Primary obstructive megaureter

Primary repair vs Delayed staged repair in infants with primary obstructive megaureters and their long term outcomes - A single centre experience

BACKGROUND

There is paucity of literature in the management of infants with primary obstructive megaureters undergoing upfront primary repair with an extravesical technique of ureteral re implantation (with or without ureteral tailoring).

OBJECTIVE

To compare 2 different approaches in the management of infants with unilateral primary obstructive megaureters.

STUDY DESIGN

This was a retrospective analysis of a prospectively maintained data base between 2005 and 2021. Infants <1 year with unilateral primary obstructive megaureter were included. They were divided into 2 groups: those who underwent an upfront extravesical ureteric reimplantation with or without ureteral tailoring during infancy -Primary Repair (PR), and those who initially underwent a low end cutaneous ureterostomy during infancy followed by take down of ureterostomy and intravesical ureteric reimplantation after 1 year of age -Delayed staged repair (DSR). Children presenting with sepsis, in whom a diversion was imperative, were excluded. All children were followed up annually after their definitive repair with a renal ultrasound, diuretic renogram, estimated glomerular filtration rate and assessment of voiding dysfunction if present. The 1st year and 3rd year follow up details were collated and analysed. Failure was defined as persistent obstructive pattern on renogram with worsening differential renal function or presence of high grade reflux with recurrent breakthrough urinary tract infection; both of which necessitated a redo reimplantation following the definitive surgery.

RESULTS

There were 18 infants in Primary repair and 16 infants in Delayed Staged Repair. Urinary tract infections was the commonest presenting symptom amongst both groups i.e. > 50%.The post operative complication rate was 11% in Primary repair and 31% in Delayed Staged Repair. One child in each of the groups (2 girls) required redo reimplantation (5.8%). At the end of the 3rd year follow up (from the definitive repair) there was significant reduction in the hydronephrosis, improvement in the differential renal function with no evidence of obstruction and improvement in the estimated glomerular filtration rate amongst all in both groups which was statistically significant i.e. p < 0.05. The success rate was 94.4% in Primary Repair and 93.75% in Delayed Staged Repair. The mean follow up was 9.7 years amongst those undergone Primary Repair and 9 years amongst those undergone Delayed Staged Repair.

DISCUSSION AND CONCLUSION

Primary extravesical ureteral reimplantation may be considered as the preferred line of management of unilateral obstructed megaureters during infancy.

High-pressure balloon dilatation of primary obstructive megaureter in children: a systematic review

OBJECTIVE

We aimed to evaluate the effectiveness and complication rates of endoscopic high-pressure balloon dilatation (HPBD) in treating primary obstructive megaureter (POM) in children based on current literature. Specifically, we wanted to clarify the evidence on the use of HPBD in children under one year of age.

METHODS

A systematic search of the literature was performed via several databases. The preferred reporting items for systematic reviews and meta-analyses guidelines were followed. The primary outcomes studied in this systematic review were the effectiveness of HBPD in relieving obstruction and reducing hydroureteronephrosis in children. The secondary outcome was to study the complication rate of endoscopic high-pressure balloon dilatation. Studies that reported one or both of these outcomes (n = 13) were considered eligible for inclusion in this review.

RESULTS

HPBD significantly decreased both ureteral diameter (15.8 mm [range 2-30] to 8.0 mm [0-30], p = 0.00009) and anteroposterior diameter of renal pelvis (16.7 mm [0-46] to 9.7 mm [0-36], p = 0.00107). The success rate was 71% after one HPBD and 79% after two HPBD. The median follow-up time was 3.6 years (interquartile range 2.2-6.4 years). A complication rate of 33% was observed, but no Clavien-Dindo grade IV-V complications were reported. Postoperative infections and VUR were detected in 12% and 7.8% of cases, respectively. For children under one year of age, outcomes of HPBD seem to be similar to those in older children.

CONCLUSIONS

This study indicates that HPBD appears to be safe and can be used as the first-line treatment for symptomatic POM. Further comparative studies are needed addressing the effect of treatment in infants, and also long-term outcomes of the treatment. Due to the nature of POM, identifying those patients who will benefit from HPBD remains challenging.

Endoscopic Management of Primary Obstructive Megaureter: A Systematic Review

BACKGROUND

The gold standard treatment for primary obstructive megaureter (POM) with declining renal function, worsening obstruction, or recurrent infections is ureteral reimplantation with or without tapering. In infants, open surgery can be technically demanding and associated with significant morbidity. We conducted a systematic review of the literature with special interest in endoscopic management of POM and its outcomes.

MATERIALS AND METHODS

A search was conducted of the MEDLINE/Ovid, PubMed, Embase, and Web of Science databases. Only full-text articles written in the English language and involving greater than one reported pediatric case per publication were included. Two authors independently extracted data and assessed strength of evidence for each study.

RESULTS

We found 11 retrospective and 1 prospective, single institution case series that met selection criteria, describing 222 patients with 237 obstructed renal units. Mean age at time of surgery was 24.6 months. The most common endoscopic approaches were cystoscopy+high-pressure balloon dilation+Double-J ureteral stent placement (49.5%), cystoscopy+incisional ureterotomy+Double-J ureteral stent placement (27.8%), and cystoscopy+Double-J ureteral stent placement (18.9%). For all approaches and age groups, anatomic and functional success rates were 79.3% (146/184) and 76.7% (132/172), respectively. Anatomic success rates were highest in children ≥12 months of age (82.3%, 117/142). Endoscopic retreatment was performed in 15.1% of cases with a 36.7% overall surgical reintervention rate. Forty-one ureters progressed to ureteral reimplantation. Complications were generally mild (Clavien-Dindo Grades I-II), but 12 ureters did develop vesicoureteral reflux. Mean follow-up period was 3.2 years.

CONCLUSIONS

Endoscopic management for persistent or progressive POM in children ≥12 months of age is a minimally invasive alternative to ureteral reimplantation with modest success rates. In infants, it may best be utilized as a temporizing procedure. Approximately one-third of patients require surgical reintervention.

Intravesical ureteric reimplantation for primary obstructed megaureter in infants under 1 year of age

PURPOSE

This study aimed to assess the outcome of intravesical ureteric reimplantation for primary obstructed megaureter (POM) performed in infants under 1 year of age.

MATERIALS AND METHODS

A retrospective cohort study was carried out of all infants undergoing intravesical ureteric reimplantation surgery for POM at two pediatric centers in the 12 years between 2003 and 2014. Outcomes were compared with those of children aged over 1 year undergoing intravesical reimplantation for POM during this period. Follow-up was until November 2015.

RESULTS

Thirty-seven megaureters in 34 infants were reimplanted, at median age 5.2 months (Table). Operative success was 97%, with one out of 34 patients (3%) requiring reoperation for recurrent ureteric obstruction. Renal preservation was high. One patient of 34 (3%), who had bilateral congenital renal dysplasia, showed evidence of decline in renal function. Five patients of 34 (15%) had postoperative urinary tract infections (UTIs). Four (13%) of those toilet trained had some symptoms of lower urinary tract dysfunction (LUTD). Three patients (9%) who had congenitally dysplastic kidneys developed hypertension. Comparatively, 14 children with POM underwent reimplantation over 1 year of age. Operative success was 86%, with two children requiring reoperation for recurrent stenosis. Both had evidence of bladder dysfunction before surgery, and thickened bladder walls noted during surgery. One of 14 (7%) had a decline in ipsilateral renal function after recurrent stenosis. Two (14%) had postoperative UTI. Three (25%) had evidence of LUTD.

DISCUSSION

There are few data about feasibility and long-term outcomes specifically of ureteric reimplantation for POM in infancy. This is the first study to document long-term outcomes of intravesical ureteric reimplantation in infancy for POM. The recently published British Association of Paediatric Urologists consensus statement supports delaying definitive reimplantation surgery for POM that requires intervention until after 1 year of age. There is little evidence presented for this recommendation. Our study confirms the safety and feasibility of intravesical ureteric reimplantation for POM in infants under age 1, with an operative success rate of 97%, and high renal function preservation rate. UTI risk improved after surgery in children >6 months old and remained stably low in those <6 months of age. Postoperative rates of LUTD were low. Hypertension occurred in only three cases with congenital renal dysplasia.

CONCLUSIONS

Ureteric reimplantation in infants under 1 year of age is a safe and effective option for managing POM that requires intervention, and compares favorably with those undergoing reimplantation over 1 year of age.

Origin of Motion in the Human Ureter: Mechanics, Energetics and Kinetics of the Myosin Molecular Motors

Background

Ureteral peristalsis is the result of coordinated mechanical motor performance of longitudinal and circular smooth muscle layer of the ureter wall. The main aim of this study was to characterize in smooth muscle of proximal segments of human ureter, the mechanical properties at level of muscle tissue and at level of myosin molecular motors.

Methods

Ureteral samples were collected from 15 patients, who underwent nephrectomy for renal cancer. Smooth muscle strips longitudinally and circularly oriented from proximal segments of human ureter were used for the in vitro experiments. Mechanical indices including the maximum unloaded shortening velocity (Vmax), and the maximum isometric tension (P0) normalized per cross-sectional area, were determined in vitro determined in electrically evoked contractions of longitudinal and circular smooth muscle strips. Myosin cross-bridge (CB) number per mm2 (Ψ) the elementary force per single CB (Ψ) and kinetic parameters were calculated in muscle strips, using Huxley's equations adapted to nonsarcomeric muscles.

Results

Longitudinal smooth muscle strips exhibited a significantly (p<0.05) faster Vmax (63%) and a higher P0 (40%), if compared to circular strips. Moreover, longitudinal muscle strips showed a significantly higher unitary force (Ψ) per CB. However, no significant differences were observed in CB number, the attachment (f1) and the detachment (g2) rate constants between longitudinal and circular muscle strips.

Conclusions

The main result obtained in the present work documents that the mechanical, energetic and unitary forces per CB of longitudinal layer of proximal ureter are better compared to the circular one; these preliminary findings suggested, unlike intestinal smooth muscle, a major role of longitudinal smooth muscle layer in the ureter peristalsis.

Endoureterotomy for Treatment of Primary Obstructive Megaureter in Children

PURPOSE

To describe a new approach to the treatment of primary obstructive megaureter (POMU) using endoscopic endoureterotomy. The results obtained with this technique are reviewed with long-term follow-up.

PATIENTS AND METHODS

A total of 47 children (mean age 3.7 years) with 52 POMU units and a history of failed conservative management underwent endoureterotomy of obstructed juxtavesical and intramural ureter. A 3F Double-J ureteral stent was introduced up to the obstructed segment of ureter. Then a zebra catheter was inserted into the affected ureter beside the stent, followed by a neonatal-size ureteroscope. Following delineation of the length of the narrowed portion of the ureter, a guidewire with a plastic sheath replaced the zebra catheter. A longitudinal incision was made through the detrusor muscle at the 6 o'clock position, leaving the bladder adventitia untouched. The Double-J stent was left in place, while its distal tip was fixed by long nylon suture and single knot to the external genitalia to permit easy removal 1 week after the procedure.

RESULTS

With a mean follow-up of 39 months (range 14-62 months), no leakage, ureteral-orifice obstruction, or reflux was observed. The postoperative success rate was 90% (47 of 52 ureters), defined as resolution or decrease in hydroureteronephrosis and improvement or stability of renal function determined by renal scan. In 37 ureterorenal units (71%), there was complete resolution of hydroureteronephrosis.

CONCLUSIONS

On the basis of previous studies demonstrating the value of endoureterotomy with stenting for the treatment of benign ureteral strictures in adults, we developed a modified endoscopic approach for the treatment of POMU and applied this technique in meticulously selected cases. Our results showed that this approach is a valid option for the treatment of children with POMU.

Renal function and urine drainage after conservative or operative treatment of primary (obstructive) megaureter in infants and children

We examined renal function and urinary drainage of children with primary megaureter (PMU) in dependence on conservative or operative treatment.

MATERIAL AND METHODS

The retrospective analysis covering the years 1994 to 2000 comprised children at an age of 0-7 years with 35 PMU. Sonography, dynamic MAG3 renography as well as endogenic creatinine clearance (GFR) were used to assess drainage and the renal function. Temporary urinary diversion was established in fourteen patients of both groups. In 14 children with 16 PMU a ureteroneocystostomy (UNC) was performed. The average observation period was 30 months (11-108).

RESULTS

The children of the UNC group differed from the non-neoimplanted group in the age at diagnosis (10.5 vs. < 1 months), higher degrees of hydronephrosis on average, a more distinct dilatation of the ureter as well as renographically significant obstruction. Children of the non-UNC group, including four children with a type B drainage curve (O'Reilly), had an unimpaired differential renal function or improved during the observation period (initially 51% vs. 50.5% at the end). In neoimplantation group the differential function improved from 32.5% to 38.5% (p < 0.05) and obstruction resolved with one exception.

CONCLUSION

Given a higher-grade PMU with a reduced function of the kidneys and a significant impaired drainage pattern and/or symptoms, neoimplantation without temporary diversion has proved to be an efficient renoprotective method. Furthermore, data clearly justify a conservative approach without urinary diversion in infants with large asymptomatic PMU.

A MODIFIED TECHNIQUE OF URETEROPLASTY FOR MEGAURETER IN CHILDREN

PURPOSE

Excisional ureteroplasty carries the risks of jeopardizing the ureteral vasculature and leakage from the suture. The folding techniques are theoretically less prone to these risks, although they have other disadvantages due to the bulky ureter. According to the literature, these 2 approaches have similar complication rates of 4% to 25%, to include stenosis, reflux and leakage. We introduce a modified ureteroplasty technique with the aim of ensuring effective reduction of the ureteral diameter with minor risks to the vasculature.

MATERIALS AND METHODS

A total of 42 consecutive patients underwent ureteroplasty and reimplantation (Cohen 16, Politano-Leadbetter 3, psoas hitch 23) between 1994 and 2004, and were followed for 1 to 9 years. The ureter was opened longitudinally on its less vascularized area. Two parallel longitudinal incisions were made from the luminal side up to the musculature layer, leaving the adventitia untouched. The mucosal aspects lateral to these lines were discarded. The inner layer was closed with a running suture. The adventitial layer was closed with single stitches.

RESULTS

No leakage, stenosis or reflux was observed. In 3 ureters persistent dilatation was observed, without obstruction or reflux.

CONCLUSIONS

Our modification combines some principles of the 2 classic techniques, with the purpose of decreasing the risks and disadvantages of both. We believe that our approach affords better preservation of the ureteral vasculature because the adventitia is preserved untouched, as well as effective caliber reduction so that the bulking problem is avoided. In addition, the technique is associated with a minor risk of leakage. Our results show that this approach is a valid option for megaureter correction in children.

Giant ureteral stone in association with primary megaureter presenting as an acute abdomen

A 20-year-old woman presented with abdominal pain of 4-h duration and of sudden onset. A plain abdominal radiograph showed a giant ureteral stone measuring 12 cm causing ureteral obstruction. Abdominal ultrasound revealed severe dilatation of the two upper thirds of the left ureter and a hydronephrotic ipsilateral kidney. Subsequent renal scan demonstrated that it was a non-functional kidney while the contralateral kidney was normal. A left nephroureterectomy was performed.

Congenital megaureter in adults: endoscopic management with holmium: YAG laser--preliminary experience

PURPOSE

We report our experience with the holmium laser in the endoscopic management of primary obstructive megaureter (POM) in adults.

PATIENTS AND METHODS

From February 1997 to September 1998, three women and one man 26 to 63 years old underwent ureteroscopic endoureterotomy for POM with symptomatic vesicoureteral junction obstruction. The left ureter was more commonly affected than the right (R:L 1:3). The diagnosis of POM was based on a clinical history, intravenous urography, diuretic renography (T 1/2), and micturating cystogram. Endoureterotomy of the juxtavesical and intramural part of the ureter was performed in a retrograde fashion using the holmium laser. Incision of the subepithelial part of the ureter and the ureteral orifice was avoided. A pigtail stent was left in situ for 6 weeks. Postoperatively, patients were assessed at 3 months and yearly thereafter. The mean follow-up was 30.5 months.

RESULTS

All patients demonstrated symptomatic and radiologic improvement.

CONCLUSIONS

Endoscopic incision of POM in adults with the holmium laser is safe, simple, and minimally invasive. This procedure should be considered as an initial approach for patients who have failed conservative treatment. However, further follow-up is necessary to determine its long-term efficacy.

Is primary obstructive megaureter repair at risk for contralateral reflux?

PURPOSE

Contralateral vesicoureteral reflux occurs after successful unilateral reflux repair in a significant proportion of patients without correlation to the surgical approach. Unilateral congenital obstructive megaureter was compared to primary vesicoureteral reflux with regard to the risk of onset of contralateral reflux after unilateral ureteral reimplantation.

MATERIALS AND METHODS

Unilateral congenital obstructive megaureter was diagnosed in 58 consecutive patients 2 to 10 years old (mean age 3.2). Cross-trigonal ureteroneocystostomy was performed in 57 cases and longitudinal ureteral reimplantation, according to the Politano-Leadbetter technique was done in 1. Longitudinal tapering according to Hendren was performed in 44 ureters, and the Kalicinski folding was used to repair 11 ureters. All patients underwent serial renal ultrasound, diethylenetetraminepentaacetic acid nuclear scan, excretory urogram and voiding cystourethrogram. The control group was composed of 98 age matched children with unilateral vesicoureteral reflux who underwent unilateral reimplantation with or without tapering. Fisher's exact test and Student's t test were used for statistical analysis.

RESULTS

Followup ranged from 1 to 5 years. All patients in both groups underwent a voiding cystourethrogram at 6 months, and renal ultrasound at 3, 6 and 12 months postoperatively. Grade 2 reflux developed in 1 study group patient after contralateral Kalicinski ureteral folding and cross-trigonal reimplantation (1.7%). In the control group new onset contralateral reflux developed in 11 cases (11.2%). The difference was statistically significant (p <0.005, Fisher's exact test p = 0. 033).

CONCLUSIONS

Ureteral reimplantation for unilateral congenital obstructive megaureter is not correlated with the development of contralateral reflux. The occurrence of contralateral reflux after successful unilateral reflux repair is high (11.2%), and is not correlated with age, sex and technique of reimplantation or tapering. These results support the hypothesis that the functional anatomy of the trigone is preserved in congenital obstructive megaureter but is impaired on both sides in cases of unilateral vesicoureteral reflux. The surgical management of unilateral primary vesicoureteral reflux and congenital obstructive megaureter should be differentiated based on these results.

Long-term results after megaureter folding in children

In 56 megaureters treated by the folding technique, good results were obtained in 52 (93%). Complications in four ureters included stenosis (2) and vesico-ureteral reflux (2). The width of the megaureters and minor renal calyces, the degree of hydronephrosis, and the serum urea and creatinine levels decreased significantly after the operation. The renal parenchyma thickness and the creatinine clearance level increased significantly.