Ureteral sheath may induce severe ureteric injuries

Paris-Insertion of a ureteral access sheath during retrograde intra-renal surgery may induce severe ureteric injuries, according to a prospective analysis of 136 patients undergoing procedures using ureteral access sheaths.

In the analysis, exactly half of patients had at least one iatrogenic injury of the ureteric wall, reported first author Saeed M. Al-Qahtani, MD, assistant professor of urology at Tenon University Hospital, Pierre and Marie Curie University, Paris.

“Following introduction of the ureteral access sheath in 2000-2001, it was reported that it facilitated the procedure, reduced the intra-renal pressure, minimized cost, and reduced the operative time,” Dr. Al-Qahtani said at the 2012 AUA annual meeting in Atlanta. “However, there has been no long-term follow-up of these instruments.”

The outside diameter of the sheath ranges from 9.5F to 17.5F, compared with a mean ureteric wall diameter that is usually estimated at 8F. The standard ureteral access sheath is 12/14F.

The aim of the prospective analysis was to evaluate clinical predictors of ureteric injuries during flexible ureterorenoscopy caused by ureteral access sheaths. The procedures were performed by two urologists at two centers who used a 12/14F access sheath (made by Cook Medical, Bloomington, IN). Fifty-four patients (39.7%) were pre-stented.

Ureteric endoscopic injuries were classified based on ureteral wall injury as follows:

• Grade 0: no lesion

• Grade 1: mucosal erosion of ureter without injury of smooth muscle

• Grade 2: injury of ureteral wall, including mucosa and smooth muscle with preservation of adventitia (peri-ureteral fat is not visible)

• Grade 3: injury of ureteral wall including mucosa and smooth muscle with perforation of adventitia (peri-ureteral fat is visible).

When different types of injuries co-existed, the higher grade was documented.

Fifty percent of the 136 patients had a certain degree of ureteral injury. Thirty-five percent had grade 1 injury, 11% had grade 2, and 4% had grade 3.

Pre-stenting linked to lower injury rate

Variables examined included age, gender, body mass index, history of ureteroscopy, pre-stenting or no pre-stenting, and operative time. The incidence of ureteric injuries was significantly lower in pre-stented patients (p<.0001), as was the severity of injuries (p<.0001). Moreover, operative time correlated with the incidence of ureteric injuries (p=.031). Other variables were not significantly associated with the incidence or severity of ureteral wall injuries.

In the early 2000s, some clinicians proposed using ureteral access sheaths in every case of flexible ureteroscopy, Dr. Al-Qahtani said, whereas others advocated sheathless ureteroscopy. From his data, he concludes that a full ureteroscopic evaluation is mandatory at the end of the procedure, and that pre-stenting can reduce the risk of ureteral injury.

“A great debate will be going on for 10 years, as we follow these patients to see the results and the complications,” he said.