Modified Nondismembered Pyeloplasty for Ureteropelvic Junction Obstruction Using Axial Advancement of Renal Pelvic Flaps: Technique and Clinical Outcomes.

Background and objective: Nondismembered pyeloplasty (NDMP) has been extensively used to treat ureteropelvic junction obstruction (UPJO), but broader application is limited by certain factors. Our aim was to describe a novel, concise, modified NDMP (mNDMP) procedure using an axially advanced renal pelvic flap from the self-enlarged pelvis and to report clinical outcomes. Methods and surgical procedure: Patients who underwent open or robot-assisted mNDMP between May 2018 and September 2023 were included. We collected perioperative variables and assessed the outcomes. The stenosis was longitudinally incised and cut in an antegrade fashion towards the normal distal ureter. The renal pelvic flap was advanced caudally and anastomosed to the normal distal ureter using finely interrupted sutures. Advancement of the contralateral renal pelvic flap depended on the stenosis severity. A broad "ureteral plate" was constructed by axially advancing the renal pelvic flaps, followed by antegrade placement of a double-J stent. Demographic, perioperative, and postoperative data were retrospectively compared. Success was defined as relief, stabilization, or the absence of hydronephrosis according to imaging or clinical symptoms. Key findings and limitations: The study cohort comprised 82 patients with mean follow-up of 35.38 mo. The median stenosis length was 1.00 cm (interquartile range [IQR] 0.85-1.50) and median operative time was 115 min (IQR 95.50-131.50). The median postoperative length of stay was significantly shorter in the robotic group (6 d vs 8 d; Conclusions and clinical implications: The study results demonstrate that our concise mNDMP technique via both open and robotic approaches is safe and effective for UPJO repair. Patient summary: We describe a modified technique to repair a narrow segment at the junction between the kidney and the tube draining urine to the bladder. The technique involves surgery without removing the narrow portion of tube that is blocking urine. Our results show that this is a feasible option for patients with this condition and that robot-assisted surgery resulted in faster recovery.