Missed anterior crossing vessels during open retroperitoneal pyeloplasty: Laparoscopic transperitoneal discovery and repair

Purpose: Extrinsic ureteropelvic junction obstruction due to anterior cross ing segmental renal vessels is present in more than 50% of patients in adul thood. In this situation the ureter must usually be dismembered and transpo sed anterior to the crossing vascular structures, where it is anastomosed t o the renal pelvis. Via the open retroperitoneal approach there may be a li mited view of the anterior surface of the ureteropelvic junction and, hence , anterior crossing vessels may possibly be missed. We describe 2 patients with ureteropelvic junction obstruction in whom anterior vessels were misse d during open retroperitoneal repair. Laparoscopic transperitoneal secondar y pyeloplasty with posterior displacement of the crossing renal vessel was performed in each case. Materials and Methods: Two patients presented with symptomatic congenital u reteropelvic junction obstruction after failed endopyelotomy in 1 and faile d open retroperitoneal procedures in both. Preoperatively spiral computeriz ed tomography angiography with a ureteropelvic junction protocol revealed c rossing vessels in the 2 cases. This finding was confirmed at transperitone al laparoscopic pyeloplasty. The ureter and renal pelvis were transposed an terior to the crossing vessels and 2 rows of running sutures were placed to complete the anastomosis. Results: The 2 laparoscopic procedures were completed successfully. The ant erior crossing vessels were preserved in each case. Currently the patients are asymptomatic and furosemide washout renal scan was normal. Conclusions: Spiral CT angiography reliably delineates the renal vascular a natomy in patients with ureteropelvic junction obstruction. This study may be valuable before planned open retroperitoneal ureteropelvic junction obst ruction repair. Laparoscopic pyeloplasty may successfully manage anterior c rossing vessels associated with secondary ureteropelvic junction obstructio n.