Real life indications for pyeloplasty

In a previous post, I went over the indications for a pyeloplasty and discussed their merits and drawbacks. To better inform the families of the children I take care of, I decided to look back at my last 89 robotic pyeloplasties to see what the indications for surgery were.

The 2 most common reasons to operate were:

  1. Recurrent  episodes of pain: 35%
  2. Ultrasound findings: 31%

Recurrent episodes of pain: 2 or more episodes of pain consistent with UPJ obstruction with or without nausea or vomiting.

Ultrasound findings: either really bad hydronephrosis on a single ultrasound or worsening hydronephrosis on serial ultrasound. Some of these patients had a Mag 3 renal scan after the ultrasound showing worsening drainage and/or decrease in function of less than 5% –if the function drop was more than 5% I classified them separately.

The above numbers account for 66% of the cases. The other 34% includes patients with only one episode of pain, recurrent UTI’s, stones, renal failure, decrease in function, and redos.

Renal Failure

I operated on 2 patients due to renal failure. One was a newborn with a creatinine of 3 and anuria for 3 days. He had bilateral percutaneous nephrostomies and 3 months later bilateral robotic pyeloplasties. He is now 6 years old and has a normal creatinine and almost normal ultrasound (I know, pretty amazing case).

The other patient had a solitary kidney and was followed for several years for hydronephrosis. At age 5 he got lost to follow-up. He came back at age 11 with acute renal failure and creatinine of 11! A ureteral stent got the creatinine back to normal and then I did his robotic pyeloplasty.

Decrease in function

The first sentence of the UPJ chapter on Dr Snodgrass Pediatric Urology book states:

“The primary goal in diagnosing and treating UPJO is to prevent ipsilateral renal function loss”

But how often does that happen? It seems that not very often.

I operated on 5 (6%) patients for a baseline low function, but not due to a decrease in function.

Three (3.5%) patients were referred to me after a failed pyeloplasty elsewhere with a postoperative decrease in function of more than 10% absolute points.

Two patients had a decrease in function as the main indication, but each of their studies was done at different places which questions whether the function was really decreased or not — given the known variability at estimating differetial function using different measuring techniques or radioisotopes.

Two patients seem to have had a decrease of 10% with the same study done in the same place. One of the patients was born with very dysplastic kidneys, elevated creatinine, and bilateral grade 5 reflux. The Mag 3 went from 35% to 23% in the kidney with worse reflux combined with worse hydronephrosis. The second patient also had grade 5 reflux. On follow up, the side with reflux had worsening hydronephrosis and the reflux no longer made it into the kidney. The function went from 35% to 15%.

Another 2 patients had a drop of 5-10%, which I wonder how much of that was real versus study error. In one the function went from 57% to 50%. The other patient function went from 51% to 45%.

Interestingly, of the 6 redo pyeloplasties I did, 3 were done because of a drop of the function of more than 10%. This suggests to me that the kidney is more likely to lose function after a failed pyeloplasty than with just observation.


Crossing vessels

Crossing vessels robotic pyeloplastyTwenty-two percent of patients (20/89) were found to have a crossing vessel.

84% of patients with a crossing vessel presented with pain, compared to  24% of patients with no crossing vessels.

Half of the patients with recurrent pain had a crossing vessel.

Crossing vessels were found in only 5% of asymptomatic cases.

Literature review

An older study by Salem et al (1995) found an 11% incidence of crossing vessels among their pyeloplasties. Another study by Cain et al (2001) found that 58% of patients operated because of symptoms had crossing vessels — which is very similar to what I found in my patients. One more study of 30 symptomatic children (mean age of 6) years found crossing vessels in 40%. This same study found crossing vessels in 11% of prenatally detected asymptomatic cases, similar to the 5% incidence I found. Several studies mentioned polyps as a cause of obstruction. The study by Adey et al (2003) found the incidence of fibroepithelial polyps to be under 1%. I did not encounter polyps in any of my patients.


My most common indication for surgery was symptoms, followed by ultrasound findings. A significant drop in function was very uncommon in primary cases and seemed to only happen in dysplastic kidneys with initial abnormal function.

This data suggest to me that I can probably be less aggressive in asymptomatic patients since a drop in function was an uncommon indication to operate.




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