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

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.

Disposable devices for RIRS: Where do we stand in 2013? What do we need in the future?

“…Loss of deflection was 7.1-8.0° with the Optiflex versus 10.1-11.4° with the other baskets. an even smaller 1.2Fr Urotech Surgical (achenmuehle, Germany) tipless triple-wire basket is available and was compared by another group of investigators to larger baskets, which ranged from 1.8 to 2.2Fr in size [19]. While enjoying significantly superior irrigation flow in both semirigid and flexible ureteroscopes, the 1.2Fr basket demonstrated the lowest breaking strength, at 6.4 N (vs. 15.8-32.2 N of the other tested baskets).…”

How to evaluate a flexible ureterorenoscope? Systematic mapping of existing evaluation methods

“…In all, 23 of the 27 papers evaluated irrigation flow with and without instruments inserted in the scope [6,[9][10][11][12][13][14][15][16][17][18][19]23,24,28,29,[32][33][34][35]42,45,49]. Afane et al [5] and Dragos et al [21] only evaluated irrigation without inserted instruments.…”

“…Over the years, a wide range of flexible scopes have been introduced for clinical use. Functionality as well as characteristics related to the loss of functionality of these flexible ureterorenoscopes have been studied abundantly [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 ]. Until now, studies used different approaches to evaluate the quality of flexible ureterorenoscopes.…”

“…The majority of the studies (24/27) evaluating irrigation, performed their measurements in an ex vivo setting[5,6,9-15,17,18,21,24,31- 35,42,43,45,46,49].Pressure during measurements of irrigation flow differed substantially (range 40-339.9 cmH 2 O). Measuring irrigation flow whilst applying a pressure of 100 cmH 2 O was mentioned most frequently (12/27)[9,10,13,14,17,18,24,32,33,42,43,49]. However, four articles did not describe the pressure used while measuring irrigation flow[16,19,23,29].…”

Development and Validation of a Novel Skills Training Model for Retrograde Intrarenal Surgery

“…The two main RIRS indications are renal stone treatment and urothelial upper urinary tract neoplasm diagnosis and treatment 3 . The EAU guidelines on urolithiasis are the only guidelines which indicate flexible ureteroscopy as a treatment option for renal calculi 1 .…”