[The Endovision technique in renal percutaneous lithotripsy]

In order to achieve a safer percutaneous access to the kidney, even if not systematically, it is possible to combine the use of eco-fluoro-guided puncture with the endoscopic retrograde vision through flexible ureteroscopy. Our experience has been conducted in order to standardize the technique and highlight advantages and limitations.

26 patients (15 M-11 F), mean age 46 years, underwent flexible ureterorenoscopy as first percutaneous access for pyelic or pyelocaliceal stones.
20 cases were conducted in the prone and 6 in the supine position. 
We proceeded with the study of the caliceal topography and the choice of the calyx suitable for puncture, studying the orientation of the main axis of the papilla of the lower or middle group. Leaving the endoscopic instrument in place, we proceeded with the contrast injection and the eco-fluoro-guided puncture. The retrograde instrument followed the puncture and access dilatation.

In 16 cases we identified a papilla of the lower caliceal group with a correct orientation for the renal puncture; in the other 10, we chose a papilla of the middle group, because it was more favorable. In 10 cases the puncture was made at the center of the papilla with its axis in favor; in 16 it was necessary to correct the puncture because the needle had penetrated the fornix (no. 14) or had punctured the other side of the calyx (no. 2). 
In 10 cases the puncture correction caused some bleeding, which required a careful washing in order to clear the field of vision and repeat the procedure; in other 6 cases, this was not possible: the Endovision procedure was interrupted and completed according to the conventional method. There was no difference in technique between the supine and the prone position.

It is not always likely to find a papilla of lower calyx suitable to correct puncture.
The Endovision technique is related to an inevitably blind moment linked to the displacement of the kidney, which is not followed by the flexible instrument, and to the limitations related to the visibility. The technique can be used both in the prone and supine position; chances are that it might not always be completed.