Clinical comparison of mini-percutaneous nephrolithotomy with vacuum cleaner effect or with a vacuum-assisted access sheath: a single center experience

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.