The pathophysiology of UPJ obstruction. Current concepts

Pediatric Robot-Assisted Laparoscopic Pyeloplasty: Where Are We Now?

PURPOSE OF REVIEW

This review aims to provide an in-depth exploration of the recent advancements in robot-assisted laparoscopic pyeloplasty (RALP) and its evolving landscape in the context of infant pyeloplasty, complex genitourinary (GU) anatomy, recurrent ureteropelvic junction (UPJ) obstruction, cost considerations, and the learning curve.

RECENT FINDINGS

Recent literature highlights the safety and efficacy of RALP in treating the infant population, patients with complex GU anomalies, and recurrent UPJO which were all traditionally managed using the open approach. Cost considerations are evolving, with the potential for RALP to have a lesser financial burden. In addition, the learning curve for RALP is diminishing due to robust training programs and advances in research. RALP has become the gold standard in the treatment of UPJO in pediatric urology at many children's hospitals. Surgeon comfort and research in this space allow safe and successful reconstruction in the most challenging of cases.

Decreased percent change in renal pelvis diameter on diuretic functional magnetic resonance urography following administration of furosemide may help characterize unilateral uretero-pelvic junction obstruction

BACKGROUND

A well-established definition of obstruction in the setting of congenital hydronephrosis is lacking. Multiple imaging modalities and radiographic characteristics or parameters have been described to help confirm the diagnosis of ureteropelvic junction obstruction (UPJO). We sought to evaluate the change in anterior-posterior renal pelvic diameter (APRPD) following furosemide administration in patients with unilateral hydronephrosis and confirmed UPJO on functional magnetic resonance urography (fMRU) who underwent pyeloplasty.

MATERIALS AND METHODS

There were 49 patients who met inclusion criteria (11 females, 38 males; average age 2.2 years, SD 3.4 years) from February 2006 to September 2020, diagnosed with unilateral hydronephrosis (SFU Grade 3-4) who underwent fMRU prior to pyeloplasty for confirmed UPJO. 29 of the included patients also underwent a post-pyeloplasty fMRU. A weight-adjusted dose of 1 mg/kg of furosemide (max 20 mg/kg) was administered intravenously. Two board-certified pediatric radiologists measured the APRPD of the obstructed and non-dilated kidneys prior to pyeloplasty and APRPD of the hydronephrotic kidneys on the post-pyeloplasty follow up fMRUs. Measurements were performed on images prior to and approximately 30 min following furosemide injection.

RESULTS

The average APRPD before furosemide injection in the obstructed kidney prior to pyeloplasty was 26.3 mm (SD 9.0 mm) compared to the non-dilated (not obstructed) kidney measurement of 5.1 mm (SD 3.6 mm) (p < 0.001). Following administration of furosemide, the average APRPD was 31.4 mm (SD 8.8 mm) in the obstructed kidney, and 7.8 mm (SD 4.1 mm) in the non-dilated kidney (p < 0.001). After pyeloplasty, the pre-furosemide APRPD measurement was 17.8 mm (SD 11 mm), which was significantly less compared to the pre-pyeloplasty APRPD (p < 0.001). The post-pyeloplasty, post-furosemide APRPD measurement was 25.8 mm (SD 12 mm), also significantly less compared to the pre-pyeloplasty measurement (p = 0.02). The changes in APRPD in the obstructed kidney prior to pyeloplasty was 5.1 mm (SD 3.5 mm) and after pyeloplasty was 8 mm (SD 4.6 mm) (p = 0.002). Change in APRPD in the non-dilated kidney was 2.7 mm (SD 2.3 mm). Percent APRPD change in the obstructed kidney was 22.9% (SD 18.5%), which was significantly less than 33.3% (SD 22.1%) in the post-pyeloplasty kidney (p = 0.028) and 82.8% (SD 87.9%) in the non-dilated kidney (p < 0.001).

CONCLUSIONS

A relatively smaller change in APRPD on fMRU following administration of furosemide in the setting of UPJO may serve as another predictive characteristic of obstructed kidneys.

Percutaneous management of ureteropelvic junction obstruction

PURPOSE OF REVIEW

The development of endoscopic and minimally invasive techniques has revolutionized the treatment of ureteropelvic junction obstruction (UPJO). Patients can now undergo successful UPJO repair without the morbidity and complications associated with open surgery. Laparoscopic and robotic repair has supplanted open surgery as the gold standard, but percutaneous endoscopic treatment remains a relevant alternative to more invasive surgery. This review will focus on the percutaneous approach for the treatment of UPJO.

RECENT FINDINGS

Percutaneous endopyelotomy was popularized during the 1980 s due to advances in the field of endourology, allowing for well tolerated and reliable percutaneous access to the kidney. After percutaneous access to the kidney is achieved, the narrowed ureter at the UPJ is incised in a full thickness fashion in the posterolateral position from the ureteral lumen to the periureteral fat. Success rates for this procedure are nearly 90% at high-volume centres. The ideal patient who has success with percutaneous endopyelotomy has a short segment of narrowing less than 2 cm, no crossing vessel, good ipsilateral renal function and mild hydronephrosis.

SUMMARY

Although the development of laparoscopic and robotic approaches to pyeloplasty has produced outcomes that surpass those of percutaneous endopyelotomy, it remains a viable option in the appropriately selected patient, but success rates tend to decrease with longer follow up.

Ureteropelvic junction obstruction in children by polar vessels: histological examination result

In children, ureteropelvic junction obstruction (UPJO) is mostly caused by intrinsic factors (IUPJO) such as abnormal amounts of muscle and collagen deposition; extrinsic UPJO are rare and often due to crossing vessels (CVs). What is not clear is whether there is also intrinsic UPJ pathology in patients with CV. The aim of our study was to compare the histology of the two types of obstruction and to determine whether these histologic features are distinguishable enough to enable to identify the cause of obstruction based on histologic appearance alone. We retrospectively reviewed pathology reports of 38 children with UPJO that underwent surgery in our hospital from 2008 to 2022. The intrinsic and extrinsic groups consisted of 18 and 20 patients, respectively. After ematoxylin-eosin and Gomori's trichrome staining the specimens were scored for fibrosis and muscular hypertrophy in histhopatology, and CD117 antibody were used to detect interstitial Cajal-like cells. In our study, histological analyses revealed no differences between the CV and IUPJO specimens in terms of presence and degree of fibrosis and muscular hypertrophy; likewise, for presence of interstitial Cajal-like cells.

Rare perinephric myxoid pseudotumor of fat causing ureteropelvic junction obstruction: a case report

Ureteropelvic junction obstruction (UPJO) is a congenital or acquired functionally significant impairment of urinary transport from the renal pelvis to the ureter. Congenital UPJO typically results from intrinsic disease such as the presence of an aperistaltic segment of the ureter, aberrant vessels or kidney abnormalities. Rare conditions can sometimes mimic an UPJO. We present a case of an 86-year-old woman with a UPJO diagnosed on CT. The patient was counseled on treatment options and elected to undergo a left uretherorenoscopy (URS) plus left laparoscopic pyeloplasty. The definitive histopathologic diagnosis was perinephric myxoid pseudotumor of fat, an extremely rare neoplasm, mass-forming. To the best of our knowledge, this is the first known case of a pseudotumor of fat causing UPJO. 6-month follow-up showed neither recurrence nor residual UPJO. We describe a rare presentation of extrinsic perinephric myxoid pseudotumor of fat causing UPJ obstruction. In elderly patients with no history of malignancy, UPJ obstruction can occur because of atypical masses.

Perinatal Management in a Pregnant Woman with Ureteropelvic Junction Obstruction: Case Report and Literature Review

Although giant hydronephrosis (GH) associated with ureteropelvic junction obstruction (UPJO) is extremely rarely detected in pregnant women, diagnostic methods, therapeutic approaches, and perinatal management have not been established. A 31-year-old Japanese primipara had a 15 cm × 12 cm multi-cystic mass in the right abdomen detected by transabdominal ultrasound at gestational week 26. Magnetic resonance imaging revealed that the mass was right renal GH. She underwent serial ultrasound-guided transretroperitoneal drainage as conservative treatment. She delivered vaginally at gestational week 36. Since she had flank pain and a documented non-functional right kidney, laparoscopic nephrectomy was conducted 22 months after delivery. UPJO with fewer smooth muscle cells and fibrosis was histologically diagnosed in the surgical specimen. Her postpartum and postoperative courses were uneventful for 10 months. We performed a literature review of diagnostic methods, clinical characteristics, and perinatal management in pregnant women with GH due to UPJO.

Vascular hitch for paediatric pelvi-ureteric junction obstruction with crossing vessels: institutional analysis and systematic review with meta-analysis

OBJECTIVE

To compare the outcomes for laparoscopic vascular hitch (VH) and dismembered pyeloplasty in patients with pelvi-ureteric junction obstruction (PUJO) secondary to crossing vessels (CV).

PATIENTS AND METHODS

Patients who underwent laparoscopic management of CV at our institution were identified between 2008 and 2020. Baseline characteristics and outcome measures were compared between those who underwent VH and those who underwent dismembered pyeloplasty. Those who underwent VH were selected intraoperatively by identifying CV in the absence of intrinsic obstruction by assessing resolution of hydronephrosis after cranially displacing the CV away from the PUJ, followed by intraoperative fluid bolus and diuretic test. In addition, a systematic search and meta-analysis were performed in June 2020 (International Prospective Register of Systematic Reviews [PROSPERO] ID CRD42020195833).

RESULTS

A total of 20 patients underwent VH and 74 dismembered pyeloplasty. On multivariate analysis, VH was associated with: shorter operative time (P = 0.001; odds ratio [OR] 0.455, 95% confidence interval [CI] 0.294-0.705) and length of stay (P = 0.012; OR 0.383, 95% CI 0.183-0.803), lower use of stents (P < 0.001; OR 0.024, 95% CI 0.004-0.141) and opioid administration (P = 0.005; OR 0.157, 95% CI 0.044-0.567). From our literature search, 194 records were identified and 18 records were included (three comparative and 16 non-comparative). Meta-analysis of the comparative studies and our institutional data showed similar success rates (relative risk [RR] 1.77, 95% CI 0.33-9.52) and complication rates (RR 0.75, 95% CI 0.20-2.82). VH was associated with shorter operative time (standardised mean difference [SMD] -1.65, 95% CI -2.58 to -0.72 h) and hospital stay (SMD -1.41, 95% CI -2.36 to -0.47 days). The VH success rates ranged from 87.5% to 100% in the identified studies. Failure of VH was associated with unrecognised concomitant intrinsic obstruction in addition to CV.

CONCLUSIONS

A VH, for well-selected patients with CV without concomitant intrinsic obstruction, offers a high success rate with shorter operative times.

Pediatric congenital hydronephrosis (ureteropelvic junction obstruction): Medical management guide

The prevalence of asymptomatic hydronephrosis, now detected by ultrasonography, has increased. However, definitive management guidelines for the management of congenital hydronephrosis have not been established. The Japanese Society of Pediatric Urology created a "medical management guide" based on new findings for physicians practicing pediatric urology. We developed a medical management guide focused on congenital hydronephrosis caused by ureteropelvic junction obstruction. This medical management guide consists of the definition, pathophysiology, epidemiology, diagnosis, classification, treatment using a clinical management algorithm of hydronephrosis and the long-term course of the disease. The aim of hydronephrosis management is to determine whether surgery should be carried out to avoid renal dysfunction, as there is a possibility for improvement without intervention. Ultrasonography is essential to make treatment decisions. Management is determined by a comprehensive assessment, including the degree of hydronephrosis, anterior-posterior diameter of the renal pelvis and, if necessary, a nuclear medicine evaluation of the status of urine drainage and renal function.

Ureteropelvic junction obstruction caused by metastatic cholangiocarcinoma

We describe the rare case of a 61-year-old female with right ureteropelvic junction (UPJ) obstruction caused by metastatic cholangiocarcinoma. Her past medical history was notable for cholangiocarcinoma treated with neoadjuvant chemoradiation and two orthotopic liver transplants six years earlier. Urology was consulted when she presented with flank pain and urinary tract infection. Diagnostic workup demonstrated right UPJ obstruction. She was managed acutely with percutaneous nephrostomy. She subsequently underwent robotic pyeloplasty and intrinsic obstruction of the UPJ was discovered. Histological examination revealed adenocarcinoma, consistent with systemic recurrence of the patient's known cholangiocarcinoma.

Current Concepts in Pediatric Robotic Assisted Pyeloplasty

Robotic surgery in pediatric urology has been gaining popularity since its introduction almost two decades ago. Robotic assisted pyeloplasty is the most common robotic procedure performed in pediatric urology. Advances in robotic technology, instrumentation, patient care and surgical expertise have allowed the correction of ureteropelvic junction (UPJ) obstruction in most patients using this minimally invasive technique. The excellent experience with robotic assisted pyeloplasty has challenged other approaches as a new standard for the treatment of UPJ obstruction. In this review, we will describe the technique as it relates to the different robotic platforms, review the surgical experience and compare its results to other surgical approaches. Also, we will discuss patient and parent satisfaction, cost and financial considerations, along with evaluating the future of robotic surgery in the treatment of UPJ obstruction.

Prevention and management of urosepsis triggered by ureteroscopy

Urosepsis is a potentially life-threatening phenomenon that may occur after an ureteroscopic procedure. With the increasingly widespread adoption of ureteroscopy, there is a concern that the rates of urosepsis may increase. This review examines the current work being undertaken to minimize postprocedure infections both in the field of device development and in clinical care. Guidelines for the diagnosis and management of urosepsis will be discussed.

Hydronephrosis and crossing vessels in children: Optimization of diagnostic-therapeutic pathway and analysis of color Doppler ultrasound and magnetic resonance urography diagnostic accuracy

INTRODUCTION

Ureteropelvic junction obstruction (UPJO) is one of the most frequent urological diseases affecting the pediatric population. It can be due to both intrinsic stenosis of the junction and extrinsic causes such as the presence of crossing vessels (CVs), which can be detected by color Doppler ultrasound (CD-US). Magnetic resonance urography (MRU) is a good alternative, but sedation and infusion of a contrast agent are required.

OBJECTIVE

The aim of this study was to analyze the diagnostic accuracy of CD-US and MRU in visualizing CVs in pediatric hydronephrosis, in order to decide the correct diagnostic pathway in the pre-operative phase.

MATERIAL AND METHODS

A retrospective review was performed of medical records for all patients who underwent surgical treatment for hydronephrosis from August 2006 to February 2016. Ultrasound and scintigraphy had been performed on all patients. Data about CD-US and MRU were collected. A high-level technology ultrasound scanner and a 1.5 T MR scanner were used. The presence of CVs at surgery was considered the gold standard. Sensitivity, specificity, positive and negative predictive values (NPV) were calculated and reported for both of the imaging techniques.

RESULTS

A total of 220 clinical charts were reviewed. Seventy-three CVs were identified at surgery (33.2% of UPJO). The median age was statistically higher in the group with CVs compared to the group without CVs (P < 0.001). The sensitivity and NPV of CD-US in detecting CVs were higher than MRU (sensitivity 93.3% vs. 71.7%, NPV 95.7% vs. 77.6%, respectively).

DISCUSSION

According to the data, CD-US had higher sensitivity and NPV than MRU, resulting in superior detection of CVs. It is important for a surgeon to know that a child has a CV, especially in older children in which the incidence of extrinsic UPJO is higher. The main limitation of this study was the presence of incomplete data, due to the retrospectivity.

CONCLUSIONS

In the pre-operative phase, the CD-US should be considered as the investigation of choice to detect CVs in children with hydronephrosis (Summary Fig). Moreover, CD-US has lower costs than MRU, and sedation with infusion of contrast agent is unnecessary. For the future, it could be useful to lead a prospective comparison between the two imaging techniques.

Laser Endopyelotomy in the Management of Pelviureteric Junction Obstruction in Adults: A Systematic Review of the Literature

Laser endopyelotomy (LEP) is considered as an option for the treatment of pelviureteric junction obstruction in adults. A comprehensive systematic search of the published literature was performed to assess the success rate and perioperative complications of LEP in the treatment of primary and secondary pelviureteric junction obstruction and to identify the factors that may have an impact on the success of LEP. The evidence available has significant limitations in terms of the heterogeneous study design and the definitions of outcomes. The average overall success rate of the pooled data was 75% with a mean follow-up of 29 months. Complications were predominately minor with an average rate of 12.5%.

The role of urinary KIM-1, NGAL, CA19-9 and β2-microglobulin in the assessment of ureteropelvic junction obstruction in adults

PURPOSE

The objective of this study is to evaluate the diagnostic properties of urinary biomarkers in adults with ureteropelvic junction obstruction: KIM-1, NGAL, CA19-9, and β2-microglobulin. We also assessed urinary biomarker concentrations following pyeloplasty.

MATERIAL AND METHODS

We prospectively studied adults from December 2013 to February 2015. We included 47 patients with a mean age of 38.6 ± 12.7 years. Each patient provided four samples of voided urine for biomarker measurement, one at pre-operative consultation and the others at 1, 3, and 6 months of post-operative follow-up. The control group consisted of 40 healthy individuals with no hydronephrosis on ultrasound evaluation.

RESULTS

KIM-1 had an area under the curve of 0.79 (95% CI 0.70-0.89), NGAL 0.71 (95% CI 0.61-0.83), CA19-9 0.70 (95% CI 0.60-0.81), and β2-microgloblin 0.61 (95% CI 0.50-0.73). KIM-1 was the most sensitive marker with a cut-off of 170.4 pg/mg creatinine (sensitivity 91.4%, specificity 59.1%), whereas CA19-9 was the most specific with a cut-off of 51.3 U/mg creatinine (sensitivity 48.9%, specificity 88.0%). Urinary concentrations of biomarkers decreased after pyeloplasty.

CONCLUSIONS

The evaluation of urinary biomarkers is useful in adults undergoing pyeloplasty. KIM-1, NGAL, and CA19-9 were elevated and significantly decreased after surgery.

Intraoperative inspection of the ureteropelvic junction during pyeloplasty is not sufficient to distinguish between extrinsic and intrinsic causes of obstruction: Correlation with histological analysis

INTRODUCTION

Based on current knowledge, it is possible to have an initial diagnosis of intrinsic or extrinsic ureteropelvic junction obstruction (UPJO) based solely on clinical and imaging findings. However, it may not be possible to strictly discriminate an intrinsic case with an additional extrinsic component from a primarily intrinsic stenosis because of lower pole aberrant vessels. These two disorders may coexist or trigger each other. Herein, we aimed to compare the histological changes observed in intrinsic and extrinsic types of UPJO. Our hypothesis is that inspecting the UPJ during pyeloplasty may not be a sufficient way to delineate the underlying cause of obstruction in every individual.

MATERIAL AND METHODS

We retrospectively reviewed the data of 56 patients who had dismembered pyeloplasty. The intrinsic and extrinsic groups consisted of 38 and 18 patients, respectively. Masson's trichrome stain, CD117, and connexin 43 (Cx43) antibody were used in histopathology and immunochemistry. Statistical calculations were done with chi-square and Mann-Whitney U tests.

DISCUSSION

Connexin 43 staining pattern, CD117 positive cell count, and the extent of fibrosis did not differ significantly between extrinsic and intrinsic cases. However, the difference with regard to the degree of muscular hypertrophy was close to statistical significance. The exact pathophysiological mechanism underlying UPJO has yet to be elucidated. A study directly comparing both groups histologically is indeed rare. Our study showed that there are no significant differences between the intrinsic and extrinsic groups in terms of the pacemaker activity, gap junctional communication, and extent of fibrosis. Muscular hypertrophy, which was marginally higher in our extrinsic group, may persist despite successful relocation of the obstructing vessel. The main drawbacks of our study are; the absence of a control group and the retrospective study design with its inherent selection biases.

CONCLUSIONS

Immunohistochemical profiles of intrinsic and extrinsic UPJOs resemble each other. Intraoperative inspection of the UPJ may not be enough for accurate discrimination for a surgical procedure that can correct only the extrinsic cause.

Objective improvement in renal function post-Dietl's crisis: Documented on renal dynamic scintigraphy

Dietl's crisis is one of the treatable causes of intermittent abdominal pain. The pain is due to acute hydronephrosis that leads to stretching of the pelvis. The most common cause of this intermittent hydronephrosis is aberrant renal vessel at lower pole that causes pelvi-ureteric junction obstruction.(PUJO). High insertion of the ureter is one of the other rare causes. We present a case of 5-year-old boy with intermittent abdominal pain and distension with ultrasonography features of gross left hydronephrosis. Renal dynamic scan.(RDS) with ethylene dicysteine showed negligible functioning left kidney. On third follow-up day, the patient passed a lot of urine with decrease in abdominal pain and distension. Then, again the patient was sent to us 8.days after the first study for repeat RDS, which showed significant improvement in function and decreased in the size of left kidney though with persistent PUJO. On exploration high insertion of the ureter at pelvis was found to be the cause and was treated.

Urinary Proteomics Yield Pathological Insights for Ureteropelvic Junction Obstruction

Prenatal hydronephrosis is a common condition that may spontaneously resolve after birth. However, this condition can result in renal damage and requires surgical correction in a number of cases. Preventing renal damage is paramount, but existing diagnostic technology is invasive, exposes infants to radiation, is costly, and is often indeterminate. A better understanding of the pathophysiology of renal obstruction as reflected in the urinary proteome may provide new insights into the disease that could potentially alter the clinical management of hydronephrosis. We performed a quantitative proteomics study of urine that was surgically obtained from eight clinically significant, unilaterally obstructed infants versus eight healthy controls, with the goal of identifying quantitatively varying proteins and the biological networks associated with them. Notably, urine was obtained from both the obstructed kidney and the bladder. Over 1100 proteins were identified, and a total of 76 quantitatively varying proteins were identified. Proteins involved in oxidative stress, inflammation, and renal disease pathways showed the most significant abundance differences. This study gives a deeper understanding of the critical proteomic changes associated with renal obstruction and represents the deepest proteomic profile of renal obstruction to date.

Endoscopic Removal of a Nitinol Mesh Stent from the Ureteropelvic Junction after 15 Years

We report a rare case of a patient with a large stone encrusted on a nitinol mesh stent in the ureteropelvic junction. The stent was inserted in the year 2000 after failure of two pyeloplasty procedures performed due to symptomatic ureteropelvic junction stenosis. By combining minimally invasive urinary stone therapies-extracorporeal shock wave lithotripsy, semirigid ureterorenoscopy with laser lithotripsy, and percutaneous nephrolithotomy-it was possible to completely remove the encrusted stone and nitinol mesh stent that was implanted for 15 years, rendering the patient symptom and obstruction free.

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

BACKGROUND

MR Urography (MRU) is an increasingly used imaging modality for the evaluation of pediatric genitourinary obstruction.

OBJECTIVE

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.

MATERIALS AND METHODS

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.

RESULTS

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.

CONCLUSION

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.

Long-term results with the laparoscopic transposition of renal lower pole crossing vessels

BACKGROUND

For the treatment of ureterovascular pelviureteric junction obstruction (PUJO), transposition of lower pole crossing vessels (LPCV) has been described as an alternative to dismembered pyeloplasty.

PURPOSE

To report on the long-term follow-up of children after laparoscopic transposition of LPCV.

METHODS

A retrospective analysis of 70 children consecutively treated by laparoscopic transposition of LPCV. Candidate patients were selected on the basis of clinical history, renal ultrasound (US), and pre-operative mercaptoacetyltriglycine (MAG-3) scan. Selection criteria included: presence of LPCV with SFU Grade 1-2 hydronephrosis, impaired drainage on MAG-3 and intraoperative normal pelviureteric junction (PUJ) and ureter peristalsis. Thinned parenchyma, impaired renal function, or history of prenatal hydronephrosis were not considered as exclusion criteria. Children were clinically followed up with US and MAG-3 scan. Success was defined by symptom resolution with improvement in hydronephrosis.

RESULTS

Seventy children, aged 8.3 years (range 2.75-16.0), were selected. Procedures were performed through transperitoneal laparoscopy (n = 42) or were robotic-assisted (n = 28). Operative time was 120 min and length of hospital stay was 2 days. The outcome was successful in 67/70 patients (96%), with a median follow-up of 52 months (range 13-114). There were three failures in children who eventually underwent dismembered pyeloplasty for a symptomatic, undiagnosed, intrinsic PUJ obstruction. Two of them had been postnatally followed for a resolving prenatally diagnosed hydronephrosis. Three children became free of symptoms, had improved hydronephrosis, but still showed impaired drainage on MAG-3 and are being closely followed up.

DISCUSSION

Although this procedure proves to have long-term efficiency in selected indications, the main challenge is to intraoperatively ascertain the absence of associated intrinsic stenosis. Objective criteria remain difficult to establish, but intraoperative findings, including dependent, funnel-shaped, normal-looking PUJ with decreasing hydronephrosis after pelvis and LPCV mobilisation, and efficient peristalsis across the PUJ under intraoperative diuretic test, represent a low likelihood of associated intrinsic stenosis. Ipsilateral impaired renal function doesn't seem to be associated with an adverse outcome. In contrast, a prenatal history of mild or self-resolving hydronephrosis in a patient later presenting with intermittent dilatation, raises the suspicion of associated intrinsic PUJ obstruction, as it is associated with a higher risk of failure.

CONCLUSION

With a long postoperative follow-up, the robotic-assisted or laparoscopic vascular hitch procedure has been successful in treating a selected group of children with obstructive LPCV, and represents a safe and reliable alternative to standard dismembered pyeloplasty in the absence of intrinsic PUJO suspected on prenatal US.

Laparoscopic pyeloplasty with cephalad translocation of the crossing vessel - a new approach to the Hellström technique

Introduction

It is believed that lower pole crossing vessels may play an important role in the etiology of ureteropelvic junction obstruction (UPJO). A conventional operative technique, which seems to be widely used in patients with UPJO, is Anderson-Hynes (A-H) plasty with dorsal transposition of the vessel. An attractive alternative to dorsal transposition of the vessel might be its cephalad translocation.

Aim

To assess the effectiveness of cephalad translocation of the crossing vessel in patients who underwent laparoscopic A-H or Y-V pyeloplasty.

Material and methods

Eighty-five patients were included in the study. To assess the effectiveness of cephalad translocation of the crossing vessel in patients who underwent laparoscopic pyeloplasty, the results of the procedure were compared to the results of laparoscopic pyeloplasties performed in patients without crossing vessels (control group). Success was defined as the following factors taken collectively: 80% or greater pain relief according to VAS, no sign of obstruction on intravenous urography (patent UPJ), decreasing excretion curve with T1/2 < 12 min, and improved or stable differential renal function on diuretic renography.

Results

The mean follow-up was 53.7 months. There was no statistically significant difference in the success rate between the compared groups (group 1 – cases with cephalad translocation of the crossing artery, and group 2 – cases without crossing vessels) in patients who underwent A-H plasty or Y-V plasty.

Conclusions

The analysis of our data seems to indicate that cephalad translocation of the anterior crossing vessel gives good therapeutic results in patients who undergo laparoscopic pyeloplasty.

Multidetector CT of vascular compression syndromes in the abdomen and pelvis

Certain abdominopelvic vascular structures may be compressed by adjacent anatomic structures or may cause compression of adjacent hollow viscera. Such compressions may be asymptomatic; when symptomatic, however, they can lead to a variety of uncommon syndromes in the abdomen and pelvis, including median arcuate ligament syndrome, May-Thurner syndrome, nutcracker syndrome, superior mesenteric artery syndrome, ureteropelvic junction obstruction, ovarian vein syndrome, and other forms of ureteral compression. These syndromes, the pathogenesis of some of which remains controversial, can result in nonspecific symptoms of epigastric or flank pain, weight loss, nausea and vomiting, hematuria, or urinary tract infection. Direct venography or duplex ultrasonography can provide hemodynamic information in cases of vascular compression. However, multidetector computed tomography is particularly useful in that it allows a comprehensive single-study evaluation of the anatomy and resultant morphologic changes. Anatomic findings that can predispose to these syndromes may be encountered in patients who are undergoing imaging for unrelated reasons. However, the diagnosis of these syndromes should not be made on the basis of imaging findings alone. Severely symptomatic patients require treatment, which is generally surgical, although endovascular techniques are increasingly being used to treat venous compressions.

A curable and probably often-overlooked cause of cyclic vomiting syndrome

Cyclic vomiting syndrome is a disorder of many causes. The major challenge is to label the disorder as idiopathic or primary only when all possible etiologies, particularly those that can be specifically treated, have been ruled out. In retrospect, our patient had subtle prenatal and early postnatal radiological findings supportive of a urological cause for his symptoms, the importance of which was initially missed. It would probably be wise to include an abdominal ultrasound examination (looking for hydronephrosis) in the "must-do" battery of tests for the investigation of all cases of recurrent cyclic vomiting without apparent cause. Otherwise, it seems likely that many cases of ureteropelvic junction obstruction will be missed, cases in which surgical intervention can be curative.

Urologic surgery in gynecologic oncology: a large single-institution experience

OBJECTIVE

The increasing tendency to a tailored treatment in gynecologic oncology has required the extension of the intervention to other non-gynecological structures, as the urinary district. Moreover the role of the urological surgery in gynecologic oncology is still not completely explored. The objective of the study is to evaluate the occurrence of urological procedures in gynecologic oncology surgery.

METHODS

Patients admitted to the Division of Gynecologic Oncology, Catholic University of Sacred Hearth, Rome, Italy, between January 2009 and December 2012, were retrospectively analyzed. Clinical charts identified the occurrence of urological procedures in major gynecological surgery.

RESULTS

A total of 728 patients were analyzed for the study. A total of 204 urologic procedures were carried out in 83 patients. In all patients, preoperative hydronephrosis appears to be the only statistically significant predisposing factor to urological procedures. At multivariate analysis, stratifying data for different neoplasm, recurrence was the only adjunctive significant variable for ovarian cancer, as well as neo-adjuvant treatment and recurrence for cervical cancer.

CONCLUSIONS

This study has identified preoperative factors influencing the needing of urological procedures in different gynecologic neoplasms, allowing a proper planning of surgical treatment, tailored on each patient.

Retroperitonoscopic pyelopexy for pelviureteral junction obstruction with crossing vessel in adolescents: Hellstrom principle revisited

OBJECTIVE

To present our new approach using a minimally invasive technique for the management of pelviureteral junction (PUJ) obstruction with a crossing vessel.

MATERIALS AND METHODS

In December 2009 to December 2011, out of 23 cases of retroperitoneoscopic laparoscopic pyeloplasty, four adolescents presenting with PUJ obstruction due to an aberrant crossing vessel, with intermittent attacks of renal colic and mild dilatation of the renal pelvis and calyces, were operated by retroperitoneoscopic pyelopexy. A retroperitoneoscopic approach was used in all patients using three trocars. After dissection of the PUJ from the anterior crossing vessel, and ensuring good funneling of the PUJ that proved to show mild dilatation, an interrupted 3/0 polyglycolic suture was used to fix the renal pelvis to the psoas muscle away from the crossing vessel (pyelopexy). A retrograde DJ stent was placed at the end of the procedure.

RESULTS

The four patients had a mean age of 18.25 years (16-20): 2 males and 2 females, two right sided and two left sided. Average operative time was 46 min (40-55). All patients were discharged on the same day. No intraoperative complications were encountered. The DJ stent was removed 6 weeks postoperatively. After a mean follow up of 2.125 years (6 months-3 years) no recurrences were observed.

CONCLUSION

Retroperitoneoscopic pyelopexy is shown to be a reliable, effective, safe and minimally invasive technique for the management of PUJ obstruction with a crossing vessel in selected cases. Long-term follow up is needed to assess any recurrence or development of complications.

Laparoscopic vascular relocation: alternative treatment for renovascular hydronephrosis in children

AIMS

The standard treatment for pelviureteric junction obstruction (PUJO) has been dismembered pyeloplasty. The open surgical, Hellström procedure in which crossing polar vessels are relocated, has been an option in adult urological practice. We present our experience with laparoscopic vascular relocation in children.

METHODS

Data were retrospectively gathered on all patients who underwent laparoscopic relocation of lower pole vessels (LRLPV) at our institution between July 2004 and March 2008. Follow-up ultrasounds and MAG3 were obtained.

RESULTS

LRLPV was performed in 10 boys and 9 girls. Patients were between 5.8 and 15.25 years (median 9.9 years). They presented with recurrent abdominal pain (n = 17), urinary tract infections (n = 7) and haematuria (n = 3). On ultrasound, MAG3 and retrograde studies they had hydronephrosis, obstructed drainage and a normal calibre ureter with a sharp cut-off. They were further assessed at laparoscopy and were found to have aberrant lower pole crossing vessels. All underwent laparoscopic mobilization of the lower pole vessels from the region of the PUJ thereby freeing the junction and relocating them superiorly onto the anterior wall of the pelvis. The median operating time was 120 min (range 60-240 min). The median hospital stay was 2 days (range 1-3 days). They were followed up for a median period of 12 months (range 6-36 months). All patients have remained asymptomatic. Ultrasound done at 6 months showed decreased hydronephrosis. MAG3 study showed improved drainage in 17, while 1 had poor drainage. This patient remains symptom free and is under regular follow up.

CONCLUSION

Laparoscopic vascular relocation is an unconventional technique in carefully selected patients with PUJO. It obviates disrupting an intrinsically normal PU junction and treats the cause rather than the effect. Our intermediate-term results are encouraging and further long-term assessment is needed.

The roles of extracellular matrix proteins, apoptosis and c-kit positive cells in the pathogenesis of ureteropelvic junction obstruction

AIM

To investigate histopathological changes in ureteropelvic junction obstruction (UPJO) from an etiological perspective.

PATIENTS AND METHODS

Medical records of patients with UPJO were reviewed and pathological specimens collected. Nephrectomy materials from forensic autopsies were taken as controls. Specimens were assessed with light microscopy. Fibronectin, type 4 collagen, laminin, Bax and Bcl-2 expression for apoptosis, together with interstitial cells of Cajal determination with c-kit were determined immunohistochemically. Staining scores were evaluated semiquantitatively. Results were evaluated using Mann-Whitney U-test.

RESULTS

Control group comprised 14 children (median age, 3.5 years; 6 months-17 years). Study group comprised 22 children with UPJO (median age, 9 months; 1 month-10 years). Light microscopy revealed non-specific inflammation, epithelial proliferation and atrophy with fibrosis in the smooth muscle of the UPJ in all patients. Fibronectin, type 4 collagen and laminin were found to be significantly increased in UPJO at the intrafascicular space of smooth muscle and the matrix of stroma. Bcl-2 expression was increased in UPJO. c-Kit was unable to stain interstitial cells of Cajal, but staining for mast cells was significant.

CONCLUSIONS

High expression of fibronectin, laminin and type 4 collagen may indicate a relation to the pathogenesis of UPJO. Defective kidney morphogenesis, during branching and tubulogenesis of ureteric bud, may be responsible for this congenital pathology.

[Prenatal diagnosis of hydronephrosis: utility of diuretic renography]

OBJECTIVE

To investigate the value of diuretic renography in patients with prenatally diagnosed unilateral hydronephrosis.

MATERIAL AND METHOD

We reviewed 44 patients who underwent ultrasonography in the first week of life and 1 month after birth, and cystography and diuretic renography at 1 month to evaluate differential renal function and the diuretic washout pattern. Patients with vesicoureteral reflux were followed-up according to the protocol for this disorder. In the remaining patients, ultrasonography and/or diuretic renography was performed every 3-6 months.

RESULTS

In 4/44 patients vesicoureteral reflux was detected as cause a of hydronephrosis. In the remaining 40 patients, diuretic renography showed a washout pattern not suggestive of obstruction in 32 (only one patient needed surgery due to pyohydronephrosis). An indeterminate washout pattern was detected in one patient (who required surgery due to worsening of the washout pattern). A pattern suggestive of obstruction was detected in seven patients, four of whom required surgery (three due to a decrease in differential renal function and one due to worsening of the degree of pelvic dilatation).

CONCLUSIONS

Diuretic renography is highly useful in risk stratification and in the management of newborn infants with hydronephrosis since infants with washout patterns not suggestive of obstruction will rarely develop obstructive hydronephrosis and can initially be followed-up with ultrasonography alone. In indeterminate and obstructive patterns, however, close monitoring that includes diuretic renography is mandatory.

Intermittent hydronephrosis secondary to ureteropelvic junction obstruction: clinical and imaging features

OBJECTIVE

We sought to assess the clinical and imaging findings in intermittent hydronephrosis secondary to ureteropelvic junction obstruction, with particular emphasis on the characteristic ultrasonographic findings.

METHODS

This prospective, longitudinal, observational study included all children who had intermittent ureteropelvic junction obstruction and presented with abdominal pain over 6 years. Renal ultrasound was used as an initial screening tool to detect intermittent hydronephrosis. Renal ultrasonography was repeated every 1 to 2 days to record serial changes from the symptomatic to the asymptomatic stage. Their clinical manifestations and imaging findings were studied.

RESULTS

Eighteen patients (14 boys, 4 girls) were studied. Most had sharp pain that began acutely and typically lasted for <2 days. Most of the children (16 of 18) had nausea and vomiting that accompanied the pain. The acute episode generally resolved spontaneously and was followed by a pain-free interval that ranged from days to months. Factors that predisposed to an attack included increased water intake, vigorous exercise, or bladder distention. All patients had clearly demonstrable obstruction of the renal pelvis during an acute attack, a finding that diminished or resolved during the symptom-free intervals. During convalescence, all patients had renal pelvic wall thickening on ultrasonography. This finding appeared on the second or third day after a painful episode subsided, persisted for 6 to 9 days, and then disappeared in the symptom-free stage. Pyeloplasty was performed in 17 patients, none of whom had recurrent pain on follow-up. Extrinsic obstructions were found in 9 patients.

CONCLUSIONS

The keys to diagnosis are awareness of the syndrome, a detailed history, and immediate and serial imaging studies during painful crises. A thickened renal pelvic wall during convalescence is an important ultrasonic sign of intermittent hydronephrosis.

Dynamic Contrast-Enhanced MR Urography in the Evaluation of Pediatric Hydronephrosis: Part 2, Anatomic and Functional Assessment of Uteropelvic Junction Obstruction

OBJECTIVE

The purpose of our study was to retrospectively review our experience using MR urography in the diagnosis of ureteropelvic junction (UPJ) obstruction in children.

MATERIALS AND METHODS

Sixty-one studies were performed in 50 children with hydronephrosis but without hydroureter. Anatomic criteria assessed included degree of hydronephrosis, morphology of the renal pelvis, atrophy of medulla, swirling contrast material, fluid levels, and the presence of fetal folds and crossing vessels. Functional criteria included renal transit time, differential renal function, and time-intensity curves when available.

RESULTS

Thirty-one kidneys were classified as obstructed, 15 as equivocal, and 15 as nonobstructed. Obstructed systems had more marked hydronephrosis, more extensive medullary atrophy, more fluid levels, and more swirling contrast material. Fetal folds were seen in only the equivocal and nonobstructed groups. Crossing vessels were seen in all groups. Obstructed systems also showed greater functional derangement, decreased split renal function, and abnormal time-intensity curves.

CONCLUSION

MR urography provides both excellent anatomic and functional information in children with UPJ obstruction in a single test that does not use ionizing radiation. MR urography may lead to greater understanding of the pathophysiology of UPJ obstruction.

Renal Multidector Row CT

Multidetector row CT is the most recent advance in CT technology. An increased number of detector rows and more powerful x-ray tubes result in faster scanning time, increased volume coverage, and improved spatial and temporal resolution. MDCT technology allows superior image quality, decreased examination time, and the ability to perform complex multiphase vascular and three-dimensional examinations.

Adult Ureteropelvic Junction Obstruction: Insights with Three-dimensional Multi–Detector Row CT

Ureteropelvic junction obstruction (UPJO) is a benign, congenital condition that remains an enigma in terms of both diagnosis and therapy. On the basis of a series of cases that were referred to the authors in their clinical practice, they found that the unprecedented quality and novel perspectives of multi-detector row computed tomography (CT) with two- and three-dimensional postprocessing allow a comprehensive, single-study assessment of the ureterovascular relationships in UPJO. This topic is important because the causative role of crossing vessels may be questioned on the basis of such studies, and the therapeutic approach may be altered by using precise anatomic images customized to the pathologic features of the individual patient. Although CT images can provide only circumstantial or supportive evidence of the pathophysiology of UPJO, they greatly facilitate therapeutic intervention when it is clinically indicated and may eliminate the need for it in select cases. Careful attention to the postprocessing of CT images may show that the crossing vasculature has no direct relationship to the transition point of the UPJO in many cases.

The expression of epidermal growth factor and transforming growth factor-beta1 in the stenotic tissue of congenital pelvi-ureteric junction obstruction in children

PURPOSE

The aim of this study was to test the hypothesis that expression of epidermal growth factor (EGF) and transforming growth factor-beta 1 (TGF-beta 1) may be altered in stenotic tissue of patients with congenital hydronephrosis caused by pelviureteric junction (PUJ) obstruction and to evaluate the role of these 2 growth factors.

METHODS

The expression of EGF and TGF-beta 1 was evaluated in tissue specimens in 25 children with PUJ obstruction and 15 controls with normal PUJs by immunohistochemistry, in situ hybridization, and reverse transcriptase polymerase chain reaction (RT-PCR) techniques. All the signals of mRNA products were normalized to the mRNA levels of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) a housekeeping gene, as a ratio.

RESULTS

On RT-PCR study, the amount of TGF-beta 1 mRNA in stenotic tissue was higher than in controls, in addition, EGF gene expression in the obstructed junction was significantly lower than in normal junctions. The TGF-beta 1 to GAPDH ratio was 0.57 +/- 0.26 and 0.36 +/- 0.19 in the stenotic tissue and the normal ureter, respectively (P =.012). The EGF to GAPDH ratio was 0.17 +/- 0.08 and 0.37 +/- 0.14 in the stenotic tissue and the normal ureter, respectively (P =.0001). Furthermore, the positive correlations were found between TGF-beta1 gene and protein expression (r = 0.601; P =.001), TGF-beta 1 gene and drainage clearance half-time (T1/2) (r = 0.474; P =.017), TGF-beta 1 protein expression, and T1/2 (r = 0.516; P =.008). A negative correlation was found between EGF gene and T1/2 (r = -0.448; P =.025). On immunolabeling and in situ hybridization labeling, the expression of TGF-beta 1 protein was strongly positive and confined to the muscle cells, spindle cells, and collagen fibers in the stenotic tissue; the expression of TGF-beta 1 mRNA was moderately positive and mainly distributed in the collagen of the stenotic segment, both the expression of EGF protein and mRNA were negative in the normal ureter.

CONCLUSIONS

There were increased TGF-beta 1 mRNA expression and decreased EGF mRNA expression in the stenotic tissue after clinical ureteropelvic junction obstruction. The alteration of EGF and TGF-beta 1 expression may be involved in the pathogenesis of congenital hydronephrosis.

Ureteropelvic Junction Obstruction: Some new Acquisitions about Etiology, Pathophysiology and Diagnostics

The etiopathogenesis of uretero-pelvic junction obstruction (UPJO) has been the subject of many speculations and it remains, in some ways, a debatable matter. Some recently reported thorough research refer to neuro-mediated pathogenetic mechanisms rather than (or together with) myogenic ones.

Advances in US, radioisotopic functional imaging, CT and RM contribute to differentiate the obstructive conditions from the non-obstructive ones and to afford today a better assessment of renal functional damage. Particularly, diuretic renography is a non-invasive test for characterization of the renal functional abnormalities resulting from UPJO. Helical CT with angiography is a useful technique for identification of crossing vessels (pyelo-vascular tangle) which can be used for the pre-surgical planning of endopyelotomy. Endoluminal ultrasonography can be used to guide the position of the incision for endopyelotomy (US-guided endopyelotomy).

Laboratory examinations are important to determine the overall renal function (serum creatinine, acid-base balance, serum electrolytes, etc.), urinary MCP-1 and NAG (markers of tubular damage), and to rule out urinary tract infections.

The management of UPJO (watchful waiting; either open or laparoscopic dismembered pyeloplasty; endoluminal procedures) is greatly influenced by the diagnostic evaluation.

The paper aims to outline the advances in both physiopathology and diagnostics of UPJO on the basis of a review of the literature.

Ureteropelvic junction obstruction: an innovative approach combining metallic stenting and virtual endoscopy

PURPOSE

We report our experience with auto-expandable metallic stents for treating ureteropelvic junction obstruction.

MATERIALS AND METHODS

We treated 4 patients with a mean age of 45 years who had ureteropelvic junction obstruction with placement of a self-expandable intraureteral metallic stent (Wallstent, Schneider, Zurich, Switzerland). All patients presented with recurrent ureteropelvic junction obstruction after open pyeloplasty. Excretory urography and 3-dimensional reconstruction computerized tomography were performed 1 and 6 months after stent insertion. Virtual endoscopy images were obtained at followup due to the need to define ureteral patency.

RESULTS

Mean followup was 16 months (range 9 to 24). Wallstent placement was successful and immediate patency was achieved in all cases. During followup 3 patients required no further intervention and the stented ureteropelvic junction remained patent. In the remaining patient stricture recurred 2 months after initial stent insertion due to the ingrowth of scar tissue through the prosthesis. Additional intervention was deemed necessary after placing a longer 6 cm., completely coaxial overlapping metal stent. Virtual endoscopy and excretory urography findings concurred. Virtual endoscopy allows visualization of the stented ureteropelvic junction lumen cephalad and caudal to the prosthesis. It also enables easy navigation within the stent at different angles of view.

CONCLUSIONS

The concept of applying metallic stents for ureteropelvic junction obstruction and adjacent adynamic ureteral segments combined with virtual endoscopy is strengthened by the results of this study.