Renal Parenchymal Damage After Percutaneous Nephrolithotomy with One-Stage Tract Dilation Technique: A Randomized Clinical Trial

Purpose: To compare the effects of one-stage vs gradual dilation techniques during percutaneous nephrolithotomy (PCNL) on postoperative renal scar formation and overall renal function. Patients and Methods: Of 152 adult patients who underwent surgery during the study period, 48 were randomized into two groups. In group 1 (n = 19), gradual tract dilation with Alken metallic dilators was used, and in group 2 (n = 29), one-stage tract dilation was used. We compared patient demographics, intraoperative and preoperative parameters, postoperative overall renal function, and renal scar formation on the target renal pole. Results: Access time (P = 0.001; 95% confidence interval [CI]: 3.19-6.30) and radiation exposure during access (P = 0.03; 95% CI: 0.03-0.66) were significantly shorter in group 2. In group 1, the decrease in mean technetium-99m dimercaptosuccinic acid (99m-Tc DMSA) uptake from 44.1 +/- 20.1% to 43.4 +/- 19.6% 4 weeks postoperatively (-0.7% +/- 0.5%; P = 0.27; 95% CI: -0.56-1.93) was not significant. In group 2, however, there was a significant decrease in post-PCNL 99m-Tc DMSA uptake 2 (-2.4 +/- 0.3%, from 50.1 +/- 13.5% to 47.7 +/- 13.8%; P = 0.001; 95% CI: 1.13-3.66). Four weeks after surgery, new scar formation or progression of the preoperative scar at the site of access were seen in 14 of 29 (48.3%) patients who were treated with one-stage dilation whereas only 2 of 19 (11.0%) patients who were treated with gradual dilation developed new scarring at the access site (P = 0.007). Conclusion: Although the one-stage tract dilation technique reduced radiation exposure and access time, in the short term, it may cause more parenchymal damage than the gradual dilation technique.