Long-term results of pediatric renal transplantation into a dysfunctional lower urinary tract

Bladder dysfunction in children and adolescents after renal transplantation

The underlying mechanisms of urinary-tract infections (UTI) in renal transplant recipients are still not fully understood. In otherwise healthy children, bladder dysfunction increases the susceptibility to UTI. The aim of this study was to evaluate lower-urinary-tract function in children and adolescents after renal transplantation. Sixty-eight recipients of renal transplants, 5-20 years of age and 1-15 years after transplantation, were evaluated for their bladder function with a questionnaire, uroflowmetry and bladder ultrasound, and for renal function (glomerular filtration rate) by measuring clearance of inulin or iohexol. Forty-nine patients (72%) had some type of abnormality of bladder function. Abnormal bladder capacity was found in 26%, abnormal urinary flow in 50% and residual urine in 32% of the patients. There was no significant difference in bladder or renal function in children with urinary-tract malformations compared with those with normal urinary tract. Furthermore, there was no significant difference in renal function in patients with bladder dysfunction compared with those without. The incidence of bladder dysfunction is high in children and adolescents after renal transplantation, but the clinical significance of this finding and whether there is a correlation between bladder dysfunction and UTI in these patients need to be clarified further.

Renal transplantation in children with posterior urethral valves

The objective of this study was to analyze whether renal transplantation (RT) in children with posterior urethral valves (PUV) constitutes a special group with respect to groups with different etiologies of end-stage renal disease (ESRD). Between 1979 and 2004, 22 RT were performed in 19 children with PUV. The median age at RT was 10 years (range: 1.3-17). Immunosuppression was provided by triple therapy and polyclonal/monoclonal antibodies. This group was compared with the two control groups: (1) glomerulopathy (n=62) and (2) pyelonephritis/dysplasia (n=42) without lower urinary tract disease, transplanted in the same period. Ten graft losses occurred in 22 transplants: thrombosis (2), acute rejection (3), chronic graft nephropathy (2), and death of patients (3) with a functioning graft in the 1st postoperative month. We did not find significant differences versus the control group in renal function or probability of graft or patient survival at 1, 5, and 10 years. We observed a greater risk of urological complication in patients with PUV. RT with PUV constitutes a special group due to the compulsory young age and the need for careful and complex medicosurgical management; nevertheless, the results achieved were similar to those obtained in our general RT population.

Outcome of renal transplantation in children with low urinary tract abnormality

INTRODUCTION

Patients with end-stage renal disease and lower urinary tract abnormality are often considered high risk for renal transplantation.

METHODS AND SUBJECTS

To examine the degree of risk, we studied patients who received renal transplants between 1985 and 2003. Forty eight patients had congenital lower urinary tract anomalies and 168 patients comprised a control group without these anomalies.

RESULTS

Mean age and distribution of sex were not significantly different between the case and the control group. Among patients with anomalies, 8% had delayed graft function; 75%, acute rejection; and 39.5%, chronic rejection. Among the controls 2.3% had delayed graft function; 59%, acute rejection; and 35%, chronic rejection. None of these differences was significant. Mean survival time was 6 years in affected patients and 7.3 years in the control group (P = .7). Among patients with anomalies the rate of graft survival in the first year after transplantation was 90%; and those in the third, fifth, and seventh years, 76%, 65%, and 40%, respectively. For the controls, the graft survivals were 88% at 1 year; 73% at 3 years; 70% at 5 years; and 49% at 7 years after transplantation.

CONCLUSION

This study showed that a history of lower urinary tract anomalies had no effect on graft function. Graft survival was not different among these patients compared with patients free of these anomalies.

Kidney Transplantation into Bladder Augmentation or Urinary Diversion: Long-Term Results

BACKGROUND

We report on a single-institutional experience with renal transplantation in patients with severe lower urinary tract dysfunction (LUTD) who underwent bladder augmentation or urinary diversion, and assess the long-term results.

METHODS

From September 1987 to January 2005, 255 patients (161 male and 94 female), 7 months to 39 years old of age (median age at time of transplantation 14 years), received 271 kidney transplants. Etiology of end-stage renal disease was LUTD in 83 cases. Among these patients, 24 had undergone bladder augmentation or urinary diversion.

RESULTS

We identified two groups of patients surgically treated due to LUTD: group 1 included 16 patients (eight male, eight female) aged 4 to 39 years (median 19 years) with bladder augmentation, whereas in group 2, seven patients (five male, two female) 7 months to 31 years old (median 17 years) with incontinent urinary diversion were reported. In the first group, surgical complications after kidney transplantation included one urinary fistula, one ureteral stenosis. Three patients of second group developed recurrent urinary tract infection. Cumulative graft survival rates of all patients transplanted was 69.4% after 15 years, whereas in the two investigated groups, group 1 and group 2, was 80.7% and 55.5% respectively (P=NS.).

CONCLUSIONS

Drainage of transplanted kidneys into an augmented bladder or urinary diversion is an appropriate management strategy when the native bladder is unsuitable. Kidney transplantation in patients with bladder augmentation or urinary diversion for LUTD let achieve similar results to those obtained in the general population with normal lower urinary tracts.

Urolithiasis after kidney transplantation in pediatric recipients: a single center report

BACKGROUND

Urolithiasis occurs in approximately 6% of adult kidney transplant (KTx) recipients. Limited data are available on urolithiasis after pediatric KTx. We report the incidence, management of, and risk factors for stone development in children after KTx.

METHODS

We reviewed the medical records of 399 children who received KTx at our center between September 1986 and January 2003. Transplant outcomes were compared in stone formers and controls.

RESULTS

Twenty (5%) patients, age 9+/-5 (X +/- SD) years, developed stones over the follow-up period (74+/-53 months). Time to stone presentation was 19+/-22 months post-KTx. Presenting features were urinary tract infection (UTI), 8; gross hematuria, 5; microscopic hematuria, 2; dysuria without infection, 6; difficulty voiding, 3; and silent stones, 2. Stones were removed by cystoscopy in 11 (55%) patients. Stone composition was determined in 11 patients: calcium phosphate (55%), calcium oxalate (18%), mixed calcium phosphate and oxalate (9%), and struvite (18%). Factors predisposing to stones in study patients included suture retention (n = 4), elevated urinary calcium excretion (n = 2), recurrent UTI (n = 2), and urinary stasis (n = 2). The incidence of UTI was higher (P = 0.003) and of acute rejection was lower (P = 0.02) in stone patients compared with controls. Patient and graft survival rates and the incidence of chronic rejection did not significantly differ between study patients and controls (P = NS).

CONCLUSIONS

Urolithiasis is not uncommon in pediatric KTx patients. Factors associated with post-KTx urolithiasis include retention of suture material, recurrent UTI, hypercalciuria, and urinary stasis. Treatment is associated with excellent outcome and low recurrence rate.

The continent bladder: indications and techniques for the continent catheterizable segment

PURPOSE OF REVIEW

Continent catheterizable segments are a substantial part of the urologist's armamentarium for providing bladder drainage. It is used for a myriad of indications, and there are multiple techniques currently used for its formation. Despite refinements in these techniques significant complications still occur, and there is continued advancement and ongoing investigation. This review examines the current status of the continent catheterizable segment with regard to indications for its use, techniques in its formation, discussion of complications, and ongoing and future directions in research.

RECENT FINDINGS

The continent catheterizable segment is indicated when it is not feasible to use the urethra for evacuation (e.g. bladder exstrophy, neurogenic bladder, radiation injury, and marked urethral dysfunction) or to facilitate catheterization. Compliance with catheterization and irrigation regimens is essential in patient selection. Multiple methods exist for its formation, either with or without the need for bladder augmentation. Although Mitrofanoff techniques with multiple applications predominate, "hemi" augments with efferent limbs also play a significant role. Stoma placement should be performed to best facilitate catheterization. Complications relating to catheterizable segments mainly pertain to continence, stenosis, and ability to catheterize, with more significant morbidity relating to the bladder augmentation. Ongoing research to develop more physiologic tissue substitutes and less invasive techniques may hopefully be superseded by prevention of the underlying lower urinary tract pathology.

SUMMARY

Catheterizable segments allow the patient to control bladder evacuation, and continue to be refined by ongoing investigations in terms of indication and technique, with attendent decreasing morbidity.

Pediatric renal transplantation and the dysfunctional bladder

We retrospectively reviewed our long-term experience with pediatric renal transplantation into a dysfunctional lower urinary tract to evaluate graft survival, function, and special urological complications. Between 1967 and March 2000, a total of 349 renal transplantations were performed in children younger than 18 years. Malformations of the lower urinary tract were the reasons for end-stage renal failure in 66 children (18.6%). The cause of urinary tract disorders included: meningomyelocele connected with neuropathic bladder (n = 4 transplantations); prune belly syndrome (n = 5 transplantations); VATER association (n = 2 transplantations); posterior urethral valves (n = 27 transplantations); and vesico-uretero-renal reflux (n = 28 transplantations). The majority of the patients underwent surgical interventions to preserve renal function or to prepare renal transplantation. The 1- and 5-year graft survival rate was evaluated with special reference to the underlying disease. The 1-year graft survival rate in all children with lower urinary tract malformations was 83.3%, compared with 88% for all children. In those children with vesico-ureteral reflux, it was 92.8% and in the children with Vater association and prune belly syndrome, it was 85.7%. One graft was lost in the children who had neurogenic bladder, so the 1-year graft survival rate was 75%. The worst 1-year graft survival rate was obtained for boys who had posterior urethral valves (1-year graft survival rate: 74%; 5-year graft survival rate: 62.9%). Concerning the 5-year graft survival rate, it was 70% for all children with malformations of the urinary tract. The best rate was obtained for children with reflux in the native kidneys (78.5%), followed by those with VATER association and prune belly syndrome. As an additional child with neurogenic bladder lost his graft, the 5-year graft survival rate was 50%. Pediatric renal transplantation into a dysfunctional bladder can be connected with high urological complication rates which may contribute to worse graft survival. The 1- and 5-year graft survival rate in children with malformations of the lower urinary tract is worse than in children without bladder dysfunction. We regarded a striking difference between graft survival and the urological disorders which led to renal insufficiency. We obtained the worst graft survival rates in children with posterior urethral valves which are usually connected with bladder emptying problems and dysfunctional voiding. Potential pediatric transplant recipients must be classified according to pathophysiological as well as anatomical abnormalities of the urinary tract and all urological problems have to be solved prior to transplantation. At our center, living donors are favored to plan transplantation of these children properly.