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Abstract

Purpose:

The purpose of this study is to ascertain the coexistence of ipsilateral vesicoureteric reflux (VUR) with ureteropelvic junction obstruction (UPJO) and to compare postpyeloplasty outcome in patients with and without associated VUR.

Materials and Methods:

Prospective study from 2014 to 2016 of consecutive children (n = 135) undergoing pyeloplasty. Data of patients without (Group 1) and with (Group 2) associated ipsilateral VUR were compared.

Results:

Thirty-five patients (25.9%) had ipsilateral VUR along with UPJO (Group 2). This group showed the following unique features: (1) Higher percentage of infants (31/35) compared to Group 1 (62/100) (P = 0.003) (2) VUR in the contralateral (normal) kidney in 21/35 (60%) cases and nil in Group 1 (3) Significantly less preoperative differential renal function in children above 1 year (P = 0.007) (4) Presence of renal scars (18 units) and pyelonephritic changes (6 units) in Group 2 at the 1-year follow-up dimercaptosuccinic acid renal scan. Both groups showed improvement in function 3 months after pyeloplasty with no statistically significant difference. Improvement in drainage on the renal scan was better in Group 1 at 3 months postoperative (P = 0.015) as well as between 3 months and 1-year follow-up (P = 0.052).

Conclusion:

The prevalence of VUR was 25.9% in this study and 33.3% in ≤1 year age group. There was a loss of function in delayed presenters with associated ipsilateral VUR. There was delayed drainage postpyeloplasty in patients with VUR. A preoperative voiding cystourethrogram should be done in children <1 year age before pyeloplasty so that associated VUR if detected can be concurrently managed along with pyeloplasty and preserve nephrons affected by the dual pathology.

KEYWORDS: Ipsilateral, outcome, pediatric, pyeloplasty, ureteropelvic junction obstruction, vesicoureteric reflux

INTRODUCTION

Ureteropelvic junction obstruction (UPJO) and vesicoureteric reflux (VUR) are the most common pathological conditions in pediatric urology, with 9%–14% of patients with UPJO likely to have concomitant VUR.[1,2,3] Whether the coexistence is a random event, attributable to a single developmental abnormality or due to ureteral kinking and inflammation caused by VUR has not yet been established.[3] Children may present years after a successful pyeloplasty, with urinary tract infection (UTI) and deteriorating renal function due to missed reflux. A diagnostic dilemma exists in casting a net wide enough to identify all cases with associated VUR while avoiding the unpleasant effects of a voiding cystourethrogram (VCUG) in those without the association.[4,5,6,7] There is also a debate as to which of them should be treated first.

The purpose of this study was to assess the prevalence of VUR in all patients diagnosed with UPJO over a 2-year study period and to study the effect of ipsilateral VUR on drainage and differential renal function (DRF) at 3 months and 1 year after the pyeloplasty.

MATERIALS AND METHODS

A prospective study was conducted in the Pediatric Surgery department of a tertiary care center from March 2014 to August 2016 of consecutive children, aged between 0 and 12 years diagnosed with UPJO to specifically assess the presence of associated VUR and its implications on the outcome. Approval was taken from the Institute Ethics Committee before the start of the study (1TRG/PG-2014/16137-63).

All patients initially underwent ultrasonography (USG) of kidney, ureter, bladder (KUB) region, blood urea and serum creatinine measurement and urine culture and sensitivity (C and S).

The UPJO was defined by an obstructive drainage pattern on renal dynamic scan using ethylene dicysteine (EC) with a draining per-urethral catheter. Lasix was given at the start of the study. If the renal function tests were normal, the diagnosis was further confirmed by an intravenous urography (IVU) with a draining per-urethral catheter. Retention of contrast in the pelvicalyceal system in the post-lasix 20-min film was considered as UPJO. Use of a draining urinary catheter for EC scan and IVU helped to confirm UPJO in the presence of VUR, especially Grade 3–5. All patients also underwent VCUG in the filling and voiding phase preoperatively. Radiological features of bladder outlet obstruction, for example, posterior urethral valves, and neurogenic bladder, especially in patients with bilateral VUR were carefully looked for on the VCUG as well as by history and clinical examination and ruled out. VUR was graded as per the International study classification.[8]

Patients who had previously undergone pyeloplasty or intervention for VUR and those with other associated urological problems were excluded from the study. The remaining patients were divided into two groups as follows: Group 1: patients with UPJO alone and Group 2: patients with UPJO and associated VUR.

Informed consent was taken from the parents for pyeloplasty and the requirement for preoperative VCUG. All the patients underwent open modified Anderson Hynes pyeloplasty through an anterolateral retroperitoneal approach. Double J (DJ) stent placed at the time of pyeloplasty was removed 2–3 weeks later under short general anesthesia as a day care procedure. Patients were discharged 2 days after the pyeloplasty on uroprophylaxis (oral amoxycillin; 10 mg/kg hs) until DJ stent removal in Group 1 or until advised to stop in Group 2. Parents were advised to maintain preputial hygiene as we have no routine policy of performing circumcision in boys with VUR. Urine C & S was repeated after DJ stent removal.

Postoperatively, renal function and drainage were assessed by diuretic renogram (EC scan) and IVU after 3 months with draining catheter in situ. The EC scan was repeated 1 year after surgery. Subsequently, only USG KUB was performed on a yearly basis.

Some general guidelines were followed in the management of VUR. In asymptomatic VUR of any grade in infants and Grade I–II VUR in children >1 year age, initial conservative management with uroprophylaxis was preferred, and VCUG repeated at 1-year follow-up. Patients with high-grade VUR, recurrent UTI, and/or a single functioning system were advised early endoscopic dextranomer injection or ureteric reimplantation 3–6 months after the pyeloplasty. VCUG was repeated 3 months later to confirm resolution of VUR. Dimercaptosuccinic acid (DMSA) scan was performed in Group 2 patients preoperatively and 1 year after pyeloplasty. Renal scar was defined as the presence of persistent photopenia.

Successful pyeloplasty was defined as resolution of preoperative symptoms, nonobstructive drainage pattern and improvement or maintenance in function on renal dynamic scan and IVU. The stable function was defined as DRF ±5% compared to preoperative values with values above or below that considered as improvement or deterioration. The drainage on renal dynamic scan was defined as follows: unobstructed drainage (UOD): significant clearance by the end of the dynamic study and minimal retention at 3 h; slow UOD: Significant retention with moderate tracer clearance by the end of the dynamic study and minimal retention at the end of 3 h; and delayed drainage: significant retention with moderate tracer clearance by the end of the dynamic study with moderate tracer retention at 3 h.

A scoring system created by us was used to assess function and drainage on IVU [Table 1]. After an initial plain film, nonionic contrast solution was given as intravenous bolus. The first film was routinely taken at 7 min followed by films at 15 min, 30 min, 1 h, 2 h and occasionally at 4 h. Intravenous lasix was then given and the films taken after 5, 10, and 20 min. Patients were followed up in the outpatients on a regular basis and only those with at least 1-year follow-up were analyzed.

Statistical analysis

Discrete categorical data were presented as n (%). Continuous data were written either in the form of its mean and standard deviation or as median and interquartile range. The normality of quantitative data was checked by measures of Kolmogorov–Smirnov tests of normality. For skewed data or ordered categorical data, nonparameteric Mann–Whitney U-test was used for statistical analysis of two groups. For normally distributed data, Student t-test and for categorical data, comparisons were made by Pearson Chi-square test or Fisher's exact test. Intergroup and intragroup comparison of drainage was performed with Chi-square test. All the statistical tests were two-sided and were performed at a significance level of α = 0.05. The analysis was conducted using Statistical software SPSS version 22.0, (IBM Corporation, Armonk, New York, USA).

RESULTS

A total of 173 patients were investigated for UPJO during the study period. Those with crossing vessel (n=13), previous pyeloplasty elsewhere (n=8), associated vesico-ureteric junction obstruction (n=2), urogenital sinus (n=1), and duplex system (n=3) were excluded. Four patients with papery thin parenchyma and DRF <5% required nephrectomy. Another 7 patients were excluded as they were considered to have only VUR and not UPJO after repeated investigations.

The final analysis was performed in 135 patients who satisfied the eligibility criteria [Table 2]. The prevalence of VUR was 25.9% (35/135) in the study group and 33.3% (31/93) in children aged ≤1 year. The number of infants in Group 2 was statistically highly significant (P = 0.003). The mean age of presentation above 1 year age was lesser in Group 2, but not statistically significant (P = 0.2234) [Table 2].

All except 7 in Group 1 and 2 in Group 2 had normal renal function tests. The blood urea was 26.357 ± 22.699 mg/dL, (8–142 mg/dL) (median 21 mg/dL) in Group 1 and 21.022 ± 13.69 mg/dL (5–80 mg/dL) (median 15 mg/dL) in Group 2. The serum creatinine levels were 0.528 ± 0.527 mg/dL (0.1–4.8 mg/dL), (median 0.4 mg/dL) in Group 1 and 0.422 ± 0.279 mg/dL (0.1–1.8 mg/dL), (median 0.4 mg/dL) in Group 2. One patient in Group 1 had hypertension and another presented with renal rickets.

On USG, the parenchyma was grossly thin in 70/100 (70%) in Group 1 and 23/35 (65.7%) in group 2. In children >1 year, the preoperative DRF was significantly reduced in Group 2 patients (P = 0.007) [Table 3]. Preoperative IVU did not show any statistically significant difference in the function (P = 0.785) or drainage (0.919) between both groups. Narrow adynamic segment of the ureter at the UPJ was confirmed in all the patients during pyeloplasty. There were no intra-operative or immediate postoperative complications, and the DJ stent was removed uneventfully in all, 2–3 weeks after surgery.

Pre-operative abnormal blood urea and serum creatinine levels normalized after surgery. Although there was a mean increase in DRF in both groups, it was not considered significant as it was within 5% range [Table 3]. IVU showed statistically significant improvement in function (Group 1, P = 0.000, Group 2: P =0.003) and drainage (Group 1, P = 0.00, Group 2: P =0.001).

There was a statistically significant improvement in drainage in Group 1 (P = 0.015) compared to Group 2 on EC scan [Table 4]. This was specifically seen in infants (P = 0.043) but not in older children. On IVU drainage at 3 months postoperative, 18.7% units had a score of 1, 12.5% a score of 2, and 68.8% a score of 3 in Group 2 compared to 5.2%, 22.4%, and 72.4%, respectively, in Group 1. Within a group, comparison of drainage on renal scan between 3 months and 1 year showed significant improvement in Group 1 overall (P = 0.052) and Group 1 infants (P = 0.054). In all others, although improvement was present, it was not statistically significant.

Bilateral VUR was noted in 23 patients (65.7%) overall in Group 2, including two patients with bilateral UPJO. There were no abnormalities in the bladder or urethra in these patients on the VCUG. The VUR on the side of the UPJO was invariably of a higher or similar grade compared to the contralateral side. Contralateral VUR (i.e., in the kidney without UPJO) was seen only in Group 2 (21/35 patients [60%]) with the following Grades: I: 1 (4.7%); II: 1 (4.7%); III: 14 (66.7%); IV: 5 (23.8%). Gr IV-V VUR was noted in 24 of 37 units (64.8%) ipsilaterally compared to 5 of 21 (23.8%) contralateral units. Of the 37 units in Group 2, DMSA scan showed no scars in 13, scars in 18 units and resolution of pyelonephritic changes in 6 at 1-year follow-up.

Although asymptomatic, three patients were lost to follow-up in Group 1, 3–9 months after surgery without undergoing any postoperative renal scans. The rest are on regular follow up ranging from 12 - 42 months and remain asymptomatic. No patient required redo pyeloplasty, nephrectomy, or percutaneous nephrostomy after pyeloplasty. Two patients in Group 2 with Grade V VUR had recurrent symptomatic UTI which stopped after ureteric reimplantation [Table 5]. Four others managed conservatively for VUR had 2–3 UTIs in the 1st postoperative year. There were no immediate or late postoperative complications except for the above