History of the Development of Guidewires, Access Sheaths, Baskets, and Ureteral Stents

Abstract

Guidewires are a mainstay of endourologic procedures, as they provide safe access to the urinary tract and allow the passage of catheters and stents [1]. The development of guidewires in urology began with the application of angiographic tools in urologic endoscopy. Fritzche et al. reported the use of angiographic guidewires in 7 patients with ureteral obstruction in 1981 [2]. The authors noted in this study that their methods allow the “placement of angiographic guide wires and catheters past ureteral obstacles when standard urological retrograde procedures are not feasible technically.” The transvesical approach was described as where a 6Fr open-ended polyethylene catheter was placed at the ureterovesical junction and followed by advancing a 0.035 in. diameter guide wire [2]. The authors noted several advantages of the angiographic catheters and wires that allowed their urological application. The smaller diameter floppy tip reduced the risk of ureteral injury. A curve could be applied to the wire to facilitate manipulation and a wide range of shapes and sizes available for angiography allowed the urologist to attach a stone basket to the catheter for multiple passages through the level of obstruction [2]. Advances over subsequent years created specialized categories of guidewires which allowed the urologist to select the most appropriate tool for a given circumstance. These wires include hydrophilic straight and angled guidewires (used for bypassing more difficult obstructions or for the tortuous ureter), the hybrid wires (wires with a hydrophilic distal tip for bypassing obstructing stones and a nitinol core which is kink resistant to be used as a working wire) and stiffer wires such as Amplatz extra stiff (used to straighten ureter or for stabilization when passing dilating catheters and access sheaths) [1, 3]. More recent studies have evaluated the mechanical characteristics and performance elements of guidewires, including tip bending, resistance, pull force, shaft bending resistance, tip puncture force, shaft stiffness, and lubricity [1, 4]. The authors corroborated that hybrid wires offer the combination of the hydrophilic tip and stiffer shaft than standard wires, while the extra stiff wires may be best-suited for placement of ureteral access sheaths or larger stents. Interestingly they also noted that “brand name” guidewires designed for the same purposes may differ from one manufacturer to the next.