Transient stent placement versus tubeless procedure after ureteroscopy retrograde surgery stone extraction (Fast Track Stent study 2): A randomized prospective evaluation.

OBJECTIVES: To determine whether in pre-stented patients undergoing ureteroscopic stone removal (ureteroscopy retrograde surgery) a tubeless procedure provides a better outcome compared with short-term (6 h) ureteral stenting using an external ureteral catheter. METHODS: In this single academic center study (Fast Track Stent study 2), carried out between May 2016 and April 2018, 121 patients with renal or ureteral calculi were initially treated with double-J insertion. Before secondary ureteroscopy retrograde surgery, patients were prospectively randomized into two groups: tubeless versus ureteral catheter insertion for 6 h after ureteroscopy retrograde surgery. Exclusion criteria were acute urinary tract infection, solitary kidney or stone diameter >25 mm. Study end-points were stent-related symptoms assessed by a validated questionnaire (ureteral stent symptom questionnaire), administered both before and 4 weeks after surgery. Numerical ureteral stent symptom questionnaire scores were compared using the Mann-Whitney-U-test. The level of significance was defined as P < 0.05. RESULTS: Ureteroscopy retrograde surgery procedures carried out by 13 surgeons resulted in >90% stone removal in all patients (n = 121), with a mean operation time of 19.9 versus 18.0 min for ureteral catheter versus tubeless, respectively (P = 0.37). Patient groups did not differ significantly in their ureteral stent symptom questionnaire scores (urinary index P = 0.24; pain index P = 0.35). Patients showed a significant preference for tubeless procedure over ureteral catheter reinsertion (Question GQ P < 0.0001). The reintervention rate was 13.3% for the tubeless procedure (n = 8) and 1.6% for the ureteral catheter group (n = 1), respectively (P = 0.034). CONCLUSIONS: Short-term ureteral catheter and no stent insertion after ureteroscopy retrograde surgery stone extraction in pre-stented patients result in comparable quality of life. However, the reintervention rate is higher for tubeless procedures.

Interdisciplinary Comparison of PADUA and R.E.N.A.L. Scoring Systems for Prediction of Conversion to Nephrectomy in Patients with Renal Mass Scheduled for Nephron Sparing Surgery.

PURPOSE: We examined interdisciplinary variability using 2 established preoperative nephrometry scores to predict conversion to nephrectomy in patients with a renal mass who were scheduled for partial nephrectomy. MATERIALS AND METHODS: A total of 229 consecutive candidates for partial nephrectomy were included in this study at a single institution between January 2013 and May 2017. Patient, tumor and treatment characteristics were assessed. The PADUA (preoperative aspects and dimensions used for an anatomical) score and the R.E.N.A.L. (radius, exophytic/endophytic, nearness of tumor to collecting system or sinus, anterior/posterior, location relative to polar lines) score were independently calculated by board certified radiologists and urological residents using computerized tomography or magnetic resonance imaging. Statistical analyses were done with the κ statistic, ROC curves, and univariable and multivariable binary logistic regression analyses. RESULTS: Partial nephrectomy was performed in 198 of the 229 cases (86.5%) while 31 (13.5%) were converted to nephrectomy. The prevalent tumor stage was pT1a, noted in 94 of the 229 cases (41.1%), and the predominant histological entity was clear cell carcinoma, found in 128 (55.9%). Radiologist and urologist interdisciplinary comparison of the PADUA and R.E.N.A.L. scores revealed a κ of 0.40 and 0.56, respectively. ROC curve analyses demonstrated a higher AUC predicting conversion to nephrectomy using the PADUA score by the urologist and the radiologist (0.79 and 0.782) compared to that of the R.E.N.A.L. score (0.731 and 0.766, respectively). Using a cutoff of 10 or greater the PADUA score determined by the urologist had 81% sensitivity and 71% specificity, and it was independently associated with conversion to nephrectomy (OR 10.98, p<0.001). CONCLUSIONS: Our results indicate higher prediction of conversion to nephrectomy when using the PADUA score compared to the R.E.N.A.L. score. Calculation of the PADUA and the R.E.N.A.L. score by physicians without specialized radiological training is feasible and might achieve comparable results to predict conversion to nephrectomy compared to the gold standard provided by board certified radiologists. This information is helpful if nephrometry scores are not regularly included in the radiology report.

Short-term external ureter stenting shows significant benefit in comparison to routine double-J stent placement after ureterorenoscopic stone extraction: A prospective randomized trial - the Fast track stent study (FaST).

OBJECTIVES: To determine whether short-term stenting using an external ureter catheter following ureterorenoscopic stone extraction provides a better outcome in comparison to double-J stent ureteral stenting. METHODS: Between August 2014 and August 2015, 141 patients initially managed with a double-J stent insertion were prospectively randomized to ureter catheter for 6 h vs double-J stent insertion for 5 days after stone extraction via ureteroscopy retrograde surgery (including flexible ureteroscopy retrograde surgery) in a single academic center. Endoscopic procedures were performed by nine surgeons. Exclusion criteria were acute urinary tract infection, a solitary kidney, or a stone mass more than 25 mm. Study endpoints were ureter-stent related symptoms and pain assessed by a validated questionnaire (ureteral stent symptom questionnaire) and visual analogue scale before and 4 weeks after surgery. RESULTS: Overall stone-free rate was more than 90%. Mean operative time was 24 min (range 5-63). Groups did not differ in terms of age, body mass index, and stone size. Patients who received short-term ureter catheter showed a significantly higher quality of life. In the ureter catheter group, the urinary index score (16.8 vs 27.8; P < 0.0001), the pain score (9.7 ± 1.3 vs 20.2 ± 1.5; P < 0.0001), and general health index (15.3 ± 0.7 vs 8.5 ± 0.6; P < 0.0001) were significantly lower. Consultation of a physician and antibiotic treatment were rarely needed (1.3 ± 0.1 vs 1.6 ± 0.1; P = 0.017). CONCLUSION: A short-term ureter catheter insertion for 6 h following ureteroscopy retrograde surgery stone removal is a safe procedure and superior to double-J stent insertion with regard to urinary symptoms, pain, quality of life, and stent related symptoms. Patients treated with a short-term ureter catheter recover more quickly, return to work earlier, and need less doctor visits. Most patients would recommend a ureter catheter, and would prefer this strategy in case of future stone treatments.

Detection of Acute Tubular Necrosis Using Blood Oxygenation Level-Dependent (BOLD) MRI.

BACKGROUND/AIMS: To date, there is no imaging technique to assess tubular function in vivo. Blood oxygen level-dependent magnetic resonance imaging (BOLD MRI) measures tissue oxygenation based on the transverse relaxation rate (R2*). The present study investigates whether BOLD MRI can assess tubular function using a tubule-specific pharmacological maneuver. METHODS: Cross sectional study with 28 participants including 9 subjects with ATN-induced acute kidney injury (AKI), 9 healthy controls, and 10 subjects with nephron sparing tumor resection (NSS) with clamping of the renal artery serving as a model of ischemia/reperfusion (I/R)-induced subclinical ATN (median clamping time 15 min, no significant decrease of eGFR, p=0.14). BOLD MRI was performed before and 5, 7, and 10 min after intravenous administration of 40 mg furosemide. RESULTS: Urinary neutrophil gelatinase-associated lipocalin was significantly higher in ATN-induced AKI and NSS subjects than in healthy controls (p=0.03 and p=0.01, respectively). Before administration of furosemide, absolute medullary R2*, cortical R2*, and medullary/cortical R2* ratio did not significantly differ between ATN-induced AKI vs. healthy controls and between NSS-I/R vs. contralateral healthy kidneys (p>0.05 each). Furosemide led to a significant decrease in the medullary and cortical R2* of healthy subjects and NSS contralateral kidneys (p<0.05 each), whereas there was no significant change of R2* in ATN-induced AKI and the NSS-I/R kidneys (p>0.05 each). CONCLUSION: BOLD-MRI is able to detect even mild tubular injury but necessitates a tubule-specific pharmacological maneuver, e.g. blocking the Na+-K+-2Cl- transporter by furosemide.

Drug dosage in isolated limb perfusion: evaluation of a limb volume model for extremity volume calculation.

BACKGROUND: Exact drug dosing in isolated limb perfusion (ILP) and infusion (ILI) is essential. We developed and evaluated a model for calculating the volume of extremities and compared this model with body weight- and height-dependent parameters. METHODS: The extremity was modeled by a row of coupled truncated cones. The sizes of the truncated cone bases were derived from the circumference measurements of the extremity at predefined levels (5 cm). The resulting volumes were added. This extremity volume model was correlated to the computed tomography (CT) volume data of the extremity (total limb volume). The extremity volume was also correlated with the patient's body weight, body mass index (BMI) and ideal body weight (IBW). The no-fat CT limb volume was correlated with the circumference-measured limb volume corrected by the ideal-body-weight to actual-body-weight ratio (IBW corrected-limb-volume). RESULTS: The correlation between the CT volume and the volume measured by the circumference was high and significant. There was no correlation between the limb volume and the bare body weight, BMI or IBW. The correlation between the no-fat CT volume and IBW-corrected limb volume was high and significant. CONCLUSIONS: An appropriate drug dosing in ILP can be achieved by combining the limb volume with the simple circumference measurements and the IBW to body-weight ratio.