Unilateral Ureteropelvic Junction Research Articles

Risk factors for adverse outcomes after pediatric pyeloplasty: A retrospective cohort study.

To identify the risk factors for adverse outcomes after pediatric pyeloplasty. We conducted a retrospective review of all children under the age of 14 years who underwent primary pyeloplasty for unilateral ureteropelvic junction (UPJ) obstruction at a single teaching hospital in Tunisia between January 1, 2013, and December 31, 2022. A total of 103 patients were included. Median age of patients at surgery was 27 months (interquartile range [IQR], 13-44). On ultrasound, median renal pelvic anteroposterior diameter was 3.2 cm (IQR, 2.3-4), and the median renal cortex thickness (RCT) was 2.5 mm (IQR, 2-3.5). Median differential renal function (DRF) on preoperative radionuclide renal scan was 40% (IQR, 30-46). Postoperative adverse outcomes occurred in 28 patients (27.2%). These included 19 cases of urinary tract infections (UTIs), 11 cases of UPJ restenosis, four cases of UPJ leakage, two cases of urinoma, and two cases of diversion-related complications. Multivariate logistic regression analysis revealed two factors significantly and independently related to postoperative negative outcomes: RCT <3 mm and DRF > 50%. Our study demonstrated that preoperative RCT on ultrasound of less than 3 mm and preoperative DRF on radionuclide renal scan of more than 50% were independent risk factors for adverse outcomes following pediatric pyeloplasty. These factors could be of interest in identifying, early on, patients who will develop postoperative negative outcomes, giving them more attention and support, and explaining the prognosis to the patient and family.

Urinary Emmprin, matrix metalloproteinase 9 and tissue inhibitor of metalloproteinase 1 as potential biomarkers in children with ureteropelvic junction narrowing on conservative treatment

Rapid diagnosis and initiation of the treatment on congenital obstructive nephropathy are important for young children to slow down renal injury. The aim of our study was to investigate the role of urinary extracellular matrix metalloproteinase inducer (Emmprin), matrix metalloproteinase 9 (MMP-9) and tissue inhibitor of metalloproteinase 1 (TIMP-1) in the long-term follow-up of children with ureteropelvic junction (UPJ) narrowing on conservative treatment. The study included 40 children with non-obstructed hydronephrosis due to unilateral UPJ narrowing who were treated conservatively and followed up for 24 months. Voided urine samples were collected at diagnosis and at 3, 9, 15 and 24 months of follow-up, respectively. Three enzymes concentrations were measured in urine. During the follow-up, 25 children showed renal function stabilization (non-obstructed group) and 15 children renal function deterioration (obstructed group). In the non-obstructed group, a comparison between urine three enzymes levels at the last follow-up and at baseline showed no significant differences (all P > 0.05). Glomerular filtration rate (GFR) and split renal function (SRF) showed similar trends. In the obstructed group, a comparison between the three enzymes levels at diagnosis and at basal condition showed a significant increase (all P < 0.01). But GFR and SRF showed a marked reduction at diagnosis (all P < 0.001). Receiver operator characteristic (ROC) analyses revealed a better diagnostic profile for uEmmprin, uMMP-9 and uTIMP-1 in identifying children with abnormal SRF (<40%) at 24 months of follow-up [area under the curve (AUC) 0.877, 0.727 and 0.823, respectively]. Urinary Emmprin, MMP-9 and TIMP-1 may be noninvasive potential biomarkers that could be used for long-term follow-up of children with UPJ narrowing on conservative treatment to determine those who might develop obstruction.

Comparison of Surgical Outcomes between Dismembered Pyeloplasty with or without Ureteral Stenting in Children with Ureteropelvic Junction Obstruction

PurposeTo evaluate the impact of temporary internal ureteral stents on the surgical outcomes of dismembered pyeloplasty in children.Materials and MethodsThe medical records of 70 children (76 renal units) who underwent dismembered pyeloplasty for ureteropelvic junction (UPJ) obstruction at at Asan Medical Center between January 2005 and December 2010 were retrospectively reviewed. We classified the renal units into the stented group (22 renal units) and the nonstented group (54 renal units). Fifty-four of 70 patients were male and their mean age was 2.2±3.8 years old. The mean follow-up period was 29.6±16.8 months.ResultsSixty-four children had unilateral UPJ obstruction. The mean stent duration was 31.9 days. As shown by evaluation of radiologic images, there were no significant differences between the stented group and the nonstented group during the follow-up period (p>0.05). The mean preoperative and postoperative anteroposterior pelvic diameters (APPDs) of the nonstented group were 31.3 mm and 15.1 mm, respectively (p<0.001). The preoperative and postoperative grades of hydronephrosis were 3.9 and 2.9, respectively (p=0.037). The mean preoperative and postoperative APPDs of the stented group were 36.4 mm and 15.6 mm, respectively (p<0.001). The preoperative and postoperative grades of hydronephrosis were 4 and 3.1, respectively (p<0.001). Repeat obstruction was shown in 4 subjects as a postoperative complication (5.7%). Two children from each group had recurrent UPJ obstruction, with percentages of 3.7% and 9%, respectively (p=0.575).ConclusionsIn a comparison of nonstented and stented groups during pediatric dismembered pyeloplasty for UPJ obstruction, no significant differences were found in the resolution of hydronephrosis or overall postoperative complications.

Thickness of the renal pelvis smooth muscle indicates the postoperative course of ureteropelvic junction obstruction treatment

ObjetiveTo investigate the relationship between the histopathologic findings and the postoperative course of children surgically treated for ureteropelvic junction (UPJ) obstruction. Material and methodsTwenty-eight patients operated for unilateral UPJ obstruction from 1998 to 2005 with adequate histopathologic specimens and postoperative follow up were retrospectively reviewed. Specimens were stained using elastic van Geisson to differentiate smooth muscle from collagen and elastin. Postoperative follow up included renal ultrasound (U/S) and diuretic renogram studies. ResultsTwelve patients with mean renal pelvis smooth muscle thickness (mRPSMT) of 136.97±34.17 improved on the 6th postoperative month. Nine patients that improved after 9 months postoperatively had mRPSMT=173.61±33.91. The rest 7 patients that improved on the 12th postoperative month had mRPSMT=258.78±96.09. Correlation between renal pelvis smooth muscle and time of postoperative improvement was extremely significant (r=0.7928, p<0.0001). ConclusionThe thickness of the renal pelvis smooth muscle is significantly correlated to the postoperative course of patients with UPJ obstruction and can be used as a prognostic tool for the onset of their improvement.

El grosor del músculo liso de la pelvis renal indica el curso postoperatorio del tratamiento de la obstrucción de la unión ureteropélvica

Objetive To investigate the relationship between the histopathologic findings and the postoperative course of children surgically treated for ureteropelvic junction (UPJ) obstruction. Material and methods Twenty-eight patients operated for unilateral UPJ obstruction from 1998 to 2005 with adequate histopathologic specimens and postoperative follow up were retrospectively reviewed. Specimens were stained using elastic van Geisson to differentiate smooth muscle from collagen and elastin. Postoperative follow up included renal ultrasound (U/S) and diuretic renogram studies. Results Twelve patients with mean renal pelvis smooth muscle thickness (mRPSMT) of 136.97 ± 34.17 improved on the 6 th postoperative month. Nine patients that improved after 9 months postoperatively had mRPSMT=173.61 ± 33.91. The rest 7 patients that improved on the 12 th postoperative month had mRPSMT=258.78 ± 96.09. Correlation between renal pelvis smooth muscle and time of postoperative improvement was extremely significant (r = 0.7928, p < 0.0001). Conclusion The thickness of the renal pelvis smooth muscle is significantly correlated to the postoperative course of patients with UPJ obstruction and can be used as a prognostic tool for the onset of their improvement.

Is Retroperitoneal Approach Feasible for Robotic Dismembered Pyeloplasty: Initial Experience and Long-Term Results

To present our initial series of robotic-assisted retroperitoneal dismembered pyeloplasty in adults patients using the da Vinci Surgical System (Intuitive Surgical, Inc., Sunnyvale, CA). Ten adult patients with unilateral ureteropelvic junction (UPJ) obstruction underwent robotic-assisted retroperitoneoscopic Anderson-Hynes dismembered pyeloplasty between February 2004 and March 2005. UPJ obstruction was primary in six patients and secondary in four patients after failed endopyelotomy. Dismembered pyeloplasty was performed utilizing a retroperitoneal approach (developed by balloon dissection). Three retroperitoneal laparoscopic ports were placed for the robot, and a fourth port was used by the assistant. Robotic-assisted laparoscopic technique was utilized to perform the entire procedure in all cases. All cases (seven right, three left) were successfully completed using the robot without conversion to conventional laparoscopic or open technique. Median surgical time was 175 minutes (95% confidence interval [CI] 128-185), median estimated blood loss was 50 mL (95% CI, 26-62), and the median hospital stay was 48 hours (95% CI, 27-65). No complications occurred. At a mean follow-up of 30 months (range 24-36), clinical symptomatic assessment with a numeric pain scale, health-related quality of life evaluation with the Short Form 36 health survey, and functional assessment with Tc-99m-mercaptoacetyltriglycine, diuretic renography, and intravenous urogram demonstrated a successful outcome in all cases. Robotic-assisted dismembered pyeloplasty can be performed efficiently by the retroperitoneal laparoscopic technique. Our surgical outcomes are comparable to previously published laparoscopic and transperitoneal robotic-assisted dismembered pyeloplasty series in adults with excellent clinical and radiologic success rates.

Pattern of Renal Function Deterioration as a Predictive Factor of Unilateral Ureteropelvic Junction Obstruction Treatment

ObjectivesTo assess the process of renal function deterioration in patients with unilateral ureteropelvic junction (UPJ) obstruction and its impact on their treatment course. Material and methodsThe files of patients treated for unilateral UPJ obstruction at our department from 1996 to 2003 were retrospectively reviewed. All patients were initially treated conservatively and followed up regularly. Criteria for conversion to surgical treatment were increase in anteroposterial renal pelvis diameter, increase in T½ washout pattern, and drop of relative renal function (RRF) below 40% in diuretic renogram. Patients operated on because of multiple urinary infections, pelvic stones, or solitary kidneys were excluded. Patients were divided into group A, which included those whose treatment was converted from conservative to surgical, and group B in which patients were treated conservatively. All patients operated on underwent dismembered pyeloplasty. ResultsSixty-four patients with grade three or four hydronephrosis in postnatal ultrasound examination and an obstructive pattern in diuretic renogram were studied. All group A patients (n=47) reached an RRF below 40%; in 41 (87.2%) deterioration of RRF was detected in at least two sequential follow-up studies. In group B patients (n=17), deterioration was also detected in seven (41.1%) patients in two sequential studies (p<0.0005), although the RRF never dropped below 40%. No differences in gender, side of obstruction, or frequency of follow-up were detected between the two groups. ConclusionsRRF deterioration and its progression for at least two sequential follow-ups could serve as a predictive factor for surgical treatment.

Dismembered Percutaneous Endopyeloplasty: A New Procedure

We recently described a novel technique of percutaneous non-dismembered endopyeloplasty (Fenger type). Herein, we extend this transrenal technique further and report percutaneous dismembered endopyeloplasty (Anderson-Hynes type). In five pigs with unilateral ureteropelvic junction (UPJ) obstruction created 3 to 6 weeks earlier, percutaneous dismembered endopyeloplasty was performed. Percutaneous transrenal access to the UPJ was obtained, and the UPJ was completely dismembered from within the renal pelvis through the solitary percutaneous tract. The dismembered proximal ureter was circumferentially mobilized, and in two animals, the UPJ segment was completely excised and removed. A spatulated end-to-end endopyeloplasty anastomosis (Anderson-Hynes) was created transrenally with 5 to 10 interrupted sutures using a novel nephroscopic suturing device (Sew-Right SR-5; LSI Solutions, Rochester, NY). In two animals, the entire percutaneous procedure was performed with CO2 insufflation instead of fluid irrigation. The technique was developed in three pigs. Subsequently, two pigs were treated and sacrificed at 2 and 5 weeks. All UPJs were dismembered successfully, and a precisely sutured mucosa-to-mucosa anastomosis was created. Intraoperative bleeding was negligible, and the operative time ranged from 3 to 5 hours, with the majority of the time dedicated to transrenal retroperitoneal dissection of the scarred, fibrotic UPJ. Carbon dioxide insufflation was efficacious because it minimized fluid extravasation and tissue edema and additionally enhanced visibility. Postoperative pyelograms revealed an adequately funneled UPJ, with good flow into the distal ureter. The two survival animals had minimal apparent morbidity from the procedure, and retrograde pyelograms at euthanasia revealed a patent anastomosis without extravasation. A 6F catheter easily crossed the reconstructed UPJ at autopsy in all animals. Dismembered percutaneous Anderson-Hynes endopyeloplasty is technically feasible and is promising. Further technical experience and additional functional outcome analysis in the survival model are necessary. With the technique described herein, we introduce the concept of percutaneous intrarenal reconstructive surgery (PIRS), wherein advanced intrarenal and retroperitoneal dissection with reconstruction can be performed endourologically, further broadening the horizons of conventional percutaneous techniques.

Ureteropelvic junction obstruction causes histologic alterations in contralateral kidney

Background/Purpose: Ureteropelvic junction (UPJ) obstruction causes histologic alterations both in ipsilateral and contralateral kidney. Because these alterations directly affect the fate of renal damage, definition of these alterations is of utmost importance from the clinical point of view. Thus, an experimental study is designed to determine the alterations of renal histology in response to partial and complete UPJ obstruction. Methods: Fifteen adult female New Zealand rabbits were assigned randomly into 3 groups (each containing 5 rabbits) according to the degree of unilateral UPJ obstruction as group I, sham operation was performed and served as the control group; group II, partial UPJ obstruction was made; group III, complete UPJ obstruction was made. The animals in group I and II were killed after 3 weeks, and animals in group III were killed after 2 weeks. Tissue samples were prepared and processed according to routine light microscopic tissue processing. Results: UPJ obstruction led to glomerulosclerosis, dilatation of proximal and distal tubules of loops of Henle, and dilatation of collecting tubes consistent with necrotic and apoptotic changes in ipsilateral kidneys. Severity of these degenerative changes depended on degree of obstruction. UPJ obstruction also led to histologic alterations on the contralateral kidneys such as glomerular edema, congested blood vessels, dilated tubuli, and necrotic and apoptotic changes in epithelia, which were more prominent in group III than group II. Conclusions: It is well known that compensating changes including increased blood flow and parenchymal hypertrophy occurs in contralateral kidney as a response to unilateral UPJ obstruction. However histologic findings of this study confirmed progression of parenchymal damage and presence of apoptosis in contralateral kidney for the first time.

Role of endogenous nitric oxide in unilateral ureteropelvic junction obstruction in children

Obstructive nephropathy leads to tubulointerstitial fibrosis and loss of renal function. Nitric oxide has been shown to have antifibrotic properties. We examined nitric oxide synthase (NOS) activity and expression in kidneys from children who underwent surgery release of unilateral ureteropelvic junction (UPJ) obstruction in relation to clinical and histologic parameters. NOS activity and the expression of NOS isoforms measured at the mRNA level by reverse transcription-polymerase chain reaction (RT-PCR) assay were determined in tissue obtained by biopsy from obstructed kidneys of 18 children at the time of pyeloplasty. Tissue from kidneys removed because of various malignancies were issued as control. A significant increase in calcium/calmodulin-independent NOS activity (iNOS) and iNOS mRNA expression was found in the medulla of obstructed kidneys. Calcium/calmodulin-dependent NOS activity (cNOS) and endothelial (eNOS) mRNA, by contrast, were increased in the cortex from obstructed kidneys. A role of tumor necrosis factor-alpha (TNF-alpha) on enhanced iNOS was suggested by the finding of increased urine levels in obstructed pelvis. Increased interstitium macrophage number, by immunolabeling of CD68, was related to the delay in obstruction release and to decreased glomerular filtration rate (GFR) at surgery. A positive linear relationship was found between cNOS activity in cortex and creatinine clearance. The degree of interstitial fibrosis correlated negatively with cNOS activity in cortex. In kidneys from children with UPJ obstruction an increased activity and expression of iNOS in medulla and cNOS-dependent eNOS in cortex were demonstrated. A role of cNOS in modulating GFR and interstitial fibrosis can be suggested. Prolonged UPJ obstruction would lead to a worsened prognosis on renal injury.

Predictive value of renal histological changes for postoperative renal function improvement in children with congenital ureteropelvic junction stenosis.

The aim of this study was to evaluate the relationship between renal function, as measured by diuretic radionuclide renography, and the outcome of pyeloplasty. A study was designed to evaluate renal parenchymal biopsy specimens derived from children undergoing corrective surgery for ureteropelvic junction (UPJ) stenosis, and compare these to preoperative and postoperative renal function status. Thirty-five children with congenital unilateral UPJ stenosis were evaluated. In addition to all conventional diagnostic procedures for UPJ stenosis, differential renal functional (DRF) activity was assessed in each of these children by obtaining 99mTc diethylenetriaminepentaacetic acid renogram curves. All children underwent dismembered pyeloplasty, and follow-up renogram evaluation was conducted 6 and 12 months after surgical repair. Biopsy specimens from renal cortical regions obtained during the surgical correction of UPJ stenosis were evaluated, and changes in renal histology were graded from I to V according to their severity. Spearman's correlation test was used to compare the histological evaluation results and the basal, 6- and 12-month follow-up DRF findings. A Wilcoxon paired test was used to evaluate statistical differences between values. The findings showed a positive correlation between the severity of histological changes and DRF activity. All kidneys (22) with a DRF activity value of < 40% preoperatively demonstrated at least grade III changes when biopsy specimens were examined. Of children with a DRF activity value > 40% (13), only three showed severe histological changes. Histological grades were correlated between basal (r = -0.4; P = 0.019), 6-month (r = 0.54; P = 0.002) and 12-month (r = 0.54; P = 0.02) findings. In the Wilcoxon paired test, there was a statistically significant difference between basal and 6-month values (P < 0.05), and also between basal and 12-month values (P < 0.01). There was no statistically significant difference between 6- and 12-month values (P > 0.20). Comparative evaluation of postoperative renal function with DRF activity and renal parenchymal histological alterations revealed a close correlation in terms of renal function improvement potential following reconstructive surgery in children with UPJ stenosis.