Extrinsic Ureteropelvic Junction Obstruction Research Articles

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.

Uretero-pelvic junction obstruction in children: Is vascular hitch an effective and safe solutions in very long term outcome? Report of 25 years follow-up

Vascular (VH) according to Hellstrom-Chapman technique is considered a safe and effective alternative approach to pure extrinsic Ureteropelvic Junction Obstruction (UPJO) with good results in short and medium term, but few data are available on long and verylong term outcomes. Our aim is to evaluate VH long and very-long term outcomes in patients treated in pediatric age focusing on relapse, development of hypertension and/or inferior polar kidney hypotrophy during puberty and adulthood. From 1990 to 2015 in our Department 76 children were treated by open or laparoscopic VH for pure extrinsic-UPJO. We were able to contact 54 of 76. 41 patients (25 males, 16 females) accepted to be studied. Mean follow- up time was 12.7 years (range 6-27 years); mean age at the assessment was 22.2 years. We excluded patients who were younger than 13 (if females) or 14 (if males) at the assessment (upper limits of physiological puberty onset). Patients were followed with US, MAG-3-scan and arterial blood pressure measurement. Collected data were compared with the preoperative ones by Student t-test. 95% of US images and MAG-3-scan reports were compatible with complete resolution of obstruction with good renal functionality. 87% of patients were completely healthy. We recorded 3 cases of hypertension (7%) not secondary to renovascular origin; 2 cases with recurrent flank pain (5%) with slightly dilated pelvis at the US and sub-obstructive pattern at MAG-3-scan with preserved renal function. Our experience confirms that VH, (open/laparoscopic) is a safe and effective procedure with good outcomes at very longterm follow-up. No patients at puberty and in adulthood required reoperation or presented polar hypotrophy and related vascular hypertension. VH is an alternative approach to pure extrinsic-UPJO. There were few data about long and very-long term outcomes in patients after this kind of surgery. We followed-up 41 patients confirming that VH (open/laparoscopic) is safe and effective with good long-term outcomes.

Minimally invasive vascular hitch to treat pediatric extrinsic ureteropelvic junction obstruction by crossing polar vessels: A systematic review and meta-analysis

Vascular hitch (VH) gained an increasing success in treating ureteropelvic junction obstruction (UPJO) by crossing vessels (CV) in pediatrics. We aimed: (i) to compare laparoscopic VH versus laparoscopic dismembered pyeloplasty (DP) to treat UPJO by CV; (ii) to review possible amelioration given by a robot-assisted procedure. Using defined search strategy, three investigators identified all studies on laparoscopic VH. Those studies comparing VH versus DP or versus robot-assisted VH were included in the meta-analysis. The meta-analysis was conducted using RevMan 5.3. Data are mean±SD. Systematic review - Of 2783 titles/abstracts screened, 43 full-text articles were analyzed. Twelve studies on laparoscopic VH (298pts) reported 98.3% success rate, with 1.3% intra-operative complications. Meta-Analysis - Five studies compared laparoscopic VH versus laparoscopic DP (277pts). Operative time was reduced in VH (102.5±47.5min) compared to DP (165.7±53.7min; p<0.00001). Complications were similar (VH 4/119pts, 3.4±1.2% versus DP 15/158pts, 9.5±6.8%; p=ns). Hospital stay was shortened in VH (1.1±0.9dd) versus DP (3.3±3.2dd; p<0.0001; Summary Figure). The success rate was comparable (VH 115/118pts, 97.5±1.6% versus DP 157/158pts, 99.4±0.5%; p=ns). Two prospective studies compared robot-assisted VH to laparoscopic VH (53pts). No differences were found among complications (robot-assisted VH 0/13pts, 0% versus laparoscopic VH 1/40pts, 2.5%; p=ns) and success rate (robot-assisted VH 13/13pts, 100% versus laparoscopic VH 39/40pts, 97.5%; p=ns). Several studies have been reported long-term results of laparoscopic VH in children. However, few papers demonstrated its superiority over laparoscopic DP to treat extrinsic UPJO. In the present study, we found similar incidence of complications and success rates when comparing VH versus DP. Nonetheless, the operative time and the length of hospital stay were significantly reduced in VH compared to DP. An increasing number of surgeons performed robotic-assisted VH, reporting promising outcomes. However, only a couple of studies compared robot-assisted VH to laparoscopic VH, with a similar incidence of complications and success rate in both procedures. The main limitations of the study were related to the slight number of papers included and to their quality, since all of them were retrospective studies or prospectively followed-up cohort of patients. Laparoscopic VH seems to be a safe and reliable procedure to treat UPJO by CV. The procedure appeared quicker than laparoscopic DP, with shortened hospital stay. Further studies are needed to corroborate these results and to establish amelioration given by a robot-assisted procedure.

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.

Uretero-pelvic junction obstruction due to crossing pole vessel: contra vascular hitch

Hydronephrosis in infants and children is most commonly due to a congenital, intrinsic obstruction of the uretero-pelvic junction. The Gold standard of care is defined as a dismembered pyeloplasty, nowadays mostly performed in a minimally-invasive procedure, either through a laparoscopic (also robotic-assisted) or retroperitoneoscopic approach. Less common is an extrinsic obstruction of the ureter or the uretero-pelvic junction caused by an aberrant crossing pole vessel, a condition more likely to affect children beyond infancy. This entity most often becomes apparent when it causes intermittent abdominal or flank pain. For this entity, Hellström described a surgical procedure avoiding dismembered pyeloplasty by hitching the crossing vessel in a tunnel at the pyelon. This has been increasingly advocated as a valuable therapeutic alternative to dismembered pyeloplasty. The discussion on whether dismembered pyeloplasty or a vascular hitch procedure is preferable to resolve the obstruction is controversial and ongoing. There is evidence in the literature that in the case of a crossing pole vessel an intrinsic stenosis of the ureter may additionally be present in up to 57 % of cases. However, this finding can only be proven histologically. The intraoperative aspect of a crossing pole vessel and the uretero-pelvic junction does not serve to discriminate between intrinsic and extrinsic stenosis. Therefore, a vascular hitch procedure bears the risk that a remaining intrinsic obstruction will be disregarded, which, in turn, may lead to urodynamic obstruction and consecutive loss of differential renal function. In addition, there is a general risk of compromising the perfusion of the affected kidney while hitching an aberrant vessel providing significant blood supply. Dismembered pyeloplasty can avoid a false selection of patients. In addition, there is sufficient evidence showing that dismembered pyeloplasty is a procedure with a low complication rate ranging from 2 to 3 %, providing very good results in functional outcome in terms of improving drainage and preserving differential renal function. Therefore, we prefer dismembered pyeloplasty as the method of choice for both the treatment of intrinsic as well as extrinsic uretero-pelvic junction obstruction.

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

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. 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. 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 1.5TMR 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. 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). 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. 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.

Re: Differences between Intrinsic and Extrinsic Ureteropelvic Junction Obstruction Related to Crossing Vessels: Histology and Functional Analyses.

No AccessJournal of UrologyUrological Survey1 Nov 2017Re: Differences between Intrinsic and Extrinsic Ureteropelvic Junction Obstruction Related to Crossing Vessels: Histology and Functional Analyses Douglas A. CanningMD Douglas A. CanningDouglas A. Canning More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2017.08.044AboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail "Re: Differences between Intrinsic and Extrinsic Ureteropelvic Junction Obstruction Related to Crossing Vessels: Histology and Functional Analyses." The Journal of Urology, 198(5), p. 968 © 2017 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 198Issue 5November 2017Page: 968 Advertisement Copyright & Permissions© 2017 by American Urological Association Education and Research, Inc.MetricsAuthor Information Douglas A. Canning More articles by this author Expand All Advertisement PDF downloadLoading ...

Minimally Invasive Treatment of Pediatric Extrinsic Ureteropelvic Junction Obstruction by Crossing Polar Vessels: Is Vascular Hitching a Definitive Solution? Report of a Multicenter Survey.

This article aimed to evaluate the outcome of laparoscopic vascular hitch (VH) as an effective alternative to dismembered pyeloplasty in the treatment of children with extrinsic ureteropelvic junction obstruction (UPJO) by crossing vessels (CVs), by reporting the experience of three Italian centers of Pediatric Surgery. From 2006 to 2014, 54 children (18 girls and 36 boys, average age 10.7 years) affected by suspected extrinsic UPJO by CV were treated in three different institutions: 51 patients underwent laparoscopic VH, while 3 patients, in which a coexisting intrinsic etiology of UPJO was doubtful, underwent laparoscopic dismembered pyeloplasty. Preoperative diagnostic workup included: ultrasound (US)/Doppler scan, mercaptoacetyltriglycine (MAG3)-renal scan, and functional-magnetic-resonance-urography (fMRU). Symptoms at presentation were recurrent abdominal/flank pain and hematuria. All patients presented intermittent hydronephrosis (range 18-100 mm) on US and an obstructive pattern on MAG3 renogram. Average operative time was 108 minutes, and average hospital stay was 1.8 days. As for complications, we reported a small abdominal wall hematoma and a high UPJ distortion without obstruction in 2 patients, not requiring reintervention (grade I Clavien-Dindo). At follow-up (range 12-96 months), all patients reported resolution of symptoms, decrease in the hydronephrosis grade, and improved drainage on MAG3 renogram. Our results demonstrated the safety and efficacy of laparoscopic VH for treatment of extrinsic UPJO by CV, registering excellent outcomes in a very selected patient population. The careful selection of patients through intraoperative assessment of anatomical and functional aspects is a crucial step to confirm indications for VH and maintain a high success rate with the procedure. We believe that any concerns regarding the coexistence of intrinsic stenosis should certainly lead to opening the collecting system and to performing a classic dismembered pyeloplasty.

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

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. 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. 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. 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.

Differences between intrinsic and extrinsic ureteropelvic junction obstruction related to crossing vessels: histology and functional analyses.

In children, ureteropelvic junction obstruction (UPJO) is mostly caused by intrinsic factors (IUPJO); extrinsic UPJO are rare and often due to crossing vessels (CVs). We retrospectively reviewed all data of children with UPJO that underwent surgery in our institution from 2004 to 2011. Analyses included age at surgery, gender, preoperative and postoperative results of ultrasound and renal scans [differential renal function (DRF); signs of obstruction], and pathology reports. Available histological specimens of cases with CV were compared to a random selection of intrinsic cases in a blinded fashion. After additional Masson's trichrome staining, the specimens were scored for fibrosis, muscular hypertrophy, and chronic inflammation. Out of 139 patients with UPJO, 39 cases were associated with CV. Median age at surgery was 68 months (range 2-194) in the CV group and 11.5 months (range 0-188) in IUPJO group. Laparoscopic dismembered pyeloplasty (LDMP) was carried out in 134 and open DMP in five patients. Preoperative ultrasound identified 28/39 cases with CV. DRF below 40 % was more frequently seen in CV patients (p = 0.020). Histological analyses revealed no differences between the CV and IUPJO specimens in total. CV patients with higher grades of muscular hypertrophy had lower preoperative DRF, compared to those with higher preoperative DRF (p = 0.026). Functional recovery after (L)DMP was excellent in both groups. We could not find any significant histological differences between CV and IUPJO in children. To obtain excellent functional recovery, surgical procedures with a definite correction of the UPJ should be preferred in paediatric patients with CV.

Hydronephrosis: Comparison of extrinsic vessel versus intrinsic ureteropelvic junction obstruction groups and a plea against the vascular hitch procedure

Pediatric ureteropelvic junction obstruction (UPJO) due to an extrinsic crossing vessel (CV) is rare and often remains undiagnosed preoperatively. Vascular hitch procedures are often performed as associated intrinsic obstruction is not expected. We compared data and intravenous urography (IVU) findings of patients with aberrant CV versus those with intrinsic UPJO, all undergoing open dismembered pyeloplasty. Is accurate pre-operative diagnosis of aberrant CV causing extrinsic UPJO possible? To assess differences in the demographic, clinical, radiological, intra-operative features and postoperative improvement after pyeloplasty between patients with a CV and those with only intrinsic UPJO. Prospective study of all children below 12 years with UPJO presenting to a tertiary referral centre and who underwent open Anderson - Hynes dismembered pyeloplasty between 2003 and 2013 was conducted. Pre-operative investigations included serial ultrasonography, renal dynamic [ethylene di-cysteine (EC)] scan and IVU. These were repeated 3 months after pyeloplasty. Pre-operative IVUs of children with CV were compared with the IVUs of an equal number of similar aged children, randomly selected from the intrinsic obstruction group. Pyeloplasty was performed in 643 children during the study period. Data of 33 children with aberrant CVs (mean age 6.99 years) were compared with the remaining 610 children (mean age 3.27 years) with only intrinsic obstruction. Highly significant associations of those with CV included age above 2 years, female gender, associated anomalies, abdominal pain in those above 2 years and poor preoperative function on IVU. Specific IVU features which were statistically highly significant in favor of presence of CV were small, intrarenal and globular flat bottomed pelvis. (Figure) Calyceal dilatation was also more prominent in the CV group. A funnel shaped, extrarenal pelvis was highly significant in favor of intrinsic obstruction. There was associated intrinsic obstruction in addition to CV obstruction in 8 children. All children symptomatically improved after pyeloplasty and did well on long term follow up. The majority showed improvement or stabilization of function on EC scan. With the advent of antenatal ultrasonography, most children with UPJO are detected early. Children with CV tend to present later. This is often detected during surgery. Color Doppler is useful but is operator dependant and not performed routinely. In this study, IVU showed the presence of obstruction and loss of function unlike color Doppler, but also revealed specific diagnostic features not previously reported in literature. This can help in accurate preoperative prediction and avoid endopyelotomy, or a dorsal lumbotomy/retroperitoneal approach. Renal function in CVs is expected to be good as the obstruction is thought to be intermittent. However, we noted delayed contrast uptake on IVU in 60.6% and differential renal function on EC scan below 40% in 17 patients (56.6%). These indicate the effect of the obstruction on the renal parenchyma and the importance of early detection. Higher association with other anomalies and higher incidence in females has also not been emphasized in the literature so far. We noted associated intrinsic obstruction in 24.24% patients which is highly significant. This category of patients is likely to be missed and inappropriately treated if a "vascular hitch procedure" is performed. None of our patients had postoperative complications. Characteristic features were seen on IVU helping in preoperative diagnosis which can be extrapolated to magnetic resonance urography. There is a higher association of CV in age above 2 years, females, associated congenital anomalies, delayed uptake on IVU and differential renal function below 40% compared to intrinsic obstruction. Associated intrinsic obstruction in 24% with no postoperative complications indicates the superiority of dismembered pyeloplasty over vasculopexy procedures.

Contributions of the Retroperitoneoscopy to the Diagnose of the Ureteropelvic Junction Obstruction in Children: New Surgical Alternatives to Conventional Pyeloplasty

PURPOSE To assess:The correlation between pre and post-retroperitoneoscopy diagnose of the ureteropelvic junction obstruction (UPJO) causes. The impact of Retroperitoneoscopy on the surgical technique used for the resolution of the extrinsic UPJO. MATERIAL AND METHODS Between 2004 and 2006 we have treated 14 patients, with congenital hydronephrosis due to UPJO, by retroperitoneoscopic approach. The mean age of surgery was 22 months (range between 3 months and 12 years). In all patients preoperative study included: ultrasound (US), cystography, diuretic renography and renal scintigraphy; and uro-angio-Magnetic Resonance in 10. Preoperative diagnose was: intrinsic UPJO in 10 patients and extrinsic UPJO due to crossing polar vessels in 4. The mean postoperative follow-up has been 16 months (range between 8 and 20 months). The postoperative outcome has been evaluated by US, renography and renal scintigraphy. RESULTS After -retroperitoneoscopy the diagnose became: intrinsic UPJO in 6, and extrinsic UPJO in 8, due to posterior polar vessel in 2, peri-UPJ fibrosis in 4, and anterior polar vessel in 2. UPJO is due to extrinsic causes in 57% of the patients. These findings resulted in the variation of the surgical technique in 6 patients (42.5%). We performed video-assisted ureteropyeloplasty in 6, pyelopyeloplasty in 2, ureterolysis in 4, and pelvic transposition and pexia in 2. There were no intra - or postoperative complications. The average length of stay was 1,6 days. The postoperative result was improvement of the obstruction in 100%, without differences between those who underwent some kind of plastia from those who did not. CONCLUSIONS Retroperitoneoscopy is an effective method for diagnose and minimally invasive treatment of the ureteropelvic junction obstruction. Retroperitoneoscopy raises new surgical alternatives to ureteropyeloplasty. Surgical technique should be based on Retroperitoneoscopical findings.

Minimally Invasive Treatment of Ureteropelvic Junction Obstruction: Long-Term Experience With an Algorithm for Laser Endopyelotomy and Laparoscopic Retroperitoneal Pyeloplasty

First line treatment of ureteropelvic junction obstruction is still open dismembered pyeloplasty. The development of videoendoscopic techniques like endopyelotomy and laparoscopy offers less invasive alternatives. The long-term outcome of an algorithm selectively using these techniques is presented. From February 1995 to March 2006, 256 patients with ureteropelvic junction obstruction were treated with 113 laser endopyelotomies and 143 laparoscopic retroperitoneal pyeloplasties. According to changing selection criteria, an early group (92 in 1995 to 1999) treated with laser endopyelotomy for extrinsic as well as intrinsic stenoses, and a late group (164 in 2000 to 2006) treated with laser endopyelotomy for intrinsic stenosis, were evaluated. In the late group extrinsic ureteropelvic junction obstruction was treated with nondismembered pyeloplasty in cases of anteriorly and by dismembered pyeloplasty in cases of posteriorly crossing vessels or a redundant renal pelvis. Operating time of laser endopyelotomy averaged 34 (range 10 to 90) minutes with a complication rate of 5.3% and a success rate of 72.6% (intrinsic 85.7% vs extrinsic 51.4%). Operating time of laparoscopic retroperitoneal pyeloplasty averaged 124 (range 37 to 368) minutes with a 6.3% complication rate and an overall success rate of 94.4% (intrinsic 100% vs extrinsic 93.8%). In the late group the LAP success rate was 98.3% with no significant differences related to the cause of ureteropelvic junction obstruction (intrinsic 100% vs extrinsic 98.1%) or the type of pyeloplasty (YV plasty 97.0% vs Anderson-Hynes 97.7%). Laparoscopic retroperitoneal pyeloplasty yields an efficacy similar to that of open surgery. The inferior success of laser endopyelotomy even in optimally selected cases and the increasing expertise with endoscopic suturing may favor laparoscopic pyeloplasty with or without robotic assistance in the future.

Minimally invasive therapy of obstruction of the kidney pelvis

We report on 109 patients with ureteropelvic junction obstruction (UPJO) treated according to the following algorithm: intrinsic stenoses were treated by laser endopyelotomy (LEP). We used retroperitoneoscopy with ureterolysis to manage significant extrinsic UPJO due to a crossing vessel and either non-dismembered pyeloplasty in cases of an anterior vessel or dismembered pyeloplasty in cases of a posterior crossing vessel. Children were mostly treated by open dismembered pyeloplasty. Analysis of the factors that influence the postoperative results in the group of 64 patients treated by LEP showed significance for the presence of extrinsic causes of UPJO and the underlying grade of hydronephrosis. Based on our own results and the review of the literature, minimally invasive approaches for the management of UPJO have been proven safe and effective with results comparable to open surgery.

MISSED ANTERIOR CROSSING VESSELS DURING OPEN RETROPERITONEAL PYELOPLASTY: LAPAROSCOPIC TRANSPERITONEAL DISCOVERY AND REPAIR

Extrinsic ureteropelvic junction obstruction due to anterior crossing segmental renal vessels is present in more than 50% of patients in adulthood. In this situation the ureter must usually be dismembered and transposed anterior to the crossing vascular structures, where it is anastomosed to the renal pelvis. Via the open retroperitoneal approach there may be a limited view of the anterior surface of the ureteropelvic junction and, hence, anterior crossing vessels may possibly be missed. We describe 2 patients with ureteropelvic junction obstruction in whom anterior vessels were missed during open retroperitoneal repair. Laparoscopic transperitoneal secondary pyeloplasty with posterior displacement of the crossing renal vessel was performed in each case. Two patients presented with symptomatic congenital ureteropelvic junction obstruction after failed endopyelotomy in 1 and failed open retroperitoneal procedures in both. Preoperatively spiral computerized tomography angiography with a ureteropelvic junction protocol revealed crossing vessels in the 2 cases. This finding was confirmed at transperitoneal laparoscopic pyeloplasty. The ureter and renal pelvis were transposed anterior to the crossing vessels and 2 rows of running sutures were placed to complete the anastomosis. The 2 laparoscopic procedures were completed successfully. The anterior crossing vessels were preserved in each case. Currently the patients are asymptomatic and furosemide washout renal scan was normal. Spiral CT angiography reliably delineates the renal vascular anatomy in patients with ureteropelvic junction obstruction. This study may be valuable before planned open retroperitoneal ureteropelvic junction obstruction repair. Laparoscopic pyeloplasty may successfully manage anterior crossing vessels associated with secondary ureteropelvic junction obstruction.

Extrinsic ureteropelvic junction obstruction from a crossing renal vessel: demography and imaging.

The increase in the use of prenatal ultrasound has revolutionized the detection of hydronephrosis and has had an unanticipated consequence. To describe the new demographics of symptomatic ureteropelvic junction (UPJ) obstruction and the characteristic imaging findings, when the obstruction is extrinsic, from a crossing renal vessel. From a uroradiology database (1994 through 1999) we identified children with surgically corrected UPJ obstruction from intrinsic and extrinsic causes. One hundred children had symptomatic UPJ obstruction treated by surgery. In 51 (49 %), obstruction was due to a crossing vessel. One hundred and one had UPJ obstruction detected by prenatal sonography. Only 11 (11%) were due to a vessel. Two clinical and imaging findings were strongly suggestive of obstruction from a vessel: (1) in 5 of the 100 children the symptoms (pain, nausea, and vomiting) were intermittent. Only when symptoms were present were there hydronephrosis and obstruction; (2) in 51 of the 100 children a short segment of ureter, just below the UPJ, was filled with contrast or urine (on renal sonography, intravenous urography, or retrograde/antegrade ureterography). Extrinsic UPJ obstruction caused by a vessel is an uncommon cause of obstruction when all patients are considered. However, in symptomatic older patients whose hydronephrosis was not first identified on prenatal sonography, a vessel was the cause of obstruction in one half.

Pyelopexy

A new surgical technique to correct extrinsic ureteropelvic junction obstruction is described. Two cases with follow-up are presented. The results are excellent.