Tubeless supra-costal percutaneous nephrolithotomy is associated with significantly less hydrothorax: a prospective randomized clinical study.

OBJECTIVES: To evaluate prospectively whether a tubeless (JJ stent-only) percutaneous nephrolithotomy (PCNL) might reduce the risk of hydrothorax, compared to an approach where a nephrostomy tube is left. MATERIALS AND METHODS: We conducted a two-arm open-label prospective randomized study (NCT02036398) comparing tubeless supra-costal PCNL (with a JJ stent only) to standard PCNL (with nephrostomy tube and JJ stent) using intention-to-treat (ITT) and per-protocol (PP) analyses. All patients underwent a standard single-stage prone supra-costal procedure with single-tract access. Complication data were collected according to the Clavien-Dindo grading system. The primary endpoint was the rate of hydrothorax, and secondary endpoints included stone-free rate (SFR) and complication rate. Multivariable logistic regression analysis identified factors associated with hydrothorax formation. RESULTS: Out of 101 patients approached, 75 were finally analysed. No differences were observed between the two arms with regard to baseline demographic and stone characteristics. The mean largest stone size ranged between 23 and 24.2 mm. No significant difference was seen in the mean operating time and length of hospital stay. The incidence of hydrothorax was significantly higher in the nephrostomy group in comparison to the tubeless group (37.8% vs 15.8%, P = 0.031, and 38.4% vs 13.8%, P = 0.016, in the ITT and PP analyses, respectively). The SFR and complication rate were similar in both groups using the ITT and PP analyses. Multivariable logistic regression analysis showed that nephrostomy tube placement was the only covariate associated in a statistically significant manner to hydrothorax (odds ratio 3.628, 95% confidence interval 1.073-12.265; P = 0.038). CONCLUSION: The rate of hydrothorax in supra-costal PCNL is associated with the type of postoperative drainage left. When possible, a tubeless approach should be applied as it may confer a lower risk of hydrothorax.