Prediction of outcome of extracorporeal shock wave lithotripsy in the management of ureteric calculi.

The present study was designed to evaluate the clinical outcome of using extracorporeal shock wave lithotripsy (ESWL) in the treatment of ureteric calculi and to establish a predictive model for the stone-free rate in patients receiving the treatment. A total of 831 patients with ureteric calculi were accepted in this study. Several parameters, including stone site, stone number, stone size, history of urolithiasis, renal colic, hydronephrosis, and double-J ureteric stent, were analyzed using univariate and multivariate analyses. A prediction model was established based on the logistic regression analysis of the significant factors, and the goodness-of-fit of the model was evaluated by employing the Hosmer-Lemeshow test. At a 3-month follow-up after ESWL treatment, the overall stone-free rate was 96.8% (804/831) with no serious complications being found, while the treatment failed in 3.2% (27/831) of the patients. Five factors, including stone number, stone size, history of urolithiasis, renal colic, and double-J ureteric stent contributed significantly to the clinical outcome of the ESWL treatment. The prediction model had a sensitivity and overall accuracy of 99.8 and 96.9%, respectively. The results show that ESWL remains an effective method for treating ureteric calculi. The prediction model established in this study could be used as a method for estimating prognosis in patients following ESWL treatment.

Renal ultrasonography in the evaluation of acute kidney injury: developing a risk stratification framework.

BACKGROUND: In adult inpatients with acute kidney injury (AKI), clinicians routinely order a renal ultrasonography (RUS) study. It is unclear how often this test provides clinically useful information. METHODS: Cross-sectional study, including derivation and validation samples, of 997 US adults admitted to Yale-New Haven Hospital from January 2005 to May 2009, who were diagnosed as having AKI and who underwent RUS to evaluate elevated creatinine level. Pregnant women, renal transplant recipients, and patients with recently diagnosed hydronephrosis (HN) were excluded. Demographic and clinical characteristics were abstracted from the medical records. A multivariable logistic regression model was developed to create risk strata for HN and HN requiring an intervention (HNRI); a separate sample was used for validation. The frequency of incidental findings on RUS was assessed for each stratum. RESULTS: In a derivation sample of 200 patients, 7 factors were found to be associated with HN: history of HN; recurrent urinary tract infections; diagnosis consistent with obstruction; nonblack race; and absence of the following: exposure to nephrotoxic medications, congestive heart failure, or prerenal AKI. Among 797 patients in the validation sample (mean age, 65.6 years), 10.6% had HN and 3.3% had HNRI. Of 223 patients in the low-risk group, 7 (3.1%) had HN and 1 (0.4%) had HNRI (223 patients needed to be screened to find 1 case of HNRI). In this group, there were 0 incidental findings on RUS unknown to the clinical team. In the higher-risk group, 15.7% had HN and 4.7% had HNRI. CONCLUSION: In adult inpatients with AKI, specific factors can identify patients unlikely to have HN or HNRI on RUS.

Direct primary or secondary percutaneous ureteral stenting: what is the most compliant option in patients with malignant ureteral obstructions?

The objective of this study was to analyze three ureteral stenting techniques in patients with malignant ureteral obstructions, considering the indications, techniques, procedural costs, and complications. In the period between June 2003 and June 2006, 45 patients with bilateral malignant ureteral obstructions were evaluated (24 males, 21 females; average age, 68.3; range, 42-87). All of the patients were treated with ureteral stenting: 30 (mild strictures) with direct stenting (insertion of the stent without predilation), 30 (moderate/severe strictures) with primary stenting (insertion of the stent after predilation in a one-stage procedure), and 30 (mild/moderate/severe strictures with infection) with secondary stenting (insertion of the stent after predilation and 2-3 days after nephrostomy). The incidence of complications and procedural costs were compared by a statistical analysis. The primary technical success rate was 98.89%. We did not observe any major complications. The minor complication rate was 11.1%. The incidence of complications for the various techniques was not statistically significantly. The statistical analysis of costs demonstrated that the average cost of secondary stenting (637 euros; SD, 115 euros) was significantly higher than that of procedures which involved direct or primary stenting (560 euros; SD, 108 euros). We conclude that one-step stenting (direct or primary) is a valid option to secondary stenting in correctly selected patients, owing to the fact that when the procedure is performed by expert interventional radiologists there are high technical success rates, low complication rates, and a reduction in costs.

[Prenatal hydronephrosis: incidence, management and final diagnoses in 2003]. / Ectasia piélica de diagnóstico prenatal. Incidencia y protocolo de estudio durante el año 2003.

BACKGROUND: Prenatal diagnosis of renal pyelectasis usually involves postnatal studies to determine whether treatment is necessary or not. OBJECTIVES: To determine the incidence of fetal pyelectasis in our environment, to review our postnatal management protocol, and to review definitive diagnoses. PATIENTS AND METHOD: We performed a retrospective review of newborns with a prenatal diagnosis of pyelectasis. The variables recorded included prenatal ultrasound examinations, gestational age, sex, anthropometric data, postnatal study (ultrasound, cystography, isotopic renogram) and indication for antibiotic prophylaxis. RESULTS: There were 21 newborns (nine boys and 12 girls). Pyelectasia were located in the right kidney in 10 patients, on the left in seven and were bilateral in four. Antibiotic prophylaxis was administered at birth in seven neonates. Postnatal ultrasound was performed at 17.19 +/- 12.7 days of life and revealed no abnormalities in seven patients, hydronephrosis grade I-II in nine, hydronephrosis grade III in three and suspected double excretion system in two. Cystourethrography and isotopic renogram were performed in six neonates. The definitive diagnoses in the 21 patients were: no abnormalities in 10, non-complicated renal dilatation in seven, double excretion system in two, vesicoureteral reflux grade IV in one and pyeloureteral stenosis in one. None of these newborns had urinary tract infection. CONCLUSIONS: The incidence of prenatal pyelectasis in our hospital is 2 %. Most pyelectasia resolve spontaneously in the first year of life and invasive investigations are not required. Adequate monitoring of these children can avoid urinary tract infections and their sequelae.

Assessment and management of newborn hydronephrosis.

The incidence of asymptomatic hydronephrosis in newborns is high. Despite extensive clinical and scientific research much controversy still exists about the assessment and management of hydronephrosis during infancy. Postnatal management demands a detailed prenatal history. Initial workup in newborns with unilateral hydronephrosis starts with a physical examination and sonography of the urinary tract on day 3-5. Grades 3 and 4 hydronephrosis are further investigated with a voiding cystourethrogram (VCUG) and diuretic renogram between weeks 4 and 6. An infant with an asymptomatic unilateral hydronephrosis of any grade, without urinary infection and stable washout, and stable normal differential function on serial controls can be managed conservatively. The goal of all therapeutic strategies in the management of newborn hydronephrosis is to select all infants with severe obstructive dilatation during serial follow-ups and to perform surgical repair before irreversible deterioration and functional renal damage occurs. Interdisciplinary cooperation between experienced pediatric urologists, nephrologist and radiologists is the basis for optimal decision making.

Acute ureterolithiasis: incidence of secondary signs on unenhanced helical CT and influence on patient management.

AIM: The purpose of this study was to determine the incidence of secondary signs associated with ureteral stones on unenhanced helical computed tomography (CT) of patients with acute renal colic, and to correlate these with patient management and outcome. MATERIALS AND METHODS: One hundred and ten patients with ureterolithiasis were evaluated prospectively for the secondary signs of obstruction on unenhanced helical CT. Our attention was focused primarily on the presence or absence of seven secondary signs on unenhanced helical CT, including hydronephrosis, unilateral renal enlargement, perinephric oedema, unilateral absence of the white pyramid, hydroureter, periureteral oedema and lateroconal fascial thickening. RESULTS: Of the 110 patients, 91 (82.7%) had hydroureter, 88 (80%) had hydronephrosis, 65 (59%) had periureteric oedema and 63 (57.2%) had unilateral renal enlargement. Ninety stones passed spontaneously and 21 required intervention. CONCLUSION: Secondary signs of urinary tract obstruction are useful and supportive findings in interpretation of the CT examination. In our experience, the most reliable signs indicating ureteral obstruction are hydroureter, hydronephrosis, periureteral oedema and unilateral renal enlargement, respectively. In addition, stones larger than 6 mm, located within the proximal two thirds of the ureter, and seen associated with five or more the secondary signs of obstruction, are more likely to require endoscopic removal and/or lithotripsy.

Primary antegrade ureteric stenting: prospective experience and cost-effectiveness analysis in 50 ureters.

AIM: To evaluate the success rate and cost efficiency of primary antegrade ureteric stenting (antegrade ureteric stent insertion as a single procedure without preliminary drainage). MATERIALS AND METHODS: A policy of primary stenting was tested in 38 patients (50 ureters) with obstructive hydronephrosis, of acute or chronic onset and of benign or malignant origin. Patients with suspected pyonephrosis were excluded. Patients successfully primarily stented (group 1) were compared to a group stented as a traditional two-stage procedure (group 2). End point assessments were screening time, equipment used, procedure-related costs, bed occupancy and technical and clinical success rate. Using these cost and outcome measures, a cost-efficiency analysis was performed comparing the two strategies. RESULTS: 40/50 (80%) ureters were considered primary stent successes. The average procedure-related bed occupancy was 2 days (range 1-2 days). Simple equipment alone was successful in 16 cases. Van ( pound46/case). The mean screening time was similar for the two groups (13.5 min vs Andel dilatation catheters and peel-away sheaths were frequently used (23 ureters). Expensive equipment was rarely necessary (four cases) and average extra equipment cost was small 15.3 min; P > or = 0.05). There was a minimum saving of pound800 per successful primary stent. The cost-effectiveness of a primary antegrade stenting strategy was pound1229 vs pound2093 for secondary stenting. CONCLUSION: In carefully selected patients, the majority of obstructed ureters can be primarily stented using simple equipment. The reduced hospital stay and overall success rate significantly improves the cost competitiveness of antegrade ureteric stenting.

[Development and assessment of an artificial pacemaker of the ureter with feedback]. / Entwicklung und Erprobung eines künstlichen Schrittmachers des Harnleiters mit Rückkopplung.

In 16 patients who had been operated on according to Andersen-Hynes an electrostimulation of the upper urinary passages was carried out. One electrode consisting of a carbon filament was induced into the pelvis of the ureter, a second one with an at least 100 times larger contact surface than in the carbon electrode was placed on the skin. When the motor activity was restored (usually on the 9th to 12th day after operation) the electrostimulation was discontinued. The advantage of the method presented consists in the fact that the electrostimulation takes place in physiologically established time intervals. The presence of a feedback allows to discontinue the electrostimulation in such cases in which the restored independent contractions of the ureter transgressed the given level of 1 mV.