INFANTS
LAPAROSCOPIC · 3 ports3 ports · 5 mmSMALL INCISION · FASTER RECOVERY
ROBOTIC · ports + armsrobotic armsPRECISE SUTURING · OLDER CHILD/ADULT
three approaches: open (single incision), laparoscopic (3 ports), robotic (ports + arms)
01 · Timing first: at what age is pyeloplasty done in infants02 · Why open pyeloplasty is still common in infants03 · Is robotic or laparoscopic surgery possible in infants?04 · The balance shifts in older children and adolescents05 · What stays the same regardless of approach
In brief5 madde
  • Timing first: at what age is pyeloplasty done in infants: In UPJ obstruction (ureteropelvic junction obstruction; informally, kidney outlet narrowing), there is no single "correct month" for surgery.
  • Why open pyeloplasty is still common in infants: Under one year of age, many centers consider open Anderson–Hynes (dismembered) pyeloplasty through a small flank incision the standard.
  • Is robotic or laparoscopic surgery possible in infants?: Technically yes, but for selected cases and at experienced centers.
  • The balance shifts in older children and adolescents: As a child grows, the abdominal cavity widens, instruments have more room to work, and the advantages of minimally invasive approaches become clearer: a shorter…
  • What stays the same regardless of approach: Whichever route is chosen, the steps of the repair are the same: the narrow segment is removed, the widened renal pelvis is reduced if needed, and the ureter is…
01

Timing first: at what age is pyeloplasty done in infants

In UPJ obstruction (ureteropelvic junction obstruction; informally, kidney outlet narrowing), there is no single "correct month" for surgery. The decision is based on the combination of the hydronephrosis's (kidney swelling's) course over time, split (renal) function, and symptoms.

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  • In infants, this evaluation usually begins with ultrasound in the first weeks after birth; MAG3 diuretic renography (a kidney scan) gives a meaningful result only after the 4th–6th week of life, once the kidneys have matured. This is why most infants are followed in the first months, and surgery only comes up if function drops, widening progresses clearly, or symptoms appear.
  • Guidelines indicate that roughly a quarter of infants with UPJ-type high-grade hydronephrosis eventually need pyeloplasty; the majority can be followed without surgery. So the goal isn't "surgery at an early age" but "surgery at the right time" — and that time arrives, for some infants, within a few months, and for others, years later or not at all.
02

Why open pyeloplasty is still common in infants

Under one year of age, many centers consider open Anderson–Hynes (dismembered) pyeloplasty through a small flank incision the standard. In infants the kidney sits close to the skin; the repair can be done through a 2–3 cm incision, and healing is quick.

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  • The EAU/ESPU 2024 guideline reports that the success and complication rates of open, laparoscopic and robotic pyeloplasty are comparable. Minimally invasive approaches have also been reported to give results similar to open surgery even in infants under one year at experienced centers; but the small size of the abdominal cavity and instrument size limit these approaches in infants.
  • Success depends more on the technique of the repair than the approach: Anderson–Hynes pyeloplasty is reported in the literature at roughly 90–95% success and above. So "open surgery is an outdated method" isn't accurate — in infants it's often the most suitable and least traumatic route.
03

Is robotic or laparoscopic surgery possible in infants?

Technically yes, but for selected cases and at experienced centers. Laparoscopic pyeloplasty can be done in infants; for robotic surgery, instrument size, the tight working space inside the abdomen, and cost are limiting factors.

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  • Guidelines state clearly that the choice of approach depends on center experience. At one center an open repair may give the safer result in infants, while another center may have more laparoscopic experience; the approach recommended to a family is shaped by this experience.
  • In our approach, the choice between open, laparoscopic or robotic pyeloplasty is made through the joint assessment of two pediatric urology specialists, weighing the infant's age, weight, anatomy and the family's expectations together.
04

The balance shifts in older children and adolescents

As a child grows, the abdominal cavity widens, instruments have more room to work, and the advantages of minimally invasive approaches become clearer: a shorter hospital stay, less pain, smaller scars. Laparoscopic and robotic pyeloplasty are chosen more often in this age group.

  • Under one year: usually a small open repair; laparoscopy in selected cases.
  • School age: open, laparoscopic or robotic, depending on center experience.
  • Adolescents: laparoscopic or robotic more often; a crossing vessel is more likely.
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  • In older children, UPJ obstruction is more often caused by a crossing vessel (an extra vessel running to the kidney's lower pole that presses on the junction from outside). The laparoscopic and robotic view gives the surgeon a comfortable look at this vessel and at moving the ureter in front of it.
  • That said, open pyeloplasty remains a valid option in older children too; previous abdominal surgery, anatomical features and center experience all influence the decision.
05

What stays the same regardless of approach

Whichever route is chosen, the steps of the repair are the same: the narrow segment is removed, the widened renal pelvis is reduced if needed, and the ureter is re-sewn to the renal pelvis with a wide opening. Drainage — a JJ (double-J) stent, an externalized stent, or in selected cases a stentless repair — is the surgeon's choice.

  • If there's fever, discharge from the wound, increasing pain or vomiting in the first weeks after surgery, contact us without waiting.
  • With a stent in place, fever, severe pain, or noticeable bleeding needs same-day evaluation.
  • Follow-up after surgery is also independent of approach: ultrasound around month 3, then every 6–12 months; the hydronephrosis isn't expected to disappear completely, and a decrease in widening can take years. Success means "symptom-free, widening decreased or stable, function preserved."
UPJ Obstruction video guide3 short videos, in order
Frequently asked questions
Isn't surgery risky while the baby is so small — could we wait until they grow?
The decision for surgery is based on the kidney's condition, not age. If function is dropping or widening is clearly progressing, waiting can harm the kidney; if there's no such finding, most infants are already followed without surgery. Pyeloplasty is performed safely at infant age at experienced centers.
Is robotic surgery possible for our infant?
There are centers that perform robotic pyeloplasty in infants; but because of instrument size and a tight working space, many centers prefer open repair under one year of age. Since outcomes are reported as comparable across approaches, what determines the choice is the infant's size and the center's experience.
Will the scar from open surgery be large?
In infants, open pyeloplasty is usually done through a small, 2–3 cm incision on the flank. As the child grows, the scar stays proportionally small and often fades to a barely visible line.
Which approach has higher success?
Guidelines report similar success rates for all three approaches; the literature gives roughly 90–95% success and above for pyeloplasty in general. The difference shows up more in hospital stay, pain and scar size — differences that are smaller in infants and more noticeable in older children.
Next • By age, and special situationsUPJ Obstruction in Adolescents→
Related pagesFull index →
Pyeloplasty and approachesOpen Pyeloplasty: Repair Through a Small Incision in InfantsOpen pyeloplasty is a repair for UPJ obstruction done by reaching the kidney through a small, several-centimeter incision in the flank. It is the standard approach at many centers for infants; this page explains where the incision is placed, how surgery proceeds, recovery, and the scar.Pyeloplasty and approachesOpen vs. Laparoscopic vs. RoboticIn UPJ obstruction, all three approaches perform the same operation (Anderson–Hynes pyeloplasty) through different routes of access. This page lays open, laparoscopic and robotic pyeloplasty side by side — on success, pain, hospital stay, scarring, age and cost — without taking sides.Follow-up or surgery?UPJ Obstruction: Follow-Up or Surgery? How the Decision Is MadeNot every child with UPJ obstruction (ureteropelvic junction obstruction; informally, kidney outlet narrowing) needs surgery. The decision is made from the combination of the kidney's share of function, its emptying speed, the course of the hydronephrosis over time, and any symptoms. This page explains what goes on each side of that scale.After surgery and follow-upAfter Pyeloplasty: Care at HomeThe first days after pyeloplasty raise more questions for most families than the operation itself. This page walks through what happens in the hospital, what the drain and catheter are for, pain, feeding and wound care at home, and when you should call us right away.
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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