Could surgical experience of adult endourologist overcome the learning curve of retrograde intrarenal surgery in children?

With the increasing of the prevalence of pediatric urolithiasis (1-5%), retrograde intrarenal surgery (RIRS) is emerging as preferred option for the management of stones in pediatric patients. Although the principles of RIRS developed in adults can be applied in children, also expert adult endourologists feel uncomfortable to approach young patients due to long learning curve that usually is expected to be required in this particular setting. The aim of the study was to compare peri- and postoperative outcomes of RIRS in pediatric and adult patients performed by a single surgeon expert in adult endourology (> 500 RIRS) with no experience in pediatric urology. Data on patient characteristics of 30 consecutive patients (15 adults and 15 children) undergoing RIRS at our institution were collected retrospectively from January 2016 to October 2018. Mean age for the pediatric group was 11.8 years (IQR 8-16) and for the adult group was 56 years (IQR 49-58). No significative differences between the two groups in terms of peri- and postoperative outcomes were found. The most common complication was hematuria in 2/30 patients (1 children vs 1 adults) and fever 2/30 (1 pediatric patient vs 1 adult) (p = 1.00) that required antibiotic treatment (Clavien Dindo 2). Median length of stay was 1 day (IQR 1-1 days) in both groups (p = 1.00). Stone-free rate was 86.7% in children and 80% in adults (p = 0.624). Our preliminary experience suggests that expert adult endourologist can manage successfully also pediatric cases with results comparable to adults and low complication rate.