Cost-effectiveness of agents used for evaluation of ureteral patency during intraoperative cystoscopy in gynecologic and urogynecologic surgery.

BACKGROUND: Intraoperative evaluation of ureteral patency is often performed in gynecologic and urogynecologic surgery. Many agents are used to help assess the patency, each with its own associated cost, ease of use, and adverse reactions. Some agents, such as dextrose, are used as an instillation fluid to create a viscosity difference and aid the visualization of a ureteral jet. Others, such as oral phenazopyridine or the intravenous use of sodium fluorescein and indigo carmine, cause a color change of the urine to directly aid the visualization of ureteral jets. Recently, numerous studies have examined the efficacy and surgeon satisfaction of these agents. The studies have also emphasized certain options as associated with a lower cost. However, there have not been any cost studies comparing these agents. OBJECTIVE: To compare the cost-effectiveness of the following 4 agents that are commonly used in assessing ureteral patency intraoperatively: oral phenazopyridine, dextrose instillation, intravenous sodium fluorescein, and intravenous indigo carmine. STUDY DESIGN: We constructed a decision-analytic model to compare cystoscopy using oral phenazopyridine, dextrose instillation, intravenous sodium fluorescein, and intravenous indigo carmine. Failure to see efflux resulted in work-ups for ureteral obstruction. The probabilities were obtained from published studies, and the probability of successfully seeing efflux ranged from 0.92 with oral phenazopyridine to 0.99 with intravenous indigo carmine. The costs of the agents, adverse effects, and ureteral obstruction work-ups were obtained from the University of North Carolina at Chapel Hill Department of Pharmacy, the Healthcare Cost and Utilization Project 2016 database and the FAIR Health Consumer database. The cost of a ureteral obstruction work-up used in our model ranged from $9755 for intraoperative evaluation with retrograde pyelograms and stents to $29,034 for hospitalization. Our primary outcome was the incremental cost-effectiveness ratio per unnecessary work-up for ureteral obstruction avoided. Sensitivity analyses were performed to identify the key uncertainties. RESULTS: Oral phenazopyridine, followed by an intravenous agent if needed, had a mean cost of $110 per patient. Dextrose averaged $151 more per patient, with only a slight improvement in avoiding unnecessary ureteral obstruction work-ups and a higher cost associated with adverse reactions (incremental cost-effectiveness ratio, $62,000). Intravenous agents cost approximately $1000 more per patient and were less effective at preventing unnecessary work-ups. Sensitivity analyses did not identify any thresholds that would significantly change the outcomes. CONCLUSION: Our model suggests that oral phenazopyridine and dextrose instillation are the least expensive and the most effective agents to aid in the visualization of ureteral patency during intraoperative cystoscopy, although dextrose is associated with higher costs owing to a higher rate of adverse reactions (primarily urinary tract infections). Intravenous sodium fluorescein and indigo carmine are historically popular first-choice agents. However, they were found to be more expensive and less effective as primary agents in our model and should likely be reserved for use as secondary agents in the event that the visualization of ureteral jets is unclear with the initial use of phenazopyridine or dextrose.

Incidence, management, and sequelae of ureteric obstruction in women with cervical cancer.

PURPOSE: Hydronephrosis due to ureteric obstruction (UO) is stage-defining at cervical cancer presentation but may occur after primary staging. We aimed to determine the incidence and review the presentation and management of UO in women with cervical cancer attending our center. Particular attention was paid to the evolving role of interventional radiology (IR) in management. METHODS: Women with a new diagnosis of cervical cancer between January 2012 and December 2016 formed the cohort that was retrospectively reviewed from the oncology database and patient records. RESULTS: There were 310 women diagnosed with cervical cancer; 240 were stages I/II and 70 were stages III/IV. Primary treatments were chemoradiotherapy (n = 168; 54.2%), surgery (n = 121; 39.0%), and palliative care alone (n = 21; 6.8%). UO occurred in 74 (23.9%); present at primary staging in 53 (71.6%) and arising after staging in 21 (28.4%). Primary interventions for hydronephrosis were IR (n = 50; 67.6%), cystoscopic stenting (n = 19; 25.7%), bowel urinary conduit construction (n = 2; 2.7%), and none (n = 3; 4.1%). For those who attended IR, the mean number of IR procedures was 2.2, range 1-7. Maximum serum creatinine was 303 µmol/L for women with UO at primary staging compared with 252 µmol/L for UO after staging (P = 0.267). Thirty-eight women experienced substantial morbidity related to UO. Stage-adjusted mortality risk was 2.3 times higher for UO cases compared with those without UO. CONCLUSIONS: UO is associated with substantial morbidity and survival disadvantage in cervical cancer and may present after primary cancer staging. We recommend renal biochemistry during routine follow-up. A majority of cervical cancer-associated UO cases are managed with IR in our center.

The role of urinary KIM-1, NGAL, CA19-9 and ß2-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 ß2-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 ß2-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.

Postoperative vesicoureteral reflux after high-pressure balloon dilation of the ureterovesical junction in primary obstructive megaureter. Incidence, management and predisposing factors.

OBJECTIVE: To describe the incidence, predisposing factors and management of postoperative vesicoureteral reflux (VUR) after high-pressure balloon dilation to treat primary obstructive megaureter (POM). MATERIALS AND METHODS: We have reviewed patients that underwent endoscopic treatment for POM from May 2008 to November 2013. All patients were evaluated with renal ultrasound, voiding cystourethrography and diuretic renogram. Endoscopic treatment was done with high-pressure balloon dilation of the ureterovesical junction under general anesthesia; a double-J stenting was done in all patients. Follow-up was performed with ultrasonography, voiding cystourethrography and a diuretic renogram in all patients. RESULTS: Fifteen boys and five girls with a mean age of 14.18 months (3-103) were reviewed. A total of 22 ureters underwent HPBD to treat POM. Ureterohydronephrosis improves in 19 ureters. After endoscopic treatment, six ureters developed VUR. Four ureters were managed surgically, and in the other two, VUR disappeared in a second cystogram. The presence of parameatal diverticulum in the preoperative cystography and those patients with bilateral POM are factors related to postoperative VUR (p < 0.05). Urinary tract infection after HPBD was observed in four patients, but only one of them was affected with VUR.

Recurrent symptoms following pyeloplasty with a normal endoscopic evaluation: assessment and outcomes of a challenging patient cohort.

OBJECTIVE: To aid in counseling and managing a challenging patient cohort, we review our experience using a structured endoscopic approach to assess individuals with recurrent symptoms but a normal anatomic evaluation after pyeloplasty. METHODS: From 2008 to 2012, all patients presenting with recurrent symptoms after pyeloplasty for ureteropelvic junction (UPJ) obstruction were retrospectively evaluated. After baseline renal scanning, all underwent retrograde ureteropyelography, flexible ureteroscopy, UPJ balloon calibration, and provocative ureteral stenting. Patients without clear anatomic obstruction were assessed 2 weeks postoperatively at the time of stent removal and reassessed serially as outpatients before considering further operative management. RESULTS: Nineteen patients had undergone an average of 1.4 UPJ procedures: pyeloplasty in all 19, retrograde endopyelotomy in 6, and balloon dilation in 1. Mean age was 35.2 years, time from original management to symptom recurrence was 80 months, Lasix T1/2 was 16.6 min, and differential renal function of the affected kidney was 43%. Mean follow-up after endoscopic assessment was 16.2 months. Thirteen patients (68%) achieved long-term pain-free status after endoscopic evaluation alone, and 2 (11%) were rendered symptom free after repeat robotic pyeloplasty. Of the 4 remaining patients (21%) with persistent pain after a negative endoscopic assessment, all were referred to a pain specialist. Two patients (11%) ultimately required laparoscopic nephrectomy for definitive symptom control. CONCLUSION: Our findings support evaluation with retrograde pyelography, ureteroscopy, and balloon calibration for patients with recurrent symptoms before embarking on revision pyeloplasty. Surprisingly, two-thirds of our patients achieved pain-free status with an endoscopic approach alone.

Noninvasive assessment of acute ureteral obstruction with diffusion-weighted MR imaging: a prospective study.

PURPOSE: To prospectively assess the potential of noninvasive diffusion-weighted magnetic resonance (MR) imaging to depict changes in microperfusion and diffusion in patients with acute unilateral ureteral obstruction. MATERIALS AND METHODS: The local ethics committee approved the study protocol. Informed consent was obtained. Diffusion-weighted MR imaging was performed in 21 patients (two women, 19 men; mean age, 43 years +/- 10 [standard deviation]) with acute unilateral ureteral obstruction due to a calculus diagnosed at unenhanced computed tomography. A control group (one woman, 15 men; mean age, 44 years +/- 12) underwent the same MR protocol. Standard processing yielded an apparent diffusion coefficient (ADC) ADCT; the separation of microperfusion and diffusion contributions yielded the perfusion fraction FP and the pure diffusion coefficient ADCD. ADCT, ADCD, and FP were compared between obstructed and contralateral unobstructed kidneys and with control values. For statistical analysis, nonparametric rank tests were used. A P value of less than .05 was considered significant. RESULTS: No significant differences were observed between the ADCT of the medulla or cortex of the obstructed and unobstructed kidneys. Compared with control kidneys, only medullary ADCT was slightly increased in the obstructed kidney (P < .04). However, the ADCD in the medulla of the obstructed and unobstructed kidneys was significantly higher than that in control subjects (201 x 10(-5) mm2/sec +/- 16 and 199 x 10(-5) mm2/sec +/- 20 vs 189 x 10(-5) mm2/sec +/- 12; P < .008 and P < .03, respectively). FP of the cortex of the obstructed kidney was significantly lower than that in the unobstructed kidney (20.2% +/- 4.8 vs 24.0% +/- 5.8; P < .002); FP of the medulla was slightly lower in the obstructed kidney than in the unobstructed kidney (18.3% +/- 5.9 vs 20.7% +/- 6.4; P = .05). CONCLUSION: Diffusion-weighted MR imaging allows noninvasive detection of changes in renal perfusion and diffusion during acute unilateral ureteral obstruction, as exemplified in patients with a ureteral calculus.

The value of newborn urinary proteome analysis in the evaluation and management of ureteropelvic junction obstruction: a cost-effectiveness study.

PURPOSE: The cornerstone of management in newborns with ureteropelvic junction obstruction (UPJO) is serial imaging over time. Surgery is undertaken for disease progression. A marker of disease progression would select out those likely to progress for early surgery and diminish the intensity of imaging and follow-up in the remainder. Recently, urinary proteome analysis in the newborn has been reported to fulfill this aim. The objective of this study is to quantitatively evaluate the effect of this matrix of protein biomarkers on the overall cost-effectiveness (C-E) of UPJO evaluation and management. METHODS: A Markov process decision tree model (Tree Age Pro software, Boston, MA) is created to compare the current strategy (watchful waiting) to one incorporating a urine proteome analysis at birth as a marker of disease progression. The analysis includes the costs of surgery, imaging and office visits based on hospital charge data. We analyze a total of 53 variables. RESULTS: The incorporation of this marker of progression results on the average, in an incremental C-E gain of 8,000 US dollars per quality adjusted life year (QALY) per patient compared to the current strategy of watchful waiting. The results are not sensitive to variation of any of the probabilities including costs and quality of life parameters used for the base-case analysis. CONCLUSIONS: The incorporation of urinary proteome analysis in the initial evaluation of UPJO significantly reduces costs and increases the QALYs in this patient population. The test increases the odds of detecting UPJO progression from 1:3 to 1:1, while improving the overall C-E. These findings justify continued research in this area which in addition may have important applications in evaluating treatment outcomes.

Outcomes and cost analysis of pyeloplasty for antenatally diagnosed ureteropelvic junction obstruction using Markov models.

OBJECTIVES: The optimal timing of pyeloplasty for children diagnosed with ureteropelvic junction obstruction (UPJO) after workup for antenatal hydronephrosis is disputed. We sought to examine the potential costs and clinical outcomes of treatment protocols featuring different indications for pediatric pyeloplasty using Markov models. METHODS: Cost and outcomes analysis using Markov modeling was performed for three treatment algorithms: medical management, immediate pyeloplasty (during the first year of life), and pyeloplasty after no improvement on imaging. The costs were determined from the perspective of the medical institution. The variables tracked during Markov model simulation included age at resolution of UPJO, the proportion of patients with worsened hydronephrosis, the number of pyeloplasties, the number of pyelonephritis episodes, and costs. Sensitivity analyses were performed to determine which elements affected the model and to determine threshold values. RESULTS: Immediate pyeloplasty and pyeloplasty after no improvement on imaging resulted in rapid resolution of UPJO (mean age at resolution younger than 2 years) with lower rates of worsened hydronephrosis and pyelonephritis compared with observation alone. For the surgical protocols, the costs per resolved case of UPJO were greater than those for medical management alone at the probability values tested in the Markov models. The sensitivity analysis of all variables over realistic ranges demonstrated that the costs of surgery, annual antibiotics and imaging, and the rate of pyelonephritis were critical in determining the costs. CONCLUSIONS: Pediatric urologists should include practice-specific features such as the costs of surgery, annual antibiotics and imaging, and pyelonephritis rates when considering efficacious, yet less costly, treatment protocols for UPJO.

MRI in patients with chronic obstructive uropathy and compromised renal function: a sole method for morphological and functional assessment.

The aim of this study was to assess the role of MRI as a single modality for anatomical and functional evaluation of obstructed kidneys in patients with compromised renal function. The study included 96 adults with unilateral or bilateral chronic obstructive hydronephrosis and compromised renal function (serum creatinine >or=1.8 mg dl(-1)). Patients were subjected to gadolinium-enhanced MRI (Gd-MRI), which determined the anatomy of both renoureteral units, as well as their function, through selective calculation of the glomerular filtration rate (GFR) of each kidney. All patients underwent a technetium-99m diethylenetriamine-pentaacetic acid renal scan. Moreover, a correlation was made between the GFR determined by Gd-MRI and the isotope GFR. The study comprised 59 males and 37 females. A comprehensive MRI study detected the cause of obstruction in all kidneys with non-calcular obstruction (sensitivity of 100%) and in 21 kidneys with calcular obstruction (sensitivity of 70%). The overall sensitivity of MRI combined with plain X-ray of the abdomen and ultrasound in the detection of various causes of obstruction was 97%. A comparison between the isotope GFR of the obstructed kidneys and the corresponding magnetic resonance urography (MRU) GFR showed perfect correlation. In conclusion, combined static and dynamic MRU is a promising technique that allows anatomical and functional evaluation of obstructed kidneys in patients with impaired renal function but, owing to the possible risk of nephrogenic systemic fibrosis in patients with a GFR <30 ml min(-1), the lowest possible dose of the most stable Gd-macrocyclic chelates should be used if a functional MRI study is required.

Renal oxygenation changes during acute unilateral ureteral obstruction: assessment with blood oxygen level-dependent mr imaging--initial experience.

PURPOSE: To prospectively determine if changes in intrarenal oxygenation during acute unilateral ureteral obstruction can be depicted with blood oxygen level-dependent (BOLD) magnetic resonance (MR) imaging. MATERIALS AND METHODS: The study was approved by the local ethics committee, and written informed consent was obtained from all patients. BOLD MR imaging was performed in 10 male patients (mean age, 45 years +/- 17 [standard deviation]; range, 20-73 years) with a distal unilateral ureteral calculus and in 10 healthy age-matched male volunteers to estimate R2*, which is inversely related to tissue Po(2). R2* values were determined in the cortex and medulla of the obstructed and the contralateral nonobstructed kidneys. To reduce external effects on R2*, the R2* ratio between the medulla and cortex was also analyzed. Statistical analysis was performed with nonparametric rank tests. P < .05 was considered to indicate a significant difference. RESULTS: All patients had significantly lower medullary and cortical R2* values in the obstructed kidney (median R2* in medulla, 10.9 sec(-1) [range, 9.1-14.3 sec(-1)]; median R2* in cortex, 10.4 sec(-1) [range, 9.7-11.3 sec(-1)]) than in the nonobstructed kidney (median R2* in medulla, 17.2 sec(-1) [range, 14.6-23.2 sec(-1)], P = .005; median R2* in cortex, 11.7 sec(-1) [range, 11.0-14.0 sec(-1)], P = .005); values in the obstructed kidneys were also significantly lower than values in the kidneys of healthy control subjects (median R2* in medulla, 16.1 sec(-1) [range, 13.9-18.1 sec(-1)], P < .001; median R2* in cortex, 11.6 sec(-1) [range, 10.5-12.9 sec(-1)], P < .001). R2* ratios in the obstructed kidneys (median, 1.06; range, 0.85-1.27) were significantly lower than those in the nonobstructed kidneys (median, 1.49; range, 1.26-1.71; P = .005) and those in the kidneys of healthy control subjects (median, 1.38; range, 1.23-1.47; P < .001). In contrast, R2* ratios in the nonobstructed kidneys of patients were significantly higher than those in kidneys of healthy control subjects (P = .01). CONCLUSION: Increased oxygen content in the renal cortex and medulla occurs with acute unilateral ureteral obstruction, suggesting reduced function of the affected kidney.

Assessment of renal graft obstruction due to ureteral inguinal hernia: US detection and 3D MR confirmation.

In most cases, renal graft obstruction is caused by ureteral stenosis due to ischemia or technical error. Exceptional cases have been published where the obstacle was the result of incarceration of the ureter in an inguinal hernia. We report a case of this type, which prompt assessment was possible due to ultrasound and magnetic resonance imaging with 3D reconstruction.

[Usefulness of renal resistive index in the diagnosis and evolution of the obstructive uropathy. Experimental study]. / Utilidad del indice de resistencia renal en la valoración y evolución de la uropatía obstructiva. Estudio experimental.

OBJECTIVE: The study was focused on determining the effectiveness and reliability of using the renal resistance index as a method of diagnosing and monitoring the evolution of obstructive uropathy treatment. For this purpose, we conducted an experimental study on a homogenous group of animals that all had the same level of obstruction. MATERIAL AND METHODS: 15 healthy female pigs were used. The experiment was divided into three phases: phase I consisted of a study prior to unilateral pyeloureteral junction obstruction, performing retrograde ureteropyelography, renal B-mode ultrasound and duplex-Doppler (of both kidneys) at a level of the arcuate arteries. Then, the obstruction was performed on the animals. Phase II commenced by diagnosing the lesion, 6 weeks after the previous phase, by means of the aforementioned diagnostic methods. Finally, the endourological treatment was completed. Animals were monitored (Phase III) 15 weeks after the endopyelotomy, using the same methods as in the study, by assessing the urinary tract (fluoroscopy) and both kidneys by determining the renal resistance index and ratio. RESULTS: All the animals in the study showed signs of urinary obstruction on radiology and renal ultrasound 6 weeks after ureteral ligature. After treatment and follow-up, all animals showed signs of having recovered from the obstructive uropathy. Values of deltaRI during the 3 phases are detailed below. Fase I deltaIR = 0.01, Fase II deltaIR = 0.11, Fase III deltaIR = 0.02. CONCLUSION: RI determination using duplex-Doppler is effective for distinguishing obstructive dilatation using non-invasive techniques. However, this parameter provides very slight differences and it can also be influenced by too many direct and indirect factors (observational, patient age, anaesthesia, haemodynamic parameters, etc.), to supplant the classic diagnostic methods.

Dynamic contrast-enhanced MR urography in the evaluation of pediatric hydronephrosis: Part 2, anatomic and functional assessment of ureteropelvic junction obstruction [corrected].

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.

[Upper urinary tract: physiology, pathophysiology of obstructions and function assessment]. / Voie excrétrice supérieure: physiologie, physiopathologie des obstructions et explorations fonctionnelles.

The urine is transported from the renal papilla to the bladder through the upper urinary tract which allows this transport to be safe and comfortable, i.e., without any risk or pain for the kidney. This active transport depends on the smooth muscle contractile properties. The upper urinary tract is totally autonomous; this feature allows the preservation of its function after renal transplantation. However, despite its accessory role, the autonomous nervous system can modulate its activity. Upper urinary tract obstruction involves adaptative mechanisms which are different depending on the type (acute, chronic, acquired or congenital) of obstruction. Functional evaluations of the upper urinary tract are aimed at identify the urine transport conditions and the relationship between obstruction and clinical conditions such as hydronephrosis, pain or impaired renal function.

MR pyelography in the assessment of hydroureteronephrosis: single-shot thick-slab RARE versus multislice HASTE sequences.

BACKGROUND: We used magnetic resonance (MR) pyelography to compare the value of thick-slab single-shot rapid acquisition with relaxation enhancement (RARE) sequence with that of multislice half-Fourier acquisition single-shot turbo-spin-echo (HASTE) sequence in evaluating the full spectrum of morphologic features in a group of patients with hydronephrosis. METHODS: MR pyelographic images, with the use of thick-slab RARE and multislice HASTE sequences in 90 patients, were evaluated for image quality, presence of hydronephrosis, and level and cause of obstruction. RESULTS: HASTE sequences provided images of better quality than did RARE sequences (p < 0.001). There was no statistically significant difference in demonstrating the presence of hydronephrosis (p = 0.5) and level of obstruction (p = 0.125). Sensitivity, specificity, and accuracy in diagnosing cause of obstruction were 61.7%, 62.5%, and 62%, respectively, for RARE sequences and 80%, 82.5%, and 81%, respectively, for HASTE sequences, with a statistically significant difference (all p < 0.05). CONCLUSION: Multislice HASTE sequence provides better diagnostic information than does thick-slab RARE sequence, particularly in evaluating the cause of obstruction.

Assessment of stricture formation with the ureteral access sheath.

OBJECTIVES: To analyze the long-term incidence of ureteral stricture formation in a series of patients in whom a new-generation ureteral access sheath was used. A new generation of ureteral access sheaths has been developed to facilitate ureteroscopic procedures. However, some have questioned their safety and whether the device might cause significant ureteral trauma. METHODS: Between September 1999 and July 2001, 150 consecutive ureteroscopic procedures with adjunctive use of an access sheath were performed. A retrospective chart review to April 2002 was done. Of the 150 patients, 130 underwent ureteroscopy for ureteral stones. Patients who underwent endoureterotomy or treatment of transitional cell carcinoma were excluded from this analysis. Sixty-two patients had follow-up greater than 3 months and were included in the analysis. Overall, 71 ureteroscopic procedures were performed, with 9 patients undergoing multiple procedures. Ninety-two percent of the patients had pathologic findings above the iliac vessels. The average patient age was 45.3 years (range 17 to 76), and 70% and 30% of the patients were male and female, respectively. The mean clinical follow-up was 332 days (range 95 to 821), and follow-up imaging was performed within 3 months after ureteroscopy in all patients. RESULTS: The 10/12F access sheath was used in 8 ureteroscopic procedures (11.2%), the 12/14F access sheath in 56 (78.9%), and the 14/16F access sheath in 7 (9.8%). One stricture was identified on follow-up imaging of 71 procedures performed, for an incidence of 1.4%. The patient developed the stricture at the ureteropelvic junction after multiple ureteroscopic procedures to manage recurrent struvite calculi. The access sheath did not appear to be a contributing factor. CONCLUSIONS: The results of our series indicate that the ureteral access sheath is safe and beneficial for routine use to facilitate flexible ureteroscopy. However, awareness of the potential ischemic effects with the use of unnecessarily large sheaths for long periods in patients at risk of ischemic injury should be considered. We advocate the routine use of the device for most flexible ureteroscopic procedures proximal to the iliac vessels.

Assessment of drainage in PUJ dilatation: pelvic excretion efficiency as an index of renal function.

Renal function is important when assessing the response of a dilated renal pelvis to a diuretic stimulus. Yet there is little in the literature to suggest how this should be undertaken. Our aim was to develop a model which we have called pelvic excretion efficiency (PEE). The PEE, which may be used to assess drainage, is a mathematical model of the ratio of the total kidney excretion to the total amount of isotope extracted from the blood by the kidney. Thirty-three children with a prenatal diagnosis of unilateral renal pelvic dilatation (PUJ) were treated conservatively after birth. As a group, they underwent a total of 164 diuretic DTPA renograms up to the age of 72 months. Drainage was assessed as the response to frusemide (defined as the time for the corrected renal curve to fall to 75% of the maximum value in the frusemide part of the study; T75), response to bladder emptying, a change of posture after frusemide (PM), and PEE. The contralateral normal kidney showed a combination of both 'good' T75 and PM drainage in 51% of renograms while the PEE showed drainage in all. The affected kidney with renal pelvic dilatation showed a combination of both 'poor' T75 and PM drainage in 42% of renograms. The PEE was low in 99% of these 'poor drainage' renograms. The PEE, the ratio of the mathematical model of renal uptake to excretion, is readily calculated and may be a more accurate and specific technique to assess drainage on diuretic renography.

MR urography using HASTE imaging in the assessment of ureteric obstruction.

OBJECTIVE: The purpose of this study was to evaluate an MR sequence using half-Fourier acquisition single-shot turbo spin-echo (HASTE) imaging in the assessment of ureteric obstruction. SUBJECTS AND METHODS: We prospectively evaluated 111 kidneys in 56 consecutive patients with HASTE MR urography and compared that imaging technique with excretory urography. The HASTE sequence was used to acquire images in the axial, sagittal, and coronal planes while patients held their breath. Level of obstruction and ureteric diameter were assessed, and the time required to determine the level of obstruction by both techniques was noted. RESULTS: With HASTE MR urography, we correctly diagnosed obstruction in 41 (100%) of 41 kidneys. Of the obstructed kidneys in which the ureter was shown by both excretory urography and MR urography, agreement was high (kappa = .642) between the two imaging techniques regarding the level of obstruction. HASTE MR urography showed perirenal fluid in 20 (87%) of 23 acutely obstructed kidneys. HASTE MR urography showed the site of obstruction on the first 13-sec scan in 33 (80%) of 41 kidneys. CONCLUSION: HASTE MR urography accurately and rapidly shows the level and degree of ureteric obstruction. It can be used to differentiate between acute and chronic obstruction on the basis of its ability to show perirenal fluid.

Fast imaging MR assessment of ureterohydronephrosis during pregnancy.

PURPOSE: to assess the value of the fast imaging sequence called RARE-MR-Urography (RMU) for the diagnosis of pathologic ureterohydronephrosis during pregnancy. MATERIALS AND METHODS: 15 pregnant women with an acute flank pain were examined with RMU. Results were compared with those of ultrasonography (US), X-rays, and the evolution of symptoms. RESULTS: the accuracy of RMU in the detection of urinary tract dilatation and the localization of the level of obstruction was excellent (100%). The determination of the type of obstruction, intrinsic vs. extrinsic, was always exact. RMU alone cannot specify the exact nature of the intrinsic obstruction. Ultrasonography gave less sensitive information in terms of level (60%) and type of obstruction (53%). CONCLUSION: RMU is able to differentiate a physiological from a pathologic ureterohydronephrosis during pregnancy. It could be considered as a procedure of choice for special cases when US failed to establish this differential diagnosis.