Performing flexible ureteroscopy through a cystoscopy introducer sheath

Ureteral Access Sheath for the Management of Pediatric Renal and Ureteral Stones: A Single Center Experience

PURPOSE

Ureteral access sheaths were developed to facilitate difficult ureteroscopic access in adults. We report our use of the ureteral access sheath during standard ureteroscopic procedures in the pediatric stone population.

MATERIALS AND METHODS

Eight patients underwent flexible ureteroscopy and holmium laser lithotripsy for symptomatic renal and ureteral calculi between October 2003 and October 2004. Average patient age was 9.3 years (range 4 to 13). There were 4 males and 4 females. Five of 8 patients had bilateral stones and underwent bilateral endoscopic stone treatment at the same operation. A 14Fr 20 cm Flexor ureteral access sheath was used for dilation and access of the ureter. Flexible pediatric ureteroscope was used to enter the ureter and collecting system for stone retrieval and fragmentation.

RESULTS

All patients were rendered stone-free in a single operative setting. Average operative time was 99 minutes (range 65 to 130). Average total stone burden for the group was 9 +/- 3 mm. All patients received stents after the procedure. There were no perioperative complications. All patients were followed with renal-bladder ultrasound and plain x-ray. All patients were stone-free at a mean followup of 10 months (median 11).

CONCLUSIONS

Routine use of a ureteral access sheath in children facilitates flexible ureteroscopy with lithotripsy of multiple renal and proximal ureteral stones. The procedure is safe and time efficient, and is associated with minimal morbidity. Larger prospective studies in children with longer followup are warranted.

Characterization of intrapelvic pressure during ureteropyeloscopy with ureteral access sheaths

OBJECTIVES

To evaluate the impact of the ureteral access sheath on intrarenal pressures during flexible ureteroscopy in light of the recent resurgence in their use. As such, using human cadaveric kidneys, we studied changes in intrarenal pressure in response to continuous irrigation at different pressures with and without access sheaths of various sizes and lengths.

METHODS

This study was performed using seven cadaveric kidneys. In three kidneys the study was done in situ with a 7.5F flexible ureteroscope (URS) passed by itself and then passed through a 10/12F sheath (35 and 55 cm in length), whereas, in four kidneys, due to narrowing of the intramural ureter, the study was done ex vivo using the unsheathed URS and then passing the 7.5F flexible URS via the 10/12F, 12/14F, and 14/16F sheaths (all 35 cm in length). A 10F Cope loop pyelostomy was placed to measure intrapelvic renal pressure. Three sets of 3-minute readings (ie, flow and intrarenal pressure) were taken with the tip of the URS at the distal ureter, middle ureter, and renal pelvis (just above the ureteropelvic junction); the entire process was done at three different irrigant pressure settings: 50, 100, and 200 cm H(2)O. Irrigant flow and intrarenal pressures were measured at all three settings using the URS passed without a sheath and then with the URS passed through the various sheaths positioned at the distal ureter, middle ureter, and renal pelvis.

RESULTS

With all of the sheaths, intrapelvic pressure remained low (less than 30 cm H(2)O), and there was a 35% to 80% increase in irrigant flow versus the control unsheathed URS. With the sheath in place, the majority of the irrigant drained alongside the URS and out the sheath. Flow and pressure with the 12/14F sheath were equivalent to the 14/16F sheath.

CONCLUSIONS

The 12/14F access sheath provides for maximum flow of irrigant while maintaining a low intrarenal pelvic pressure. Even with an irrigation pressure of 200 cm H(2)O, renal pelvic pressure remained below 20 cm H(2)O.

Maximizing ureteroscope deflection: "play it straight"

We studied simple maneuvers to optimize active deflection of the flexible ureteroscope. Up to 61 degrees of active deflection is lost if the ureteroscope is not kept in a straight alignment. Holding the ureteroscope taut, placing a super-stiff guidewire in the working channel, or using an access sheath maximizes active deflection.

Ureteral access for upper urinary tract disease: the access sheath

Ureteral access with the flexible ureteroscope remains a challenge for the urologist. The routine use of a newly developed, site-specific ureteral access sheath facilitates entry into the ureter for fragmentation and basket extraction of ureteral and renal calculi. The step-by-step technique of ureteral access with the Access Sheath is described.