To investigate the feasibility and safety of robotic-assisted laparoscopic pyeloplasty (RALP) in infant ureteropelvic junction obstruction.

Of 31 infants who underwent RALP between March 2017 and August 2017 were reviewed, including 25 boys and 6 girls. 22 infants were found that the hydronephrosis was in the left kidney and 9 in the right kidney. The average age of the infants was (3.5±0.7) months, ranged from 8 days to 6 months, including 7 infants less than 2 months. The average weight of the infants was (6.7±1.2) kg, with a minimum weight of 3.3 kg. The diagnosis and outcomes of ureteropelvic junction obstruction (UPJO) were reviewed on clinical and imaging data. The ultrasound showed that the mean anteroposterior diameter of hydronephrotic kidney was (4.01±0.56)cm. The split renal function was (37.1±3.2)% in infants who were more than 2 months. Patients with proximal defect were positioned in the lateral flank position with 50°-70° inclination and as close as possible to the edge of operating table. The trocars of robotic lens and No.1 robotic arm were placed on the middle of the umbilicus and the Pfannenstiel line respectively, and the trocar of No.2 robotic arm was placed on the supraumbilical symmetry point of the trocar No.1 robotic arm, and the auxiliary trocar was placed on the Pfannenstiel line outside the 3-4 cm of healthy side of the trocar of No.1 robotic arm. During operation, the ureteropelvic junction was dissected and tailored. Then the ureter was open longitudinally at the posterior lateral side and was anastomosed at the lowest part the renal pelvis. We assessed preoperative clinical data and outcomes, and analyzed the transition experience. Data are expressed as medians for continuous variables.

All operations were successful with no serious intraoperative complication and traditional laparoscopic or open surgical conversion. The average operative time was 108 min, the average intraoperative blood loss was 9.5 ml. The average drain removal was 1.2 days, the average start oral of feeding was 3.2 hours days and the average postoperative hospital stay was 6.2 days. Postoperative pathological results showed smooth muscle hyperplasia, hypertrophy and fibrous tissue in the urothelium, accompanied by chronic inflammation of urothelial mucosa. Patients with Clavien Ⅰ and Ⅱ complications 22.6%(7/31) postoperatively were managed conservatively. Among them, there were 1 cases of flank pain, 1 cases of hematuria, 2 cases of urinary leakage, and 3 cases of urinary tract infection. Patients' symptoms disappeared by conservative treatment. No patient suffered Clavien Ⅲ and Ⅳ complication postoperatively. The renal pelvis anteroposterior diameter was 1.58 cm at three months postoperatively, which was significantly smaller than that of peroperation (P<0.05). A diuretic T_1/2 showed the improvement of split renal function without urinary obstruction in all patients at three months postoperatively. The postoperative split renal function was (39.2±3.5)%, which was slightly higher than that of preoperation (P>0.05).

Severe hydronephrosis in neonates can be acted as an indication for exploratory surgery when the surgeon's ability, anesthesia, monitoring and management conditions are available. Robotic-assisted laparoscopic pyeloplasty is a safe and feasible option for the treatment of UPJO in infant with less trauma, rapid recovery and good cosmetic result. We suggest that RALP is potentially a recommended feasible treatment option for infant with UPJO.

Robotic-assisted laparoscopic pyeloplasty; Infant; Hydronephrosis; Ureteropelvic junction obstruction