Crossing vessel transposition optional in pyeloplasty

November 1, 2006

Cleveland-Routine transposition of an anterior crossing vessel during laparoscopic pyeloplasty may be unnecessary, appears to depend on the surgeon's intraoperative subjective assessment of its obstructive nature, and seems to occur more often when a transperitoneal approach is used, Cleveland Clinic investigators reported.

Cleveland-Routine transposition of an anterior crossing vessel during laparoscopic pyeloplasty may be unnecessary, appears to depend on the surgeon's intraoperative subjective assessment of its obstructive nature, and seems to occur more often when a transperitoneal approach is used, Cleveland Clinic investigators reported.

Quite often, urologic surgeons transpose potentially obstructive crossing vessels behind pyeloplasty repairs. However, the Clinic's retrospective study of 31 patients with anterior crossing vessels showed no difference in outcomes between those who underwent transposition and those who did not.

"It's not sacrosanct that if you find a crossing vessel, you should transpose it," said Monish Aron, MD, a fellow in endourology working with Inderbir S. Gill, MD. "It sometimes depends on how you look at the vessel. If you're looking at a kidney from behind, a vessel that is anterior to the kidney may not look obstructive.

That, added Dr. Aron, was why the vessels were not transposed in 23 of the 31 patients in the study. Those 31 were a subset of 70 patients who underwent laparoscopic pyeloplasty for ureteropelvic junction obstruction at the Cleveland Clinic from March 2000 to December 2004.

All of the patients with anterior crossing vessels had resolution of their obstruction following surgery. No significant difference between the transposition and non-transposition groups was seen in terms of preoperative and postoperative function, but the investigators did note that seven of eight patients in whom transposition was performed were treated transperitoneally.

In contrast, 17 of the 23 patients whose vessels were not transposed were operated on in a retroperitoneal fashion.

"Go in and look at the vessels," Dr. Aron advised colleagues here at the 2006 World Congress of Endourology. "If the anterior crossing vessel is in the way, reassess the lie of the vessel, pelvis, and ureter once you've mobilized and dismembered the UPJ. If it's not in the way of the repair and the future position of the reconstructed UPJ, leave it alone because it may not impact outcomes.

"Why did we transpose in these eight patients? It was essentially dependent on the individual surgeon's perception of the anatomy of a given case. While they were in there looking at the vessel and the UPJ, if it didn't appear that it was in the way of the repair, they didn't transpose it."

Dr. Aron added that, to him and his Cleveland Clinic colleagues, it seemed at times that transposition could actually contribute to obstruction at the site of anastomosis.

"It would form a hump across which the anastomosis would lie, and it would be counterproductive," he said. "That's how it appeared. And in any case, we still don't know for certain right now whether vessels that cross the ureteropelvic junction actually lead to obstruction."