What is the learning curve for Paediatric Percutaneous Nephrolithotomy?

Abstract

Purpose Paediatric urinary tract stones are infrequent in the U.K. In our unit. PCNL is performed jointly by the paediatric urologist and paediatric radiologist only. We reviewed our experience to determine what constituted the ‘learning curve’ for paediatric PCNL. Material and Methods We reviewed the notes of 26 children who underwent PCNL in 2 years. Measures of outcome to achieve competence was defined as time taken (number of cases) to attain the plateau phase of the learning curve. Defined outcome measures were success of first pass puncture and track formation, complete stone clearance by preoperative fluoroscopy and postoperative ultrasonography, overall time required for the procedure and complications. Results There were 28 episodes of PCNL. The first 4 cases performed under supervision had a successful puncture and track formation and complete stone clearance without complications. The overall time required was 97 minutes (46-128). Of the next 4, two had a failed puncture. The remaining two had successful track formation and complete stone clearance without complications. The overall operating time was 183 minutes (150-237). The subsequent 20 (including the two with failed puncture) had a successful puncture and complete stone clearance in all but the last case with abnormal calyceal anatomy in a scarred upper pole. Of these a first pass puncture was successful in all cases after case 12. There were no complications. The overall operating time was 146 minutes (90-220). All children were discharged within 48 hours of surgery. Conclusions Numerous factors are responsible for determining the learning curve for paediatric PCNL including the stone burden, dilatation of the collecting system and renal scarring. In our review a consistent steady state was achieved after 12 cases. Failure may still occur in difficult cases despite overcoming the learning curve.