who were at least 17 years old and Tanner 5 who underwent preop- erative and postoperative semen analyses were available for analysis. Clinical and demographic data were reviewed, as well testicular size evaluated by sonography, and pre and postoperative semen parame- ters (volume, sperm count, motility, and morphology). Descriptive sta- tistics, and paired t-tests were used to calculate statistical significance defined as p<0.05. RESULTS: From 2005-2014, there were 13 patients who had both pre and post-operative semen analyses available. The surgical approach was laparoscopic (12) or microsurgical (1). Average patient age was 18.1 years (17-20), mean varicocele grade was 2.6. Mean total testicular volume was 28.8 (9-45), left testicular volume was 13.9 (4-20), average size discrepancy was 7.3%. Compared to the preop- erative semen analysis, surgery led to a significant improvement in sperm count (61.2 vs 37.5 million, p<0.005).percent motiilty (55.5 vs 42.3%, p<0.012). 7 patients had low sperm counts, as defined by WHO criteria; 4 (57%) patients had normalized sperm counts after surgery. Four of 7 (57%) with abnormal morphology (<50%) had postoperative improvement. There was no significant improvement in motility in this cohort. CONCLUSIONS: Our early results demonstrate that objective semen analyses parameters are significantly improved in a select population of adolescents undergoing surgical varicocelectomy. Pro- spective pre and postoperative semen parameters will help better define which patients benefit from surgical repair. Source of Funding: none MP40-07 RECURRENCE OF SYMPTOMATIC KIDNEY STONES DIAGNOSED DURING CHILDHOOD Gregory Tasian*, Angela Kalmus, Susan Furth, Philadelphia, PA INTRODUCTION AND OBJECTIVES: The incidence of kidney stones among children and adolescents has risen dramatically over the last 25 years; however, the probability of and time to recurrence for patients whose first stone formed during childhood is unknown. We sought to define the recurrence rate of symptomatic nephrolithiasis for healthy patients in whom the first kidney stone occurred during childhood. METHODS: We performed a retrospective cohort study of all patients without urologic abnormalities, medical comorbidities, or a genetic predisposition for nephrolithiasis treated at a tertiary children’s hospital for a symptomatic first kidney stone at or before 18 years be- tween January 2008 and April 2013. Patients were followed until they developed the primary endpoint of symptomatic recurrence, defined as pain, vomiting, or hematuria with new stone on ultrasound or CT, or were censored at last follow-up, death, or transition to adult care. Kaplan-Meier curves and Cox proportional hazard regression were used to estimate the time to stone recurrence and patient characteris- tics associated with stone recurrence, accounting for differential follow-up. RESULTS: Of 559 patients with no prior history of neph- rolithiasis treated during the study period, 130 had symptomatic kidney stones and met inclusion criteria. These children were followed for 221 person-years with a median follow-up of 1.8 years (IQR 1.2 e 3 years). The median age at diagnosis was 14.3 years (IQR 11.6 e 16.1 years). Forty-seven patients had at least one recurrence with a rate of 2 recurrent stones per 1000 patient-months. Kaplan Meier curves esti- mated that 50% of children had a symptomatic recurrence within 3 years of the first stone. On Cox proportional hazard regression, no association was detected between stone recurrence and age at diag- nosis, gender, or urine chemistries on initial 24-hour urine analysis. CONCLUSIONS: The risk of symptomatic kidney stone recur- rence within 3 years of the index stone is high. There is a need to identify modifiable risk factors for stone recurrence among children and adolescents. Source of Funding: Dr. Furth was supported by K24DK78737 from the National Institutes of Health/National Institute of Diabetes and Digestive and Kidney Diseases MP40-08 MEDICAL EXPULSIVE THERAPY FOR PEDIATRIC UROLITHIASIS: SYSTEMATIC REVIEW AND META-ANALYSIS Nermarie Velasquez, Daniel Zapata, Hsin-Hsiao Wang, John Wiener, Michael Lipkin, Jonathan Routh*, Durham, NC INTRODUCTION AND OBJECTIVES: Despite its well- documented success in adults, published success rates of medical expulsive therapy (MET) for pediatric urolithiasis vary widely. Our objective was to determine whether the aggregated evidence supports the use of MET in children. METHODS: We searched the Cochrane Controlled Trials Register, clinicaltrials.gov , MEDLINE, EMBASE databases and recent meeting abstracts for reports in any language. The bibliographies of included studies were then hand-searched. Manuscripts were assessed and data abstracted in duplicate with differences resolved by the senior author. Risk of bias was assessed using standardized instruments. The primary outcome was the odds ratio (OR) of spontaneous stone passage vs. placebo/NSAID. Descriptive statistical analyses were performed using OR and 95% confidence intervals (95% CI) as appropriate. For univariate pooling and meta-regression, standard Dersimonian-Laird random-effects models were used. RESULTS: We identified 11,197 studies, 5 of which (3 ran- domized controlled trials, 2 retrospective cohorts) were included in the pooled meta-analysis of 465 patients. Mean patient ages ranged from 5.6-14.5 years. Included study populations were from Turkey, Egypt, and the United States. All studies only used alpha-adrenergic blockers (tamsulosin/doxazosin). Pooled results demonstrate that MET increased the odds of spontaneous stone passage (OR 2.21, 95% CI 1.40-3.49, p¼0.0007). Between-study heterogeneity was not significant (I2¼14%, p¼0.36). Univariate meta-regression models revealed no significant association between the likelihood of stone passage and COI (0.9), country (p¼0.7), age (p¼0.4), gender (p¼0.4), follow-up (p¼0.3), or stone size (p¼0.7). There was little evidence of publication bias via funnel plot. Selection bias could not be ruled out in any study. Adverse effects of MET were reportedly minimal (1 study withdrawal out of 465 included patients). CONCLUSIONS: Consistent with the adult literature, pediatric studies demonstrate that MET results increases the odds of sponta- neous stone passage with a low rate of adverse events. However, due to inconsistent reporting it is unclear whether published studies are at risk of bias. Vol. 193, No. 4S, Supplement, Sunday, May 17, 2015 THE JOURNAL OF UROLOGY â e465