Factors Affecting the Stone-Free Status and Complication Rates of Swl in Children: A Large Scale Retrospective Analysis

Abstract

Purpose To evaluate the factors affecting the stone-free status and complication rates of SWL in children patients with urolithiasis. Material and Methods We retrospectively reviewed the data of 377 children (217 male, 160 female) treated with SWL for urolithiasis between 1992 and 2008. The treatment was performed with a Siemens Lithostar litotriptor. Shielding of the lung fields or gonads was not used. Patients were evaluated by ultrasonography and KUB 12 weeks after the last session. They were categorized as stone-free and failure. Data was analyzed with respect to patient demographics, stone parameters, treatment characteristics for the stone-free status and complication rates. Backward stepwise logistic regression method was used for statistical analysis. Results The mean patient age was 7.78 (1-16) years. The mean of stone burden, SWL session, energy level and shock waves were 1,15 cm 2 , 1.71, 16.9 kV, and 1702, respectively. Double J stent and percutaneous nephrostomy tube as auxiliary procedures were used in 28 (7.4%) and in 8 renal units (2.1%), respectively. Sixty-four (17%) patients had stone disease at the same renal unit in previous history and 8 patients (2.1%) had renal anomalies. The stone-free rate was 77,2% and failure was 22.8%. Stone-free status was achieved after first session in 67.4% of them. Complications developed in 25 (6.6%) patients; steinstrasse in 24 and fever in 1. In multivariate analysis, while the stone burden, auxiliary procedures and previous stone history negatively correlated with stone-free status, complications were associated with stone burden and number of sessions. Conclusions ESWL treatment in pediatric patients is the most preferred method because of the minimally invasive nature. However, every single factors affecting the stone-free status and complication rates should be counseled the parents of children with urolithiasis.