New lithotripter data: improved stone clearance

Dr Oliver Wiseman (Cambridge University, UK) discussed available options for ballistic lithotripsy and which modality is best for breaking stones during percutaneous nephrolithotomy (PCNL) [1]. In particular, he focused on a study, also presented at the EAU, investigating the safety and efficacy of a new lithotripter, the Swiss Lithoclast® Trilogy lithotripter (hereafter referred to as the Trilogy) [2]. Results indicated that the Trilogy is highly effective at stone removal, had excellent safety outcomes, and was perceived by surgeons to be highly effective overall and compared with their most commonly used lithotripter.

Available PCNL options include pneumatic, ultrasonic, and electrohydraulic lithotripsy and laser, each having its own positive and negative attributes. Most modern lithotripters combine energy sources; however, there is no general consensus as to the single best modality for stone breakage. Dr Wiseman compared the newer lithotripters currently available. Specifically, the Trilogy is a single-probe device that delivers both ultrasonic and electromagnetic ballistic energy, with suction capability as well.

When compared with other devices in 10 European centres in a prospective non-randomised study, run by the EAU Section of Uro-Technology (ESUT), the Trilogy was found to have superior stone clearance time and clearance rate, and it required no conversions to another device. The published clinical stone clearance rates for other dual energy lithotripters based on surface area for other lithotripters (24-32.3 mm²/min), and the 3D calculated stone volume were compared with the single published series for the Trilogy (591 mm³/min). Objective measures were stone clearance rate, device malfunction, stone-free rate, and complications. In addition, surgeons scored subjective parameters for ergonomic and device effectiveness on a visual analogue 1-10 scale (10=extremely ergonomic/effective), and compared it with their usual lithotripter (10=extremely effective).

The study included 53 patients; 25 participants were female and the mean age was 57 years (range 16-84). The mean stone clearance rate was 58 mm²/minute, or 1,202 mm³/minute based on calculated 3D stone volume, double the clearance rate of previously published rates (see Figure). The stone-free rate on fluoroscopy screening at the end of the case was 75%. The subjective ergonomic score was 8.2, suction effectiveness was rated 9.4, with 9.3 for combination effectiveness, and 9.13 for overall effectiveness compared with the lithotripter most commonly used previously.

Figure: Comparative stone surface area clearance rate [2]

Figure kindly provided by Dr Wiseman.

With regard to safety, 3 patients required a blood transfusion, 2 patients developed post-procedure sepsis, 2 required JJ stent placement after clamping or removal of nephrostomy tube, and 1 patient had a prolonged bleed. Probes broke during 5 procedures (9%), and there were 2 other device-related complications, none of which required using a different lithotripter, and all of which were attributed to the lack of familiarity of using a new device.

Long-term follow up is awaited, but the device was perceived to be highly effective overall. The stone removal efficiency of Trilogy is almost 100% greater compared with published data on other lithotripters. Disadvantages include the 1,200 gram weight of the device.

1. 1. Wiseman O. EAU20 Virtual Congress, 17-26 July 2020, Plenary session 06 – Stones: The role of innovation.

Posted on 20 August, 202026 October, 2020