V03-05: The new device for lithoextraction during conventional PCNL. No baskets, no graspers.

V03-05: The new device for lithoextraction during conventional PCNL. No baskets, no graspers.



Traditional percutaneous nephrolithotomy (PCNL) with pneumatic/laser lithotripsy requires the use of lithoextractors. PCNL is associated with additional economic and time costs. We developed a new device that may offer an alternative to the lithoextractors.


In collaboration with the Institute of Theoretical Physics  we invented a new additional Amplatz device for PCNL, that is for the inflow of the irrigational fluid into the cavity of the pelvicalyceal system through the sheath and the outflow through the irrigation channel of the nephroscope. Taking into consideration the change of the core principles of the fluid flow circulation the method was named «The Inversion Technique». 21 patients with a single kidney stone were enrolled in the prospective non-randomized study. For the first group (1st, N=10) an additional devise was used to create the inversion flow of the fluid, while for the second group (2nd, N=11) a conventional PCNL with a traditional fluid supply through the nephroscope was performed. Each surgery was video recorded in order to estimate the exact time required for the change of the instruments used in the 1st group and lithotripsy duration in the 2nd group. In addition, changing of the intrarenal pressure stone-free rate (SFR) and complications were evaluated.


The stones sizes were 23±3 mm in the 1st and 23.5±2 mm 2nd group, respectively. The average time of procedure was 45±10min in the 1st group and 50±3 min – 2nd group. The median of the overall time of both lithotripsy and lithoextraction was 14±2 min in the first group and 17±3 min in the 2nd group. The required time for the instruments change in the 2nd group was 8±4 min. No complications were noted in the postoperative period. The SFR was 99% in the 1st group and 96% in the 2nd group. The intrarenal pressure of the 1st group did not exceed 10cm H2O, of the 2nd - 55cm H2O.


The new approach is safe and enables to reduce the time of lithotripsy in case of the simultaneous lithoextraction. Achievement of the effect even at vertical position, the possibility of the permanent capture of fragments, no proximal migration of the stones and no significant changes of the intrapelvical pressure were observed. The above-mentioned advantages allow to avoid the use of lithoextractors in routine treatment of the stones.

Funding: none