Four dilation techniques in percutaneous nephrolithotomy: a single-institute comparative analysis.

Background: The aim of this study was to compare four renal access techniques in percutaneous nephrolithotomy (PCNL).
Methods: A total of 437 patients who underwent PCNL at our center from January 2015 to December 2019 were included in the analysis. Telescopic metallic coaxial dilation (TMD) was used in 146 patients, single step balloon dilation (BD) in 98 patients, one-shot dilation with 30F Amplatz (OS 30F) in 106 patients, and one-shot dilation with 16F Amplatz (OS 16F) in 87 patients. Primary endpoints were perioperative outcomes and complications of the procedures.
Results: Similar baseline characteristics were observed in the four groups. Fluoroscopy time was significantly shorter in OS 30F and OS 16F groups (P<0.0001). The drop in hemoglobin level was not significantly different between TMD and BD groups, but it was significantly lower in OS 16F group versus the OS 30F group and lower in OS 30F group versus the BD Group (P<0.0001). Despite this, the rate of blood transfusion was similar across groups (P=0.837). Moreover, a smaller tract was associated with reduced postoperative morbidity including time to nephrostomy removal (P=0.001), hospital stay (P<0.0001), VAS scale (P<0.0001). There were no significant differences in postoperative complications (P=0.683), and Clavien-Dindo grade ≥3 complication rates (P=0.486) among the groups. Stone-free rates and number of auxiliary procedures required to achieve stone-free status were also similar among all groups (P=0.964 and 0.988, respectively). Multinomial logistic regression analysis showed that BMI (P=0.002), stone size (P=0.002) and previous PCNL (P=0.038) were predictive factors associated with the choice of OS 16 approach.
Conclusions: Different dilation methods are equally effective and safe to use in a PCNL procedure for kidney stone treatment, allowing similar stone free rates and risk of complications. The OS dilation techniques seem to allow a shorter X-ray exposure time, which might be beneficial for both patients and operators. The use of a 16 F dilator can reduce the postoperative morbidity. Risk of sepsis should be always kept in mind.