Cause Of Ureteropelvic Junction Obstruction Research Articles

Clues for the early loss of renal function in congenital hydronephrosis: Analysis of renal pelvis collagen ratio, diuresis renography and upper urinary tract morphology

Diagnosing real urinary obstruction and surgical decision making for the operative correction of urinary obstruction, are still problematic in congenital hydronephrosis (CH). Compliance of the renal pelvis is one of the important defense mechanisms of renal parenchyma against urinary obstruction. We observed early loss of function in some cases of CH with low and moderate anteroposterior diameter of the renal pelvis (APDRP). To evaluate structural properties of the renal pelvic tissue of patients with CH and the relation of these structural properties with renal function and Anteroposterior diameter of the renal pelvis. Ureteropelvic junction (UPJ) excised during UPJ obstruction operations from 2013 to 2019 were evaluated histopathologically. The patients were divided into the two groups according to initial renal function, i.e. group with initial preoperative differential renal function (DRF) less than 35% and group with initial DRF greater than 35%. The percentage of collagen to whole tissue area were analyzed using image processing program. The relationship between DRF and tissue collagen ratio, SFU and APDRP was evaluated. There were 5 patients in the DRF <35% group and 16 patients in the DRF >35% group. However, APDRP's of the DRF <35% group were also significantly lower than the DRF >35% group. The collagen distribution in the muscle layer was more prominent in the DRF <35% group. Proportionally, percentage of collagen stained surface was significantly higher in DRF <35% group. There are numerous histopathological studies evaluating the cause of UPJ obstruction. Besides these studies that are oriented to etiology, there are many studies comparing the histopathological changes at UPJ with surgical outcome and prognosis. In the present study, we found that renal pelvis collagen ratio was significantly increased in patients with lower APDRP and with severe renal function loss. This increase in the collagen content in the renal pelvis have been shown to affect the compliance negatively and decrease APDRP, which leads to a faster loss of renal function. Thus, pelvic structural changes accompanying UPJ obstruction may aggravate urinary obstructive process. Increased renal pelvis collagen ratio negatively affects the expansion of the renal pelvis, which is one of the protective mechanisms of the renal parenchyma, and may be one of the triggering mechanisms of early loss of renal function.

Parapelvic cyst: A rare cause of ureteropelvic junction obstruction in a pediatric patient managed with robotic cyst decortication

We report a case of a right parapelvic renal cyst causing intermittent ureteropelvic junction obstruction (UPJO). A 13-year-old male was referred for right flank pain. Stone protocol CT revealed renal pelvis dilation with punctate stones. Due to concern for intermittently obstructive calculi, he underwent ureteroscopy, which was unremarkable. A diuretic renogram showed symmetric uptake with partial emptying on the right with pain after diuretic administration. In office, we potentiated a Dietl's crisis with ultrasound obtained before and after fluid intake. Comparison of ultrasounds revealed a parapelvic cyst causing calyceal dilation. He was counseled for robotic cyst decortication and possible pyeloplasty. A robotic cyst decortication was performed. Once decorticated, the cyst base was fulgurated and pararenal fat was interposed into the cyst base. Console time was 70min with minimal blood loss. The patient was discharged post-operative day 1. Follow-up renal ultrasound at 4 months demonstrated resolution of hydronephrosis and parapelvic cyst. Parapelvic renal cysts causing intermittent UPJO is a rare entity that may be missed on a diuretic renogram. Clinical suspicion and appropriate imaging with ultrasound or magnetic resonance imaging are useful. Robotic cyst decortication is a technically feasible approach to treat this condition.

Urinary Ultrasound and Other Imaging for Ureteropelvic Junction Type Hydronephrosis (UPJHN).

Ultrasound is the main imaging study used to diagnose ureteropelvic junction (UPJ) obstruction. On ultrasound, abnormal dilatation of the pelvicalyceal system of varying degrees is seen, whereas the ureter is normal in caliber. A properly performed study provides essential information regarding laterality, renal size, thickness, and architecture of the renal cortex and degree of dilatation of the pelvicalyceal system. Doppler ultrasound may identify a crossing vessel, when present. This imaging method also has been used differentiating obstructive from non-obstructive hydronephrosis by renal arterial resistive index measurements. Abdominal radiographs may show soft tissue fullness, bulging of the flank, and displacement of bowel loops from the affected side. The voiding/micturating cystourethrogram helps exclude other causes of upper tract dilatation, including vesicoureteral reflux, urethral valves, and ureteroceles. Computerized Tomography angiography with multiplanar reformation and three-dimensional images may be used to depict suspected crossing vessels as a cause of UPJ obstruction in older children and adults. Magnetic Resonance Urography has progressed significantly in recent years due to the development of both hardware and software that are used to generate high-resolution images. This imaging technique currently allows for the detailed assessment of urinary tract anatomy, while also providing information regarding renal function, including differential renal function, and the presence or absence of obstructive uropathy.

Is the lower pole crossing vessels transposition a valid option for the treatment of extrinsic ureteropelvic obstruction in children? Considerations from a single-centre experience

To assess the efficacy of the vascular hitch procedure in extrinsic ureteropelvic junction obstruction (UPJO) by crossing vessels in children, both by open and mini-invasive approach. Retrospective analysis on patients treated by open or mini-invasive vascular hitch during the period 2006–2020. Preoperative imaging included renal ultrasound (US) and functional studies by magnetic resonance or renogram. Crossing vessels obstruction and UPJ anatomy were evaluated at surgery. Success was defined as the resolution of symptoms and improvement of hydronephrosis at US or functional studies. Forty-eight patients were included with mean age at surgery of 7.6 years and 25% had an antenatal diagnosis. Aberrant vessels were suspected preoperatively in 72.9%; mean hydronephrosis and renal function were 30.9 mm and 38% respectively. Seven cases were treated by open approach, 37 by laparoscopy and 4 were robotassisted. Mean operative time was 58.3 min and mean hospital stay was 2 days. Mean follow-up was 16.9 months; success rate was 91.6% and 5 patients required secondary surgery. Vascular hitch shows to be a safe, feasible and effective alternative to pyeloplasty. Careful pre and intra-operative patients’ selection is essential to exclude any intrinsic cause of UPJO. Mini-invasive surgery could be helpful for better evaluation of UPJ anatomy and its relationships with crossing vessels. Complications and secondary surgeries could be related to incorrect patients’ selection.

Long-term Outcome of Children with Ureteropelvic Junction Obstruction: Thirty-one years’ Experience at a Tertiary Teaching Hospital in South Africa.

B ackground and Aim: Being the most common pathologic cause of hydronephrosis in children, we characterized and evaluated the long-term outcome of Ureteropelvic junction obstruction (UPJO) at a tertiary hospital in South Africa Methods: Children confirmed to have UPJO between 1985 and 2016 were characterized based on demographic and baseline clinical data. Long term outcomes were need for surgical intervention, loss to follow up rates, anthropometric measures, renal outcomes (Glomerular Filtration Rate and Blood pressure). Results: Of 107 children, 74.8% were male, 47% had hydronephrosis identified antenatally, 47.7% had the left kidney unilaterally affected, 31.8% had an additional urogenital anomaly, 19.6% presented with an abdominal mass, and 37.4% had a urinary tract infection. On enrolment, 54.2% and 30.8% had normal systolic and diastolic BP, 59.8% had normal BMI for age and 72% had normal length/height for age. The median follow-up time was 35(9.0 - 191.0) months, 65% had surgery with a median time to surgery of 2 (0 - 6.8) months. Children lost to follow-up had a higher proportion of extrinsic causes of UPJO (12.0% vs. 0%, P =0.041) and other urogenital anomalies (38.7% vs. 15.6%, P=0.019). There was no significant effect of time or surgical intervention on mean BMI and height for age, blood pressure percentile and eGFR for age. Conclusion: In our setting, UPJO has an early presentation, with an early time to surgery. Long-term outcome is favorable, but loss to follow-up presents a significant drawback that needs to be addressed. Keywords: Ureter; Hypertension; Congenital anomalies of kidney and urinary tract; CAKUT; Urological Diseases; Hydronephrosis.

Crossing Into the Unknown. A Peculiar Cause of Ureteropelvic Junction Obstruction in a 14-Year-Old Boy

Ureteropelvic junction obstruction (UPJO) is a common cause of upper urinary tract obstruction and consequent hydronephrosis. We present a case of right UPJO caused by a crossing vessel suspected to be the right second lumbar vein. While crossing vessels are a common cause of UPJO in older children and adults, they are usually attributed to lower pole vessels. We believe that this is the first case report of UPJO caused by a lumbar vein. Recognition of crossing vessels requires knowledge of variant vasculature anatomy around the kidneys. Due to this unusual crossing vessel origin, our case likely represented an anatomical variant that would be of interest to both fields of urology and radiology.

VE41 - 180° Kidney lateral rotation: A rare cause of Ureteropelvic junction obstruction

VE41 - 180° Kidney lateral rotation: A rare cause of Ureteropelvic junction obstruction

Fibroepithelial ureteral polyps as a cause of ureteropelvic junction obstruction in children: A case report

We present a ten-year-old boy with episodic left flank pain, vomiting and microscopic hematuria. Imaging showed hydronephrosis characteristic for ureteropelvic junction (UPJ) obstruction. Pyeloplasty revealed a ureteral polyp, histopathologic examination confirmed the diagnosis of a fibroepithelial polyp. Fibroepithelial polyps of the ureter are a rare cause of UPJ obstruction in children. The most common presentation is episodic flank pain and/or hematuria. Imaging can be guiding, but pre-operative diagnosis is difficult. After surgical resection recurrence is rare.

Pediatric ureteropelvic junction obstruction: can magnetic resonance urography identify crossing vessels?

MR Urography (MRU) is an increasingly used imaging modality for the evaluation of pediatric genitourinary obstruction. To determine whether pediatric MR urography (MRU) reliably detects crossing vessels in the setting of suspected ureteropelvic junction (UPJ) obstruction. The clinical significance of these vessels was also evaluated. We identified pediatric patients diagnosed with UPJ obstruction by MRU between May 2009 and June 2014. MRU studies were evaluated by two pediatric radiologists for the presence or absence of crossing vessels. Ancillary imaging findings such as laterality, parenchymal thinning/scarring, trapped fluid in the proximal ureter, and presence of renal parenchymal edema were also evaluated. Imaging findings were compared to surgical findings. We used the Mann-Whitney U test to compare continuous data and the Fisher exact test to compare proportions. Twenty-four of 25 (96%) UPJ obstructions identified by MRU were surgically confirmed. MRU identified crossing vessels in 10 of these cases, with 9 cases confirmed intraoperatively (κ = 0.92 [95% CI: 0.75, 1.0]). Crossing vessels were determined to be the primary cause of UPJ obstruction in 7/9 children intraoperatively, while in two children the vessels were deemed incidental and noncontributory to the urinary tract obstruction. There was no significant difference in age or the proportions of ancillary findings when comparing children without and with obstructing vessels. MRU allows detection of crossing vessels in pediatric UPJ obstruction. Although these vessels are the primary cause of obstruction in some children, they are incidental and non-contributory in others. Our study failed to convincingly identify any significant predictors (e.g., age or presence of renal parenchymal edema) that indicate when a crossing vessel is the primary cause of obstruction.

Significance of MR angiography in the diagnosis of aberrant renal arteries as the cause of ureteropelvic junction obstruction in children.

To determine the importance of MRI with contrast-enhanced MRA for the detection or exclusion of aberrant or obstructing renal arteries in ureteropelvic junction obstruction in children. Key word-based search in RIS database (ureteropelvic junction obstruction/ MRI) and retrospective comparison of arterial findings from preoperative contrast -enhanced MRA and intra-operative inspection. From 2007 to 2013, 19 children with ureteropelvic junction obstruction underwent contrast-enhanced MRA. Based on the results of the MRI scan and MAG3 scintigraphy, the children were referred to surgery (Anderson-Hynes-pyeloplasty). An aberrant renal artery was diagnosed with MRI in 14 of 19 children, and intra-operative inspection confirmed 13 of those 14. In the remaining 5 children, no aberrant vessel could be observed in MRI and this was confirmed intra-operatively in 3 of the 5 cases, while in the remaining 2, an aberrant vessel was found. Of the 14 children with aberrant vessels, 12 underwent surgery due to assumed ureteral obstruction, which was confirmed by surgery in 11 cases. In one case, an aberrant artery was found intra-operatively, but obstruction could not be confirmed. In one of the 14 children, the vessel was found in MRI, but its obstructing character was negated via MRA, which was confirmed intra-operatively. In the diagnosis of aberrant and obstructing renal arteries, contrast-enhanced MRA presents 85% sensitivity and 80% specificity, with a positive predictive value of 0.8. MRI with contrast-enhanced MRA is suitable to detect aberrant and obstructing renal arteries. An obstructive effect of the aberrant vessel is to be assumed if the vessel has a close relationship to the ureteropelvic junction and if it is linearly stretched. • MRI with contrast-enhanced MRA is a sure method for the detection of aberrant renal arteries in children with ureteropelvic junction obstruction. • The obstructive effect of the aberrant vessel can be derived from the close proximity of the vessel to the ureteropelvic junction and from the streched course of the vessel.

Diagnosis and treatment of ureteropelvic junction obstruction caused by renal crossing vessels:an analysis of 24 cases

To investigate the diagnosis, treatment and surgical outcomes of ureteropelvic junction obstruction (UPJO) caused by renal crossing vessels. The case records of 24 patients discharged from Peking University Third Hospital between June 2001 and September 2011 with the diagnosis of UPJO caused by renal crossing vessels were reviewed .Of the 24 patients, 17 were male and 7 were female patients. The mean age was 28 years (range, 2-63 years). The mean disease duration was 22.3 months (range, 7 days to 180 months). Of which, 4 patients underwent open surgery, and the other 20 patients were treated with laparoscopic surgery. Surgical approach was decided by operative conditions: adhesion release technique, dismembered pyeloplasty or Y-V anastomosisor, with or without cut off the crossing vessels. The kind of crossing vessels was recorded, and the effect of surgery was evaluated by follow-up. Fifteen cases were caused by oppressed renal crossing artery, 8 cases by renal crossing vein, and 1 case by 2 renal crossing arteries and 1 renal crossing vein. Among them, 11 cases were followed up successfully. Average follow-up time was 48.2 months (range, 13-120 months). Eight cases (8/11) were relieved, and 1 case (1/11) had no obvious improvement, another 2 cases (2/11) were aggravating. Among those 6 cases underwent adhesion release technique, 3 cases were relieved, 1 case had no obvious improvement, and 2 cases were aggravating. Five cases who underwent dismembered pyeloplasty was relieved significantly. Renal crossing artery is one of the main causes of UPJO, the crossing artery should be retained as far as possible. Crossing vessel oppression is not the only pathological cause of UPJO, so the treatment of UPJ constriction is also very important. Dismembered pyeloplasty seems to be the most efficacies treatment procedure for UPJO caused by repressed vessels, and the remission rate of adhesion release technique seems limited.

Laparoscopic Anderson-Hynes procedure as a treatment of ureteropelvic junction obstruction caused by fibroepithelial polyp.

Fibroepithelial polyps (FEPs) are rare benign ureteral neoplasms of mesodermal origin. As an intrinsic cause of ureteropelvic junction obstruction (UPJO) they are very uncommon. Excretory urography and diuretic renography used by many urologists to diagnose a UPJO may not detect the ureteral polyp. We present a case of ureteropelvic junction obstruction caused by a fibroepithelial polyp, which was not diagnosed preoperatively. The patient underwent successful laparoscopic excision of the polyp with Anderson-Hynes pyeloplasty. We believe that laparoscopy is a useful, minimally invasive operative technique in the treatment of FEPs and may be considered a procedure of choice in large polyps, in which cases the endoscopic procedure is difficult or impossible to perform.

V577 PEDIATRIC ROBOTIC-ASSISTED LAPAROSCOPIC PYELOPLASTY IN HORSESHOE KIDNEY

You have accessJournal of UrologyPediatrics1 Apr 2013V577 PEDIATRIC ROBOTIC-ASSISTED LAPAROSCOPIC PYELOPLASTY IN HORSESHOE KIDNEY Candace F. Granberg, Daniel DaJusta, and Patricio Gargollo Candace F. GranbergCandace F. Granberg Rochester, MN More articles by this author , Daniel DaJustaDaniel DaJusta Louisville, KY More articles by this author , and Patricio GargolloPatricio Gargollo Dallas, TX More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.1973AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES The surgical approach to ureteropelvic junction obstruction (UPJO) in horseshoe kidneys is challenging secondary to the inherent aberrant anatomy. Historically, some have recommended division of the isthmus, while others have advocated transection of crossing vessels, both of which carry risk of nephron damage or loss. With the advent of minimally-invasive surgery, robotic-assisted laparoscopic pyeloplasty (RALP) has become routine in otherwise anatomically normal kidneys; however, there is limited data on the robotic approach to UPJO in children with horseshoe kidneys. Thus, the objective of this video is to detail the surgical approach to RALP in the horseshoe kidney. METHODS Hidden incision endoscopic surgery (HIdES) was developed at our institution, and is applied in all RALP cases. One robotic port is placed infraumbilically, while all remaining ports are hidden below the level of a Pfannensteil incision, thus rendering them nonvisibile when wearing a bathing suit. A 5mm assist port is optional. Using a transmesenteric approach, the UPJ is localized. In this case, a mesenteric vessel overlying the UPJ was divided to maximize exposure of the UPJ and proximal ureter. High insertion was identified as the cause of UPJO in this case. No renal crossing vessels were found, and the isthmus was not a factor, thus was left intact. A hitch stitch is placed in the renal pelvis to elevate the UPJ. After transescting above the UPJ, the ureter is relocated to lie above the mesentery. The UPJ is excised and the ureter spatulated. 5-0 Vicryl is used for the anastomosis over a stent. RESULTS We have performed RALP for UPJO in 4 children with horseshoe kidneys, all of whom were male, with a mean age of 4.7 years. All cases of UPJO in this cohort occurred within the left renal moiety. Mean operative time in these four cases was 120 minutes. The isthmus and renal vasculature were maintained in all cases, and there were no intra- or post-op complications. All patients were dismissed within 24 hours. At mean follow-up of 9 months, all patients were radiologically and clinically improved. CONCLUSIONS In conclusion, RALP in children with horseshoe kidneys is safe and efficacious. Meticulous intraoperative examination of the anatomy is germane to ensure aberrant crossing vessels are not overlooked. Moreover, adequate drainage can be achieved without dividing the isthmus or renal vasculature, which not only maintains blood supply to all nephrons but also avoids inherent risks associated with these maneuvers. Thus, RALP is an excellent minimally-invasive approach for UPJO in children with horseshoe kidneys. © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e236-e237 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Candace F. Granberg Rochester, MN More articles by this author Daniel DaJusta Louisville, KY More articles by this author Patricio Gargollo Dallas, TX More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Ureteropelvic junction obstruction by aberrant lower pole artery

Obstruction of the ureteropelvic junction (UPJ) is one of the causes of obstruction uropathy and it may be either congenital or acquired. Aberrant lower pole crossing vessels is one of the congenital causes. In order to determine the exact cause of UPJ obstruction, imaging examinations are performed. Computed tomography (CT) with reformatted three-dimensional images is the best imaging examination for demonstrating the aberrant crossing vessels in the case of UPJ obstruction. Because the aberrant crossing vessels may aggravate, but is not the primary cause of UPJ obstruction, dismembered pyeloplasty with anterior transposition of the collecting system and preservation of the aberrant crossing vessels are usually performed to treat UPJ obstruction.

Robotic Anderson–Hynes dismembered pyeloplasty: initial experience

The introduction of the da Vinci(®) robotic system in 2000 has been a new step forward in the treatment of ureteropelvic junction obstruction (UPJO). The aim of this study was to analyse our initial experience with robot-assisted dismembered Anderson-Hynes pyeloplasty and to perform a bibliographic review on the topic. We performed 11 robot-assisted pyeloplasties between March 2007 and April 2011. UPJO diagnosis was made on clinical presentation and imaging techniques (CT scan and intravenous urography). All patients underwent basal and diuretic isotopic renograms to evaluate the degree of obstruction and impaired renal function. Median follow-up was 10 (range 1-26) months. Mean patient age was 38.8 (range 23-62) years. There were six women (55%) and five men (45%). All cases were primary surgeries. In four patients the cause of UPJO was a crossing vessel; the other seven patients had intrinsic obstruction. One case was associated with extraction of a calyceal lithiasis. Mean operative time was 189.4 min (125-270 min). Average time from robotic arms docking was 116.5 (range 55-180) min. Average hospital stay was 4.18 (range 2-8) days. Conversion to open or laparoscopic surgery was not necessary in any case and there were no postoperative complications. Postoperative radiological evaluation and renograms showed good results in all cases. Robotic surgery offers better ergonomics, enhanced three-dimensional (3D) vision and more precise movements, easing intracorporeal suturing.These advantages make robotic pyeloplasty a reproducible technique that combines the high success rates of open surgery and the benefits of laparoscopic surgery.

Ureteral fibroepithelial polyp causing urinary obstruction

Ureteral polyps are rare causes of ureteropelvic junction (UPJ) obstruction, particularly in children. We report a nine year-old boy with UPJ obstruction initially suggestive of an obstructive urinary stone. CT showed intraureteral calcification at the UPJ and hydronephrosis. A retrograde pyelogram showed narrowing at the UPJ and partial obstruction that was found to be a ureteral polyp. This case illustrates a rare cause of UPJ obstruction that should be considered when the imaging findings and presentation are atypical for more common etiologies of ureteral obstruction.

Laparoscopic Transposition Pyelo-Pyelostomy for Repair of Adult Uretero-Pelvic Junction Obstruction Secondary to Lower Pole Crossing Vessels: A Novel Technique

An aberrant crossing vessel(s) (CV) is considered an important cause of uretero-pelvic junction obstruction (UPJO) in adults. Intrinsic defect at the uretero-pelvic junction (UPJ) is not necessarily present and so, dismembered pyeloplasty would not be necessary. We introduce in the present study a novel technique, laparoscopic transposition pyelo-pyelostomy (LTP) to treat UPJO caused by aberrant CV in adults. From July 2004 to August 2010, 21 adult patients were diagnosed as having UPJO secondary to aberrant CV and were treated laparoscopically by transposition pyelo-pyelostomy. The main presentation was pain in 13 patients, while 3 patients presented with fever. Five patients were accidentally discovered as having hydronephrosis in ultrasound (U/S). Preoperative intravenous urography and U/S revealed grade III hydronephrosis in 11 patients and grade IV in 10 patients. Diagnosis of CV was suspected preoperatively in the IVU in 15 patients and was confirmed by computed tomography. The remaining six patients were diagnosed intra-operatively. The operative time ranged from 75 to 125 minutes with a mean of 93 minutes. The mean time for anastomosis was 12 minutes. No intra-operative complication was reported. Drain was removed after 48 hours, and mean hospital stay was 3 days. Symptom improvement was encountered in all symptomatic patients. Postoperative US done at 3 months revealed resolution of the hydronephrosis in 10 patients, and 11 patients had a residual grade I hydronephrosis. Diuretic renography at 1 year postoperatively revealed normal T1/2 in 19 patients. LTP is a simple procedure that spares the normal UPJ and provides a wide, stentless anastomosis which nullifies the risk of re-stenosis and failure.

A Single Institute's Experience in Retroperitoneal Laparoscopic Dismembered Pyeloplasty: Results with 86 Consecutive Patients

To report our institute's retroperitoneal technique of laparoscopic pyeloplasty (LP) and present results of 86 consecutive patients. From January 2004 to January 2009, 86 patients who were affected with ureteropelvic junction obstruction (UPJO) underwent retroperitoneal LP. In all operations, a four-port, balloon-dissecting, retroperitoneal approach was used and a simple "personalized" modification of the conventional Anderson-Hynes technique consisting of an approaching and stabilizing stitch made between the renal pelvis and proximal ureter. A needle introductor at the level of the surgical assistant's trocar was used as well to facilitate the Double-J stent introduction. Follow-up studies were performed postoperatively with intravenous urography and renal ultrasonography at 6, 12, and 18 months. All operations were completed laparoscopically, and no open conversions were needed. The mean operative time was 79.3 minutes (range 65-125 min). The mean blood loss was 10 mL (range 5-40 mL), and the mean postoperative hospitalization stay was 5.7 days (range 3-14 d). No intraoperative complications occurred. Aberrant crossing vessel and primary stricture as the cause of UPJO were noted in 31 and 55 patients, respectively. Transient anastomotic leakage occurred in six patients and was successfully treated by conservative management. A persistent UPJO was detected at first follow-up visit in three patients and was treated by conservative management in two cases and by performing an open pyeloplasty in one case. A mean follow-up of 29 months (range 18 to 48 mos) was performed and showed a 96.6% success rate after the first operation. Our experience with LP in accordance with the Anderson-Hynes procedure has demonstrated that this technique is an effective treatment for UPJO, with a high overall success rate, a short hospital stay, and a negligible incidence of early complications.

Multiple Metachronous Fibroepithelial Polyps in Children

We present our experience with a new phenotype of fibroepithelial polyps recurring in the urinary tract in children after robotic or laparoscopic pyeloplasty, and discuss the most appropriate treatment for these multiple metachronous neoplasms. At our institution 14 children had fibroepithelial polyps as the cause of ureteropelvic junction obstruction at pyeloplasty. Of the patients 12 had at least 1 additional polyp in the ureter, necessitating concomitant ureteroscopy at either robotic or laparoscopic pyeloplasty. Of these 12 patients 9 had followup of at least 1 year. In 6 patients with at least 1 year of followup neoplasms were seen on retrograde pyelography and ureteroscopy that were not present on ureteroscopy at pyeloplasty. At 6 months after stent removal following the first recurrence 2 patients (33%) showed a second recurrence on imaging at a different location in the upper tract requiring laser ablation. One of these patients had a third recurrence that required further intervention before all were disease-free. No major intraoperative or preoperative complications developed. We should always consider the possibility of recurrent fibroepithelial polyps in children with ureteropelvic junction obstruction, and recommend routine retrograde pyelography and ureteroscopy at stent removal after laparoscopic or robotic pyeloplasty. Although ureteroscopic management seems to be the most appropriate modality in children with multiple metachronous fibroepithelial polyps, larger studies are needed.

Robotic correction of Östling folds as a rare cause of ureteropelvic junction obstruction in children.

Östling folds are considered to be normal variants of ureteral growth at a quicker rate than body lengthening and, therefore, have been reported to be of no clinical significance. We report a robotic correction of the first documented cases of Östling folds causing a persistent ureteroplevic junction obstruction in children.