Does the body weight influence the outcome in children treated with robotic pyeloplasty?

Aim of the study: To investigate the influence of the body weight on peri and postoperative outcome in a series of pediatric patients with a diagnosis of ureteropelvic junction obstruction (UPJO) treated with robot-assisted laparoscopic pyeloplasty (RALP) at a single tertiary referral centre. Materials and methods: Fifty consecutive patients treated with RALP from January 2016 to October 2018 were divided according to their weight: group A < 15 Kg, group B ≥ 15 Kg and were included in the present study. Eligible criteria for surgery were symptomatic UPJO, worsening of hydronephrosis or obstructive pattern at renogram. Success criteria were resolution of the hydronephrosis at imaging and absence of flank pain. All procedures were performed by one expert robotic surgeon. Results: 14 patients were included in group A (median weight 12 Kg) and 36 patients in group B (median weight 36 Kg). We registered one (7.1%) Clavien 3b complication (omental hernia after removal of the drainage requiring surgical correction) and one (2.8%) Clavien 2 complication in group B (urinary infection). No difference has been found in length of hospital stay, length of catheterization, duration of procedure between the groups (p > 0,05). At a median follow up of 21.5 months, overall success rate was 98%. One patient needed nephrostomy positioning for persistent hydronephrosis. Discussion: RALP in children <15 Kg was feasible and effective to treat UJPO with superimposable results to heavier counterparts. In our experience, the need for a different trocar placement and limited space in patients <15 Kg did not affect perioperative and functional outcomes.