Bilateral Ureteropelvic Junction Obstruction: Which Side Should We Start With?
Mohamed A. Elbaset, MD, Ahmed Abdelhalim, MD, Mohamed Edwan, MD, Ali M. Elmeniar, MD, Mohamed A. Sharaf, MD, Osama Ezzat, MD, Mostafa Elgamal, MD, Rawdy Ashour, MD, Mohamed Badawy, MD, Mohamed A. Soltan, MD, Tamer E. Helmy, MD, Ashraf T. Hafez, MD, Mohamed E. Dawaba, MD.
Mansoura Urology and Nephrology Center, Mansoura, Egypt.
Background: Although bilaterality is seen in 10-40% of cases with ureteropelvic junction obstruction (UPJO), the criteria based on which surgeons should choose the side of first intervention are poorly defined. We aim to provide guidance on choosing the side of first intervention in patients with bilateral UPJO based on changes of the postoperative estimated glomerular filtration rate (eGFR) and risk of renal injury.Methods: The database of a single tertiary center was reviewed for children less than two years of age who underwent bilateral pyeloplasty between January 2000 and December 2017. Patients with other associated urologic anomalies or nearly equal split renal function (45-55% bilaterally) were excluded. The study cohort was subdivided into two groups: •Group A: children who had intervention first on the less functioning renal unit.•Group B: children who had intervention first on the better functioning renal unit.Serum creatinine values were retrieved and eGFR was calculated, using the modified Schwartz formula, at four time points:•Point I: before the first intervention.•Point II: within 48 hours of the first intervention.•Point III: before the second intervention.•Point IV: within 48 hours of the second intervention.
Preoperative and postoperative values were compared. The incidence of early postoperative acute kidney injury (AKI) in both groups was examined using the Acute Kidney Injury Network (AKIN) criteria.Results:The study comprised 46 patients (28 in group A, 18 in group B). All procedures were done by open approach using the Anderson-Hynes technique. None of the patients required redo surgery. Age at first intervention, interval between both interventions, baseline serum creatinine and eGFR were not significantly different between both study groups.Group A patients had a significant decline of eGFR after the first intervention (p=0.006) and another, though insignificant, decline of eGFR after the second intervention. Changes of eGFR in group B patients were insignificant after the first or second interventions. Starting intervention on the less functioning renal unit was associated with a significantly higher incidence of early postoperative AKI [18 (64.3%) vs. 6 (33.3%) for groups A and B, respectively; p=0.04]. Results are summarized in table 1 and figure 1.Conclusion: Although other parameters can be taken into account when choosing the side of first intervention in patients with bilateral UPJO, our results suggest that starting intervention on the less functioning renal units is associated with a higher risk of early postoperative AKI.
Table 1: Postoperative renal function changes
| Variable | Group A (N=28): starting intervention on the less functioning renal unit | Group B (N=18): starting intervention on the better functioning renal unit | P-Value |
| Serum creatinine (mg/dl) | |||
| Point I: before the first intervention | 0.31 ± 0.14 | 0.38 ± 0.16 | 0.06 |
| Point II: after the first intervention | 0.36 ± 0.16 | 0.39 ± 0.19 | 0.9 |
| Point III: before the second intervention | 0.37 ± 0.18 | 0.42 ± 0.2 | 0.3 |
| Point IV: after the second intervention | 0.41 ± 0.2 | 0.46 ± 0.21 | 0.8 |
| p-value* | 0.001 | 0.85 | |
| p-value ** | 0.9 | 0.09 | |
| p-value*** | <0.0001 | 0.1 | |
| eGFR (ml/min/1.73m2) | |||
| Point I: before the first intervention | 123.25±36.3 | 95.7±35.04 | 0.07 |
| Point II: after the first intervention | 105.1±36.03 | 95.08±39.6 | 0.01 |
| Point III: before the second intervention | 109.2±36.3 | 97.77±46.7 | 0.2 |
| Point IV: after the second intervention | 87.3±38.05 | 94.3±38.7 | 0.02 |
| p-value* | 0.006 | 0.9 | |
| p-value ** | 0.2 | 0.1 | |
| p-value*** | <0.0001 | 0.2 | |
| Postoperative AKI incidence | 0.04 | ||
| Yes | 18 (64.3%) | 6 (33.3%) | |
| No | 10 (35.7%) | 12 (66.7%) | |
| Postoperative AKI staging according to serum creatinine (AKIN criteria) | 0.01 | ||
| Stage I (increase 1.5-1.9 times from baseline) | 10 (35.7%) | 4 (22.2%) | |
| Stage II (increase >2-3 fold from baseline) | 7 (25%) | 2 (11.1%) | |
| Stage III (increase >3 fold from baseline) | 1 (3.6%) | 0 | |
P-value* comparison between preoperative 1 and post-operative 1P-value** comparison between preoperative 2 and post-operative 2P-value*** comparison between preoperative 1 and postoperative 2
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