Does Early Upper Tract Diversion and Delayed Undiversion in Megaureters Secondary to Severe Posterior Urethral Valves Lead to Better Renal Outcomes?

Background: There are conflicting reports for the management of severe posterior urethral valve (PUV) after ablation. The primary objective was to assess the renal outcomes using the estimated glomerular filtration rate (eGFR) and secondary outcomes in severe PUVs who underwent early partially diverting reduction ureterostomy (PDRU) and a delayed undiversion protocol. Materials and
Methods: This 10-year retrospective study reviewed the records of 1094 boys with PUV, where severe PUV cases were treated with early PDRU (324 surgeries). We then analyzed those patients who completed the early diversion and delayed undiversion protocol. The long-term renal outcomes using eGFR and antero-posterior diameter (APD) were compared at various time points using appropriate statistical methods.
Results: Of the 171 severe PUV patients who underwent PDRU, 31 completed undiversion and 26 (47 renal units) were analyzed after exclusions. The mean age (standard deviation) at presentation was 1.46 ± 4.1 months. Thirty-two units were refluxing and 15 were nonrefluxing megaureters. PDRU was closed at a mean age of 3.9 years and had a mean duration of follow-up of 6.4 years. The mean eGFR increased from a minimum of 10.78 ± 10.25 at baseline and remained stable at 28.69 ± 18.89 after closure of both stoma. Similarly, mean APD decreased from 12.07 ± 6.79 at the diagnosis to 7.00 ± 6.20. Three patients (3 renal units) required revision of the stoma for stenosis and 1 patient had a parastomal hernia that was repaired at the time of undiversion. Conclusions: In severe PUVs, early PDRU with delayed undiversion is a reliable surgical option that may ensure better renal outcomes in the long-term. Nonrefluxing renal units recover better than the refluxing. APD measurements also are shown to improve favorably. Copyright:

INTRODUCTION

Posterior urethral valve (PUV) is one of the most common obstructive uropathies of male genitourinary tract with effects at multiple levels leading to end-stage renal disease (ESRD) in many cases. Bladder hypertrophy with reduced capacity leads to increased intravesical pressure causing vesicoureteral reflux (VUR) or vesicoureteric junction obstruction. This further leads to dilation and tortuosity of ureters causing secondary megaureters.[1] Management and outcome often differ in the hands of different surgeons. However, most agree that a combination of ablation of valves, medications, re-implantations and urinary diversions is essential for best results and the treatment is to be individualized,[23] as each of these methods have their pros and cons. Although valve ablation is the treatment of choice for most PUVs, the long-term management strategies for its secondary proximal effects are still contentious.

The renal and bladder dysfunction in later life remains a concern nevertheless and has been linked to several factors, including patient age at presentation, prenatal diagnosis, VUR, initial serum creatinine, nadir serum creatinine after bladder drainage, and nadir creatinine at the 1st year of life.[45] A bladder exposed to high pressures as in PUV for prolonged time intervals undergoes a cascade of changes ultimately resulting in the architectural changes of bladder, ureters, and alterations in renal morphology and function, namely obstructive uropathy and renal dysplasia.[6] This has led to proponents of supravesical urinary diversion who believe that direct decompression of the upper tracts with simultaneous bladder cycling will produce direct, low-pressure urinary drainage, allowing optimization of renal function.[7] The primary objective of this study was to assess the effects on glomerular filtration rate (GFR) and secondary outcomes in severe PUV patients with megaureters who underwent an early partially diverting reduction ureterostomy (PDRU) and a delayed undiversion protocol.

MATERIALS AND METHODS

This is a retrospective cohort study on all pediatric patients with confirmed PUV treated in our institution between June 2009 and January 2019 (10 years). Their hospital records were reviewed. The milder variants (with no significant bladder or upper tract effects) and those treated by means of other protocols (for e.g., valve ablation alone, vesicostomy, delayed diversion after failure of other treatments, etc.) were excluded, as were those with other urological and major systemic anomalies. All patients with severe PUV and secondary megaureters who were planned and treated with the early PDRU and delayed undiversion protocol were then grouped. They had to satisfy the following criteria: Early diagnosis and early PDRU (<6 months of age), treatment begun and continued in our hospital, and followed up by us for at least 5 years. Among these, only those who completed undiversions were finally analyzed for outcomes. Cystoscopic ablation was performed in the same sitting as PDRU or later. This study was approved by the Institutional Ethics Committee (GMCKKD/RP2018/IEC/99).

Treatment protocol

Prenatally suspected PUV patients were evaluated postnatally with renal ultrasound (US) for dilatation of renal pelvis, bladder effects and megaureter. This is followed by a micturating cystourethrogram (MCU) to confirm diagnosis and to assess the ureters (if there is a VUR). Besides, if VUR is not present unilaterally or bilaterally, these patients also undergo a magnetic resonance urogram (MRU) to look for megaureter/s (possible with obstructed ureters). All such severe PUVs, regardless of serum creatinine values at diagnosis, then undergo early PDRU which is a modification of the existing ureterostomy technique (described below). This form of diversion is performed either in conjunction with ablation of valve or is done before it, for the very small newborns. Most ablations were performed in a month or two. The stoma thus created is maintained for at least 3 years. Check cystoscopy is performed to ensure completion of valve ablation in the meanwhile. After 3 years, the vesicoureteric junction (VUJ) is reassessed with a repeat MCU (for resolution of VUR) or distal ureterogram (for obstructed megaureters), where a feeding tube is inserted into distal ureter through the stoma and dye injected while image is obtained. The renal function is also assessed by serial renal function tests and Dimercapto-Succinic Acid isotope renogram (DMSA) scan. If VUR is found to have resolved by then (or if there is no obstruction on distal ureterogram) on that particular side, undiversion of the ureter is carried out on that side. On the other hand, if reflux or obstruction is noted at VUJ, then ureteric reimplantation is performed before undiversion. Both stoma are thus closed based on these principles, one at a time. These infants were followed up every month for 6 months and then every 6 months till early adulthood, post undiversion. Periodic assessments through renal function tests, urine analysis, MCU and US, were done as indicated. Clean intermittent catheterization (CIC) was not performed (as it is not easily accepted in our setting and also painful in the sensate urethra) but bladder medications such as anticholinergics (Oxybutynin) were given to prime the bladder (oxybutynin induced protective effect by decreasing intravesical pressure and detrusor over activity, inhibition of stretch induced smooth muscle proliferation), till fully toilet trained. Vitamin D (active form) and calcium supplements were also given. Antibiotic uroprophylaxis and prophylactic circumcision were not followed.

Technique of partially diverting reduction ureterostomy

After trimming and straightening the middle segment of the ureter, the proximal and the distal limbs of the ureter are brought out and anastomosed in a side-to-side fashion, so that the mouth of the stoma is wider (lumen of both limbs are utilized). A schematic representation of the same is provided in Figure 1.

Figure 1

Technique of partial diversion reduction ureterostomy

Definitions

Severe PUV - definitive dilatation of the posterior urethra on MCU (confirmed on cystoscopy) [Figure 2] with significant secondary effects on bladder (thickened/contracted), ureters (grossly elongated and tortuous megaureters) and kidneys (dysplastic changes), regardless of serum creatinine level at diagnosis. The secondary effects were determined on US, MCU, and MRU

Figure 2

(a-h)Appearances of megaureters on micturating cystourethrogram and magnetic resonance urogram. Each horizontal set of images is of the same posterior urethral valve patient. The megaureters that are not well appreciated on micturating cystourethrogram are better visualized on magnetic resonance urogram. The magnitude of the grossly dilated tortuous ureters that were diverted in this series is exemplified here

Megaureter – ureter above 7 mm in diameter

Split renal function (SRF) – Renal function on a particular side as determined on DMSA

Total estimated GFR (eGFR) - estimated using Pottel Method. eGFR-Pottel [mL/min/1.73 m2] = 107.3 × Q/serum creatinine [mg/dl], where Q is the median serum creatinine concentration for children based on age and sex[8]

eGFR for each unit - eGFR-Pottel (mL/min/1.73 m2) × SRF of that renal unit[8]

Nonrefluxing/obstructed megaureters – dilated, tortuous megaureters on MRU with no VUR on MCU. For bilateral VUR (with good visualization of ureters on MCU) MRU was not necessary [Figure 2]

Early diversion - diversion performed as soon as diagnosis is confirmed and baseline investigations done (<6 months age)

Delayed undiversion – closure of stoma after 3 years of age, it is performed one side at a time

Chronic kidney disease (CKD) was defined as total eGFR <60mL/min/1.73 m2 and

ESRD was defined as total eGFR <15mL/min/1.73 m2 or the need for renal replacement therapy

Baseline eGFR – the eGFR checked at about 6–8 weeks age (if presented as newborn) or the first GFR checked (for later presentations). The eGFR values were based on the DMSA SRF and the serum creatinine at the time

1-year post ureterostomy – eGFR checked 1 year after PDRU

3-year post ureterostomy – eGFR checked 3 years after PDRU

After first undiversion – eGFR checked 3 months after closure of one stoma

3 months post second undiversion-eGFR checked after 3 months of bilateral undiversions in two functioning kidneys.

Statistical analysis

The collected data were verified, coded, entered, and analyzed using the SPSS (Statistical Package for the Social Sciences) software version 21 (IBM,New York, US). Data were presented as numbers and frequencies or as medians (quartile 25–75). Nonparametric tests were used to make statistical inference as data were not normally distributed. Wilcoxon rank-sum test (Mann–Whitney U test) was used to compare the two groups in terms of eGFR at each of the time points. Friedman test was used to explore the change in eGFR over time within each group (comparison with baseline). Generalized Estimating Equations method was used to explore the difference in change in eGFR between the two groups over time. Statistical significance was set at P < 0.05.

RESULTS

Of the total 1094 cases with confirmed PUV (over 10 years), 171 patients with severe PUV (324 renal units) underwent PDRU during the study period. All patients who had milder variants of PUV or had other miscellaneous diagnoses, or those lost to follow up or those who were treated with other protocols were excluded. Among the 171 patients currently on PDRU, 31 completed delayed undiversion (closure of bilateral stomas or one stoma in single kidney) protocol. We had to further exclude 5 out of these 31 patients for the lack of complete documentation, being lost to follow up or had irregular visits. After these exclusions, we were left with 26 patients and 47 renal units in total (3 were solitary kidneys and 2 were nonfunctioning dysplastic at diagnosis). Only these patients were analyzed [Table 1]. None of them had prenatal interventions. Among the 26 babies, 84.6% (n = 22) presented at birth and they were suspected prenatally, 15.2% (n = 4) presented in the first 6 months of life with symptoms of poor voiding and recurrent urosepsis. The mean age (standard deviation [SD]) at presentation was 1.46 ± 4.1 months (range: day 1–5.5 months). Among the 47 renal units studied, 68.1% (n = 32) were refluxing and 31.9% (n = 15) were nonrefluxing. The initial treatment consisted of early diversion alone (with later ablation) in four patients and early diversion with first valve ablation in same sitting for 22 patients. The ureterostomy was closed at a mean age of 3.9 years (range: 3.2–4.4 years). The mean duration of follow-up was 6.4 years (range: 5.3–11.1 years).

Table 1

Flow chart for patient selection in this series and cohort finally analyzed

PUV: Posterior urethral valve, PDRU: Partially diverting reduction ureterostomy

The mean eGFR values for each renal unit at various stages and a detailed assessment of change in eGFR values over a period of time are shown in Table 2. Nonparametric tests (Friedman test) were used to make statistical inference as data were not normally distributed. Friedman test was used to explore whether the eGFR changed significantly over time. The mean eGFR increased from a minimum of 10.78 ± 10.25 at baseline to maximum of 30.62 ± 20.09 after first undiversion and then remained stable at 28.69 ± 18.89 after 3 months post closure of both stoma. This change was statistically significant (Friedman Test: X2= 145.4, P ≤ 0.001).

Table 2

Detailed assessment of change in estimated glomerular filtration rate values over a period of time

	Mean eGFR±SD	Median eGFR (SD)	Range	P
Baseline	10.78±10.25	7.63 (7.76)	0.60-52.04	<0.001
1 year post ureterostomy	30.40±18.04	28.39 (19.86)	1.45-70.98	<0.001
3 year post ureterostomy	29.47±19.66	27.36 (21.34)	1.61-78.87	<0.001
After first stoma closure	30.62±20.09	27.36 (19.19)	1.61-78.87	<0.001
3 months after second undiversion	28.69±18.89	27.23 (17.93)	1.61-78.87	<0.001

Statistical comparison is with baseline values. eGFR: Estimated glomerular filtration rate, SD: Standard deviation

Comparison of a particular time point eGFR with the baseline eGFR is shown in Table 3. Post hoc pairwise tests for Friedman test were performed using Nemenyi Test method for P value correction. Statistically significant difference at P < 0.05 was found at every time point chosen.

Table 3

Comparison of a particular time point estimated glomerular filtration rate with the baseline estimated glomerular filtration rate

Comparison of GFR at various time points versus baseline	Mean±SD of difference	Median (IQR) of difference	Range of difference	P
1 year post ureterostomy	19.62±13.00	18.82 (16.02)	0.56-57.13	<0.001
3 years post ureterostomy	18.69±14.76	17.53 (14.91)	−0.72-61.07	<0.001
After first closure	19.84±15.77	18.28 (17.67)	−0.72-67.51	<0.001
After second closure	17.90±13.28	17.53 (15.82)	−0.72-57.13	<0.001

GFR: Glomerular filtration rate, SD: Standard deviation, IQR: Interquartile range

When the eGFR over the period was compared for the two main types of renal units (refluxing versus nonrefluxing megaureter), the groups differed significantly. Their differences are shown in Table 4.

Table 4

Assessment of change in antero-posterior diameter at different stages after ureterostomy

Time point	APD (mm)
	Mean±SD	Median (IQR)	Range
Baseline	12.07±6.79	12.00 (8.00)	0.00-38.00
3 years post ureterostomy	5.51±4.18	3.00 (4.00)	2.00-17.00
After first stoma closure	5.98±4.14	3.00 (5.00)	2.00-17.00
3 months after second stoma closure	7.00±6.20	5.00 (5.00)	2.00-31.00

SD: Standard deviation, IQR: Interquartile range, APD: Antero-posterior diameter

In VUR, the mean eGFR increased from a minimum of 8.34 ± 7.27 at baseline to a maximum of 26.15 ± 20.04 after first stoma closure and then remained stable at 23.31 ± 17.43 3 months after bilateral stoma closure. The P value for change in eGFR over time within each group showed statistical significance (Friedman Test: X2= 88.7, P ≤ 0.001).

For nonrefluxing megaureter in comparison, the mean eGFR started at a higher level at baseline (15.99 ± 13.62) which rose to a maximum of 41.02 ± 14.64 at the 1-year post-ureterostomy time point, and then stabilized to 40.05 ± 16.23 after 3 months of bilateral ureterostomy closure. This favorable change was also statistically significant (Friedman test: X2= 61.9, P ≤ 0.001). The overall change in eGFR over time was compared in the two groups using the generalized estimating equations method. There was a significant difference in the trend of eGFR over time in both the groups (P ≤ 0.001). In summary, with nonrefluxing megaureters, the renal function recovers faster than refluxing megaureters. A bar diagram depicting the change in GFR over time in both the groups is shown in Figure 3.

Figure 3

Bar diagram depicting the change in glomerular filtration rate over time in refluxing and non refluxing megaureters

With regard to pressure effects on the kidney, assessment of change in antero-posterior diameter (APD) over the time line was studied and is shown in Table 3. The mean APD and SD (mm) decreased from a maximum of 12.07 ± 6.79 at diagnosis to a minimum of 5.51 ± 4.18 at the 3 years postdiversion time point, and then stabilized to 7.00 ± 6.20 3 months after bilateral ureterostomy closure was performed. This positive change (decrease in APD) after ureterostomy was found to be significant (Friedman Test: X2= 48.4, P ≤ 0.001).

Regarding the complications with stoma, three patients (3 out of 47 renal units) needed revision of the stoma. One patient had a parastomal hernia that was left alone and repaired at the time of undiversion. Only three patients needed bilateral ureteric reimplantation prior to closure of stoma for unresolved VUR even after 3 years of follow-up (18.7%). Urosepsis of upper tracts was not noted in any of these patients after PDRU, but cystitis was recorded in two infants after primary PDRU was done but before they could undergo valve ablation. Bladder cycling was deemed satisfactory after diversions as about 20%–30% of the urinary output was seen to be voided per urethra. No particular difficulty was noticed during stoma undiversions (there were no stenosis or leaks related to closure).

DISCUSSION

To recount our history with the management of PUVs, we used to follow the internationally accepted “step ladder protocol” of titrated approach including diversions in nonresponders (persistently elevated serum creatinine values and/or recurrent urosepsis) despite valve ablation. However, in severe PUVs, the incidence of recurrent urosepsis, renal deterioration, and frequent hospitalizations prompted us to look for measures that prevent upper tract stasis and at the same time maintain bladder cycling. Over the years, with growing experience in high diversions using PDRU that circumvented some of these issues, it has led to a paradigm shift in our belief. Hence, we have started proactively performing a salvaging PDRU for severe PUVs, sometimes even before valve ablation itself. Moreover, in the bargain, we also observed that the need for ureteric reimplantation for these megaureters drastically came down. This is the rationale for our justification of high diversions, with our added modification. The availability of MRU has also helped us vastly appreciate the magnitude of the anomaly, as the reconstructed images provided a view of the enormity of megaureters [Figure 2] unlike US which often underestimates the proximal effects and is performer dependent. The vertical anatomy of the whole length of ureter, presence of duplications, urinary ascites/urinoma, and thickness of cortex are beautifully demonstrated on MRU.

PUVs are characterized by their unique sequelae of bladder dysfunction, even after the relief of obstruction, and hence, many children develop either a CKD or ESRD. Unfortunately, even after successful relief of urethral obstruction, many still have various urological issues related to disease severity.[59] Various investigators have shown that early detection and reversal of bladder dysfunction are associated with a better chance of preservation of kidney function.[369] This in turn results in relief of pressure effects on kidneys, lower rates of infection, lower severity of dysfunctional voiding, and less dependence on CIC.

Although the main treatment strategy for patients with PUV is relief of urinary obstruction, an additional urinary diversion (vesicostomy/ureterostomy) is still favored by many urologists for better long-term outcomes.[10] While vesicostomy helps with efficient drainage of the bladder, it may potentially lead to bladder dysfunction by interfering with physiologic bladder cycling and has complications with the stoma (stenosis or prolapse).[911] Some proponents have also shown that a primary initial temporary vesicostomy (with delayed valve ablation) demonstrated favorable outcomes, in comparison with ablation alone, when assessed according to serum creatinine and eGFR.[12] Therefore, it is unclear if primary valve ablation alone or an initial temporary vesicostomy with later ablation is more helpful. Be that as it may, in contrast to these approaches, some urologists claim that a high diversion has superior efficacy in stabilizing biochemical parameters of the blood more efficiently and also leading to improvements in 90% of cases with upper urinary tract problems.[1314] With the PDRU described above, we have attempted to improvise the situation by alleviating ongoing upper tract damage, effectively decompressing the ureters, avoiding stasis of urine and thereby urosepsis, removing effects of refluxing urine (which gets diverted outward through the stoma) and at the same time ensuring bladder cycling. In addition, the chances of stomal stenosis are also minimal as walls of both loops of the stoma are utilized and hence wider.

The ultimate renal function in PUV depends on a number of well-known factors, like age at presentation, GFR, prenatal diagnosis, renal dysplasia, VUR, renal scarring, nadir creatinine during the 1st year of life, upper tract obstruction, bladder dysfunction, and urinary tract infection (UTI).[15] Among the objective factors, initial serum creatinine, serum creatinine at age 1 year, and mean GFR are the most studied. Sarhan et al. have reported that initial serum creatinine was significantly higher in boys with a poor renal outcome than in those with favorable outcomes. Similarly, Bhadoo et al. showed that with an initial serum creatinine ≤1 mg/dl, the incidence of chronic renal failure (CRF) was 23% and when above 1 mg/dl, the incidence increased to 72%. Subsequently, it was realized that serum creatinine at age 1 year (<0.8 mg/dl) has an even better predictive value than the initial values.[415] On similar lines, mean GFR was also reported to be reflective of renal failure in future. Mean GFR at presentation in patients who did not develop CRF was 70.39 ± 24.03 ml/min/1.73 m2 compared to 39.55 ± 19.97 ml/min/1.73 m2 in patients who ultimately developed CRF.[1617] Hence, the main challenge in managing these patients is to avoid, as much as possible, deterioration in renal function which may eventually occur. To achieve this, factors that affect the improvement of renal function must be better identified. The most commonly used equation for calculating eGFR in children is the Schwartz equation (eGFR-Schwartz),[18] which is calculated from serum creatinine concentration, height, and an empirical constant, k, that adjusts for muscle mass and the creatinine measurement method. A major disadvantage of eGFR-Schwartz is the need for height information, which hampers its use in settings in which height data are not available. It has been shown that the performance of eGFR-Pottel is comparable with the eGFR-Schwartz and is a valid alternative to eGFR-Schwartz in children and could be reported by the laboratory if height data are not available.[8] In order to study the effect of ureterostomy on the individual kidney, the eGFR for that particular renal unit was calculated using SRF as determined on DMSA (see “Definitions”). As the kidneys are disconnected from high pressure effects of the bladder after PDRU, the eGFR of individual renal units when thus calculated is reasoned to be reliable. This is in contrast to serum creatinine levels used to prognosticate, which is reflective of total renal function (both kidneys).

Just like the renal factors, the bladder dysfunction will be decisive and a poorly compliant bladder has recently been associated with the worst prognosis.[19] Bladder associated factors are known to affect and be affected by age at diagnosis, renal dysplasia, renal function before and after treatment to remove the obstruction, VUR, UTI, proteinuria, hypertension, and initial treatment.[20] Bilateral high diversion that permits bladder cycling simultaneously can potentially ameliorate bladder dysfunction, and at the same time, it allows for a better renal growth in the initial years. Vesicostomy in small capacity, high pressure thickened bladders is technically cumbersome, has higher chances for stenosis and often do not drain the upper tracts well leading to upper tract UTI and thereby secondary renal scars. As suggested by Parag et al., these patients are particularly susceptible to persistent sepsis despite bladder drainage as they have ureteral dilatation, elongation, angulation, and attenuation of ureteral musculature which prevents their rapid decompression even after correction of bladder outlet obstruction.[20] The infant kidney has a hope for the recovery of whatever function they have when they are free of recurrent pyelonephritis. The ultimate renal function depends upon periods free of urosepsis, back pressure, and dysplasia. Antibiotic prophylaxis was also not deemed necessary after this diversion. Lopez Pereira et al. and some others proved that initial serum creatinine levels did not correlate with final renal function, but GFR at age 1 year was strongly associated with it (P < 0.001). Most of the patients with a GFR of ≥80 mL/min/1.73 m2 at age 1 year had a normal renal function at the end of the study. Further, they also showed that patients treated with an early temporary pyelo-ureterostomy had a better function at age 1 year than patients treated with valve ablation alone. Moreover, these changes persisted during the first 5 years of life.[151621]

With our data, we have also showed good recovery in eGFR values of individual renal units at every stage post PDRU and they were maintained even after undiversion. We have also seen that nonrefluxing megaureters recover better in the long term, than the refluxing variety. This is possibly reasonable, as it is known that the refluxing units bear the brunt of high pressures (pop off mechanism) to safeguard the other unit and conserve overall renal function. Our data have also demonstrated significant fall in APD measurements and they remain so even after undiversion. APD measurements are an indirect indicator of the pressure effects on the kidney. In summary, the proximal adverse effects of a high pressure, acontractile, and thickened bladder are largely taken off the kidneys allowing their optimal growth. At the same time, stomal complications and incidents of urosepsis have also been kept low with the mentioned modification. Although the initial serum creatinine values did not reach uremic levels and/or there were no recurrent urosepsis in some of the cases, the approach of preemptive PDRUs for severe PUVs has been found to be beneficial in our setting.

There are some limitations to this study. The retrospective nature and the small sample population analyzed here limit the generalizability of our results. We hope to take this study forward. Moreover, there was no comparative analysis with patients who underwent other forms of management such as vesicostomy and with primary valve ablation alone. The duration of follow-up of 5 years (as long as 11 years in some children) is although long enough to prognosticate, is not entirely reliable, as the ESRD mostly is seen in the second or third decade of life. Since the renal growth is maximally affected in the first few years of life, it could be surmised that the renal function could well be preserved in these boys well beyond late adulthood. We have not used urodynamic evaluation in this series, as we believe the renal outcomes outweigh the bladder outcomes and they are less useful and practical in age <4 years.

CONCLUSIONS

In patients with severe PUVs, early PDRU and delayed undiversion are a reliable surgical option that can salvage renal function and lead to better renal outcomes in the long term. It may even mitigate bladder effects by not interfering with the physiological actions of bladder cycling. Nonrefluxing renal units recover better than the refluxing. APD measurements also are shown to improve favorably. The instances of urosepsis (despite not using uroprophylaxis) and complications with stoma were minimized with this technique.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.