COMPARATIVE OUTCOMES OF STANDARD, TUBELESS AND TOTALLY TUBELESS PERCUTANEOUS NEPHROLITHOTOMY FOR RENAL CALCULI: A PROSPECTIVE OBSERVATIONAL STUDY

Abstract

Background: Percutaneous nephrolithotomy (PCNL) is the standard surgical treatment for large renal calculi. Tubeless PCNL omits the nephrostomy tube while retaining an internal ureteric stent; totally tubeless PCNL omits both. Trials comparing all three exit strategies within one cohort remain uncommon, and the two tubeless variants are often reported together despite differing in whether antegrade drainage is preserved. Methods: Ninety-six consecutive patients with renal calculi of 1-3.5 cm undergoing PCNL at a tertiary teaching hospital over 18 months were studied. The exit strategy was not allocated by the investigators: each procedure was performed by a faculty urologist who selected standard (n = 27), tubeless (n = 34) or totally tubeless PCNL (n = 35) according to intraoperative judgement, and the resulting groups were observed prospectively. Operative time, blood loss, postoperative fever, urinary tract infection, urinary leakage, haematuria, complications, hospital stay and overall outcome were compared. Categorical comparisons used the FisherFreeman-Halton exact test because expected cell counts were sparse; continuous outcomes were compared by analysis of variance or the Kruskal-Wallis test with Tukey and Dunn post hoc testing. Proportions are reported with 95% Wilson confidence intervals. Reporting follows the STROBE statement. Results: The groups were similar in age, sex and Guy's Stone Score but differed sharply in intraoperative difficulty, rated substantial in 81.5% of standard, 37.1% of totally tubeless and 5.9% of tubeless procedures (p < 0.001), reflecting the basis on which the technique was chosen. Operative time differed between techniques (p < 0.001): tubeless PCNL was faster than standard (1.37 ± 0.18 versus 2.00 ± 0.52 hours, adjusted p < 0.001) and faster than totally tubeless PCNL (adjusted p = 0.001), whereas totally tubeless and standard
PCNL did not differ (adjusted p = 0.14). Hospital stay was shortened equally by both tubeless variants relative to standard PCNL, by 1.45 days (95% CI 0.50-2.40) and 1.39 days (95% CI 0.44-2.34). Postoperative fever, urinary tract infection, urinary leakage, haematuria and overall outcome all differed between groups. Pairwise, fever occurred in 14.7% after tubeless PCNL against 74.1% after standard (adjusted p < 0.001) and 48.6% after totally tubeless PCNL (adjusted p = 0.012); totally tubeless and standard PCNL did not differ significantly in fever (adjusted p = 0.20) or urinary tract infection (20.0% versus 18.5%, adjusted p = 1.00). Both tubeless variants reduced urinary leakage. Conclusion: Patients managed tubeless had the shortest operations and the lowest rates of fever, urinary tract infection and urinary leakage, and those managed totally tubeless occupied an intermediate position. Because the exit strategy was chosen by the operating surgeon rather than allocated, and because that choice is made on the basis of intraoperative course, these differences cannot be attributed to the techniques themselves: a model in which fever depends only on case difficulty reproduces the observed three-group gradient almost exactly. The findings describe how exit strategies are selected in routine practice and what follows, and should not be read as a comparison of their effects.