Evaluation of Renal Function after Percutaneous Nephrolithotomy—Does the Number of Percutaneous Access Tracts Matter?

Ilya Gorbachinsky, Ilya Gorbachinsky, Kyle Wood, Marc Colaco, Sij Hemal, Sij Hemal, Jayadev Mettu, Jayadev Mettu, Majid Mirzazadeh,

Dean G. Assimos, Jorge Gutierrez-Aćeves

Department of Urology, Wake Forest Baptist Medical Center, Winston Salem, North Carolina

Department of Urology, University of Alabama (DGA), Birmingham, Alabama



Renal function following percutaneous nephrolithotomy has long been a concern to urologists, especially in the setting of multi-tract access. We determined whether the risk of renal injury after multi-tract percutaneous nephrolithotomy was greater than after a single access approach.

Materials and Methods

We retrospectively reviewed the records of 307 consecutive patients treated with percutaneous nephrolithotomy from 2011 to 2012 at Wake Forest Health. Perioperative 99mTc-mercaptoacetyltriglycine nuclear renogram parameters along with serum creatinine values were assessed within 1 year of the procedure. Patients were stratified by single access vs multi-access (2 or more).


We identified 110 cases in which renography was done before and after percutaneous nephrolithotomy. A total of 74 patients (67.3%) underwent single access percutaneous nephrolithotomy while 36 (32.7%) underwent multi-access percutaneous nephrolithotomy. Serum creatinine did not significantly differ between the 2 cohorts postoperatively (p = 0.09). There was a significant 2.28% decrease in renal function based on mercaptoacetyltriglycine nuclear renogram results after percutaneous nephrolithotomy of the affected kidney in patients with multiple accesses (p <0.01). This relationship was not observed when patients were stratified by multiple comorbidities associated with nephrolithiasis.


Multi-access percutaneous nephrolithotomy is associated with a small reduction in the function of the targeted kidney compared to a single access approach.

Key Words:

kidney, nephrolithiasis, nephrostomy, percutaneous, radioisotope renography, technetium TC 99m mertiatide

Abbreviations and Acronyms:

BMI (body mass index), CKD (chronic kidney disease), DM (diabetes mellitus), eGFR (estimated glomerular filtration rate), MAG3 (mercaptoacetyltriglycine), PCNL (percutaneous nephrolithotomy)

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Comparing Image Perception of Bladder Tumors in Four Different Storz Professional Image Enhancement System Modalities Using the íSPIES App

Guido M. Kamphuis, MD,1 D. Martijn de Bruin, MSc, PhD,1,2 Martin J. Brandt, MSc,2 Thomas Knoll, MD, PhD,3 Pierre Conort, MD,4 Alberto Lapini, MD,5 Jose L. Dominguez-Escrig, MD, PhD,6 and Jean J.M.C.H. de la Rosette, MD, PhD1

1Department of Urology, Academic Medical Center, Amsterdam, the Netherlands.

2Department of Biomedical Engineering, Academic Medical Center, Amsterdam, the Netherlands.

3Department of Urology, Klinikum Sindelfingen-Böblingen, Sindelfingen, Germany.

4Department of Urology, Pitie-Salpetriere Academic Hospital, Paris, France.

5Department of Urology, University of Florence Careggi Hospital, Florence, Italy.

6Department of Urology, Fundación Instituto Valenciano de Oncología, Valencia, Spain.

Journal of Endourology

Published in Volume: 30 Issue 5: May 6, 2016


Objectives: To evaluate the variation of interpretation of the same bladder urothelium image in different Storz Professional Image Enhancement System (SPIES) modalities. SPIES contains a White light (WL), Spectra A (SA), Spectra B (SB), and Clara and Chroma combined (CC) modality.

Materials and Methods: An App for the iPAD retina was developed to study evaluation of images. A total of 80 images from 20 bladder areas acquired in four modalities were included. Seventy-three participants completed the study. Images were analyzed on differences in delineated tumor margin variation, perceived quality of the image, and delineation time.

Results: A separation between high agreement (n = 14) and low agreement (n = 6) images was found. In high agreement images, no difference in root mean square (RMS) was found between modalities. In low agreement images, WL (26.5 pixels) and SA (33.4 pixels) had a higher RMS than CC (18 pixels) and SB (21.4 pixels). The quality of SPIES modalities images was rated significantly higher. Delineation time was similar.

Conclusion: In low agreement cases, images in CC and SB have less variation in interpretation than WL and SA. The image quality in SPIES modalities is graded significantly higher than WL. There is no difference in delineation time between modalities.

Journal of Endourology

Published in Volume: 30 Issue 6: June 15, 2016

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Endoscopically Determined Stone Clearance Predicts Disease Recurrence Within 5 Years After Retrograde Intrarenal Surgery

Simon Hein, MD,1 Arkadiusz Miernik, MD, PhD,1 Konrad Wilhelm, MD,1 Daniel Schlager, MD,1 Dominik Stefan Schoeb, MD,1 Fabian Adams, MD,1 Werner Vach, MSc, PhD,2 and Martin Schoenthaler, MD, PhD1

1Department of Urology, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Germany.

2Center for Medical Biometry and Medical Informatics, University of Freiburg, Freiburg, Germany.

German Trial Register (WHO-registered): DRKS00009745.


Objective: To assess stone-related events (SREs) requiring retreatment in a series of 100 consecutive patients treated by retrograde intrarenal surgery (RIRS) for renal stones and to evaluate potential risk factors thereof.

Patients and Methods: The primary outcome was incidence of SRE (medical or surgical treatment). Secondary outcomes included side of SRE, time to SRE, and late complications. Analysis of potential risk factors included high-risk stone formers (HRSFs), obesity, high stone burden, and lower pole stones. In addition, we evaluated endoscopically determined small residual fragments (SRF) of <1 mm (i.e., fragments too small for retrieval) as an independent risk factor.

Results: Eighty-five of the 99 patients were followed up for a mean of 59 months (31–69), among whom 26 (30.1%) had SRE. Thirty-four of the 85 (40%) patients were HRSFs, 22 of whom experienced SRE (both sides) during follow-up (64.7%, p < 0.001). Eight of the 17 patients (47.1%) with SRF experienced ipsilateral side SRE compared with 13 (19.1%) of the 68 without SRF (p = 0.022, hazard ratio 2.823, 95% confidence interval [95% CI] 1.16, 6.85). Risk for ipsilateral SRE was unaffected by the presence of SRF among HRSFs (p = 0.561). Of low-risk patients with SRF, 33.3% experienced ipsilateral SRE, while those without SRF experienced no ipsilateral SRE (p < 0.001).

Conclusion: Endoscopically determined stone clearance predicts disease recurrence within 5 years after RIRS. Even SRF are an important risk factor for future stone-related (ipsilateral) events; therefore, patients with residual fragments of any size should not be labeled “stone free” and endoscopic stone treatment should aim at complete stone clearance.

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Comparison of New Single-Use Digital Flexible Ureteroscope Versus Nondisposable Fiber Optic and Digital Ureteroscope in a Cadaveric Model

Journal of Endourology. June 2016, 30(6): 655-659. doi:10.1089/end.2016.0051.

Published in Volume: 30 Issue 6: June 15, 2016

Author information

Silvia Proietti, MD, FEBU,1,2 Laurian Dragos, MD,2 Wilson Molina, MD,3 Steeve Doizi, MD, MSc,2 Guido Giusti, MD,1 and Olivier Traxer, MD2

1Department of Urology, Ville Turro Division, IRCCS San Raffaele Scientific Institute, Milan, Italy.

2Department of Urology, Tenon Hospital, Paris, France.

3Department of Surgery/Urology, Denver Health, Denver, Colorado.


Purpose: To evaluate LithoVue, the new single-use digital flexible ureteroscope, in a human cadaveric model and compare it with a nondisposable fiber optic and digital flexible ureteroscopes.

Materials and Methods: LithoVue, a conventional fiber optic, and digital flexible ureteroscopes were each tested in four renal units of recently deceased female cadavers by three surgeons. The following parameters were analyzed: accessibility to the kidney and navigation of the entire collecting system with and without ureteral access sheath (UAS), lower pole access measuring the deflection of the ureteroscope with the working channel empty, and with inside two different baskets and laser fibers. A subjective evaluation of maneuverability and visibility was assessed by each surgeon at the end of every procedure.

Results: Kidney access into the Renal unit 1 was not possible without UAS for all ureteroscopes because of noncompliant ureter at the level of sacroiliac joint. The reusable digital ureteroscope was unable to reach one calix of the lower pole and one calix of the upper pole (Renal units 2 and 3) without UAS placement. Lower pole access with baskets and laser fibers was possible for each ureteroscope after UAS placement. No statistically significant differences were detected in angle deflection between ureteroscopes. The digital ureteroscope was preferred for visibility in all procedures: LithoVue for maneuverability in six procedures, fiber optic in five procedures, and the digital ureteroscope in one procedure.

Conclusions: LithoVue seems to be comparable with conventional ureteroscopes in terms of visibility and manipulation into the collecting system in fresh human cadavers. Further studies in humans are needed to determine the clinical value of this new instrument.

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Supine Versus Prone Position in Percutaneous Nephrolithotomy for Kidney Calculi: A Meta-Analysis

Published in Volume: 30 Issue 7: July 11, 2016

Author information

DongBo Yuan, MD,1,* YongDa Liu, PhD, MD,2,* HaoFu Rao, MD,1 TianFei Cheng, MD,1 ZhaoLin Sun, MD,1 YuanLin Wang, MD,1 Jun Liu, MD,1 WeiHong Chen, MD,1 WeiDe Zhong, PhD, MD,3,4,5,6 and JianGuo Zhu, PhD, MD1,3

1Department of Urology, Guizhou Provincial People’s Hospital, The Affiliated Hospital of Guiyang Medical College, Guizhou, China.

2Guangdong Key Laboratory of Urology, Department of Urology, Minimally Invasive Surgery Center, The First Affiliated Hospital of Guangzhou Medical University, Guangdong, China.

3Guangdong Key Laboratory of Clinical Molecular Medicine and Diagnostics, Department of Urology, Guangzhou First People’s Hospital, Guangzhou Medical University, Guangzhou, China.

4Guangdong Provincial Institute of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China.

5Department of Urology, Huadu District People’s Hospital, Southern Medical University, Guangzhou, China.

6Urology Key Laboratory of Guangdong Province, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, China.


Background: There are several positions in the operation of percutaneous nephrolithotomy (PCNL), such as prone position, supine position, flank position, and modified supine position for PCNL, but the supine and prone positions are the main two choices for several years. However, there is still discrepancy on the optimal position for PCNL. Therefore, we performed this meta-analysis to evaluate safety and efficacy of the supine versus the prone position in PCNL for renal calculi.

Methods: We searched MEDLINE, SCOPUS, and the Cochrane database libraries to look for relevant studies. All eligible controlled trials comparing supine versus prone positions for treating renal calculi were included in the meta-analysis. The main outcome of efficacy (stone-free rate, mean operative time, and hospitalization time) and safety (complication, blood transfusions) were assessed by using Review Manager 4.2 software. We calculated the estimate of effect associated with the two positions according to the heterogeneity using random-effects or fixed-effects models.

Results: Thirteen studies (six randomized controlled trials and seven retrospective studies) with a total of 6881 patients contributed to this meta-analysis. The meta-analysis indicated/suggested that PCNL in the prone position was associated with a higher rate of stone clearance than PCNL in the supine position (odds ratio [OR]: 0.74; 95% confidence interval [CI]: 0.65, 0.84; p < 0.00001). A shorter mean operative time was observed in the supine groups (weighted mean difference [WMD]: −18.27; 95% CI: −35.77, −0.77; p = 0.04). Compared with the prone position, there was also a lower incidence of blood transfusions in the supine groups (WMD: 0.73; 95% CI: 0.56, 0.95; p = 0.02). No difference was observed between the positions with regard to the hospital stay (WMD: −0.14; 95% CI: −0.76, 0.47; p = 0.65) and complications (OR: 0.88; 95% CI: 0.76, 1.02; p = 0.10).

Conclusion: Compared with the prone position, the PCNL in the supine position has a slightly lower rate of stone clearance, albeit shorter mean operative time, and lower incidence of blood transfusions. The meta-analysis suggests that the PCNL in the supine position is a promising alternative.

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February 2016, Volume 44, Issue 1, pp 65–76

How should patients with cystine stone disease be evaluated and treated in the twenty-first century?

Andreassen KH1, Pedersen KV2, Osther SS1, Jung HU1, Lildal SK1, Osther PJ3.


Cystinuria continues to be one of the most challenging stone diseases. During the latest decades our knowledge of the molecular basis of cystinuria has expanded. Today 160 different mutations in the SLC3A1 gene and 116 in the SLC7A9 gene are listed. The full implications of type A, B or AB status are not yet fully understood but may have implications for prognosis, management and treatment. Despite better understanding of the molecular basis of cystinuria the principles of recurrence prevention have remained essentially the same through decades. No curative treatment of cystinuria exists, and patients will have a life long risk of stone formation, repeated surgery, impaired renal function and quality of life. Therapy to reduce stone formation is directed towards lowering urine cystine concentration and increasing cystine solubility. Different molecules that could play a role in promoting nucleation and have a modulating effect on cystine solubility may represent new targets for cystinuria research. Investigation of newer thiol-containing drugs with fewer adverse effects is also warranted. Determining cystine capacity may be an effective tool to monitor the individual patient’s response. Compliance in cystinuric patients concerning both dietary and pharmacological intervention is poor. Frequent clinical follow-up visits in dedicated centres seem to improve compliance. Cystinuric patients should be managed in dedicated centres offering the complete range of minimal invasive treatment modalities, enabling a personalized treatment approach in order to reduce risk and morbidity of multiple procedures.