Is renal biopsy a better predictor of the outcome of pyeloplasty in adult ureteropelvic junction obstruction?

Does Preoperative Function Affect the Outcome Following Pyeloplasty in Poorly Functioning Kidneys among Pediatric Population?

Aim:

To determine the efficacy and outcome of pyeloplasty in poorly functioning kidneys in the pediatric population and whether pyeloplasty could be offered as an upfront procedure in such patient population, instead of nephrectomy.

Materials and Methods:

A retrospective data analysis of 83 patients who underwent pyeloplasty in poorly functioning kidneys from 2010 to 2015 was performed. Success was defined based on improvement in symptoms, stable or improved function, and better drainage on post-operative Tc-99m Diethylene Triamine Pentaacetic acid scan instead of DTPA scan renography done after 3 months and yearly thereafter.

Results:

Eighty-three patients with a mean age of 6.8 ± 2.88 years with poor function on isotope renogram (<30%) were included in the study. Three patients were excluded in view of postoperative outflow obstruction. Out of the remaining 80 patients, 56 were male and 24 were female. They were divided into two groups based on preoperative differential renal function (DRF), Group I (n = 26) having preoperative DRF of <10% and Group II (n = 54) having preoperative DRF of 10%–30%. All patients underwent laparoscopic dismembered pyeloplasty with ureteral stenting. The mean DRF improved from 7.58 ± 2.39 to 29.71 ± 5.16 postoperatively in Group I. However, in Group II, DRF improved from 20.81 ± 5.68 to 37.25 ± 7.11 postoperatively. At a follow-up of 24 months, the overall success rate was 98%.

Conclusion:

Pyeloplasty gives good intermediate-term results even in extremely poorly functioning kidneys and an upfront pyeloplasty instead of nephrectomy should be offered to all pediatric patients irrespective of preoperative function.

Clinical and radiographic outcomes following salvage intervention for ureteropelvic junction obstruction

Purpose:

We aimed to assess failure rates of salvage interventions and changes in split kidney function (SKF) following failed primary repair of ureteropelvic junction obstruction (UPJO).

Materials and Methods:

A retrospective review of adult patients at an academic medical center who underwent salvage intervention following primary treatment for UPJO was performed. Symptomatic failure was defined as significant flank pain. Radiographic failure was defined as no improvement in drainage or a decrease in SKF by ≥7%. Overall failure, the primary outcome, was defined as symptomatic failure, radiographic failure, or both.

Results:

Between 2008-2017, 34 patients (median age 38 years, 50% men) met study criteria. UPJO management was primary pyeloplasty/secondary endopyelotomy for 21/34 (62%), primary pyeloplasty/secondary pyeloplasty for 6/34 (18%), and primary endopyelotomy/secondary pyeloplasty for 7/34 (21%). Median follow-up was 3.3 years following secondary intervention. Patients undergoing primary pyeloplasty/secondary endopyelotomy had significantly higher overall failure than those undergoing primary pyeloplasty/secondary pyeloplasty (16/21 [76%] vs. 1/6 [17%], p=0.015). Among patients undergoing secondary endopyelotomy, presence of a stricture on retrograde pyelogram, stricture length, and SKF were not associated with symptomatic, radiographic, or overall failure. Serial renography was performed for 28/34 (82%) patients and 2/28 (7%) had a significant decline in SKF.

Conclusions:

Following failed primary pyeloplasty, secondary endopyelotomy had a greater overall failure rate than secondary pyeloplasty. No radiographic features assessed were associated with secondary endopyelotomy failure. Secondary intervention overall failure rates were higher than reported in the literature. Unique to this study, serial renography demonstrated that significant functional loss was overall infrequent.

Pyeloplasty in Adults With Ureteropelvic Junction Obstruction in Poorly Functioning Kidneys: A Systematic Review

OBJECTIVES

To systematically summarize the available evidence concerning the impact of pyeloplasty on symptoms and differential renal function (DRF) in adults with unilateral UPJO in poorly functioning kidneys (PFK), and to identify potential predictors of kidney function recovery that could help clinicians select candidates for pyeloplasty.

METHODS

A literature search (MEDLINE, Embase, Google Scholar, Scopus, ClinicalTrials.gov, and the WHO Clinical Trials Registry) and systematic review were performed up to September 2020 according to the PRISMA guidelines. PFK were defined as a baseline DRF ≤30% on renal scintigraphy. The primary endpoints were symptom relief and postoperative scintigraphic DRF. Predictors of kidney function recovery were evaluated and compared among studies.

RESULTS

Nine studies comprising 731 patients met the inclusion criteria and were included for evidence synthesis. A DRF increase >5% occurred in 13.3%-53.8% of 160 patients with a pre- and postoperative renal scan. Symptoms improved in 73.3%-93.3% of 141 adults after pyeloplasty. Neither patient's age, baseline DFR, comorbidities, degree of hydronephrosis, kidney parenchymal thickness, nor kidney biopsy findings consistently predicted a significant DRF increase among 375 patients undergoing pyeloplasty.

CONCLUSION

Based on a low level of evidence, pyeloplasty may relieve symptoms and stabilize kidney function in adults with UPJO in PFK. A significant number of patients showed a DRF increase >5%, yet no consistent predictor of kidney function recovery was identified. Until more evidence becomes available, pyeloplasty could be considered for selected cases after accounting for the risks of a failure requiring a future nephrectomy.

Evaluation of Renal Histopathological Changes, as a Predictor of Recoverability of Renal Function Following Pyeloplasty for Ureteropelvic Junction Obstruction

Background:

Pyeloplasty is a widely accepted treatment for ureteropelvic junction obstruction (UPJO). However, the renal function recoverability after pyeloplasty is still a matter of debate. Different parameters have been used to predict renal functional recoverability after corrective surgery, with conflicting results.

Objectives:

In this study, renal biopsy was carried on a series of cases of UPJO, during pyeloplasty, to study the extent of histological alterations in renal parenchyma, as a result of obstruction, and its predictive value in renal function recoverability after pyeloplasty.

Patients and Methods:

We retrospectively analyzed the renal biopsy obtained during pyeloplasty in 53 adult patients. Histopathological changes were graded on a scale of 1 to 3, according to their severity, and compared with the differential renal function (DRF) revealed on the preoperative and postoperative follow up diethylene triamine pentaacetic acid (DTPA) renal scan. A Fischer’s t test was used to evaluate statistical differences between values.

Results:

This study showed a linear relationship between the severity of histological changes and renal function recovery, after pyeloplasty. Out of 24 obstructed renal units (ORU), with minimal histopathological changes (grade I), 21 ORU (87.5%), with > 35% DRF preoperatively, showed significant improvement in renal function after 12 months of pyeloplasty (P < 0.05). On the other hand, all kidneys (n = 29) with moderate to severe obstructive changes (grade II and III) had minimal improvement in DRF, after pyeloplasty, which was clinically insignificant (P > 0.05). Renal function deterioration after pyeloplasty was not observed in any of the cases.

Conclusions:

The severity of pathological changes in renal parenchyma, due to UPJO, is a good predictor of renal function recoverability, after pyeloplasty. The ORUs, with DRF > 35%, usually have normal (grade I) renal biopsy and might be expected to present better functional recoverability after pyeloplasty.

Delayed redo pyeloplasty fails to recover lost renal function after failed pyeloplasty: early sonographic changes that correlate with a loss of differential renal function

Purpose

To evaluate changes in differential renal function (DRF), as a functional outcome, in children who underwent redo pyeloplasty for management of failed pyeloplasty and to examine the factors that affect functional outcomes.

Materials and Methods

Between January 2002 and November 2010, a total of 18 patients who underwent redo pyeloplasty for persistent ureteropelvic junction obstruction after failed pyeloplasty were enrolled in this study. We assessed perioperative factors and evaluated changes in renal cortical thickness (RCT), renal function, and hydronephrosis by use of serial ultrasound and diuretic renography.

Results

The mean follow-up period was 44.83±28.86 months. After redo pyeloplasty, prevention of further functional deterioration was observed in only 12 of the 18 patients. After dividing the patients according to this observation, we discovered significant differences in both change in DRF (dDRF) and change in RCT (dRCT) (difference between before and after initial pyeloplasty) between the two groups (p<0.001). Additionally, we noted a significant positive correlation between dRCT and dDRF. All patients showed improvements in hydronephrosis grade and relief of symptoms compared with before redo pyeloplasty.

Conclusions

Redo pyeloplasty should be considered in cases of failed pyeloplasty to preserve renal function and obtain relief from symptoms. If patients show severe deterioration of DRF or a decrease in RCT after initial pyeloplasty, preservation of DRF in these patients after redo pyeloplasty could be difficult. Therefore, redo pyeloplasty should be performed before severe deterioration of DRF or decrease in RCT.