Comparison of Scoring Systems in Pediatric Mini-Percutaneous Nephrolithotomy

To apply urolithiasis scoring systems to the pediatric miniperc procedure and to compare their predictive capability for postoperative outcomes.

Records from 2 referral centers of patients under 18 years of age who had the miniperc procedure between 2010 and 2015 were retrospectively investigated. All patients included in the study were graded by the same surgeon according to Guy's and Clinical Research Office of the Endourological Society (CROES) scoring systems using preoperative imaging methods. Patient demographics and outcomes were compared according to the complexity of the procedure as graded by each scoring system.

The mean age of the 97 patients was 7.1 ± 5.2 (1-17) years. The mean stone burden and number were 388.4 ± 233.9 mm(2) and 1.5 ± 1.3, respectively. The mean procedure, fluoroscopy, and hospitalization times were 78.2 ± 32.8 minutes, 144.8 ± 84.3 seconds, and 4.1 ± 2.8 days, respectively. The mean hematocrit drop was calculated as 2.2 ± 2.2. The mean scores were 1.7 ± 1.0 and 259.9 ± 50.6 for Guy's and CROES scoring systems, respectively. In the multivariate analysis, stone-free status was found to be associated with Guy's (r: -0.464, p: .000) and CROES (r: 0.490, : 0.000) scoring systems and stone burden (r: -0.161, p: .041). In the analysis of factors related to complication, Guy's score was identified as an independent predictor of complication (p: .02, odds ratio: 1.9, 95% confidence interval 1.097-3.319).

According to our results, using Guy's and CROES scoring systems, stone-free ratios after percutaneous nephrolithotomy may be predicted preoperatively. In addition, Guy's system is a predictor of postoperative complication rate.