Ureteral complications after renal transplant in children: timing of presentation, and their open and endoscopic management

The Extended Utilization of Bulking Agents in Pediatric Urology

PURPOSE OF REVIEW

Traditional surgical management for urinary incontinence and vesicoureteral reflux often requires complex reconstructive surgery and extended hospitalizations. Since the introduction of endoscopic bulking agents in 1973, there has been increasing interest in the use of endoscopic injection (EI) and bulking for the treatment of a variety of pediatric urologic disorders. The purpose of this review is to summarize the most recent literature addressing the use of bulking agents in pediatric urology.

RECENT FINDINGS

The most recent literature has focused primarily on the use of EI of bulking agents at the bladder neck for the treatment of urinary incontinence. Other uses of EI of bulking agents has focused on the treatment of vesicoureteral reflux (VUR) in patients with anatomic abnormalities or treatment of incontinence catheterizable channels. The development of advanced techniques for endoscopic injection along with safe, stable bulking agents has allowed for the treatment of a variety of urologic conditions. This minimally invasive procedure offers an additional tool for the pediatric urologist's armamentarium in the treatment of urinary incontinence and VUR.

Ureteral stricture after pediatric kidney transplantation: Is there a role for percutaneous antegrade ureteroplasty?

INTRODUCTION

Ureteral obstruction following pediatric kidney transplantation occurs in 5-8% of cases. We describe our experience with percutaneous antegrade ureteroplasty for the treatment of ureteral stricture in pediatric kidney transplant patients.

METHODS

We retrospectively reviewed all pediatric kidney transplantation patients who presented with ureteral stricture and underwent percutaneous antegrade ureteroplasty at our institution from July 2009 to July 2021. Variables included patient demographics, timing of presentation, location and extent of stricture, ureteroplasty technique and clinical outcomes. Our primary outcome was persistent obstruction of the kidney transplant.

RESULTS

Twelve patients met inclusion criteria (4.2% of all transplants). Median age at time of ureteroplasty was 11.5 years (range: 3-17.5 years). Median time from kidney transplantation to ureteroplasty was 3 months. Patency was maintained in 50% of patients. Seven patients (58.3%) required additional surgery. Four patients developed vesicoureteral reflux. Patients with persistent obstruction had a longer time from transplant to ureteroplasty compared to those who achieved patency (19.3 vs 1.3 months, p = 0.0163). Of those treated within 6 months after transplantation, two patients (25%) required surgery for persistent obstruction (p = 0.06). All patients treated >1 year after transplantation had persistent obstruction following ureteroplasty (p = 0.06).

CONCLUSION

Percutaneous antegrade ureteroplasty can be considered a viable minimally invasive treatment option for pediatric patients who develop early ureteral obstruction (<6 months) following kidney transplantation. In patients who are successfully treated with ureteroplasty, 67% can develop vesicoureteral reflux into the transplant kidney. Patients who fail early percutaneous ureteroplasty or develop obstruction >1 year after transplantation are best managed with surgical intervention.

Overview of pediatric kidney transplantation

Kidney transplantation is the treatment of choice for pediatric patients with end-stage kidney disease. Unlike adult recipients undergoing transplantation, special considerations must be taken when transplanting children based on the underlying etiology of kidney disease, previous surgical procedures, anatomical limitations and necessary technical adjustments. Additionally, the choice of donor must be measured to ensure optimal graft survival given a longer post-transplant life expectancy. Those topics as well as frequently encountered postoperative complications are also discussed in this publication.

The utility of native ureter in the management of ureteral complications in children after renal transplantation

BACKGROUND

Ureteral complications after renal transplantation in children are a major source of morbidity. Management is complex and variable.

METHODS

With IRB approval, health records were retrospectively reviewed of patients who: were <18 years, underwent kidney transplant between 1997 and 2017, had at least 2 years of follow-up, and underwent interventions due to post-transplant ureteral complications.

RESULTS

Of 136 patients, seventeen (13%) required ureteral intervention due to stricture (n = 3), reflux (n = 12), or both (n = 2). Transplant occurred at median 10.5 years (3.1-14.7). Reconstruction occurred at median 10 months (7-15) after transplant. Pre-existing bladder pathology was present in 6 (35%) patients. Four of five patients with strictures had at least one endoscopic balloon dilation. Ultimate management included reimplantation, ureteroureterostomy of native to transplant ureter, pyeloureterostomy to native ureter, multiple endoscopic interventions followed by a Boari flap, or multiple failed endoscopic interventions. Fourteen patients with VUR underwent reimplantation (n = 5), ureteroureterostomy of native to transplant ureter (n = 4), pyeloureterostomy to native ureter (n = 4), and one underwent endoscopic injection with Deflux of the transplant ureter. Only one patient had a non-functioning graft due to ureteral complication. All patients were alive at follow-up (median 17 years [12-19]).

CONCLUSIONS

Transplant ureteral reflux and stricture are significant complications following pediatric renal transplantation and may require surgical management. In our population, reflux or stricture requiring ureteral reconstruction occurred in 10% and 4%, respectively. Endoscopic interventions were rarely successful. Native ureters were used for ureteral reconstruction in more than two thirds of patients should be considered in management of ureteral complications.

A systematic review of outcomes of Deflux® treatment for vesicoureteral reflux following pediatric renal transplantation

INTRODUCTION

Vesicoureteral reflux (VUR) after renal transplant in the pediatric population may be associated with an increased incidence of urinary tract infection (UTIs) leading to increased morbidity, including graft dysfunction and graft loss. The non-orthotopic location of the transplanted ureter, and lack of submucosal tunnel may pose challenges in correcting the VUR using endoscopic injection techniques. Herein we report the results of a systematic review evaluating the outcomes of endoscopic treatment of VUR using Deflux® in this population.

METHODS

Pubmed and Embase databases were searched from October 2001 to April 2019. Full-text English articles involving patients less than 18 years old at the time of transplant, with a diagnosis of VUR post-transplantation, who underwent Deflux® treatment were included. Figure 1 outlines our PRISMA-compliant search strategy.

RESULTS

We found 6 eligible studies describing Deflux® treatment outcomes in 67 pediatric patients with post-transplant VUR where voiding cystourethrogram (VCUG) confirmed the diagnosis and resolution of VUR. The mean success rate was 36.8%. Ureteral obstruction occurred in 7/67 cases (10.4%). In all these 7 cases of obstruction, ureteric stenting was the initial management, but was only successful in 1 patient. Open ureteroneocystostomy (UNC) was performed in 4/7 cases, while 2/7 were managed expectantly (unknown outcomes). Persistent VUR with UTI despite Deflux® were reported in 20 out of 67 cases. Of these, 7 were managed with prophylactic antibiotics, and 13 with UNC. Success rates were consistently low for UNC after failed Deflux® in comparison to redo UNC in transplant ureters without prior injection.

CONCLUSION

Low success rates are seen following injection techniques for VUR after pediatric renal transplant. Although an appealing option, Deflux® may prove counterintuitive due to the high rate of obstruction and suboptimal results if open reimplantation is required. A multi-institutional prospective study with a larger population size may further elucidate these results.

Risk factors for urological complications following living donor renal transplantation in children

The aim of this study was to detect possible risk factors for UC and UTI following pediatric renal Tx and effect of these complications on outcome. One hundred and eight children who underwent living donor Tx between 2009 and 2015 were retrospectively included. Extraperitoneal approach was used with stented tunneled extravesical procedure. Mean recipient age was 9.89 ± 3.46 years while mean weight was 25.22 ± 10.43 kg. Seventy-three (67.6%) recipients were boys while 92 (85.2%) were related to donors. Urological causes of ESRD were present in 33 (30.6%) recipients (14 [13%] posterior urethral valve, 16 [14.8%] VUR, and 3 [2.8%] neurogenic bladder). Augmentation ileocystoplasty was performed in 9 (8.3%) patients. Mean follow-up was 39.3 ± 17.33 months. UC were detected in 10 (9.3%) children (leakage 4 [3.7%], obstruction 3 [2.8%], and VUR 3 [2.8%]) while UTIs were reported in 40 (37%) children. After logistic regression analysis, UC were significantly higher in children with cystoplasty (44.4% vs 6.1%; P = .001). UTIs were significantly higher in girls (51.4% vs 30.1%; P = .001) and in children with urological causes of ESRD (51.5% vs 30.7%; P = .049). UC and UTI were not significantly associated with increased graft loss or mortality. UC were significantly higher in children with cystoplasty while UTIs were significantly higher in girls and children with urological causes of ESRD. Presence of UC did not affect the rate of graft loss or mortality due to its early detection and proper management.

Urological complications following unstented pediatric renal transplantation

Urological complications which develop post-renal transplantation can be associated with significant morbidity especially in children. We evaluated the occurrence and management of all urological complications in a series of unstented pediatric renal transplants in a tertiary pediatric hospital. We reviewed the medical records of children who underwent unstented renal transplant between January 1996 and December 2014. Postoperative urological complications and the outcomes of their management were analyzed. A total of 160 unstented renal transplants were performed, and 32 urological complications were noted in 29 transplants (18%). There were 20 boys and nine girls with an age range of 2.5 years to 18.4 years. Nine (31%) of these patients had LUTD. The most common complication was VUR occurring in 17 patients (10.6%). Urine leaks occurred in six patients (3.8%) and ureteric obstruction in six patients (3.8%), and three patients (1.9%) had unexplained hydronephrosis. Loss of graft occurred in three patients (1.9%), and one patient died from sepsis post-uretero-ureterostomy. Patients with LUTD had more urological complications (P = .037). Unstenting is feasible in most pediatric renal transplants. LUTD is associated with a higher incidence of urological complications, especially VUR.

Urological complications following kidney transplantation in pediatric age: A single-center experience

Surgical complications during kidney transplantation can seriously affect renal outcomes. We assess occurrence, risk factors, and results of all urological complications in a series of renal transplants in a single center. Children who underwent renal transplant between January 2008 and December 2014 were retrospectively evaluated. Postoperative urological complications were reviewed. Demographic details, cause of ESRD, donor type, and surgical procedures at transplant were analyzed. For statistical analysis, the chi-square test or Fisher's exact test were used as appropriate. One hundred and twenty-one kidney transplants were performed in 117 children (median age 12 yr). Sixty-two of 121 (53%) had an underlying urological malformation. At a median follow-up of three yr, 28 urological complications were recorded (23%): 12 lymphocele (10%), 10 ureteral obstruction (8%), three urinary leakage (2.5%), two symptomatic VUR (1.7%), and one hydropyonephrosis. When lymphocele was excluded, the complication incidence rate dropped to 13%. Ureteral obstruction mostly occurred late after transplant (more than six months). Presence of urological malformation was the only factor related to increased occurrence of urological complication (p = 0.007) and, in particular, ureteral obstruction (p = 0.018). Children with urological malformations presented a statistically significant risk of developing urological complications after kidney transplantation, ureteral obstruction being the most common complication.

Renal transplantation in children weighing <15 kg: does concomitant lower urinary tract dysfunction influence the outcome?

BACKGROUND

We reviewed our experience with renal transplantation (RTx) in children weighing <15 kg to determine if the presence of lower urinary tract dysfunction (LUTD) influenced the outcome.

METHODS

Between 1987 and 2012, 68 RTx were performed in patients weighing less than 15 kg, including 17 with associated LUTD and 51 without. We detailed the lower urinary tract management in these patients, and compared graft survival rates and estimated clearance 12 and 60 months after RTx between groups.

RESULTS

None of the patients without LUTD required any lower urinary tract surgery vs 8 out of 17 (47 %) with LUTD (p = 0.0001). The latter included a temporary incontinent urinary diversion in 5 cases (29 %), namely 2 vesicostomies and 3 cutaneous ureterostomies. After comparable follow-ups, there was no difference in patient survival, graft survival, and glomerular filtration rates between groups.

CONCLUSIONS

Provided that there is appropriate bladder management, a concomitant LUTD does not adversely influence the outcome of RTx in patients weighing less than 15 kg. However, 50 % of our patients required lower urinary tract reconstruction and, in 30 %, a temporary incontinent urinary diversion was placed at RTx, since lower urinary tract function could not be assessed reliably, the patient was not collaborative enough to be involved in a voiding program, and/or the RTx was prioritized.