Electroconductive Lithotripsy: Principles, Experimental Data, and First Clinical Results of the Sonolith 4000*

Abstract

The electroconductive lithotripter (ECL) is a new concept for shockwave generation in which a highly conductive solution channels the discharge between the anode and cathode. In vitro experiments showed a linear relation between the voltage setting and the pressure at F2. In vitro stone disintegration studies showed a considerable reduction in shockwave pressure variability, improved energy transfer to the stone, and a unique linear relation between fragmentation and electrode voltage without a saturation effect. This new concept has been used clinically in the Sonolith 4000 lithotripter. In 142 evaluable treatments with a 3-month follow-up, the overall stone-free rate was 82%, and the retreatment rate in stone-free patients was 10%. For stones equal or less than 10 mm, the 3-month stone-free rate, retreatment rate, and secondary procedure rate were 85%, 5%, and 0%, respectively. For stones between 11 and 20 mm, these figures were 83%, 4%, and 2%, respectively. The efficiency quotient was found to be 81% for stones equal or less than 10 mm and 78% for stones between 11 and 20 mm. These clinical results confirm the improvements in efficacy observed in vitro with very satisfactory tolerance.

Outcomes using a fourth‐generation lithotripter: a new benchmark for comparison?

“…Pre-treatment procedures included stent insertion in 58 (18.7%) patients. The mean (range) follow-up after ESWL was 8 (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) months. There were 190 stones treated in the lower calyx, 76 in the renal pelvis, and 51 and 56 treated in the upper and middle calyx, respectively.…”

“…The Sonolith uses an electroconductive generator, characterized by an electrode surrounded by an envelope filled with a highly conductive fluid medium, that forces the electrical impulse created at F1 to follow a precise and reproducible pathway. This allows a linear relation between power settings to pressure at F2 [12,13].…”

Efficacy of the Sonolith Vision Lithotripter According to the Electrode Lifespan: An in Vitro Study

“…8 However, one of the limitations of a classic electrohydraulic generator is the increase of the gap seen between the electrodes over time due to wear. 9 Although newer electroconductive generators show decreased change in electrode gaps to about 1 / 50 the rate seen in earlier electrohydraulic generators, 9 the gap increase still occurs. As the gap widens during electrode consumption, the focal volume tends to increase and the pressure distribution of the shockwave may also widen, leading to decreased SWL efficacy.…”

Lithotripsy

“…It is at F2 that the stone is positioned. One drawback of electrohydraulic sources is that, except for two clinical lithotripters that are now marketed with long-life electrodes [30,31], the spark source needs to be replaced at regular intervals (1000-2000 shock waves, which is less than one typical treatment) owing to their vaporization and erosion by the spark [32].…”