Ureteropelvic junction obstruction (UPJO) is a prevalent cause of hydronephrosis in pediatric patients, with an incidence of 1 in 1,000 to 1,500. Approximately 50% of surgically treated UPJO cases are due to entrapment of the ureter by a crossing accessory renal vessel. We present a case who was diagnosed with UPJO following a urinary tract infection (UTI) and subsequently treated with robot-assisted pyeloplasty.

The patient is a 15-year-old male with no underlying diseases. He experienced a UTI in 2023 and was admitted to a local hospital. During the admission, a CT scan revealed right UPJO with severe hydronephrosis. A temporary double-J ureteral stent was placed for three months and later removed. Despite this, a follow-up CT scan in January 2024 still showed severe hydronephrosis (Fig. 1 & 2). The patient sought a second opinion at our hospital, where surgical intervention was recommended. Consequently, a right robot-assisted pyeloplasty was performed.

During surgery, an accessory renal artery was identified compressing the UPJ, along with the renal vein, exacerbating the obstruction and resulting in severe hydronephrosis. The previously placed double-J stent was initially removed under cystoscopy, and a 4Fr ureteral catheter was inserted intra-operatively. The UPJ was examined laparoscopically to precisely locate the obstruction. The accessory renal artery was looped, and the UPJ was excised cautiously and repositioned to bypass the artery. Spatulation of the resected site was performed, and a continuous suture was applied for anastomosis. A double-J stent was inserted with guidewire assistance antegradely. The upper half of the anastomosis was then completed. The follow-up sonography one month after the operation showed resolution of hydronephrosis.

The resolution of hydronephrosis in this case underscores the effectiveness of robot-assisted pyeloplasty in managing UPJO, highlighting the significant value of robotic surgery in upper urinary tract reconstruction.