Impact of Anterior Kidney Calyx Involvement of Complex Stones on Outcomes for Patients Undergoing Percutaneous Nephrolithotomy

Abstract

Introduction: A number of factors that can impact the outcomes of percutaneous nephrolithotomy (PCNL) procedures have previously been investigated. Complex stones that extend to the anterior calyx could affect the success and complication rates of PCNL. Objective: We analyzed the effect of anterior calyx involvement on the outcomes of patients with complex stones treated with PCNL. Methods: A total of 132 consecutive patients who underwent PCNL due to complex stones (multiple, partial staghorn, or staghorn stones) between 2015 and 2017 were enrolled in this study. They were stratified into two groups based on whether the stone extended to the anterior calyx (group 1, n = 45) or not (group 2, n = 87). The stratification was achieved through contrast-enhanced computerized tomography (CT). Demographics, laboratory tests, and peri- and postoperative findings (operation and fluoroscopy duration, hospital stay, utilization of flexible instruments, access numbers, total blood count change, stone-free rate [SFR], and complications) were compared between the groups. The SFR was evaluated by plain kidney-ureter-bladder radiography or CT. Results: The demographics, operation and fluoroscopy duration, access number, and hospital stay were similar between the groups (p < 0.05). A higher drop in the hemoglobin level in group 1 was identified (group 1 [2.14 ± 1.49 g/dL] vs. group 2 [1.43 ± 1.31 g/dL]) (p = 0.006). The SFR among the patients with extension to the anterior calyx was 60%, compared to 77% among the patients with no extension to the anterior calyx (p = 0.041). Flexible instruments were utilized in 60% of the patients of group 1, which was a higher rate than for group 2 (36%) (p = 0.007). Complication rates were similar in the two groups according to the Clavien-Dindo classification (p > 0.05). Conclusions: Our study demonstrated that complicated stones with extension to the anterior calyx are more challenging than cases without extension to the anterior calyx. This was noted by a lower SFR, a more prominent drop in total blood count, and more frequent utilization of flexible scopes.