Stone-free rates improve with access sheaths

March 1, 2005

Mumbai, India—Overall stone-free rates are significantly improved in patients with renal calculi who undergo ureteroscopy using a ureteral access sheath compared with those treated without access sheaths, report researchers from Duke University, Durham, NC. Stone-free rates are improved for calculi in all portions of the kidney, they said during a presentation at the World Congress on Endourology.

Mumbai, India-Overall stone-free rates are significantly improved in patients with renal calculi who undergo ureteroscopy using a ureteral access sheath compared with those treated without access sheaths, report researchers from Duke University, Durham, NC. Stone-free rates are improved for calculi in all portions of the kidney, they said during a presentation at the World Congress on Endourology.

Several advantages of ureteral access sheaths during flexible ureteroscopy have been documented previously, including the facilitation of repetitive access, improved irrigant flow to wash out small fragments, improved visualization, and decreased intrarenal pressure. Previously, the ability of ureteral access sheaths to improve stone-free rates during the management of calculi has been unknown.

In the Duke study, 249 flexible ureteroscopic procedures for the removal of renal calculi were analyzed (166 with ureteral access sheaths, 83 without), said James L'Esperance, MD, an endourology fellow working with Glenn M. Preminger, MD. Stents were placed in nearly 80% of the cases. The lower renal pole represented the most common presenting location and required stone displacement with an ureteroscopic basket for efficient fragmentation in 34% of the cases. The difference in overall stone-free rate was significantly greater among the ureteral access sheath group than the non-access sheath group (79% vs. 67%, respectively; p=.04).

In addition to facilitating ureteroscopy, the use of ureteral access sheaths may reduce overall costs, according to urologists at the University of Utah, Salt Lake City.

"The regular use of ureteral access sheaths in flexible ureteroscopy would result in decreased mechanical breakage of the ureteroscope and thereby justify the added cost of the ureteral access sheaths," said Blake Hamilton, MD, associate professor of urology at the University of Utah, working with D. Brooke Johnson, MD.

The Utah group retrospectively reviewed 180 consecutive cases of ureteroscopy in 193 renal units over a 24-month period, in which 135 cases included flexible ureteroscopy with a single ureteroscope (DUR-8, ACMI, Southborough, MA). Group 1 consisted of 57 flexible ureteroscopy procedures over 9 months, while group 2 consisted of 78 flexible ureteroscopy procedures over 15 months.

Of the 57 flexible ureteroscopy cases in group 1, 14 (24.6%) were performed with ureteral access sheaths and 43 (75.4%) were performed without them. Of the 78 cases in group 2, 48 (61.5%) were performed with ureteral access sheaths, and 30 (38.5%) were done without ureteral access sheaths. Three mechanical scope events occurred in group 1 (19 cases per repair), and three such events occurred in group 2 (26 cases per repair).

The cost of the ureteral access sheaths was offset by the decreased cost of repairs per case, Dr. Hamilton said. More frequent use of ureteral access sheaths during flexible ureteroscopy cases also increases the working life of a flexible ureteroscope.

"We believe that this is due to the ease of passage through the ureteral access sheaths," he said. "In addition, for cases involving repetitive access, the ureteral access sheaths facilitates re-access, which should provide additional savings in OR time."

Dr. Preminger is a consultant for Boston Scientific and Olympus America, Inc.