1.2 French stone retrieval baskets further enhance irrigation flow in flexible ureterorenoscopy

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ORIGINAL PAPER

1.2 French stone retrieval baskets further enhance irrigation flow in flexible ureterorenoscopy Jens Bedke • Ulf Leichtle • Andrea Lorenz • Udo Nagele • Arnulf Stenzl • Stephan Kruck

Received: 29 October 2012 / Accepted: 18 December 2012 / Published online: 5 January 2013 Ó Springer-Verlag Berlin Heidelberg 2013

Abstract Ureterorenoscopy (URS) has revolutionized upper urinary tract stone therapy. However, the size of the working channel and the stone baskets limit irrigation flow as well as vision. This study determined further improvements of irrigation flow, deflection capacities and impairments of breaking resistance in a new 1.2 French (F) ultra-miniaturized basket. Irrigation measurements were performed in semirigid URS (semiURS, working channel 5F) and in flexible URS (flexURS, 3.6F) in 0°, 90° and 270° deflection with 1.2F, 1.8F, 1.9F and 2.2F baskets and compared with empty channel. Breaking strength of 1.2F, 1.8F and 1.9F baskets were evaluated using a material testing machine. Tested baskets affected irrigation in semiURS and flexURS (p \ 0.05). Mean ± SEM (standard error of the mean) for semiURS flow rates counted 197.1 ± 2.0, 140.9 ± 1.6, 111.1 ± 1.5, 98.0 ± 1.3 and 77.1 ± 0.9 ml/min for empty channel, 1.2F, 1.8F, 1.9F and 2.2F baskets (p \ 0.05). Using unbent flexURS flow rates of

44.2 ± 0.4, 20.4 ± 0.2, 5.9 ± 0.1, 5.4 ± 0.1 and 1.5 ± 0.1 ml/min for empty channel, 1.2F, 1.8F, 1.9F and 2.2F baskets, were observed (p \ 0.05). The 1.2F versus 2.2F basket showed a 13.6-fold increase in flexURS irrigation (p \ 0.05), while only the 2.2F basket reduced deflection by 20.3 %. The breaking strength decreased with a reduced basket size (1.2F: 6.4 ± 0.46 vs. 1.8F: 16.8 ± 2.79 vs. 1.9F: 32.2 ± 2.74 N, p \ 0.05). Ultra-miniaturized baskets of 1.2F ensured a sufficient irrigation flow as needed for high quality vision in URS stone management. However, miniaturization of the 1.2F basket resulted in a reduced breaking strength compared with larger sized devices which in turn may hamper stone removal by an increased vulnerability.

J. Bedke  A. Stenzl  S. Kruck Department of Urology, University of Tuebingen, Tuebingen, Germany

Introduction

J. Bedke (&)  S. Kruck (&) Department of Urology, Eberhard Karls University Tuebingen, Hoppe-Seyler Strasse 3, 72076 Tuebingen, Germany e-mail: [email protected] S. Kruck e-mail: [email protected] U. Leichtle  A. Lorenz Department of Orthopaedic Surgery, University of Tuebingen, Tuebingen, Germany U. Nagele Department of Urology, General Hospital Hall i.T, Hall in Tirol, Austria

Keywords Ureteroscopic surgery  Miniature instruments  Stone baskets  Irrigation flow  Deflection  Breaking strength

The incidence and prevalence of urolithiasis is rising world-wide, and the individual life-time risk for a passing kidney stone is up to 10 % [1]. Currently, there are three minimal invasive and therapeutic stone removal modalities available to remove upper urinary tract stones: shock wave lithotripsy (SWL), retrograde intrarenal surgery (RIRS) performed either by s