The ureteral orifice: its configuration and competency

Advancements in Surgical Management of Megaureters

PURPOSE OF REVIEW

To review and describe the recent evolution of surgery for the various types of pediatric megaureter.

RECENT FINDINGS

Megaureter management first relies on determining the underlying cause, whether by obstruction, reflux, or a combination, and then setting appropriate surgical indications because many cases do not require surgery as shown by observation studies. Endoscopic balloon dilation has been on the rise as a major treatment option for obstructive megaureter, while refluxing megaureters can also be treated by laparoscopic and robotic techniques, whether extravesically or transvesicoscopically. During ureteral reimplantation, tapering is sometimes necessary to address the enlarged ureter, but there are also considerations for not tapering or for tapering alternatives. Endoscopic and minimally invasive surgeries for megaureter have been the predominant focus of recent megaureter literature. These techniques still need collaborative prospective studies to better define which surgeries are best for patients needing megaureter interventions.

The correlation between ureteric orifice morphology and primary vesicoureteral reflux grade and the impact on the effectiveness of endoscopic reflux correction

INTRODUCTION

Early diagnosis and treatment of primary vesicoureteral reflux (VUR) are essential for preserving renal function.

OBJECTIVES

The study explored whether preoperative cystoscopic grading of refluxing ureteric orifices (UO) correlated with their shape in an institution with non-performance of hydrodistention of the UO in the diagnosis and grading of VUR. We also assessed the relationship between the UO shape and VUR grade with the effectiveness of endoscopic correction of primary VUR in children.

METHODS

This retrospective study included consecutive patients ≤15 years treated for primary VUR. The reflux grade was based on the results of preoperative voiding cystourethrography as mild, moderate, or severe.

RESULTS

Fifty-one patients with 77 renal refluxing units (RRU) underwent endoscopic treatment with Deflux®. VUR was bilateral in 51 % of patients. VUR was mild in 13 %, moderate in 53 %, and severe in 34 % of cases. The patients with mild and moderate VUR had stadium-shaped UOs in 60 % and 54 % RRUs, respectively. Horseshoe-shaped UOs constituted 42 % of UOs in patients with severe VUR, followed by 31 % of golf-hole UOs. The reflux resolution rate after the first endoscopic injection was 84 %. The preoperative VUR grade correlated with UOs shape (p < 0.001). No significant correlation between UOs configuration and the outcome of endoscopic treatment was seen (p = 0.452). The preoperative VUR grade negatively correlated with a favorable endoscopic treatment (p = 0.043).

DISCUSSION AND CONCLUSION

Our data indicate ureteral orifice shapes are closely related to preoperative VUR grade. There was no correlation between the UO configuration and the success rate of endoscopic treatment of VUR, in contrast to the significant negative correlation between the VUR grade and the success rate of endoscopic treatment.

Vesicoureteral reflux by contrast ultrasound, comparison with voiding and retrograde urethrocystography: A prospective accuracy study

INTRODUCTION

Diagnosis of vesicoureteral reflux (VUR) plays an important role in the management and follow-up of children presenting with urinary tract infection. This study compared voiding uronosography (VUS) as a diagnostic method for the diagnosis of VUR with the "gold standard", voiding or micturating cystourethrography (MCU). The objective of the study is not only to compare the effectiveness of both methods, but also to assess the feasibility of implementing VUS technically and economically in a large tertiary radiology center in South America.

MATERIALS AND METHOD

This was a prospective accuracy study that include 41 patients (a total of 85 ureteral units) aged between 1 month and 16 years. VUS was performed in an alternative form as regular MCU, by injecting microbubble contrast solution (SonoVue©) into the bladder through an intermittent catheter and evaluating the presence of reflux with ultrasound. MCU was always performed immediately after VUS. One pediatric radiologist evaluated all VUS exams, while a second independent pediatric radiologist evaluated all MCU exams, with both blinded to each other's assessments.

RESULTS

Comparing VUS with MCU in the diagnosis of VUR, we observed a sensitivity of 92.3 % (95 % CI 74.9-99.1 %), specificity of 98.3 % (95 % CI 90.9-100 %), positive predictive value of 96.0 % (95 % CI 79.6-99.9 %), negative predictive value of 96.7 % (95 % CI 88.5-99.6 %) and a Kappa of 0.916 (0.822-1.000). When comparing the VUR grading between VUS and MCU the agreement between the two methods was high with a Kendall's Tau-b > 0.9. VUS failed to diagnose two grade 1 VUR reflux cases in teenagers while diagnosing one grade 4 VUR in a very dilated kidney-ureter unit, which was missed on MCU. VUS and MCU had similar costs when considering the price of the ultrasound contrast agent.

DISCUSSION

VUS is a reliable alternative method to MCU for the diagnosis of VUR with the advantages of not exposing the child to ionizing radiation and potentially being more accessible due to the greater availability of ultrasound equipment. Limitations to this study include the usage of a single ultrasound equipment, which limits its generalizability and not evaluating the interobserver variability.

CONCLUSION

Consideration should be given to implementing VUS for the diagnosis of VUR, particularly in centers without fluoroscopy equipment available, since the exam's performance and cost are comparable to those of the MCU.

Laparoscopic nipple invagination combined extravesical (NICE) reimplantation technique in the management of primary obstructed megaureter

AIMS

Villanueva challenged Paquin's 5:1 tunnel length and showed in a computer simulation model that UVJ competence was more sensitive to a 2-mm protrusion of ureteric orifice into the bladder compared to an increase in the intravesical tunnel. Thompson later successfully applied the Shanfield technique of invaginating the spatulated primary obstructed megaureter (POM) laparoscopically, causing a nipple antireflux mechanism. In this study we have reported the outcomes of our modification: Nipple Invagination Combined Extravesical (NICE) reimplantation, in the management of POM.

METHODS

Patients with POM who underwent NICE reimplantation (summary figure) were followed up and outcomes were analysed. There were three modifications in this compared to Shanfield technique: 1. Detrusor myotomy was performed before opening the bladder mucosa. The detrusor edges were closed later over the invaginated ureter as an extravesical reimplantation. 2. The ureter was held invaginated inside the bladder mucosal opening by two sutures at 6 & 12 O' clock positions instead of a single suture, 3. The dilated ureter was not spatulated inferiorly, as it automatically opens out later inside the bladder to form a nipple.

RESULTS

Eleven patients underwent laparoscopic NICE reimplantation; median age: 6 months (5-24); demographics (R: L = 5:6; M:F = 7:4). The mean duration of surgery was 133 min (110-180) and the mean length of hospital stay was 3.6 days (3-5). There were no immediate post-operative complications in the form of leak in any patient. The median follow-up duration was 20 months (18-29). DRF improved in 7 patients while in 4 it remained static; no patient had deterioration. On follow-up VCUG, none had vesico-ureteric reflux (VUR). The nipple effect could be noticed later at follow-up ultrasonograms and at cystoscopy during stent removal.

DISCUSSION

Paquin emphasised on 5:1 ureteral re-implant tunnel length while Lyon felt that the shape of the ureteral orifice was more important. Shanfield introduced a technique of creating a nipple valve effect by invaginating the ureter intravesically. However it was held by a single suture and had no detrusor backing. NICE reimpantation incorporates a short extra vesical reimplant to the Shanfield technique and literally eliminates post-operative VUR. It is simple and could easily be performed laparoscopically even in small infant bladders. The ureteric orifice kept in line enables future upper-tract access. Our preliminary data suggests that the NICE reimplantation for POM is very successful. Limitations are small numbers and short follow-up. Further larger studies are warranted to authenticate this novel technique.

A real-time system using deep learning to detect and track ureteral orifices during urinary endoscopy

BACKGROUND AND OBJECTIVE

To automatically identify and locate various types and states of the ureteral orifice (UO) in real endoscopy scenarios, we developed and verified a real-time computer-aided UO detection and tracking system using an improved real-time deep convolutional neural network and a robust tracking algorithm.

METHODS

The single-shot multibox detector (SSD) was refined to perform the detection task. We trained both the SSD and Refined-SSD using 447 resectoscopy images with UO and tested them on 818 ureteroscopy images. We also evaluated the detection performance on endoscopy video frames, which comprised 892 resectoscopy frames and 1366 ureteroscopy frames. UOs could not be identified with certainty because sometimes they appeared on the screen in a closed state of peristaltic contraction. To mitigate this problem and mimic the inspection behavior of urologists, we integrated the SSD and Refined-SSD with five different tracking algorithms.

RESULTS

When tested on 818 ureteroscopy images, our proposed UO detection network, Refined-SSD, achieved an accuracy of 0.902. In the video sequence analysis, our detection model yielded test sensitivities of 0.840 and 0.922 on resectoscopy and ureteroscopy video frames, respectively. In addition, by testing Refined-SSD on 1366 ureteroscopy video frames, the sensitivity achieved a value of 0.922, and a lowest false positive per image of 0.049 was obtained. For UO tracking performance, our proposed UO detection and tracking system (Refined-SSD integrated with CSRT) performed the best overall. At an overlap threshold of 0.5, the success rate of our proposed UO detection and tracking system was greater than 0.95 on 17 resectoscopy video clips and achieved nearly 0.95 on 40 ureteroscopy video clips.

CONCLUSIONS

We developed a deep learning system that could be used for detecting and tracking UOs in endoscopy scenarios in real time. This system can simultaneously maintain high accuracy. This approach has great potential to serve as an excellent learning and feedback system for trainees and new urologists in clinical settings.

The 5:1 rule overestimates the needed tunnel length during ureteral reimplantation

AIMS

Paquin asserts that in order for ureterovesical junctions (UVJs) to prevent reflux, the ureteral tunnel length-to-diameter ratio needs to be 5:1. We hypothesize that the surgical implementation of this observation results in an overestimation of the needed length-to-diameter ratio to prevent vesicoureteral reflux.

METHODS

With finite elements, we model the urine storage phase of the bladder under nonlinear conditions. In the reference state, the bladder is assumed to be a sphere with an oblique straight elliptical hole as the UVJ. Broad parametric studies on different length-to-diameter ratios are performed as the bladder volume increases from 10% to 110% capacity.

RESULTS

The capability of the UVJ to prevent reflux during storage depends on its length-to-diameter ratio. UVJs with larger length-to-diameter ratios lengthen and narrow as the bladder volume increases, causing the closure of the UVJ and rise in its flow resistance. Our model shows that the UVJ length-to-diameter ratio decreases as the bladder volume increases. The 5:1 ratio implemented at 80% capacity-approximate volume or bladder wall stretch during ureteroneocystostomy (UNC)-corresponds to 7:1 at the reference state-used by Paquin. The 5:1 ratio implemented at the reference state corresponds to 3:1 at 80% capacity.

CONCLUSIONS

Our modeling results are consistent with Paquin's original observation on the significance of the UVJ length-to-diameter ratio in preventing reflux. They, however, indicate that the surgical implementation of this rule during UNC results in an overestimation of the requisite tunnel length-to-diameter ratio to prevent reflux. They also suggest that the UVJ closure is due to the bladder wall deformation rather than the pressure.

Laparoscopic extravesical ureteral reimplantation for correction of primary and secondary megaureters: Preliminary report of a new simplified technique

PURPOSE

To describe a simplified surgical technique for the treatment of primary and secondary obstructed megaureters in children by laparoscopic extravesical ureteral reimplantation (LEUR) and evaluate the short-term outcomes.

METHODS

Prospective study of children with primary and secondary megaureters treated at our institution between 2016 and 2018 by LEUR. A transperitoneal approach was used in all cases. The distal ureter was transected at the level of the stenosis. Detrusor muscle fibers were divided to expose bladder mucosa. The distal ureter was introduced into the bladder to create a valve-like mechanism. The ureter was fixed to the bladder mucosa by four stitches. We analyzed indications for surgery, complications and outcomes. Definition of success was relieved of obstruction and absence of VUR.

RESULTS

Six patients with a mean age of 28.83 months (SD: 21.4) underwent LEUR. Indications for surgery were: infection [2], obstruction [2], decrease in renal differential function [1] and increase in hydronephrosis [1]. There were no intraoperative complications. Resolution of hydronephrosis, obstruction and VUR was achieved in all cases. Mean follow-up was 13 months (SD: 6.67).

CONCLUSION

LEUR for the correction of primary and secondary megaureters by this new technique is safe. The most important advantage is that this technique is simpler and more easily reproducible than conventional LEUR. However, long-term follow-up is required.

TYPE OF STUDY

Prospective, observational.

LEVEL OF EVIDENCE

Level III.

Real-Time Detection of Ureteral Orifice in Urinary Endoscopy Videos Based on Deep Learning

In urology endoscopic procedures, the Ureteral Orifice (UO) finding is crucial but may be challenging for inexperienced doctors. Generally, it is difficult to identify UOs intraoperatively due to the presence of a large median lobe, obstructing tumor, previous surgery, etc. To automatically identify various types of UOs in the video, we propose a real-time deep learning system in UO identification and localization in urinary endoscopy videos, and it can be applied to different types of urinary endoscopes. Our UO detection system is mainly based on Single Shot MultiBox Detector (SSD), which is one of the state-of-the-art deep-learning based detection networks in natural image domain. For the preprocessing, we apply both general and specific data augmentation strategies which have significantly improved all evaluation metrics. For the training steps, we only utilize rescetoscopy images which have more complex background information, and then, we use ureteroscopy images for testing. Simultaneously, we demonstrate that the model trained with rescetoscopy images can be successfully applied in the other type of urinary endoscopy images with four evaluation metrics (precision, recall, F1 and F2 scores) greater than 0.8. We further evaluate our model based on four independent video datasets which comprise both rescectoscopy videos and ureteroscopy videos. Extensive experiments on the four video datasets demonstrate that our deep-learning based UO detection system can identify and locate UOs of two different urinary endoscopes in real time with average processing time equal to 25 ms per frame and simultaneously achieve satisfactory recall and specificity.

Comparative Clinical Study Between Modified Ureteral Orthotopic Reimplantation and Cohen Method Under Pneumovesicum in Pediatric Patients With Hydroureteronephrosis

Purpose: To report our initial experience with a modified ureteral orthotopic reimplantation technique under pneumovesicum and compare the outcomes vs. those obtained with the Cohen technique under pneumovesicum for the correction of primary obstructive megaureter (POM) or vesicoureteral reflux(VUR) in pediatric patients. Methods: A total of 46 patients (38 POM and 8 VUR; mean age: 16.24 months) treated with modified ureteral orthotopic reimplantation (OR) and 43 patients (34 POM and 9 VUR; mean age: 22.98 months) treated with Cohen reimplantation (CR) under pneumovesicum were included. We compared the results perioperatively and during follow-up. Results: The mean operative time was significantly shorter in the OR group (OR: 86.86 and 108.18 vs. CR: 95.14 and 124.29 min for unilateral and bilateral cases, respectively). The mean postoperative hospital stay (OR: 5.02 vs. CR: 5.07 days), blood loss (OR: 3.67 vs. CR: 3.84 ml), and follow-up time (OR: 23.17 vs. CR: 23.37 months) did not exhibit significant differences between the two groups. One patient converted to open surgery in the CR group, whereas there was no conversion in the OR group. Postoperative febrile urinary tract infection occurred in two cases in each group. Both infections were controlled using antibiotics. All patients in both groups showed improved hydroureteronephrosis, and all patients with VUR showed reflux resolution post-surgery. Conclusions: Our modified ureteral orthotopic reimplantation technique under pneumovesicum can be safely and effectively performed, achieving a high success rate that is equivalent to that obtained through the Cohen technique under pneumovesicum. Moreover, it involves a simpler procedure and shorter operation time.

Laparoscopic posterior appendix Mitrofanoff using the modified Shanfield anastomosis

Laparoscopic transperitoneal technique for appendicovesicostomy was performed in a 5-year-old boy with a non-neurogenic neuropathic bladder using a transumbilical 5-mm port, two 3-mm working ports and a modified Shanfield anastomosis. Posterior extramucosal detrusorotomy and submucosal dissection was performed. The proximal appendix was spatulated and advanced into the bladder through a mucosal window using a U-stitch and fixed. The detrusor was then approximated creating an antirefluxing extramucosal tunnel. VQ plasty was fashioned for stoma formation. The procedure and postoperative period were uneventful. Clean intermittent catheterisation (CIC) was established subsequently and continued for the last 6 months. Our experience shows that appendix Mitrofanoff can be performed with minimal number and size of ports, resulting in a good cosmetic outcome. A simplified anastomosis makes it less cumbersome, and catheterisation is reliable as there is no mucosa-mucosa junction to negotiate.

Morphological study of the ureterovesical junction in children

Morphological and morphometric assessment of the elements of the ureterovesical junction in children was performed in the present study in different age groups ranging from 24 weeks of gestation to 16 years old. We tried to answer the question whether, in human ontogenesis, there is a period of anatomical predisposition to primary vesicoureteral reflux. The study included 210 urinary bladders with juxtavesical parts of the ureters that had been obtained from routine autopsies. As a result of the study, we showed that provided the pregnancy is uncomplicated there is no inherited susceptibility that would account for reducing or disturbing the development of ureterovesical junction elements. Based on the analysis of our results concerning the anatomy and morphological changes taking place in the elements of the ureterovesical junction in different age groups, one could put forward a hypothesis that anatomical predisposition to primary vesicoureteral reflux occurs in age group II, i.e. between 28 and 37 weeks of gestation. The parameters that define interrelations between elements of the ureterovesical junction and that are considered essential for normal functioning of antireflux mechanism were still observed in age group VI in our study. This suggests that these relations are not unambiguous in children with normally structured and functionally competent vesicoureteral junction.

The Shanfield anastomosis revisited: Its applications and early outcome

BACKGROUND

Shanfield first described a simple ureteric implantation technique involving a U-stitch anchoring the spatulated end of the transplant ureter to the interior of the intact bladder through a small stab wound. We present an extrapolation of this principle to Mitrofanoff channels and native ureteric reimplantations and further extend it to a laparoscopic approach in some.

METHODS

A retrospective case-note reviewing the Shanfield ureteric reimplantation in fifteen children between October 2014 and May 2017 was performed.

RESULTS

Fifteen children (females n = 9), median age 6 years (range 8 months-15 years), underwent a Shanfield anastomosis for ureteric (n = 3) or Mitrofanoff (n = 12) implantation into the bladder. Their diagnoses were: vesicoureteric reflux (n = 2), vesicoureteric obstruction (n = 1), neuropathic bladder (n = 4), exstrophy (n = 2, bladder and cloacal), nonneuropathic bladder (n = 3), cloaca (n = 2), and one with failed urethral reconstruction of a Y-duplication. Two ureteric reimplantations and one appendix-Mitrofanoff were undertaken entirely laparoscopically. The bladder was not opened in 9/15, with the remaining six in an ileocystoplasty and one complex cloaca. Fourteen patients were available for follow-up at a median 18.2 (5.8-43.3) months. There was no anastomotic leakage in any, and one stenosis was successfully managed with simple dilatation. One complex patient required a new Mitrofanoff channel.

CONCLUSION

Our preliminary data suggest that the Shanfield anastomosis offers a safe, robust, and simple antireflux implantation technique without the need to formally open the bladder. The technique offers several advantages as it allows overcoming the problem of inadequate tunnelling when the bladder template is deficient. Meanwhile, its simplicity permits it to be faithfully reproduced with laparoscopy in select patients.

TYPE OF STUDY

Treatment study.

LEVEL OF EVIDENCE

IV.

Ureteral tunnel length versus ureteral orifice configuration in the determination of ureterovesical junction competence: A computer simulation model

INTRODUCTION

The long-held belief that a ureteral re-implant tunnel should be five times the diameter of the ureter, as proposed by Paquin in 1959, ignores the effect of the orifice on the occurrence of reflux. In 1969, Lyon proposed that the shape of the ureteral orifice (UO) is more important than the intravesical tunnel. However, both theories missed quantitative evidence from principles of physics. The goal of the current study was to test Lyon's theory through numerical models (i.e. to quantify the sensitivity of ureterovesical junction (UVJ) competence to intravesical tunnel length and to the UO).

MATERIALS AND METHODS

The closure of a three-dimensional spatial configuration of ureter, constrained within a bladder, was simulated. Two common UO shapes (i.e. golf type vs 2-mm volcano type (Summary Fig.)), and two different intravesical ureteral tunnel length/diameter ratios (3:1 and 5:1) were examined. The required closure pressures were then compared.

RESULTS

The UO was a significant factor in determining closure pressure. Given the same intravesical ureteral tunnel length/diameter ratio, the required closure pressure for the volcanic orifice was 78% less than that for the golf orifice. On the other hand, the intravesical ureteral tunnel length/diameter ratio had minimal effect on the required closure pressure. As the intravesical ureteral tunnel length/diameter ratio changed from 3:1 to 5:1, the required closure pressure was reduced by less than 7%, regardless of the orifice shape.

CONCLUSIONS

The simulation results showed that UVJ competence was more sensitive to a 2-mm protrusion of the UO compared to an increase in the intravesical tunnel length from 3:1 to 5:1. This agrees with Lyon's theory, and at the same time challenges Paquin's 5:1 rule. Researchers could use this information to consider the UO configuration in further animal, human, computer or material models.

Factors involved in the late failure of endoscopic treatment of vesicoureteral reflux

INTRODUCTION

The short-term results of endoscopic treatment of vesicoureteral reflux (VUR) are excellent. Over time, however, a number of patients have been identified for whom VUR reappeared after being resolved with this technique. The aim of this study was to analyse the factors related to this event.

MATERIAL AND METHODS

A retrospective, analytical, case-control study included 395 ureteral units with primary VUR treated successfully at our centre, with a minimum follow-up of 3 years. We identified cases in which VUR reappeared and analysed the demographic variables, those related to VUR (grade, laterality, initial study) and those related to the operation (materials used).

RESULTS

We identified 77 ureteral units with recurrence in the 395 included units (19.5%). The recurrence rate was 29.7% for the patients treated with dextranomer/hyaluronic acid (Dx/HA), 20.2% for those treated with polydimethylsiloxane (MP) and 12.2% for polytetrafluoroethylene (PTFE). The onset of recurrence rose to 35% for patients treated before 1 year of age and those with gradeV VUR. Urinary dysfunction symptoms also increased the recurrence rate to 34.9%.

CONCLUSION

The use of resorbable dextranomer/hyaluronic acid material was related to recurrence in the endoscopic treatment of VUR. The high-grade reflux and treatment at an early age, as well as the presence of urinary dysfunction, are also factors associated with recurrence.

Evaluation of Mathisen's technique for ureteral reimplantation in children with primary vesicoureteral reflux

INTRODUCTION

Although cross-trigonal ureteral reimplantation (Cohen) is a commonly used technique in children, it represents a non-physiological transfer of the ureteral orifices and may prove challenging with regard to endoscopic ureteral operations in later life. In 1964, Mathisen described an alternative method of ureteral reimplantation with lateralization of the neohiatus, creating an orthotopic course of the submucosal ureter. We have evaluated success and complication rates of both techniques that were applied sequentially at our departments.

METHODS

Forty-eight consecutive patients (83 ureters, 24 males/24 females) following Mathisen reimplantation were compared with 53 consecutive patients (98 ureters, 30 males/23 females) following Cohen reimplantation. Inclusion criteria were primary vesicoureteral reflux (VUR) and no previous intervention. Reflux grades (Mathisen 58 ureters/69.9% VUR ≥ III; Cohen 66 ureters/66.7% VUR ≥ III) and the occurence of other complicating factors (ureteroceles, megaureters, posterior urethral valves) in both groups were comparable.

RESULTS

After Cohen's reimplantation there were no immediate complications requiring intervention; during follow-up (mean 28.2 months) three patients (5.6%) suffered febrile urinary tract infections (UTIs), of which one (1.8%) was diagnosed with a persisting VUR. Persistent hydronephroses (≥II SFU) were recorded in six patients (13.2%). After reimplantation using Mathisen's technique, two patients (4.1%) suffered significant intravesical bleeding; during follow-up (mean 23.06 months) four patients (8.3%) suffered febrile UTIs, and seven patients (14.5%) were diagnosed with persisting VUR after a mean follow-up of 10.8 months. The patients with persistent VUR had more commonly high-grade (IV and V) VUR initially, compared to the whole group. Two patients (4.1%) had persistent hydronephroses (≥II SFU). Mathisen's technique for ureteral reimplantation yielded a significantly (p = 0.0256 patients, p = 0.006 ureterorenal units) lower success rate (85.5% patients, 89.2% ureterorenal units) in comparison with Cohen's technique (98.2% patients, 99% ureterorenal units). Although there was no intervention for obstruction, persistent hydronephrosis was more common in the Cohen group (13.2% vs. 4.1%, n.s.).

CONCLUSIONS

Despite the advantages of an orthotopic ureteral orifice close to the bladder neck, as achieved by Mathisen's reimplantation, cross-trigonal ureteral reimplantation proved more reliable for VUR correction. As regards optimizing the results, patient selection for either technique could prove essential. Nevertheless, as regards the difficulties with ectopic ureteral orifices in the Cohen technique in the long-term follow-up, the concept of anatomic, orthotopic ureteral reimplantation should be pursued and the technique should be further refined.

Modified ureteral orthotopic reimplantation method for managing infant primary obstructive megaureter: a preliminary study

PURPOSE

To describe a modified ureteral orthotopic reimplantation method in infant with primary obstructive megaureter (POM) and report our initial experience.

METHODS

Thirteen children with POM (range 1-7 months) underwent modified transvesical ureteral implantation surgery. Treatment consists of transecting the ureter proximal to the obstruction and performing orthotopic reimplantation in end freely fashion with distal ureter protruding into the bladder, providing dilated ureteral diameter: ureteral exposure length in bladder ratio of 1:1.5-2. All patients underwent repeat ultrasound, radionuclide imaging and voiding cystourethrography. Cystoscopy was conducted in patients at 6 months after surgery.

RESULTS

The mean operating time was 40 min. There were one redo this procedure for recurrent obstruction and one Cohen reimplantation for Grade 5 vesico-ureteral reflux in one bilateral POM. Hydroureteronephrosis improved in other 11 patients, and the ureter diameter was significantly reduced from preoperative measurements. At the time of cystoscopy, thick and large volcanic-shaped ureteral orifice was found and urine ejected intermittently.

CONCLUSIONS

The proposed 'modified ureteral orthotopic reimplantation' with no tapering or advancement for POM in infants is a simple, feasible and less invasive procedure that had good success rates in this small series. Further, larger studies are required to support or negate the usefulness of this technique.

Intravesical tunnel length to ureteral diameter ratio insufficiently explains ureterovesical junction competence: A parametric simulation study

OBJECTIVE

In 1959, Paquin recommended a tunnel length five times the diameter of the ureter to prevent vesicoureteral reflux (VUR) during ureteral reimplants. In 1969, Lyon et al. challenged Paquin's conclusions and proposed that the ureteral orifice was more important than the intravesical tunnel for UVJ competence. It is not known if the two mechanisms of UVJ competence (tunnel length and UO spatial orientation) are interdependent or if one is more critical. Although in clinical practice Paquin's rule has stood the test of time, classical mechanics of materials would predict more coaptation (less reflux) with larger diameter ureters and this contradicts Paquin's rule. The aim of this study was to test Paquin's tunnel length theory by parametrically modeling the ureterovesical junction (UVJ) to determine variables critical for ureteral closure.

STUDY DESIGN

LS-DYNA finite-element simulation software was use to model ureteral collapse (Figure). Intravesical tunnel length, ureteral diameter, ureteral thickness and ureteral stiffness were all modeled. Changes in the pressure required to collapse the ureter were studied as each variable was changed on the model. The modeled ureteral orifice was not affected by changes in bladder volume (in a real bladder, bladder distention would pull the ureteral office open) and had no constraints (which could occur by suturing the ureteral orifice to a stiff bladder).

RESULTS

As predicted by classical mechanics of materials, the pressure required to collapse the ureter was inversely related to its diameter. Above 1 cm tunnel length, pressures required to collapse a ureter did not decrease by any significant amount. Increasing ureteral thickness or ureteral stiffness did increase the pressure required to collapse the ureter, but only significantly for ureteral thicknesses not commonly seen in practice (i.e. wall thickness of 2.5 mm in a 6.4 mm ureter).

DISCUSSION

Our model showed that for most ureters seen in clinical practice (3-30 mm in diameter), and when the ureteral orifice is not constrained by the bladder mucosa, a 1 cm tunnel would allow the ureter to collapse under low pressures. Contrary to Paquin's belief, larger diameter ureters collapsed more easily. It is important to understand that our model's main limitation was that it did not study the effects of the ureteral orifice, which in light of our findings must play an important role in preventing reflux as suggested by Lyon et al., in 1969. For example, a 3 cm ureteral orifice sutured to the bladder mucosa would be difficult to collapse as the bladder distends and pulls open the orifice. One way of compensating for a difficult to collapse ureteral orifice would be creating a larger diameter tunnel, but another would be to create a better ureteral orifice, perhaps by narrowing the diameter of the UO (distal ureteral tapering) and making it protrude into the bladder like a volcano (i.e. advancement sutures, or creating an intravesical nipple).

CONCLUSION

We hope that this new understanding of the variables involved in ureterovesical junction competence can lead to further refinement in our surgical techniques to correct vesicoureteral reflux.

The influence of ureteral orifice configuration on the success rate of endoscopic treatment of vesicoureteral reflux

Background:

To investigate the effect of polyacrylate polyalcohol copolymer (Vantris) injection for the correction of VUR in children according to ureteral orifice shape and VUR grade.

Materials and Methods:

Forty children (29 girls and 11 boys) with 61 renal refluxing units (RRU) and primary VUR underwent endoscopic correction of their reflux, using Vantris. Under general anesthesia, routine cystoscopy was performed and ureteral orifice configuration and dynamic hydro distention grade were determined. The injection technique was STING, HIT or a combination of them. Ultrasound scan was performed one and 3 months after injection and radionuclide cystography (RNC) was performed 3 months after the operation.

Results:

The mean volume of injected Vantris was 0.62 cc. Reflux was corrected in 52 (85.2%) of the 61 RRU after single injection and this equates reflux correction in 37 of the 40 patients. No significant correlation was observed between ureteral orifice shape and VUR correction rate.

Conclusions:

Our results showed that there was no correlation between the ureteral orifice configuration and the success rate of endoscopic surgery for VUR in short term.

Does hydronephrosis predict the presence of severe vesicoureteral reflux?

We hypothesized that, in patients with vesicoureteral reflux (VUR) grade IV or V, hydronephrosis will likely be found, if the patient has a full bladder during the renal ultrasound examination. Eight hundred thirty-seven patients were included in the study. Patients ranged in age from <1 month to 18.7 years, with a median age of 1.3 years. Five hundred sixty-nine were female and 268 were male. In this retrospective study, each patient underwent a voiding cystourethrogram (VCUG) and a renal ultrasound examination. The presence of hydronephrosis and bladder filling status in 131 renal units with VUR grade IV or V was evaluated. Sensitivity and specificity for hydronephrosis to detect the presence of VUR grades IV and V were 60 and 92 %, respectively. Positive predictive value and negative predictive value were 74 and 87 %, respectively. Odds ratios for the relationship between hydronephrosis and severe VUR was significant (p = 0.046).

CONCLUSION

In patients with grade IV or V VUR, hydronephrosis will be observed in the presence of a full bladder. Therefore, a renal ultrasound could be considered a screening test to decide on performing a VCUG.

Hypothesis - a congenitally lax pubourethral ligament may be a contributing cause of vesicoureteral reflux

INTRODUCTION

The hypothesis derives from the field of female stress incontinence. Application of pressure on the anterior vaginal wall at midurethra with a hemostat restores the geometry of the vesicoureteral junction and continence.

METHODS

We applied unilateral midurethral pressure during a radiological investigation of a 15-year-old female patient who had undergone 2 surgeries for ureteric reflux.

RESULTS

On injection of the dye into the bladder, reflux was noted in the left ureter, and this disappeared within 2-3 seconds after pressure was applied on 2 successive occasions in the midurethral area of the vagina.

CONCLUSION

The hypothesis that a musculoelastic mechanism dependent on a competent pubourethral ligament may play a role in vesicoureteral valve closure appears to have been confirmed, at least in one case. Hopefully this observation will lead to further studies, and perhaps, new directions for therapy.

Noninvasive assessment of antenatal hydronephrosis in mice reveals a critical role for Robo2 in maintaining anti-reflux mechanism

Antenatal hydronephrosis and vesicoureteral reflux (VUR) are common renal tract birth defects. We recently showed that disruption of the Robo2 gene is associated with VUR in humans and antenatal hydronephrosis in knockout mice. However, the natural history, causal relationship and developmental origins of these clinical conditions remain largely unclear. Although the hydronephrosis phenotype in Robo2 knockout mice has been attributed to the coexistence of ureteral reflux and obstruction in the same mice, this hypothesis has not been tested experimentally. Here we used noninvasive high-resolution micro-ultrasonography and pathological analysis to follow the progression of antenatal hydronephrosis in individual Robo2-deficient mice from embryo to adulthood. We found that hydronephrosis progressed continuously after birth with no spontaneous resolution. With the use of a microbubble ultrasound contrast agent and ultrasound-guided percutaneous aspiration, we demonstrated that antenatal hydronephrosis in Robo2-deficient mice is caused by high-grade VUR resulting from a dilated and incompetent ureterovesical junction rather than ureteral obstruction. We further documented Robo2 expression around the developing ureterovesical junction and identified early dilatation of ureteral orifice structures as a potential fetal origin of antenatal hydronephrosis and VUR. Our results thus demonstrate that Robo2 is crucial for the formation of a normal ureteral orifice and for the maintenance of an effective anti-reflux mechanism. This study also establishes a reproducible genetic mouse model of progressive antenatal hydronephrosis and primary high-grade VUR.

Vesico-ureteric reflux: using mouse models to understand a common congenital urinary tract defect

Vesico-ureteric reflux (VUR) is a common congenital urinary tract defect in which urine flows retrogradely from the bladder to the kidneys because of an abnormally formed uretero-vesical junction. It is associated with recurrent urinary tract infections, renal hypo/dysplasia, reflux nephropathy, hypertension, and end-stage renal disease. In humans, VUR is genetically and phenotypically heterogeneous, encompassing diverse renal and urinary tract phenotypes. To understand the significance of these phenotypes, we and others have used the mouse as a model organism and this has led to the identification of new candidate genes. Through careful phenotypic analysis of these models, a new understanding of the genetics and biology of VUR is now underway.

The C3H/HeJ inbred mouse is a model of vesico-ureteric reflux with a susceptibility locus on chromosome 12

Vesico-ureteric reflux is the most common congenital anomaly of the urinary tract, characterized by a defective uretero-vesical junction with retrograde urine flow from the bladder toward the kidneys. Because there is strong evidence for a genetic basis for some cases of vesico-ureteric reflux, we screened 11 inbred mouse strains for reflux and kidney size and identified one strain, C3H/HeJ, that has a 100 percent incidence of vesico-ureteric reflux with otherwise normal kidneys at birth. These mice are predisposed to reflux as a result of a defective uretero-vesical junction characterized by a short intravesical ureter. This defect results from a delay in urinary tract development initially manifested by a ureteric bud arising from a more caudal location along the mesonephric duct. In contrast, C57BL/6J mice (resistant to reflux at birth) have long intravesical ureters, normally positioned ureteric buds, and no delay in urinary tract development. Genome-wide and additional fine mapping of backcross mice, derived from C3H/HeJ and C57BL/6J crosses, identified a significant reflux susceptibility locus, Vurm1, on chromosome 12 (peak logarithm of the odds=7.39). The C3H/HeJ mouse is a model of vesico-ureteric reflux without renal malformation, and further characterization of this model will allow for the identification of a pathway important for urinary tract development, a finding that will serve as a model for the human disorder.

Unilateral vesicoureteral reflux: does endoscopic injection based on the cystoscopic appearance of the ureteral orifice decrease the incidence of de-novo contralateral reflux?

OBJECTIVE

In patients with unilateral vesicoureteral reflux (VUR), it has been suggested that injection of a non-refluxing but cystoscopically abnormal contralateral ureteral orifice (UO) with dextranomer/hyaluronic acid (Dx/HA) should be performed to prevent the development of de-novo contralateral VUR. We evaluate the effectiveness of this practice.

PATIENTS AND METHODS

Patients with primary unilateral VUR undergoing injection of Dx/HA from 2002 to 2005 at two institutions were eligible. Patients with unilateral VUR with cystoscopically abnormal contralateral UOs were injected with Dx/HA, while patients with normal appearing UOs received no treatment. Multivariate logistic regression models were used to estimate the impact of prophylactic injection on the development of de-novo contralateral VUR.

RESULTS

In total, 101 patients with unilateral VUR and an abnormal appearing contralateral UO underwent prophylactic injection of Dx/HA while 45 patients with a normal appearing contralateral UO were untreated. In patients receiving prophylactic Dx/HA, 9% (9/101) of the previously non-refluxing ureters developed de-novo VUR. Similarly, 13% (6/45) of patients with a normal appearing UO treated by observation alone developed de-novo VUR (P=0.55). The overall incidence of 10% (15/146) de-novo contralateral VUR matches published results where this protocol was not followed.

CONCLUSIONS

Our findings suggest that cystoscopic assessment and prophylactic treatment of an abnormal appearing, non-refluxing contralateral UO with Dx/HA is of little clinical benefit and should be abandoned.

Vesicoureteral reflux: surgical and endoscopic treatment

The optimal management of vesicoureteral reflux (VUR) is quite controversial. For many years, only antibiotic prophylaxis and open surgery were considered possible options. Since the first descriptions in the early 1980s, endoscopic treatment (ET) has gained popularity and is now considered a valid alternative both to open surgery and antibiotic prophylaxis. Many surgical antireflux techniques have been described in the past 50 years. The general principle of reflux surgery, usually defined as ureteric reimplantation, is elongation of the submucosal ureteral tunnel with creation of a flap-valve mechanism. The antireflux operation can also be carried out laparoscopically, either extravesically or intravesically (pneumovesicum). Open surgery is associated with a high success rate (>95%) regardless of the technique adopted. However, because it is invasive, it is limited to selected cases. Laparoscopic technique is less invasive, but the mean operative time is much longer and results depend significantly on the learning curve. ET involves injecting material endoscopically into the submucosal space under the ureteric orifice. It is associated with a good success rate (about 80% after one injection). Advantages of this minimally invasive treatment include repeatability and the fact that postoperative complications are rare. With a second injection, after few months if needed, the success rate of ET approaches that of open surgery. Our 20-year experience in ET is described in detail in this paper, as this technique has changed the management algorithm for VUR dramatically.

Multi-institutional experience with PIC cystography—incidence of occult vesicoureteral reflux in children with febrile urinary tract infections

OBJECTIVES

It has been reported that all children with febrile urinary tract infections (FUTIs) and normal voiding cystourethrogram (VCUG) findings show occult reflux (vesicoureteral reflux [VUR]) when examined by cystography performed with positioning of the instillation of contrast at the ureteral orifice (PIC cystography). In this study, we evaluated the reproducibility of this finding using a prospective multi-institutional collaborative examination to determine whether PIC-VUR is as common in such cases as previously shown.

METHODS

From March 2002 to October 2003, four institutions performed PIC cystography consecutively and prospectively in pediatric cases of FUTI (greater than 101 degrees F) who had not shown VUR by conventional VCUG. We correlated the ureteral orifice (UO) configuration and position with the status of PIC-VUR.

RESULTS

PIC cystography was performed in 39 children (31 girls and 8 boys; 75 FUTIs). We identified PIC-VUR in 32 (82%) of 39 children, involving 58 (74%) of 78 ureters. The likelihood of demonstrating PIC-VUR was increased 37-fold if the UO showed a patulous configuration and was increased 9-fold if the UO showed a lateral configuration. PIC-VUR was noted uniformly in UOs showing hydrodistension.

CONCLUSIONS

This multi-institutional registry showed that the incidence of PIC-VUR (82%) in children with FUTI and normal standard VCUG findings is similar to that previously reported. We consider that PIC-VUR likely accounts for the FUTIs.

Overexpression of RET leads to vesicoureteric reflux in mice

RET, a tyrosine kinase receptor essential for kidney development, has recently been shown to be important for the formation of the urinary tract. When RET is overexpressed in the HoxB7/Ret transgenic mouse, kidneys are small and cystic, and in some of the mice, the ureters are grossly dilated. Here, we report that the observed ureteral dilatation is associated with the urinary tract abnormality vesicoureteric reflux (VUR), in which urine flows retrogradely from the bladder to the ureter. Reflux was determined in vitro by injecting methylene blue into the bladders of HoxB7/Ret and wild-type mice. At postnatal day 1, 30% of HoxB7/Ret mice had VUR compared with 4% of wild-type mice (P < 0.05). The length of the intravesical ureteral tunnel was shorter in HoxB7/Ret mice compared with wild-type mice, on both the right and the left sides (P < 0.05), suggesting a basis for the higher incidence of VUR in these mutants. At embryonic day 11, the ureteric bud was found to exit more caudally from the mesonephric duct in HoxB7/Ret mice, and this may predispose them to VUR (P < 0.05). Wild-type and HoxB7/Ret mice were tested for reflux at embryonic day 17, and both showed a high frequency of VUR (59 and 75%, respectively). These results suggest that VUR may occur transiently during normal urinary tract development before the ureter has completed its insertion into the bladder. In the HoxB7/Ret mouse, overexpression of RET appears to delay the maturation of the distal ureter, resulting in postnatal VUR. The HoxB7/Ret mouse is thus an important model in which to examine how vesicoureteric reflux arises during urinary tract development.

A Simple Way to Take Pictures During Endoscopic Procedures

PURPOSE

We describe a new method of taking pictures from endoscopic images using a digital photo camera coupled to the endoscopic lens without an adapter.

MATERIALS AND METHODS

We used a digital camera with 3.3 megapixel resolution and 6 x optical zoom. The camera was coupled to the endoscopic lens with no special adapter. The image was accompanied through the LCD (liquid crystal display) visor, and the picture was taken with the flash button on and with no macro resource. The image was then enlarged by optical and digital zoom before being easily stored in photo files at the personal computer.

RESULTS

The quality of the photos obtained by this method was at least similar to that of traditional photos, and the data were promptly stored.

CONCLUSIONS

We describe a simple method of taking pictures from endoscopic images with the additional advantage of a facility to edit and store the photographs.

The PIC cystogram: a novel approach to identify "occult" vesicoureteral reflux in children with febrile urinary tract infections

PURPOSE

When the standard cystogram does not show vesicoureteral reflux in children who have experienced febrile urinary tract infections (UTIs), clinical management is controversial. We postulated that vesicoureteral reflux accounts for such UTIs but is "occult." We tested this hypothesis by using a novel method, PIC cystography (Positioning the Instillation of Contrast at the ureteral orifice) at the time of cystoscopy.

MATERIALS AND METHODS

We performed PIC cystography with instillation of contrast medium at the ureteral orifice consecutively and prospectively in 57 children who underwent cystoscopy between November 1999 and February 2002 to evaluate febrile UTIs in 40 patients, dysfunctional voiding in 14 and hydronephrosis in 3. The control group (27 patients, 54 renal units) was used to assess the accuracy of PIC by comparing the results against those with the standard cystogram in children who did not have febrile infection and did not demonstrate vesicoureteral reflux (15 patients, 30 renal units), and in those who had febrile infection and vesicoureteral reflux (12 patients, 24 renal units). The study group (30 patients, 60 renal units) served to assess the incidence of "occult" vesicoureteral reflux in children who experienced febrile UTIs yet did not have vesicoureteral reflux on standard cystography.

RESULTS

CONTROL GROUP

In children without febrile UTIs all 30 ureteral orifices had a normal endoscopic appearance and no vesicoureteral reflux by PIC cystography. In children with febrile UTIs 15 ureteral orifices with known vesicoureteral reflux were lateral and/or patulous and demonstrated vesicoureteral reflux by PIC, 4 appeared normal and did not exhibit vesicoureteral reflux on standard cystography or by PIC, and 5 were lateral and/or patulous in appearance and did not display vesicoureteral reflux on standard cystography, but did show vesicoureteral reflux by PIC. These findings reveal that PIC cystography is 100% sensitive at demonstrating reflux already known by standard cystogram, is 87% specific as it showed reflux in 5 of 39 renal units not revealed by a standard cystogram and has an overall accuracy of 91%.

STUDY GROUP

At cystoscopy all 30 children demonstrated an abnormal appearance of one or both ureteral orifices. PIC cystography showed vesicoureteral reflux in all 30 children (48 renal units, 12 unilateral and 18 bilateral). The remaining ureteral orifices (12), which appeared normal, did not permit vesicoureteral reflux. Children with vesicoureteral reflux by PIC were treated with antimicrobial prophylaxis (26) or ureteral reimplantation (4, 2 unilateral and 2 bilateral reimplantation) Postoperatively, these children did not experience a febrile UTI during followup (average 8 months).

CONCLUSIONS

PIC cystography is simple to perform using routinely available operating room equipment and does not artifactually induce vesicoureteral reflux. The incidence of "occult" vesicoureteral reflux in children who experience febrile UTIs without vesicoureteral reflux on standard cystography is 100% by PIC cystography. PIC cystography should be done when vesicoureteral reflux is suspected in children who experience febrile UTIs but do not exhibit reflux on standard cystography.

The relationship between early renal status, and the resolution of vesico-ureteric reflux and bladder function at 16 months

OBJECTIVE

To examine, in infants presenting with vesico-ureteric reflux (VUR), the relationship between the presence of initial renal abnormalities with the outcome of VUR and bladder function at 16 months of age.

PATIENTS AND METHODS

The study group comprised 40 infants (32 boys) presenting consecutively (29 after prenatal detection) with VUR grade III or greater (bilateral in 29) on the initial micturating cystogram (median age 8 weeks). The initial presence of abnormal kidneys was determined from isotopic renography and/or ultrasonography. These data were correlated with the outcome of VUR, from direct isotope cystography, and bladder function assessed by natural filling urodynamics, examined at age 16 months (mean 16.4 months, SD 2.1).

RESULTS

Three groups were identified. Group 1 (eight boys and six girls) had normal kidneys bilaterally; initially grade III VUR was common. At 16 months bladder function was normal in 10 children and none had VUR (complete resolution). Group 2 (14 boys and two girls) had unilateral renal abnormalities; initially VUR was predominantly grade IV or grade V. At 16 months bladder function was normal in eight children and VUR resolved in eight, five of these with normal bladder function. Group 3 (10 boys) had bilateral renal abnormalities. Initially grade V VUR predominated; at 16 months the bladder function was normal in only one, and in the rest the emptying dynamics were abnormal. All 10 boys had persisting VUR (no resolution).

CONCLUSIONS

In infants with moderate or severe VUR, resolution at 16 months old is associated with normal kidneys in a similar proportion of boys and girls. Resolution also correlates well with normal bladder function. Presentation in infancy with bilateral abnormal kidneys, associated with severe VUR in boys, is a poor prognostic sign for the early outcome of VUR and for bladder function.

Ablation of uroplakin III gene results in small urothelial plaques, urothelial leakage, and vesicoureteral reflux

Urothelium synthesizes a group of integral membrane proteins called uroplakins, which form two-dimensional crystals (urothelial plaques) covering >90% of the apical urothelial surface. We show that the ablation of the mouse uroplakin III (UPIII) gene leads to overexpression, defective glycosylation, and abnormal targeting of uroplakin Ib, the presumed partner of UPIII. The UPIII-depleted urothelium features small plaques, becomes leaky, and has enlarged ureteral orifices resulting in the back flow of urine, hydronephrosis, and altered renal function indicators. Thus, UPIII is an integral subunit of the urothelial plaque and contributes to the permeability barrier function of the urothelium, and UPIII deficiency can lead to global anomalies in the urinary tract. The ablation of a single urothelial-specific gene can therefore cause primary vesicoureteral reflux (VUR), a hereditary disease affecting approximately 1% of pregnancies and representing a leading cause of renal failure in infants. The fact that VUR caused by UPIII deletion seems distinct from that caused by the deletion of angiotensin receptor II gene suggests the existence of VUR subtypes. Mutations in multiple gene, including some that are urothelial specific, may therefore cause different subtypes of primary reflux. Studies of VUR in animal models caused by well-defined genetic defects should lead to improved molecular classification, prenatal diagnosis, and therapy of this important hereditary problem.

Disappearance of vesicoureteral reflux in children

OBJECTIVE

To describe the disappearance of reflux in children with vesicoureteral reflux, in whom there are presently no population-based long-term studies.

DESIGN

An unselected cohort of children with reflux detected after their first known symptomatic urinary tract infection was followed up prospectively for up to 15 years.

SETTING

A single children's hospital in a distinct geographical area at which most children with symptomatic urinary tract infection were treated.

PATIENTS

Two hundred thirty children--173 girls and 57 boys--with unilateral (n=130) and bilateral (n=100) reflux. Dilated reflux (grades III-V) was found in 54 patients (23.5%). The frequency of reflux was 34% in girls and 31% in boys who were examined after urinary tract infection.

MAIN OUTCOME MEASURE

Disappearance of reflux.

RESULTS

The probability of spontaneous disappearance of reflux was estimated using Kaplan-Meier survival curves based on 164 children who underwent multiple voiding cystourethrographies. There was a marked tendency for disappearance of reflux, with 73% of children with dilated reflux having no or only grade I reflux after 10 years. Shorter persistence of reflux was found in children with undilated reflux at the initial investigation and in boys compared with girls. However, age at first investigation was not related to the rate of disappearance, and there was no difference between children with bilateral compared with unilateral reflux.

CONCLUSIONS

This study of an unselected group of children with urinary tract infection shows a favorable long-term outcome concerning disappearance of reflux. In children with dilated reflux, this tendency was more pronounced than previously reported.

Endoscopic creation of reflux in the pig

Vesicoureteral reflux (VUR) in the animal model for experimental purposes can be created either by open transvesical or endoscopic techniques. The concept of reflux creation is the same for both techniques: incision of the roof of the intramural portion of the ureter at the 12 o'clock position. The open method has the disadvantages of requiring a cystotomy and a lengthy healing period prior to initiating a study, thereby incurring additional expense and the problem of introducing several confounding factors. The open method is unreliable because of the resolution of reflux over time. Herein, we present a simple transurethral endoscopic technique for creating VUR in pigs. This technique was successful in producing persistent Grade II or III reflux in 94% of the incised ureters.

New 3-dimensional mapping device for cystoscopy

PURPOSE

The crucial shortcoming of cystoscopy is that it does not measure the size of observed objects, and so we developed a new device that adds measurement capability to the cystoscope.

MATERIALS AND METHODS

The device consists of 5 arms linked to each other by freely bending joints. Before use 1 end of the arm is fixed to the examination table and the other end is linked to the eyepiece of the cystoscope. While linked to the arms, the cystoscope can move freely in any direction. Each joint carries an accurate sensor to measure its angle. The angle measurements are calculated collectively to obtain the 3-dimensional coordinates at the tip of the cystoscope. The tip of the cystoscope can be moved to the other side of the objects to be measured, which provides a pair of 3-dimensional coordinates, because the distance between them can be calculated.

RESULTS

We could calculate the distance between the bladder neck and each ureteral orifice, and the angle of the bladder neck formed with the left and right orifices in clinical cases. By continuous measurement of the location of the bladder neck and the ureteral orifice, it was clearly demonstrated that the distance between them increased as the bladder filled.

CONCLUSIONS

Our computer assisted, 3-dimensional mapping device can replace unreliable cystoscopic assessment with more reliable numerical values. New diagnostic criteria based on the exact numerical values can be established with the use of this device.

Endoscopic injection of Teflon for correction of primary vesicoureteral reflux in children

BACKGROUND

Treatment of vesicoureteral reflux by endoscopic injection of Teflon paste has recently demonstrated a good success rate. This report describes our experience in treating vesicoureteral reflux in children with particular reference to follow-up data.

METHODS

Between December 1993 and November 1994, endoscopic injection of Teflon paste into the submucosa was performed on 18 children (29 ureters) to correct vesicoureteral reflux.

RESULTS

After treatment, reflux was eliminated in 75.9%, decreased in 13.8%, and unchanged in 10.3% of the ureters. The success rate was lower for high grade reflux cases and ureteral orifices with abnormal shapes.

CONCLUSION

Long-term follow-up for up to 2 years demonstrated that although late recurrence may occur in a small proportion of cases, the procedure is safe, simple and effective for correcting vesicoureteral reflux.

Unravelling the genetics of vesicoureteric reflux: a common familial disorder

Primary vesicoureteric reflux (VUR) is one of the more common genetic disorders. Little is yet known about the genetics of this potentially manageable childhood condition, which is characterised by regurgitation of urine from the bladder to the kidney. The VUR phenotype is associated with shortness of the submucosal segment of the ureter due to congenital lateral ectopia of the ureteric orifice. VUR is found in 30-50% of infants and young children with a urinary tract infection. A serious concern in families with an affected patient is that approximately one half of siblings or offspring will be affected, but up to a half of these affected siblings and offspring may be asymptomatic in childhood. If left untreated, these patients may present later in life with proteinuria, hypertension or renal failure. VUR is the commonest cause of end-stage renal failure in children, and an important cause in adults. As the kidney damage resulting from severe VUR is preventable, early detection is desirable. The techniques for clinical diagnosis are invasive and costly, reinforcing the importance of identification of a gene for VUR to facilitate genetic screening. Although family studies suggest a major dominant gene, the inheritance pattern is still a matter of debate. In rare instances, VUR occurs in association with other diseases, such as the coloboma-ureteric-renal syndrome, which is caused by a PAX2 gene mutation. In this review, we present evidence that this common disorder may be caused by mutations in the developmental pathway of which the PAX2 gene forms a part.

Reflux nephropathy and pregnancy

Reflux nephropathy is one of the renal diseases encountered most frequently in women of childbearing age. Patients with severe bilateral atrophy are the most likely to develop proteinuria, hypertension, focal glomerular sclerosis and progressive chronic renal failure, and those with persistent vesicoureteral reflux are the most likely to suffer recurrent pyelonephritic episodes. Often the disease is clinically latent and first manifests itself in pregnancy, mainly by urinary tract infection but also by proteinuria, hypertension, pre-eclampsia or renal failure. Pregnancy is most often successful and uneventful whenever renal function is normal or near normal and hypertension is absent at conception. Urinary tract infection accounts for frequent morbidity but rarely results in fetal mortality. By contrast, when renal function is significantly impaired, that is in patients whose plasma creatinine concentration is in excess of 0.20-0.22 mmol l-1 at conception, especially when hypertension is also present, there is clearly a high risk of fetal growth retardation or intrauterine death. Moreover, there is a striking risk of rapid worsening of renal function and hypertension, with accelerated progression towards end-stage renal failure. Thus, women with reflux nephropathy should attempt to conceive before the plasma creatinine concentration has reached 0.20 mmol l-1, and patients with values higher than these should be clearly advised of the high risk for both the pregnancy and the progression of the disease.