Introduction & Objectives
As flexible ureteroscopes (fURSs) have evolved over a period of time, one of the limiting factors for calyceal/stone access is the end-tip deflection of different fURSs. We wanted to develop a simplified scoring system to rank end-tip deflection of the commonly used fURSs.
Material & Methods
Nine commonly used fURSs (BOA vision, COBRA vision, R.Wolf; FLEX X2, FLEX Xc, K.Storz; LithoVue, Boston Scientific; URF- P5, URF-P6, URF-V, URF-V2, Olympus) were tested for their end-tip deflection by a team of independent endourologists. Passing the fURSs through a 10/12Fr (12/14Fr for COBRA vision) ureteral access sheath (ReTrace, Porgès-Coloplast), the maximum end-tip deflection for every fURS was measured with the tip extended out from the sheath at 1 cm, 2 cm, 3 cm and 4 cm. First scoring method (SM-1) relied on scoring these nine fURSs from 1-9 for each of the distal 4 centimetres, wherein the sum-total of all scores (at point 1cm, 2cm, 3cm and 4cm) were added to give a final score (Table 1). The second scoring method (SM-2) relied on scoring the fURSs for end tip deflection for each of the distal 4 centimetres, wherein the sum-total of all scores (degrees of deflection at point 1cm, 2cm, 3cm and 4cm) were added to give a final score (Table 2).
All fURSs were ranked twice based on both these scoring systems (Table 3). While 5 fURSs had exactly the same ranking based on the scores achieved, 4 other fURSs were ranked slightly differently with the difference being a maximum of one rank only. While FLEX X2, URF-P6, COBRA vison, URF-V and URF-V2 ranked 1st, 4th, 7th, 8th and 9th respectively in both scoring systems; FLEX Xc and URF-P5 ranked 2nd/3rd and 3rd/2nd respectively based on the scoring systems; and BOA vison and LithoVue ranked 5th/6th and 6th/5th respectively based on the scoring systems.
Our scoring systems for end-tip-deflection of fURSs are an easy and convenient way to rank existing and new fURSs. This might not only have an effect on development of new products/fURSs but also help in the decision making for endourologists interested in buying new fURSs.