Hydronephrosis After Pyeloplasty: "Will It Go Away?"

Analysis of outcomes of robot-assisted laparoscopic pyeloplasty in children from a tertiary pediatric center in South India

Aim

This study aims to analyze the outcomes of robot-assisted laparoscopic pyeloplasty (RALP) in children with pelvi-ureteric junction obstruction (PUJO) over a 10-year period at a tertiary care center in South India.

Methods

This study provides a detailed analysis of prospectively acquired data from 2013 to 2023 of all children who underwent RALP at our institution. Pre- and post-operative renal ultrasound and isotope renography were used to assess outcomes. Detailed information on patient demographics, procedural duration, post-operative pain relief, operation steps, and post-surgical follow-up protocols has been provided. The analysis included all patients who completed a 1-year follow-up.

Result

Between 2013 and 2023, 201 children underwent RALP. Of these, 185 children completed at least 1 year of follow-up and were included in the analysis. The mean age of the cohort was 4.9 years (1 month to 17 years), with males comprising the majority (77.3%). Twenty-five children (13.5%) were younger than 1 year of age. Left-sided PUJO was found to be more common. The mean console time was 76.5 min (40-180 min), and the average hospital stay was 2.8 days (2-5). After surgery, the mean reduction in antero-posterior diameter of the renal pelvis was more than 50% of its pre-operative value and statistically significant (3.3 ± 0.3 to 1.9 ± 0.9 cm). At the end of 1 year, the overall reduction in renal size was also significant (9.7 ± 2.3 cm pre-operative to 8.9 ± 1.8 cm post-operative). The pre-operative Society of Fetal Urology (SFU) grade of hydronephrosis was compared to the post-operative SFU grade, and the improvement (resolution/downgrading) was found to be statistically significant. The median split renal function in this series was 39% pre-operative and 43% post-operative, and the overall functional improvement after RALP was significant. A successful outcome was observed in 181 children (97.8%). Four children experienced persistent severe hydronephrosis and underwent redo stenting and/or redo pyeloplasty (2.1% failure rate). Post-operative complications, according to the Clavien-Dindo classification, were classified as type 1 in three children and type 3b in two children. There were no conversions to open surgery in the series.

Conclusion

RALP emerges as the minimally invasive procedure of choice for children with PUJO at our institution. It is safe, delivering consistently excellent results and minimal complications. Our outcomes are comparable to those of previously published series. We trust that our experience will serve as a roadmap for those centers (especially in South Asia) embarking on a pediatric robotic program.

What to Expect on the Long-term Follow-up of Pediatric Pyeloplasty: Critical Time Intervals and Risk Factors

BACKGROUND

Standard protocol for post-pyeloplasty monitoring in children and natural course of hydronephrosis resolution have not been well defined. We aimed to analyze critical time intervals and risk factors in the long-term clinical outcomes of children who were operated for ureteropelvic junction obstruction.

METHODS

Files of patients who underwent open dismembered pyeloplasty between January 2000 and December 2012 and had a ≥10 years follow-up were retrospectively reviewed. Changes in SFU hydronephrosis grade, pelvis anteroposterior diameter (APD), renal parenchymal thickness, split renal functions (SRF) on MAG-3 scan as well as development of hypertension and proteinuria were noted. Complete resolution was defined as SFU grade 0-1 or APD≤10 mm or ≥50 % APD decrease.

RESULTS

Overall, 223 patients (161 boys, 72.1 %) with a median age of 9 (range 1-185) months underwent unilateral pyeloplasty, whereas 14 patients (13 boys, 92.8 %) with a median age of 4 (range 2-39) months underwent bilateral pyeloplasty. Median follow-up was 13 (range 10-22) years. Complete resolution was observed in 190 patients (85.2 %). None of the cases required re-do pyeloplasty. Regarding unilateral cases, postoperative changes in hydronephrosis reached a plateau at the 60th month. Also, there was no significant difference regarding SRF between the 12th month and the 60th month (p > 0.05). Hypertension developed after a median period of 12 years in 13 (5.4 %) of the patients, while proteinuria developed in four (1.6 %) patients. Bilateral disease (HR: 2.518, p = 0.034) was found to be a significant determinant for development of hypertension and/or proteinuria.

CONCLUSIONS

Our results indicated that ultrasonographic findings stabilized after the 60th month postoperatively, and SRF remained stable between the postoperative 12th and the 60th months. The risk of developing hypertension and/or proteinuria was 2.5 times greater in bilateral cases.

LEVEL OF EVIDENCE

Level II.

Exploring the potential of the novel imidazole-4,5-dicarboxyamide chemical exchange saturation transfer scaffold for pH and perfusion imaging

Here, we describe and assess the potential of 14 newly synthesized imidazole-4,5-dicarboxyamides (I45DCs) for pH and perfusion imaging. A number of these aromatic compounds possess large labile proton chemical shifts (up to 7.7 ppm from water) because of their intramolecular hydrogen bonds and a second labile proton to allow for chemical exchange saturation transfer (CEST) signal ratio-based pH measurements. We have found that the contrast produced is strong for a wide range of substitutions and that the inflection points in the CEST signal ratio versus pH plots used to generate concentration-independent pH maps can be adjusted based on these subsitutions to tune the pH range that can be measured. These I45DC CEST agents have advantages over the triiodobenzenes currently employed for tumor and kidney pH mapping, both preclinically and in initial human studies. Finally, as CEST MRI combined with exogenous contrast has the potential to detect functional changes in the kidneys, we evaluated our highest performing anionic compound (I45DC-diGlu) on a unilateral urinary obstruction mouse model and observed lower contrast uptake in the obstructed kidney compared with the unobstructed kidney and that the unobstructed kidney displayed a pH of ~ 6.5 while the obstructed kidney had elevated pH and an increased range in pH values. Based on this, we conclude that the I45DCs have excellent imaging properties and hold promise for a variety of medical imaging applications, particularly renal imaging.

Ultrasonographic stabilization of hydronephrosis after pyeloplasty: Key determinant of postoperative follow-up?

INTRODUCTION

Although more than 1500 pediatric pyeloplasties are performed in the United States per year, there is a lack of consensus on the adequate imaging modality and timing of follow-up after surgery.

OBJECTIVE

The aim of this study is to evaluate if ultrasonographic stabilization in the grade of hydronephrosis after pyeloplasty is an adequate parameter to define the optimal length of follow-up after surgery and to detect failed procedures. Secondarily, we want to analyze clinical variables that could impact ultrasonographic stabilization.

STUDY DESIGN

This is a retrospective chart review of patients who underwent pyeloplasty between 2012 and 2020. Patients were included if they were ≤21 years-old at the time of surgery, had pre and postoperative renal-ultrasounds, had ≥3 months of postoperative follow-up, and had met the criteria for ultrasonographic stabilization after surgery. Ultrasonographic stabilization was defined as 2 consecutive ultrasounds after pyeloplasty, a minimum of 1-month apart, with the same degree of hydronephrosis according to the Society for Fetal Urology (SFU) grading system. Data concerning clinical, surgical, and postoperative variables were collected.

RESULTS

A total of 143 pyeloplasties met the inclusion criteria. Median age at surgery was 10.5 months with a median post-operative follow-up time of 29 months. Ultrasonographic stabilization was achieved in a mean time of 14.5 months post-operatively. Compared to the preoperative US SFU grade, at ultrasonographic stabilization 127 (88.9%) patients had an improvement of ≥1 grades of hydronephrosis. There were 9 pyeloplasty failures that were diagnosed and surgically corrected in a median of 7.5 months after the initial surgery. No clinical or surgical variables were associated with time to achieve ultrasonographic stabilization.

DISCUSSION

There is great variability in the length of follow-up after pyeloplasty, ranging from 3-months to 7-years. In our cohort, the bast majority of patients had achieved ultrasonographic stabilization and displayed improvement in their initial grade of hydronephrosis by 14.5 months after surgery. Timeframe in which surgical failures were diagnosed and corrected. There were not clinical or surgical variables associated to time to achieve stabilization. Similar results have been reported in the literature; however, most of them have evaluated as their main outcome resolution and not stabilization of hydronephrosis.

CONCLUSION

Ultrasonographic stabilization is a suitable and non-invasive parameter for determining the length of follow-up after unilateral pyeloplasty, as it is an adequate timeframe for identifying failed pyeloplasties, observing improvement or stabilization of hydronephrosis, and performing any additional procedure required after the primary repair.

Dynamic Contrast Enhanced-MR CEST Urography: An Emerging Tool in the Diagnosis and Management of Upper Urinary Tract Obstruction

Upper urinary tract obstructions (UTOs) are blockages that inhibit the flow of urine through its normal course, leading to impaired kidney function. Imaging plays a significant role in the initial diagnosis of UTO, with anatomic imaging (primarily ultrasound (US) and non-contrast computed tomography (CT)) serving as screening tools for the detection of the dilation of the urinary collecting systems (i.e., hydronephrosis). Whether hydronephrosis represents UTO or a non-obstructive process is determined by functional imaging (typically nuclear medicine renal scintigraphy). If these exams reveal evidence of UTO but no discernable source, multiphase contrast enhanced CT urography and/or dynamic contrast enhanced MR urography (DCE-MRU) may be performed to delineate a cause. These are often performed in conjunction with direct ureteroscopic evaluation. While contrast-enhanced CT currently predominates, it can induce renal injury due to contrast induced nephropathy (CIN), subject patients to ionizing radiation and is limited in quantifying renal function (traditionally assessed by renal scintigraphy) and establishing the extent to which hydronephrosis is due to functional obstruction. Traditional MRI is similarly limited in its ability to quantify function. DCE-MRU presents concerns regarding nephrogenic systemic fibrosis (NSF), although decreased with newer gadolinium-based contrast agents, and regarding cumulative gadolinium deposition in the basal ganglia. DCE-MR CEST urography is a promising alternative, employing new MRI contrast agents and imaging schemes and allowing for concurrent assessment of renal anatomy and functional parameters. In this review we highlight clinical challenges in the diagnosis and management of UTO, identify key advances in imaging agents and techniques for DCE-MR CEST urography and provide perspective on how this technique may evolve in clinical importance.

Resolution of hydronephrosis after pyeloplasty in children

BACKGROUND

There is still a lack of knowledge regarding the natural course of resolution of hydronephrosis after pyeloplasty, and no consensus exists on how resolution of hydronephrosis is defined or when resolution is expected to occur.

OBJECTIVE

To determine when resolution of hydronephrosis occurs following pyeloplasty, by type of obstruction and by surgical approach.

METHODS

This retrospective study included 125 children age <15 years treated with pyeloplasty and followed for two years with repeated ultrasound and MAG3 scan. Children with single kidneys, bilateral disease, and without hydronephrosis were excluded. Children with re-interventions were excluded in the evaluation of hydronephrosis but not in terms of success rate. Outcomes time to resolution of hydronephrosis (Anterior-Posterior diameter (APD) <10 mm or >50% reduction of APD) and 2-year success rate. Exposure was surgical approach and type of obstruction (intrinsic/extrinsic). Survival analysis was performed, adjusting for age, gender, year, laterality, preoperative renal function on MAG3, calyces dilatation and APD in the multivariable analysis.

RESULTS

At 12 months and 24 months follow-up, 90% and 93% had reached resolution, respectively. All children with persistent dilatation had improved drainage and stable or improved function on MAG3. There was no difference in time to resolution of hydronephrosis between open versus robotic-assisted laparoscopic surgery (adjusted HR 0.90, [0.54-1.52], p = 0.70), nor between different types of obstruction (aHR 0.84 [0.53-1.34], p = 0.47). Eight children had re-intervention, all identified within 3 months after primary surgery, and four had a postoperative drop on MAG3, giving a total success rate of 91% (121/135).

DISCUSSION

The vast majority of cases resolve and do so within 12 months from surgery. Since the improvement of hydronephrosis seems small between the first and second year after surgery, the value of follow-up beyond 12 months could be questioned. Based on the present study and previous literature we would recommend that children with persisting dilatation should continue their follow-up with ultrasound beyond 12 months. Children with complete resolution of their hydronephrosis at 12 months do not likely benefit from further follow-up. The same follow-up protocol should be applied, regardless of whether the obstruction is intrinsic or extrinsic in nature, or the surgery is performed with open or robotic-assisted approach. Overall, the definition of resolution of hydronephrosis varies in the literature and have impact on the results and may compromise comparisons.

CONCLUSION

Surgical approach or type of obstruction does not seem to affect time to resolution of hydronephrosis after pyeloplasty in children. Follow-up with ultrasound beyond 12 months does not seem to benefit children with complete resolution.

Use of double-J ureteric stents post-laparoscopic pyeloplasty to treat ureteropelvic junction obstruction in hydronephrosis for pediatric patients: a single-center experience

OBJECTIVES

We aimed to investigate the safety concerns associated with placing double-J ureteric stents post-laparoscopic pyeloplasty surgery for congenital ureteropelvic junction obstruction (UPJO) and hydronephrosis.

METHODS

A total of 1349 patients with postoperative double-J stent placement at our center were included. Clinical variables for enrolled patients were collected by two independent authors. We compared clinical variables and the efficacy of stenting post-laparoscopic pyeloplasty.

RESULTS

The mean age of the patients was 4.23 ± 2.39 years. A total of 58.49% of patients were diagnosed with left UPJO with hydronephrosis and 33.95% were diagnosed with right UPJO. Furthermore, 7.56% of patients had bilateral UPJO. In all cases, 96.96% of indwelling double-J stents were successfully removed 4 weeks post-surgery. A total of 3.04% of the patients still required further management, including stent migration to the renal pelvis (0.37%), stent migration to the bladder (0.30%), prolapse of the stent through the ureter (0.15%), blockage of stents (1.85%), and fouling of stents (0.37%).

CONCLUSIONS

Double-J ureteric stents used after laparoscopic pyeloplasty for treating UPJO in hydronephrosis for pediatric patients is a safe, feasible, and beneficial method, which can be recommended for routine procedures. However, caution should be practiced for follow-up and removal using this method.

The impact of post-procedural ureteric stent duration on the outcome of retrograde endopyelotomy for management of failed open pyeloplasty in children: a preliminary report

Background: To evaluate the outcome of retrograde endopyelotomy as a minimally invasive option for management of failed open pyeloplasty in children and assess how the duration of post-procedural stenting may affect the endopyelotomy outcome.

Methods: A total of 15 patients with secondary UPJO (Ureteropelvic junction obstruction) underwent retrograde endopyelotomy. The procedure was done using low-energy monopolar electrocautery hook under direct vision of pediatric ureteroscope and control of fluoroscopy. Double J stent was placed after the operation in all cases. Stent was removed in another session, 8 weeks (Group A, n=7) vs. 12 weeks (Group B, n=8) after endopyelotomy. Patients in both Groups were followed one, six and twelve months after the stent removal, and the anteroposterior renal pelvis diameter (APD), renal cortical thickness (CT) and degree of hydronephrosis (HDN) were recorded using the repeated measure test. P-value less than 0.05 were significant. We analyzed the data using SPSS software, version 20.

Results: The median interquartile range (IQR) age at time of surgery for group A and B were 24 (62) months and 12 (50) months respectively. Median (IQR) times between previous pyeloplasty and endopyelotomy were 6 (6) months and 12 (8.5) months in groups A and B, respectively. The success rate of endopyelotomy after 12 months was 57.1% in group A and 87.5% in group B. The resolution of HDN was more prominent in the 12 week stenting group compared to the 8 week group during the 12 months follow-up period (p=0.030). The APD and CT in group B compared to group A was improved during follow-up period.

Conclusion: A higher one-year success rate of retrograde endopyelotomy in terms of improvements in the degree of HDN, APD and CT was observed when the double j stent was remained for 12-weeks rather than 8-weeks. This observation need to be validated in a large cohort study with a long term post procedural follow up.