Purpose: To compare outcomes of two different techniques in miniaturized percutaneous nephrolithotomy (PCNL): minimally invasive PCNL (MIP) with the vacuum-cleaner effect and vacuum-assisted mini-PCNL (vmPCNL). Materials and methods: Data from 104 (66.7%) patients who underwent vmPCNL and 52 (33.3%) patients submitted to MIP at a single tertiary-referral academic center between 01/2016 and 12/2019 were analysed. Patients’ demographics, peri and post-operative data were recorded, and propensity-score matching was performed. Descriptive statistics and linear regression models were used to identify variables associated with operative time (OT) and patient’s effective dose. Logistic regression analyses were used to identify factors associated with infectious complications and stone free (SF) status. Results: Patients’ demographics and stone characteristics were comparable between groups. vmPCNL was associated with shorter OT (p <0.001), fluoroscopy time and patient’s effective dose (4.2 vs. 7.9 mSv; p<0.001). A higher rate of infectious complications was found in the MIP group (25.0% vs. 7.7%, p<0.01). Linear regression analysis showed that stone volume, multiple stone number and MIP procedure (all p≤0.02) were associated with longer OT. Similarly, OT and the MIP procedure (p≤0.02) were associated with higher patient’s effective dose. Logistic regression analysis revealed that stone volume, preoperative positive bladder urine culture and the MIP procedure (all p≤0.02) were associated with postoperative infectious complications. vmPCNL was not associated with SF rate. Conclusions: MiniPCNL performed with a continuous active suction is associated with lower rates of infectious complications, shorter OT and lower patient’s effective dose than MIP.

Background: Malignant ureteral obstruction (MUO) is variable in presentation and there is no consensus on its management, especially when caused by gastrointestinal (GI) malignancies. Our aim was to describe our experience with this oncological complication. Methods: We retrospectively analyzed the outcomes of ureteral stent and nephrostomy tube (NT) positioning for GI-related MUO from 2010 to 2020. We performed descriptive analysis, survival analysis, and uni- and multi-variate analysis. Results: We included 51 patients. NT was mainly used when bladder involvement occurred and when MUO revealed an ex novo cancer diagnosis. Survival was poorer in patients with new diagnoses and in those receiving no treatment after decompression. Moreover, MUO caused by upper-GI tumors was related to shorter overall survival. Conclusions: GI tumors causing MUO should be considered of poor prognosis. Treatment decisions should be weighted accurately by both specialists and the patient.

Objective: Miniaturized percutaneous nephrolithotomy (PCNL) reduces the risk of haemorrhagic complications, but the limited field of work represents a drawback. To obtain the best outcomes, the percutaneous access size should be intraoperatively tailored. Our purpose is to describe the indications and the procedural steps of the Matryoshka technique and to report its clinical outcomes. Materials and methods: We performed a retrospective analysis of the data from consecutive Matryoshka PCNL procedures from October 2016 to January 2018. Collected data included patients’ history, stone characteristics, intra- and post-operative items, stone clearance and need for retreatment. The main indication to the Matryoshka technique is the inability to securely position a guidewire due to an obstruction or narrowness in the pyelocalyceal system. This technique begins by puncturing the calyx hosting the stone and advancing a hydrophilic guidewire through the needle. If the guidewire cannot proceed beyond the stone, the Matryoshka technique is employed for tract stabilization. The tract is carefully dilated with small-bore instruments and a cautious lithotripsy is performed to create enough space to introduce the guidewire beyond the stone under visual control. Once the access has been stabilized the surgeon can upsize the tract to the optimum to complete the procedure. Additionally, the technique can be employed when an intraoperative reassessment induces the surgeon to further dilate the tract to quicken the procedure. Results: Sixteen patients were included, with a median stone volume of 3.49 cm3. Median operative time was 112 minutes. Three Clavien I-II (postoperative fever) and one Clavien IIIB (colon perforation) complications were reported. No blood transfusions were recorded. Three patients underwent scheduled retreatment as part of a multistep procedure. Out of the remaining 13 patients, 10 (76.9%) obtained a complete stone clearance.Conclusions: The Matryoshka technique helps the urologist to obtain a secure percutaneous access and makes PCNL flexible and progressive, potentially minimizing the risk of access-related complications.