Ureteroureterostomy: An Alternative to Ureteroneocystostomy in Select Cases of Pediatric Renal Transplantation

Review - Renal transplantation for congenital urological diseases

INTRODUCTION

Congenital Anomalies of the Kidney and Urinary Tract (CAKUT) are structural disorders originating prenatally and present at birth. Affecting 4.2 to 1000 per 10,000 births globally, CAKUT includes conditions like posterior urethral valves, cloacal anomalies, and reflux nephropathy. These anomalies can lead to chronic kidney disease (CKD) or end-stage kidney disease (ESKD) in children, necessitating renal replacement therapy or transplantation.

OBJECTIVES

This article aims to provide an updated perspective on pediatric kidney transplantation for children with CAKUT, emphasizing pre-transplant evaluation and management to optimize long-term outcomes.

METHODS

A comprehensive urologic evaluation is essential for children with ESKD being considered for kidney transplantation. Key pre-transplant investigations include kidney/bladder ultrasound (US), voiding cystourethrogram (VCUG), uroflowmetry, and urodynamics (UDS)/video-urodynamics (VUDS). Non-operative interventions such as pharmacotherapy and clean intermittent catheterization (CIC) are also considered. Surgical interventions, like augmentation cystoplasty or continent catheterizable channels, are evaluated based on individual patient needs.

RESULTS

Kidney/bladder US and VCUG provide essential anatomical information. UDS offers comprehensive functional data, identifying hostile bladders needing pre-transplant optimization. Non-surgical measures like anticholinergics and CIC improve bladder function, while surgical options enhance compliance and capacity. Concurrent interventions during transplantation are feasible but require careful consideration of risks and benefits.

DISCUSSION

Children with CAKUT undergoing kidney transplantation exhibit comparable or better graft survival rates than those without CAKUT. However, those with lower urinary tract obstructions (LUTO) may have poorer long-term outcomes. UDS is crucial for evaluating bladder function pre-transplant, guiding the need for interventions. Long-term monitoring for urinary tract infections (UTIs) and bladder dysfunction is essential.

CONCLUSION

Optimal outcomes in pediatric kidney transplantation for CAKUT patients require thorough pre-transplant evaluation and management, particularly for those with LUTO. Multidisciplinary approaches ensure careful monitoring and timely interventions, improving graft survival and quality of life for these patients.

Native nephrectomy in advanced pediatric kidney disease: indications, timing, and surgical approaches

In pediatric kidney failure, native kidneys may pose a risk to successful transplant outcomes. The indications and timing of native nephrectomy represent a controversial management decision. A lack of high-quality, outcomes-based data has prevented development of evidence-based guidelines for intervention. In this article, we review the published literature on medical indications for native nephrectomy and current knowledge gaps. In addition, we provide a surgical perspective regarding timing and approach.

Current management of symptomatic vesicoureteral reflux in pediatric kidney transplantation-A European survey among surgical transplant professionals

BACKGROUND

Vesicoureteral reflux (VUR) is common in children and adolescents undergoing kidney transplantation (KTx) and may adversely affect allograft kidney function.

METHODS

To explore the current management of symptomatic native and allograft VUR in pediatric KTx recipients, an online survey was distributed to European surgical transplant professionals.

RESULTS

Surgeons from 40 pediatric KTx centers in 18 countries participated in this survey. Symptomatic native kidney VUR was treated before or during KTx by 68% of the centers (all/selected patients: 33%/67%; before/during KTx: 89%/11%), with a preference for endoscopic treatment (59%). At KTx, 90% favored an anti-reflux ureteral reimplantation procedure (extravesical/transvesical approach: 92%/8%; preferred extravesical technique: Lich-Gregoir [85%]). Management strategies for symptomatic allograft VUR included surgical repair (90%), continuous antibiotic prophylaxis (51%), bladder training (49%), or noninterventional surveillance (21%). Redo ureteral implantation and endoscopic intervention for allograft VUR were equally reported (51%/49%).

CONCLUSIONS

This survey shows uniformity in some surgical aspects of the pediatric KTx procedure. However, with regard to VUR, there is a significant variation in practice patterns that need to be addressed by future well-designed and prospective studies. In this way, more robust data could be translated into consensus guidelines for a more standardized and evidence-based management of this common condition in pediatric KTx.

Assessing the role of upside-down (inverted) renal allografts in pediatric kidney transplantation: a propensity-score matched analysis

OBJECTIVE

To evaluate the implications of inverted (upside-down) kidney configuration in pediatric renal transplantation employing a comparative analysis with at least 1-year follow-up.

METHODS

Patients who underwent kidney transplantation at our institution between January 2011 and June 2021 were reviewed. Patients who had an inverted renal transplant were propensity-score matched (PSM) in 1:2 ratio with those who had traditional orientation transplant. The outcomes assessed included delayed graft function (DGF), urine leak, lymphocele, rejection, allograft calculus, ureteric stricture, and nadir creatinine.

RESULTS

A total of 24 patients with inverted orientation were identified. Following PSM, 41 patients were matched, with exclusions due to incompatible propensity scores. Baseline characteristics were appropriately matched, and no significant differences were noted between the two groups. There were no differences in: delayed graft function (0/24 vs. 3/41, p = 0.290), urine leak (3/24 vs. 2/41, p = 0.350), lymphocele (2/24 vs. 4/41, p = 1.000), rejection (3/24 vs. 5/41, p = 1.000), graft calculus (2/24 vs. 0/41, p = 0.133), and ureteric stricture (0/24 vs. 2/41, p = 0.527). The two cases of renal calculus seen in the inverted transplant group occurred on post-operative day 13 and 1584, both were managed without complications. There was no difference in nadir creatinine (median 34umol/L IQR23-57 vs. 35 umol/L IQR 20-50, p = 0.624) or time to nadir creatinine (8 days IQR 6-12 vs. 8 days IQR 7-28, p = 0.315).

CONCLUSION

Inverting a renal allograft does not appear to significantly contribute to increased risk of post-operative adverse outcomes. When aiming to achieve the best anatomical placement to secure a comfortable vascular anastomosis, inverting the allograft should be considered.

Utility of pre-transplant lower urinary tract investigation in pediatric renal transplant population after referral: A 16-year institutional experience

To evaluate the clinical utility of pre-renal transplant LUT investigations in pediatric populations after their referral for transplant evaluation based on the etiology of their ESRD. A 16 year retrospective review of patients undergoing RT performed at our institution was performed. Patients were stratified into two groups: Group 1-non-urologic and Group 2-urologic etiology for ESRD. Baseline characteristics, pre-transplant LUT investigations, and urologic interventions were assessed. One-year clinical outcomes were compared between those with and without LUT investigations following referral for renal transplantation (RT). 227 patients and 97 patients were identified for Groups 1 and 2, respectively. 19% of Group 1 and 73% of Group 2 had VCUG, while 1% and 13%, respectively, had UDS ordered following referral for RT. In both groups, >50% of VCUG and UDS were ordered without specific clinical concerns. These had low likelihood of prompting interventions, both pre-transplant (Group 1-VCUG 0%, UDS 0%; Group 2-VCUG 0%, UDS 8%) or post-transplant (Group 1-0%, Group 2-5%). In both groups, LUT investigation following referral for RT did not lead to differences in 1 year outcomes assessed. In anticipation of pediatric RT, LUT investigations ordered without clinical indications did not provide information that altered management prior to transplantation.

Multimodality imaging of pancreas-kidney transplants

Simultaneous pancreas-kidney transplant remains a treatment option for patients with insulin-dependent diabetes mellitus type 1, aimed at restoring normoglycemia, alleviating insulin dependency, avoiding diabetic nephropathy, and thereby improving the quality of life. Imaging remains critical in the assessment of these transplant grafts. Ultrasound with Doppler remains the primary imaging modality for establishing baseline assessment of the graft as well as for evaluating vascular, parenchymal, and perigraft complications. Noncontrast MR imaging is preferred over non-contrast CT for evaluation of parenchymal or perigraft complications in patients with decreased renal function, although contrast-enhanced CT/MR imaging may be obtained following multidisciplinary consultation in cases with high clinical and laboratory suspicion for graft dysfunction. Catheter angiography is reserved primarily for therapeutic intervention in suspected or confirmed vascular complications. An understanding of the surgical techniques and imaging appearance of a normal graft is crucial to identify potential complications and direct timely management. This article provides an overview of surgical techniques, normal imaging appearance, as well as the spectrum of imaging findings and potential complications in pancreas-kidney transplants.

Imaging of Renal Transplant Complications throughout the Life of the Allograft: Comprehensive Multimodality Review

The kidney is the most commonly transplanted solid organ. Advances in surgical techniques, immunosuppression regimens, surveillance imaging, and histopathologic diagnosis of rejection have allowed prolonged graft survival times. However, the demand for kidneys continues to outgrow the available supply, and there are efforts to increase use of donor kidneys with moderate- or high-risk profiles. This highlights the importance of evaluating the renal transplant patient in the context of both donor and recipient risk factors. Radiologists play an integral role within the multidisciplinary team in care of the transplant patient at every stage of the transplant process. In the immediate postoperative period, duplex US is the modality of choice for evaluating the renal allograft. It is useful for establishing a baseline examination for comparison at future surveillance imaging. In the setting of allograft dysfunction, advanced imaging techniques including MRI or contrast-enhanced US may be useful for providing a more specific diagnosis and excluding nonrejection causes of renal dysfunction. When a pathologic diagnosis is deemed necessary to guide therapy, US-guided biopsy is a relatively low-risk, safe procedure. The range of complications of renal transplantation can be organized temporally in relation to the time since surgery and/or according to disease categories, including immunologic (rejection), surgical or iatrogenic, vascular, urinary, infectious, and neoplastic complications. The unique heterotopic location of the renal allograft in the iliac fossa predisposes it to a specific set of complications. As imaging features of infection or malignancy may be nonspecific, awareness of the patient's risk profile and time since transplantation can be used to assign the probability of a certain diagnosis and thus guide more specific diagnostic workup. It is critical to understand variations in vascular anatomy, surgical technique, and independent donor and recipient risk factors to make an accurate diagnosis and initiate appropriate treatment.^©RSNA, 2019.

Is anuria prior to pediatric renal transplantation associated with poor allograft outcomes?

INTRODUCTION

Anuria from end-stage renal disease leads to a defunctionalized bladder and may pose technical challenges at the time of renal transplantation. Anuria's effect on bladder function after renal transplantation is considered to be minimal in adults, although a paucity of evidence is available in children. The purpose of this study was to examine the effects of anuria prior to pediatric renal transplantation for ESRD due to medical renal disease on allograft outcome.

METHODS

We performed a retrospective review of pediatric patients who underwent renal transplantation for medical renal disease at our institution between 2005 and 2016. Demographics and clinical data were assessed. We also compared GFR at 1 year post-transplant for medical renal patients with history of anuria and those without.

RESULTS

Twenty-one patients fulfilled our inclusion criteria with median duration of anuria was 10 months. Preoperative VCUG was available in five patients and their bladder capacity was 29% of expected bladder capacity for age (range 8%-41%). Anticholinergic therapy was prescribed in six patients (28%) for a mean duration of 5 months (range 1-16 months). Comparison of GFR at 1 year post-transplant in anuria group and those without anuria showed no difference (69 vs 75 mL/min, P = 0.37). No correlation was observed between duration of anuria and post-transplant GFR.

CONCLUSION

The majority of children in our pretransplant anuria cohort did not develop bladder dysfunction after renal transplantation. No difference was observed between GFR at 1 year when comparing anuric to non-anuric transplant recipients of medical renal disease etiology.

"Inverted" positioning of renal allograft during kidney transplantation in children and adolescents: A single-institution comparative analysis

Renal transplantation is the treatment of choice in children with end-stage renal failure. Limitations in patient anatomy or a short donor renal vein may necessitate intraoperative inversion of the kidney. There is little evidence to support the use of this surgical technique, and no evidence in the pediatric population. This study identifies the perioperative and post-operative outcomes of inverted renal transplants in pediatric patients. We reviewed all patients having a renal transplant between January 2012 and December 2016 and collected short- and long-term outcomes of patients who received an inverted allograft. Early graft function was defined as the time to reach creatinine nadir. During this time, our hospital performed 81 transplants, and 50 (62%) were from deceased donors, including the 6 (12%) patients who received inverted renal grafts. Half (3/6) were female, 5/6 (83%) were dialysis-dependent, and the median age at surgery was 13 years (range 9-16 years). There was no significant difference in mean creatinine nadir values (P = 0.518) and the time to creatinine nadir mean values (P = 0.190) between the upright and inverted renal transplant groups. There were also no significant differences in rates of post-operative complications between the upright and inverted allograft recipients. Inversion of renal allografts in pediatric patients is a viable surgical technique to compensate for shortcomings in patient anatomy or in special cases of renal transplantation involving a short donor renal vein. Future research should focus on outcomes of a larger group of pediatric inverted renal transplant patients.

Comparing treatment modalities for transplant kidney vesicoureteral reflux in the pediatric population

INTRODUCTION

Non-refluxing ureteral reimplantation is favored in pediatric renal transplantation to prevent complications, such as vesicoureteral reflux (VUR) in the transplant ureter. VUR resulting in febrile urinary tract infections remains a problem in this population, leading to repeated hospitalizations and increased morbidity. Revision of the vesicoureteral anastomosis can be a surgical challenge due to scar tissue and tenuous vascularity of the transplant ureter. Therefore, alternative options such as endoscopic injection of Deflux at the neo-orifice and surveillance with prophylactic antibiotics have emerged as potential treatment modalities for transplant ureter VUR.

OBJECTIVE

The authors reviewed their experience of the management of VUR in the transplant ureter, comparing outcomes of various modalities.

STUDY DESIGN

With Institutional Review Board approval, a retrospective chart review of all renal transplant patients from January 2002 to January 2017 was conducted. All patients with VUR on voiding cystourethrogram (VCUG) after surgery were identified. Indications for end-stage renal disease, urologic comorbidities, pretransplant VCUG, and operative details were recorded. After transplantation, febrile urinary tract infections, ultrasound findings, and any further interventions-surveillance, subureteral endoscopic injection of Deflux, or ureteral reimplantation-were documented along with their outcomes.

RESULTS

Overall, VUR was identified in 35/285 (12.3%) transplant patients after a non-refluxing ureteroneocystostomy. VUR was managed with surveillance in 17/35 (49%), intravesical Deflux injection in 11/35 (31%), and immediate redo ureteral reimplantation in 7/35 (20%). Ten out of 11 patients undergoing Deflux injection had a postoperative VCUG. All patients developed VUR recurrence; the majority showed immediate failure and only 1/10 showed late recurrence. Of the immediate failures, 3/9 patients were maintained on prophylactic antibiotics, and 6/9 patients underwent ureteral reimplantation. In these six patients undergoing reimplantation after failed Deflux, 3/6 (50%) patients required additional surgeries: One patient developed recurrence of reflux and two patients developed ureterovesical junction obstruction. In contrast, no complications were seen in patients undergoing primary ureteral reimplantation.

DISCUSSION

The study is limited by low numbers and a retrospective design. However, the results of this study differ significantly from the published Deflux series showing a success rate of more than 50% in the treatment of transplant kidney VUR. In fact, post-Deflux redo ureteral reimplantation was associated with an increased risk of postoperative complication.

CONCLUSION

The use of Deflux in the post-transplant setting has poor results. In the study series, 11/11 patients demonstrated clinical and radiographic failure. Therefore, as an institution the authors do not recommend Deflux as first-line treatment of VUR in the transplant patient.

Impact of Adjuvant Urinary Diversion versus Valve Ablation Alone on Progression from Chronic to End Stage Renal Disease in Posterior Urethral Valves: A Single Institution 15-Year Time-to-Event Analysis

PURPOSE

Long-term progression to end stage renal disease of valve ablation alone vs ablation followed by additional urinary diversion were compared among children with stage 3 chronic kidney disease due to posterior urethral valves.

MATERIALS AND METHODS

We performed a retrospective study of children with posterior urethral valves and stage 3 chronic kidney disease treated at a single institution between 1986 and 2011. The 3 treatment groups were classified as group 1-valve ablation alone, group 2-ablation plus subsequent vesicostomy and group 3-ablation followed by ureterostomies and/or pyelostomies. Baseline demographic characteristics were analyzed. Statistical analyses compared the incidence of time to end stage renal disease among the intervention groups using the Fisher-Freeman-Halton exact test and Kaplan-Meier analysis with the log rank test. Cox regression was used to determine predictors of end stage renal disease progression.

RESULTS

A total of 40 eligible patients were included in the study (group 1-14 patients, group 2-13 patients, group 3-13 patients). Baseline characteristics and post-intervention estimated glomerular filtration rate revealed no significant between-group differences. A statistically significant difference in progression to end stage renal disease was noted within 1 year after diagnosis of stage 3 chronic kidney disease among the treatment groups (log rank test p=0.02). However, cumulative end stage renal disease incidence at 15-year followup showed no statistical difference (log rank test p=0.628). Cox regression analysis determined that bilateral renal dysplasia (HR 2.76, 95% CI 1.21-6.30) and estimated glomerular filtration rate 60 ml/minute/1.73 m² or greater after intervention (HR 0.23, 95% CI 0.09-0.61) were predictive of the likelihood of progression to end stage renal disease.

CONCLUSIONS

Urinary diversion following valve ablation in children with stage 3 chronic kidney disease associated with posterior urethral valves may temporarily delay progression to end stage renal disease. However, no long-term benefit was noted from diversion in the ultimate incidence of end stage renal disease, suggesting that these interventions should be seen as a temporizing measure. Bilateral renal dysplasia and post-intervention estimated glomerular filtration rate are independent variables predicting overall chronic kidney disease progression.