Endoscopic assisted robotic pyelolithotomy: A viable treatment option for complex pediatric nephrolithiasis

Summary Introduction and Objective: Endourological and percutaneous approaches are the standard of care for treatment of pediatric urolithiasis. However, in certain situations, an endoscopic assisted robotic pyelolithotomy (EARP) can be an acceptable alternative. Limited data exists on pediatric EARP; thus, we describe our experience. Methods Patient Selection: We retrospectively analyzed the records of all robotic procedures performed at five institutions from 7/09 - 10/17 to identify patients who underwent EARP. We collected demographics data, indications, operative time, and postoperative complications. Stone composition was reported as the majority composition ( > 50%), unless any uric acid or struvite was noted and those stones were classified as such. Technique Through a traditional or HIdES robot pyeloplasty approach, we are able to easily pass a flexible endoscope through a robotic trocar and into the renal collecting system to perform pyeloscopy or ureteroscopy. Stones were primarily retrieved via the pyelolotomy and, if indicated, treated with laser lithotripsy. Results We identified 26 patients who underwent EARP in 27 renal units. Median patient age was 12.2 years (IQR 6.1 - 14.5 years) and BMI was 17.5 kg/m2 (IQR 16.5-25.4 kg/m2). The median preoperative dimension of the largest stone was 9.0mm (IQR 5.8mm - 15.0mm). Reasons for EARP: 21 (77.8%) concomitant pyeloplasty, 4 (14.8%) altered anatomy precluding other techniques, and 2 (7.4%) multiple large stones. Multiple stones were present in 20 renal units (74.1%). Stones were located in the renal pelvis in 9 (33.3%), lower pole in 10 (37.0%), ureter in 1 (3.7%) and multiple locations in 7 (25.9%). HIdES approach was used in 14 (51.9%) and the median operative time was 237.5 minutes (IQR 189.8 - 357.8 minutes) with a median length of stay 1.0 day (IQR 1.0 - 2.0 days). Stone composition included calcium oxalate in 14 (51.9%), calcium phosphate in 5 (18.5%), cysteine in 2 (7.4%), struvite in 2 (7.4%), and unknown in 4 (14.8%). Overall stone free status was 19 (70.4%); of the 8 (29.6%) Renal units with residual stones, 4 underwent ureteroscopy, 2 ESWL, 1 spontaneously passed, and 1 underwent PCNL. After secondary treatment, final stone free rate was 96.3%. Complications included stent migration, and admission for urosepsis. At a median follow up of 12 months (IQR 6.2 - 19.2 months), 5 (18.5%) had stone recurrence. Conclusions EARP is a reasonable treatment option for select pediatric patients with concomitant ureteropelvic junction obstruction and nephrolithiasis, or pediatric patients with stones inaccessible by standard methods.