Ureteropelvic junction obstruction in children: 10 years' experience in one institution

99mTc-MAG3 diuresis renography in differentiating renal obstruction: Using statistical parameters as new quantifiable indices

OBJECTIVE

The aim of this study was to research, develop and assess the feasibility of using basic statistical parameters derived from renogram, "mean count value (MeanCV) and "median count value (MedianCV)", as novel indices in the diagnosis of renal obstruction through diuresis renography.

SUBJECTS AND METHODS

First, we re-digitalized and normalized 132 renograms from 74 patients in order to derive the MeanCV and MedianCV. To improve the performance of the parameters, we extrapolated renograms by a two-compartmental modeling. After that, the cutoff points for diagnosis using each modified parameter were set and the sensitivity and specificity were calculated in order to determine the best variants of MeanCV and MedianCV that could differentiate renal obstruction status into 3 distinct classes - i) unobstructed, ii) slightly obstructed, and iii) heavily obstructed.

RESULTS

The modified MeanCV and MedianCV derived from extended renograms predicted the severity of the renal obstruction. The most appropriate variants of MeanCV and MedianCV were found to be the MeanCV₅₀ and the MedianCV₆₀. The cutoff points of MeanCV₅₀ in separating unobstructed and obstructed classes as well as slightly and heavily obstructed classes were 0.50 and 0.72, respectively. The cutoff points of MedianCV₆₀ in separating unobstructed and obstructed classes as well as slightly and heavily obstructed classes were 0.35 and 0.69, respectively. Notably, MeanCV₅₀ and MedianCV₆₀ were not significantly influenced by either age or gender.

CONCLUSIONS

The MeanCV₅₀ and the MedianCV₆₀ derived from a renogram could be incorporated with other quantifiable parameters to form a system that could provide a highly accurate diagnosis of renal obstructions.

Radiation-free monitoring in the long-term follow-up of pyeloplasty: Are ultrasound new parameters good enough to evaluate a successful procedure?

INTRODUCTION

Long-term evolution of residual hydronephrosis after successful pyeloplasty is not common. In this report, we have studied new ultrasound parameters, and have investigated the frequency of residual hydronephrosis. We highlight alternative radiation-free monitoring of pediatric pyeloplasties with ultrasound alone.

PATIENTS AND METHODS

Children who had undergone successful open Anderson-Hynes pyeloplasties in the period 2001-2010 were followed up. Exclusion criteria included non-clearly obstructed renography scans (tracer clearance half-time < 20 min), crossing vessels, failed pyeloplasty, bilateral disease, other renal concomitant anomaly, absence of ultrasound measurements, and loss to follow up (<1 year). Postoperative (postoperative) ultrasound parameters were anteroposterior (AP) diameter, pelvis-cortex (P/C) ratio, a proportion that takes in account these two values, enhancing sensitivity to evaluate minimal evolutive changes), and percentage of improvement (PI) in AP diameter (which reflects in relative means the evolution of each AP diameter, being 0% no change, and 100% absence of hydronephrosis) (Figure). Echographic checks were made at 3 and 6 months postoperatively and then yearly afterwards. SPSS software (v. 17.0 IBM, College Station, TX, USA) was used.

RESULTS

Out of 80 pyeloplasties performed in the above-mentioned period, 44 patients (i.e., 44 renal units) fulfilled the inclusion criteria for the main study. The median age at time of operation was 15 months (range 2 months-10.3 years). The median follow-up was 4.5 years (range 1-12 years). The mean preoperative anteroposterior diameter was 26 mm (range 16-54 mm). At the third postoperative check, the mean the PI was 29%, and rose to 53% at 6 months (p=0.027). Posterior controls showed a stable yearly PI during follow-up, without statistically significant variations (40-59% in subsequent years, p>0.5). The P/C ratio had already downgraded significantly at the third postoperative check (4.6 preoperative vs. 1.8 postoperative; p=0.03). A subgroup analysis of failed pyeloplasty (4 renal units) showed all PI < 15% at the third postoperative month (sensitivity 100%, specificity 86%). Complete resolution of hydronephrosis occurred in nine patients (20%).

DISCUSSION

The P/C ratio and PI are new feasible ultrasound parameters in pyeloplasty follow-up. Early improvement in the P/C ratio can be expected and might avoid repeated ionizing scans. A PI>15% in subsequent postoperative checks might be enough for safe monitoring with ultrasound alone. Thus, renograms may be solicited only in these cases where ultrasound parameters do not improve in the first 6 postoperative months. Afterwards, ultrasound parameters often remain stable in the long term. Absence of hydronephrosis could only be documented in the long term in one out of every five patients.

Surgical outcomes of laparoscopic dismembered pyeloplasty in children with giant hydronephrosis secondary to ureteropelvic junction obstruction

OBJECTIVE

Studies of surgical outcomes after reconstructive surgery for giant hydronephrosis (GH) secondary to ureteropelvic junction (UPJ) obstruction are limited. Over the past two decades, laparoscopic pyeloplasty has gradually replaced open repair in children in several centres. The objective of this study was to assess surgical outcomes of laparoscopic pyeloplasty in children with GH.

MATERIALS AND METHODS

Children with unilateral primary UPJ obstruction and GH were prospectively included and underwent laparoscopic pyeloplasty. Postoperative ultrasonography was repeated at 3 and 12 months to assess renal parenchymal thickness, and similarly a renogram was repeated to assess improvement in differential renal function.

RESULTS

During the study period 2005-2009, 53 children underwent laparoscopic dismembered pyeloplasty for UPJ obstruction. Of these, 8 children had GH caused by UPJ obstruction. The postoperative differential renal function improved in all of them. The postoperative improvement in renal parenchymal thickness at the end of 12 months was comparable to that of the non-GH group.

CONCLUSIONS

At 12 months, surgical outcomes after laparoscopic pyeloplasty for GH were satisfactory. Relief of obstruction allows adequate and comparable nephron sparing.