The vacuum cleaner effect in minimally invasive percutaneous nephrolitholapaxy

Abstract

This study illustrates and explains the vacuum cleaner effect which has been detected in the development of the Nagele Miniature Nephroscope System used in MIP. It combines the reduced morbidity of smaller kidney puncture diameters with the benefit of quick and complete stone removal.

Evaluation of the effect of Bernoulli maneuver on operative time during mini-percutaneous nephrolithotomy: A prospective randomized study

“…The first description of standard “minimally invasive PCNL” with specialized 12-Fr rigid nephroscope and 15-Fr access sheath came out in 2001. However, according to the authors' note, despite the fact that no hemorrhage has occurred in a group of 19 patients, miniaturized instruments were associated with significant operative time increase with larger stone masses [19], due to the fact that utilization of a smaller sheaths are associated with more difficult stone fragment retrieval and need of additional tools such as disposable retrieval baskets [4]. It was not until Nagele et al [3] in 2008 reported on a “Newly Designed Amplatz Sheath” (Karl Storz) with the vacuum cleaner effect, which was nicely depicted in a study by Nicklas et al [4].…”

“…However, according to the authors' note, despite the fact that no hemorrhage has occurred in a group of 19 patients, miniaturized instruments were associated with significant operative time increase with larger stone masses [19], due to the fact that utilization of a smaller sheaths are associated with more difficult stone fragment retrieval and need of additional tools such as disposable retrieval baskets [4]. It was not until Nagele et al [3] in 2008 reported on a “Newly Designed Amplatz Sheath” (Karl Storz) with the vacuum cleaner effect, which was nicely depicted in a study by Nicklas et al [4]. The basis of this effect lies in Bernoulli's principle, according to which an increase in the speed of a fluid in the constriction zone occurs simultaneously with a decrease in pressure [20], also known as ‘pseudocavity’ which is being located at the tip of the nephroscope during mini-PCNL able to extract stone fragments through access sheath without any additional stone extracting devices [4].…”

“…It was not until Nagele et al [3] in 2008 reported on a “Newly Designed Amplatz Sheath” (Karl Storz) with the vacuum cleaner effect, which was nicely depicted in a study by Nicklas et al [4]. The basis of this effect lies in Bernoulli's principle, according to which an increase in the speed of a fluid in the constriction zone occurs simultaneously with a decrease in pressure [20], also known as ‘pseudocavity’ which is being located at the tip of the nephroscope during mini-PCNL able to extract stone fragments through access sheath without any additional stone extracting devices [4]. Besides ‘Bernoulli effect’ or ‘Vacuum cleaner effect’ passive or active wash out as well as purging effect can also be utilized to gain maximum stonefree rate during mini-PCNL, though were not used in our study [21].…”

“…Further advances led to the development of metallic Amplatz sheath with nephroscope, where one of the prominent advantages was vacuum cleaner effect, consistent with hydrodynamic Bernoulli's principle [3]. According to this principle, during mini-PCNL, the front of a low pressure called ‘pseudocavity’ is produced at the tip of nephroscope, which can extract the stone fragments through an access sheath without any additional grasping devices [4]. At a closer look, we have noticed that the horizontal plane, being one of the necessary conditions for Bernoulli equation, possibly for negation of gravitational influence on the flow velocity [5], was for some reason neglected.…”

Feasibility of single‐session endoscopic combined intrarenal surgery for ipsilateral large renal stones and retrograde intrarenal surgery for contralateral renal stones: Initial experience

“…The 80‐W holmium laser (Trimedyne, Irvine, CA, USA) was used to break stones. No stone forceps were used to extract fragmented stones, because the endoscopy irrigation pump (Stryker, Kalamazoo, MI, USA) enabled fragments to go out of the body spontaneously through the sheath . After PCNL procedure, flexible ureterorenoscopes were inserted into the PCNL side in an antegrade or a retrograde manner, and active removal of remnant stones was carried our simultaneously, as shown in Figure .…”