V01-05: Semi-closed circuit vacuum-assisted Mini-Percutaneous Nephrolithotomy with Holmium laser lithotripsy

V01-05: Semi-closed circuit vacuum-assisted Mini-Percutaneous Nephrolithotomy with Holmium laser lithotripsy



Percutaneous nephrolithotomy (PCNL) was designed as an open circuit with a continuous water inflow inside the kidney and an outflow through the access sheath. The need to control intrarenal pressure leaded to the idea to create a semi-closed circuit with a continuous inflow and a suction-controlled outflow. Suboptimal energy transmission in Holmium laser lithotripsy may lead to stone retropulsion. Moses technology can minimize this effect. This video shows two vacuum assisted mini-PCNL (vmPCNL) procedures with Moses laser lithotripsy and presents the results from our first experience in this technique.


A 16 Fr, 13 cm long nephrostomic sheath and a 12 Fr nephroscope are employed. The sheath, externally sealed to prevent the medium outflow, is equipped with a lateral arm connected to the aspirator. The aspiration pressure can be regulated by the surgeon throughout the procedure. Lithotripsy is performed with a 550 um Moses laser fiber. Lapaxy is achieved by drawing back the nephroscope inside the sheath until the internal opening of the aspiration arm. Data from our series were prospectively collected. Complications were categorized according to the PCNL adapted Clavien score. Stone free status was defined as the absence of fragments> 4 mm at the 1-3 month imaging (CT or US).


The first case in the video is a 44 yo man with a staghorn left kidney stone and an encrusted JJ stent. The second one is a 69 yo man with a 2.2 cm stone in the lower left calix. In the first case partial lithotripsy and JJ stent removal were performed. A second procedure was needed, as already planned, to obtain a stone free status. In the second case the procedure lasted 45 minutes and the patient was stone free. From September 2017 to September 2018 we performed 60 consecutive vmPCNL procedures with Moses laser lithotripsy. Median stone volume was 1.8 cm3. The stone free rate was 88% (53 patients). The complication rate was 31.7%, of which 24.9% were low grade complications (? 2) and 6.8% grade 3 complications. Three patients (5%) experienced post-operative fever managed with antibiotics. Median lithotripsy and lapaxy time was 35 minutes.


A semi-closed circuit vacuum-assisted PCNL system may guarantee a crystal clear vision along the procedure; the low intrarenal pressure may be associated with less post-operative infections; the easy litholapaxy and the absence of fragments scatter, facilitated by the Moses technology, may reduce operative time, increase stone free rate and decrease the need of disposable devices, cutting costs.

Funding: none