Urolithiasis/Endourology
Outcomes of Flexible Ureterorenoscopy for Solitary Renal Stones in the CROES URS Global Study Andreas Skolarikos, Andreas J. Gross,* Alfred Krebs, Dogan Unal, Eduardo Bercowsky, Ehab Eltahawy, Bhaskar Somani and Jean de la Rosette† From the Departments of Urology, Sismanoglio Hospital (AS), Athens, Greece, Asklepios Hospital Barmbek (AJG), Hamburg, Germany, Clinica Alemana de Santiago (AK), Santiago, Chile, School of Medicine, Hacettepe University (DU), Ankara, Turkey, Hospital Mateu Orfila (EB), Menorca, Spain, University of Arkansas for Medical Sciences (EE), Little Rock, Arkansas, Ain Shams University (EE), Cairo, Egypt, University Hospital Southampton National Health Service Trust (BS), Southampton, United Kingdom, and Academic Medical Center (JdlR), Amsterdam, the Netherlands
Purpose: We determined the efficacy and safety of flexible ureterorenoscopy for single intrarenal calculi and further stratified efficacy by stone burden. Materials and Methods: CROES collected prospective data on consecutive patients with urinary stones treated with ureterorenoscopy at 114 centers worldwide for 1 year. Only patients who underwent flexible ureterorenoscopy for a solitary renal stone were included in study. Preoperative and intraoperative characteristics, and postoperative outcomes were evaluated. Relationships between stone size and the stone-free rate, operative time, complications, hospital stay and need for re-treatment were determined. Results: A total of 1,210 patients with a solitary kidney stone less than 10 (52.2%), 10 to 20 (43.2%) and greater than 20 mm (4.6%) were treated with flexible ureterorenoscopy. The stone-free rate negatively correlated with stone size when adjusted for body mass index. Operative time positively correlated with stone size when adjusted for body mass index. The single session stone-free rate was 90% and 80% for stones less than 10 and less than 15 mm, respectively. Patients with stones greater than 20 mm achieved a 30% stone-free rate, more often needed re-treatment and were more often rehospitalized. There was no difference in the overall complication rate by stone size. However, patients with a stone greater than 20 mm showed a higher probability of fever after flexible ureterorenoscopy than those with a smaller stone. Conclusions: Our data indicate that flexible ureterorenoscopy for a single intrarenal stone is a safe procedure. Best results after single session flexible ureterorenoscopy were obtained for stones less than 15 mm. Key Words: kidney, nephrolithiasis, ureteroscopy, body mass index, treatment outcome
KIDNEY stone size is one of the more reliable ways to stratify patient stonefree outcomes. Traditionally renal stones have been considered small if less than 1 cm, medium if 1 to 2 cm and large if greater than 2 cm. These
stratifications are based more on cutoffs derived from the SWL literature than on actual evidence-based results of URS studies. The CROES URS Global Study aimed to assess current indications for URS, the outcome in
0022-5347/15/1941-0137/0 THE JOURNAL OF UROLOGY® © 2015 by AMERICAN UROLOGICAL ASSOCIATION EDUCATION AND RESEARCH, INC.
http://dx.doi.org/10.1016/j.juro.2015.01.112 Vol. 194, 137-143, July 2015 Printed in U.S.A.
Abbreviations and Acronyms BMI ¼ body mass index CROES ¼ Clinical Research Office of the Endourological Society fURS ¼ flexible ureterorenoscopy PNL ¼ percutaneous nephrolithotripsy RIRS ¼ retrograde intrarenal surgery SFR ¼ stone-free rate SWL ¼ shock wave lithotripsy URS ¼ ureteroscopy Accepted for publication January 30, 2015. Study received institutional research board or institutional ethics committee approval. Supported by an unrestricted educational grant from Boston Scientific (URS Global Study). * Financial interest and/or other relationship with Cook Ireland. † Correspondence: Department of Urology, Academic Medical Center, P.O. Box 22700, Amsterdam, 1100 DE, The Netherlands (telephone: þ31-20-5666030; FAX: þ31-20-5669585; e-mail: [email protected]).
Editor’s Note: This article is the fourth of 5 published in this issue for which category 1 CME credits can be earned. Instructions for obtaining credits are given with the questions on pages 268 and 269.
www.jurology.com
j
137
138
FLEXIBLE URETERORENOSCOPY FOR SOLITARY RENAL STONES
terms of SFR, and intraoperative and postoperative complications using the modified Clavien grading system.1 In the current subanalysis we compared fURS outcomes in patients with a single small (less than 10 mm) intrarenal stone and patients with a single larger (10 mm or greater) intrarenal stone.
MATERIALS AND METHOD Study Protocol The URS Global Study is a prospective, observational, international, multicenter study with data collected on consecutive patients treated with URS in a 1-year period at each participating center. Institutional research board or institutional ethics committee approval was obtained at all participating centers before the start of the study. If institutional review board review was not needed, the centers followed the protocol according to Good Clinical Practice. The overall study period was January 2010 to October 2012.
Study Population Patients eligible for inclusion in the current analysis were 18 years old or older and candidates for URS of renal stones as primary treatment or after failed previous treatment. Patients with multiple stones were excluded from study. A large solitary renal stone was defined as a single renal stone with a longest dimension of 10 mm or greater. Treatment details, including secondary treatment and patient followup, were previously described.1 Centers were asked to evaluate, treat or re-treat patients according to the local protocol. Classification of a patient as stone-free was based on absence of stones or fragments greater than 1 mm.
Data Collection Data were encrypted and collected electronically through a web based website (http://www.croesoffice.org) and held in a central database at the CROES office. Data included patient epidemiological characteristics, calculus specification, treatment type, and postoperative outcomes and complications. Centers were asked to treat patients according to local protocols.
Data Analysis Statistical analysis was performed to describe patient general characteristics and study outcomes using R, version 2.12.2 (http://www.r-project.org/). To compare outcomes among stone sizes (less than 10, 10 to 20 and greater than 20 mm), intrarenal stone locations (renal pelvis, and upper, mid and lower pole) and access sheath use we applied Pearson chi-square analysis for dichotomous or categorical variables and ANOVA for continuous variables. Outcomes were measured preoperatively (epidemiological characteristics) and postoperatively (operative time, SFR, complications, hospital stay, re-treatment and rehospitalization). Relationships between renal stone size, operative time and SFR were analyzed by general multivariate regression models or multivariate regression models using a 3-knot restricted
cubic spline.2 Statistical significance was considered at p
Outcomes of Flexible Ureterorenoscopy for Solitary Renal Stones in the CROES URS Global Study Andreas Skolarikos, Andreas J. Gross,* Alfred Krebs, Dogan Unal, Eduardo Bercowsky, Ehab Eltahawy, Bhaskar Somani and Jean de la Rosette† From the Departments of Urology, Sismanoglio Hospital (AS), Athens, Greece, Asklepios Hospital Barmbek (AJG), Hamburg, Germany, Clinica Alemana de Santiago (AK), Santiago, Chile, School of Medicine, Hacettepe University (DU), Ankara, Turkey, Hospital Mateu Orfila (EB), Menorca, Spain, University of Arkansas for Medical Sciences (EE), Little Rock, Arkansas, Ain Shams University (EE), Cairo, Egypt, University Hospital Southampton National Health Service Trust (BS), Southampton, United Kingdom, and Academic Medical Center (JdlR), Amsterdam, the Netherlands
Purpose: We determined the efficacy and safety of flexible ureterorenoscopy for single intrarenal calculi and further stratified efficacy by stone burden. Materials and Methods: CROES collected prospective data on consecutive patients with urinary stones treated with ureterorenoscopy at 114 centers worldwide for 1 year. Only patients who underwent flexible ureterorenoscopy for a solitary renal stone were included in study. Preoperative and intraoperative characteristics, and postoperative outcomes were evaluated. Relationships between stone size and the stone-free rate, operative time, complications, hospital stay and need for re-treatment were determined. Results: A total of 1,210 patients with a solitary kidney stone less than 10 (52.2%), 10 to 20 (43.2%) and greater than 20 mm (4.6%) were treated with flexible ureterorenoscopy. The stone-free rate negatively correlated with stone size when adjusted for body mass index. Operative time positively correlated with stone size when adjusted for body mass index. The single session stone-free rate was 90% and 80% for stones less than 10 and less than 15 mm, respectively. Patients with stones greater than 20 mm achieved a 30% stone-free rate, more often needed re-treatment and were more often rehospitalized. There was no difference in the overall complication rate by stone size. However, patients with a stone greater than 20 mm showed a higher probability of fever after flexible ureterorenoscopy than those with a smaller stone. Conclusions: Our data indicate that flexible ureterorenoscopy for a single intrarenal stone is a safe procedure. Best results after single session flexible ureterorenoscopy were obtained for stones less than 15 mm. Key Words: kidney, nephrolithiasis, ureteroscopy, body mass index, treatment outcome
KIDNEY stone size is one of the more reliable ways to stratify patient stonefree outcomes. Traditionally renal stones have been considered small if less than 1 cm, medium if 1 to 2 cm and large if greater than 2 cm. These
stratifications are based more on cutoffs derived from the SWL literature than on actual evidence-based results of URS studies. The CROES URS Global Study aimed to assess current indications for URS, the outcome in
0022-5347/15/1941-0137/0 THE JOURNAL OF UROLOGY® © 2015 by AMERICAN UROLOGICAL ASSOCIATION EDUCATION AND RESEARCH, INC.
http://dx.doi.org/10.1016/j.juro.2015.01.112 Vol. 194, 137-143, July 2015 Printed in U.S.A.
Abbreviations and Acronyms BMI ¼ body mass index CROES ¼ Clinical Research Office of the Endourological Society fURS ¼ flexible ureterorenoscopy PNL ¼ percutaneous nephrolithotripsy RIRS ¼ retrograde intrarenal surgery SFR ¼ stone-free rate SWL ¼ shock wave lithotripsy URS ¼ ureteroscopy Accepted for publication January 30, 2015. Study received institutional research board or institutional ethics committee approval. Supported by an unrestricted educational grant from Boston Scientific (URS Global Study). * Financial interest and/or other relationship with Cook Ireland. † Correspondence: Department of Urology, Academic Medical Center, P.O. Box 22700, Amsterdam, 1100 DE, The Netherlands (telephone: þ31-20-5666030; FAX: þ31-20-5669585; e-mail: [email protected]).
Editor’s Note: This article is the fourth of 5 published in this issue for which category 1 CME credits can be earned. Instructions for obtaining credits are given with the questions on pages 268 and 269.
www.jurology.com
j
137
138
FLEXIBLE URETERORENOSCOPY FOR SOLITARY RENAL STONES
terms of SFR, and intraoperative and postoperative complications using the modified Clavien grading system.1 In the current subanalysis we compared fURS outcomes in patients with a single small (less than 10 mm) intrarenal stone and patients with a single larger (10 mm or greater) intrarenal stone.
MATERIALS AND METHOD Study Protocol The URS Global Study is a prospective, observational, international, multicenter study with data collected on consecutive patients treated with URS in a 1-year period at each participating center. Institutional research board or institutional ethics committee approval was obtained at all participating centers before the start of the study. If institutional review board review was not needed, the centers followed the protocol according to Good Clinical Practice. The overall study period was January 2010 to October 2012.
Study Population Patients eligible for inclusion in the current analysis were 18 years old or older and candidates for URS of renal stones as primary treatment or after failed previous treatment. Patients with multiple stones were excluded from study. A large solitary renal stone was defined as a single renal stone with a longest dimension of 10 mm or greater. Treatment details, including secondary treatment and patient followup, were previously described.1 Centers were asked to evaluate, treat or re-treat patients according to the local protocol. Classification of a patient as stone-free was based on absence of stones or fragments greater than 1 mm.
Data Collection Data were encrypted and collected electronically through a web based website (http://www.croesoffice.org) and held in a central database at the CROES office. Data included patient epidemiological characteristics, calculus specification, treatment type, and postoperative outcomes and complications. Centers were asked to treat patients according to local protocols.
Data Analysis Statistical analysis was performed to describe patient general characteristics and study outcomes using R, version 2.12.2 (http://www.r-project.org/). To compare outcomes among stone sizes (less than 10, 10 to 20 and greater than 20 mm), intrarenal stone locations (renal pelvis, and upper, mid and lower pole) and access sheath use we applied Pearson chi-square analysis for dichotomous or categorical variables and ANOVA for continuous variables. Outcomes were measured preoperatively (epidemiological characteristics) and postoperatively (operative time, SFR, complications, hospital stay, re-treatment and rehospitalization). Relationships between renal stone size, operative time and SFR were analyzed by general multivariate regression models or multivariate regression models using a 3-knot restricted
cubic spline.2 Statistical significance was considered at p
