Success of Laparoscopic Robot-Assisted Approaches to Ureteropelvic Junction Obstruction Based on Preoperative Renal Function

Background and Purpose: No literature exists examining the risk factors for failure after robot-assisted laparoscopic pyeloplasty for ureteropelvic junction obstruction (UPJO) in children. The goal of this study was to compare the success of robot-assisted pyeloplasty between UPJO kidneys with preoperative renal function <30% versus >30%. Methods: We performed a retrospective review of all patients who underwent a robot-assisted laparoscopic pyeloplasty for UPJO at a single institution from June 2009 to September 2013 by four surgeons. A failed procedure was defined as necessitating a second surgery for the UPJO, nonresolution of symptoms with no improvement of washout on postoperative mercaptoacetyltriglycine (MAG)-3 scan, and/or a reduction in renal function of the obstructed kidney to <10%. Success was compared between patients with <30% and >30% preoperative differential renal function via the Fisher exact test. Results: There were 116 patients who were included. At a mean follow-up of 507 days after the surgical procedure, there were eight (8%) failures. The majority of the failures (5/8) were in kidneys whose preoperative function was <30%. There was a significant difference in the success of procedures performed on kidneys with >30% (86/89, 97%) versus <30% (7/12, 58%) preoperative renal function (P=0.0005). Conclusions: In this large cohort of patients, kidneys with preoperative function >30%, robot-assisted pyeloplasty had a 97% success rate. This was significantly different than the success of robot-assisted pyeloplasty (58%) in kidneys with preoperative function <30%. This information is useful for patient counseling as these patients may be at higher risk for a secondary procedure such as a subsequent nephrectomy or may benefit from a preoperative trial of nephrostomy tube drainage.