A Novel Robot-Assisted Laparoscopic Pyeloplasty Technique to Ensure Secure Anastomosis for Lower Pole Ureteropelvic Junction Obstruction in a Patient With an Incomplete Duplicated Collecting System.

INTRODUCTION: Ureteropelvic junction obstruction (UPJO) in patients with a duplicated collecting system is rare, and evidence on robot-assisted laparoscopic pyeloplasty (RALP) and technical strategies for end-to-side pyeloureterostomy in such cases remains limited.

MATERIALS AND SURGICAL TECHNIQUE: We present technical refinements used during RALP in a patient with an incomplete duplicated collecting system. First, an open-ended ureteral catheter was used to guide accurate ureteral incision and secure anastomosis. Second, the dorsal pelvis of the lower pole was anastomosed to the larger-caliber common ureter rather than the narrow upper pole ureter. To ensure a tension-free anastomosis, the kidney and pelvis were mobilized as needed. Third, an M-shaped traction technique was applied during posterior wall suturing: the lateral stay suture was tied, while the medial one was left untied and retracted with a bulldog clamp to create a groove, enhancing lumen visibility and enabling continuous posterior suturing under direct vision.

DISCUSSION: This case demonstrates the feasibility of end-to-side pyeloureterostomy for UPJO with incomplete duplication using robotic techniques. Key modifications-catheter-assisted incision, anatomical mobilization, and M-shaped traction-allowed for precise anastomosis. Further case accumulation is needed to validate these strategies for similar anatomical variations.