Outcomes of robot-assisted laparoscopic pyeloplasty among pediatric patients with complex renal anatomy: A retrospective comparative study.

Introduction: Robot-assisted laparoscopic pyeloplasty (RALP) has been increasingly utilized in the treatment of pediatric ureteropelvic junction obstruction (UPJO) with reported success rates of >95%. Complex renal anatomy can make some cases challenging to reconstruct.

Objective: To evaluate outcomes of children undergoing RALP with aberrant renal anatomy and compare it to those with simple renal anatomy.

Methods: An IRB approved prospective registry was queried to retrospectively identify all patients who underwent robotic pyeloplasty at our institution from 2012 to 2022. Patients undergoing re-do pyeloplasty were excluded. Complex anatomy was defined as horseshoe kidney, ectopic/pelvic kidney, duplex collecting system, fully bifid renal pelvis and severe malrotation (≥180°). A comparative analysis of baseline demographics, pre-operative clinical/radiological characteristics, intra and post-operative details, and long-term success was performed between those patients with complex anatomy and those without.

Results: Of 405 total robotic pyeloplasty's, 375 patients (378 total pyeloplasty; 353 simple, 22 complex) met inclusion criteria. 27 re-do were excluded from analysis. The complex pyeloplasty cohort included 9 horseshoe kidneys, 8 duplex collecting systems, 3 ectopic/pelvic kidneys and 2 kidneys with severe malrotation. There was no difference in age (58 vs 31 months; p = 0.38), procedure time (203 vs 207 min; p = 0.06), length of stay (1.4 vs 1.3 days; p = 0.99), or success (91.6% vs 100%; p = 0.24) between the simple and complex groups. Etiology of obstruction differed significantly between groups - high insertion was more common (3.9% vs 18.2%, p = 0.02) and intrinsic narrowing was less common (60.1% vs 36.4%, p = 0.04) in patients with complex anatomy. A multivariate logistic regression was adjusted for age, gender, etiology of obstruction, preoperative differential renal function and post-operative complications and found no difference in success between complex and simple RALP.

Discussion: The findings showed no significant differences in age, procedure time, length of hospital stay, or success rates between the two groups. Specifically, the success rates were 91.6% for the complex group and 100% for the simple group (p = 0.24), indicating comparable efficacy. However, the etiology of obstruction varied significantly, with high ureteral insertion more common in the complex anatomy group (18.2% vs. 3.9%, p = 0.02) and intrinsic narrowing less common (36.4% vs. 60.1%, p = 0.04). Despite these differences, multivariate logistic regression, adjusted for confounders, confirmed no difference in success rates between the groups.

Conclusion: RALP is a safe and efficacious approach in patients with complex anatomy with success rates comparable to index patients. High ureteral insertion does appear to be more common in patients with complex anatomy undergoing pyeloplasty.