ORIGINAL PAPER Anand Srivastava Æ Tapan Sinha Æ S. C. Karan A. S. Sandhu Æ S. K. Gupta Æ G. S. Sethi R. Talwar Æ V. Narang Æ N. Adlakha A. Agarwal Assessing the efficiency of extracorporeal shockwave lithotripsy for stones in renal units with impaired function: a prospective controlled study Received: 30 November 2005 / Accepted: 27 January 2006 / Published online: 15 February 2006 Ó Springer-Verlag 2006 Abstract The objective was to determine the efficiency of extracorporeal shockwave lithotripsy (ESWL) in clear- ing stones from renal units with impaired function. Thirty-five patients with poorly functioning kidneys determined by intravenous urogram and 99m technetium diethylene triamine pentacetic acid renal dynamic scan underwent ESWL. Stone clearance was assessed at 3 months and compared with that in normally func- tioning kidneys. The study group was divided into two subgroups. Those with split glomerular filtration rate (GFR) of the concerned kidney between 10 and 20 ml/ min were in group 1. Group 2 consisted of patients with split GFR between 20 and 30 ml/min. A control group (group 3) was formed from patients with urolithiasis and normally functioning kidneys. The overall retreatment rate was 84.4%. The overall stone clearance rate in the study group was 34.2% while it was 57.7% in the con- trol group. The stone clearance rate in group 2 was 40%. The difference in stone clearance rate between the study and control groups was statistically significant (P=0.023) but that between group 2 and the control group was not (P=0.159). The incidence of steinstrasse between the study group 2 and control group was not statistically significant (P=0.408). The clearance rate for ureteral stones was comparable in all the three groups. The stone-free rate and rate of steinstrasse for renal stones in kidneys with moderately impaired function were comparable to normally functioning kidneys. However, kidneys with severely impaired function had poor results. The clearance rate for ureteral stones was not influenced by the impairment of renal function. Keywords Extracorporeal shockwave lithotripsy Æ Poorly functioning kidneys Æ Renal stones Æ Ureteral stones Æ Clearance rates Æ Steinstrasse Introduction With its low morbidity and acceptable success rate, extracorporeal shockwave lithotripsy (ESWL) has be- come the preferred treatment for stone disease by pa- tients and urologists [1]. The majority of renal calculi less than 2 cm are treated by ESWL as the first-line management [2]. In situ ESWL of proximal ureteral calculi has high success rate [3–5]. Customarily ESWL is believed to result in poor stone clearance rates in kidneys with impaired function, as adequate post-procedural urine flow is fundamental to successful fragment passage [6]. Bhatia et al. [7] reported satisfactory results with ESWL of renal and ureteral stones in chronic renal insufficiency (CRI). However, no study has methodically evaluated the clearance of calculi in kidneys with impairment due to diverse causes such as obstructive nephropathy and medical renal disease. There is a need to assess the efficiency of ESWL in such kidneys and correlate it with their degree of impairment. This would allow more accurate estimation of their stone clearance rate, thus enabling objective decision making in indi- vidual patients. We report our prospective study de- signed to evaluate clearance rate of calculi from poorly functioning renal units or their proximal ureters with ESWL and correlate this with a quantitative assessment of their function. Materials and methods All patients undergoing ESWL from January 2003 to June 2005 were eligible for inclusion in the study. Pre- procedure investigations included a complete haemo- gram, renal function profile, coagulogram, urine culture, A. Srivastava (&) Æ T. Sinha Æ S. C. Karan Æ A. S. Sandhu S. K. Gupta Æ G. S. Sethi Æ R. Talwar Æ V. Narang N. Adlakha Æ A. Agarwal Department of Urology, Army Hospital (Research & Referral), Delhi Cantt, 110010, Delhi, India E-mail: annand_srivastava@yahoo.com Tel.: +91-11-9868427195 Fax: +91-11-23338063 Urol Res (2006) 34: 283–287 DOI 10.1007/s00240-006-0046-4