ENDOUROLOGY & LAPAROSCOPY

Use of a ureteral access sheath to facilitate removal of large stone burden during extracorporeal shock wave lithotripsy
Okeke Z, Lam JS, Gupta M
Department of Urology, New York-Presbyterian Hospital, Columbia University College of Physicians and Surgeons, New York, New York, USA
Urology 2004; 63: 574-576.

• Large renal stone burdens within a nondilated collecting system in patients with a relative contraindication to percutaneous nephrolithotomy can be a challenging problem. We describe a novel technique using a ureteral access sheath combined with extracorporeal shock wave lithotripsy to facilitate passage of stone fragments in such patients.
  
  
• Editorial Comment
  A ureteral access sheath is a hollow sheath that is placed with an obturator over a wire into the ureter. After removing the obturator, the sheath allows rapid placement and removal of ureteroscopes and improves irrigant outflow. The internal diameter of the devices ranges from 9.5 to 16 F, with lengths from 20 to 55 cm. Although ureteral access sheaths have been available for many years, they did not become popular until some modifications by Applied Medical (Rancho Santa Margarita, CA, USA) made them easier to insert and more rigid. Further modifications by Applied and then others - there are now sheaths available from at least 3 other companies - have included additional kink resistance, hydrophilic coatings, extra channels for guidewires, and improved obturators. Many endourology experts have advocated their routine use in all flexible ureteroscopic procedures, to ease ureteroscope passage, minimize pressure in the upper tract, and facilitate rapid removal and re-insertion of the ureteroscope for fragment or biopsy retrieval. Others use them only for specific indications. I consider them to be most useful when there is a good reason to remove stone fragments rather than simply fragmenting the stone ureteroscopically and depending on spontaneous fragment passage. This typically is the case when renal drainage is poor (i.e., very dependent and dilated lower pole) and even small fragments are unlikely to pass, or if the stone burden is very large and the sheer volume of fragments might be problematic. Okeke and associates found a novel use for a ureteral access sheath in the setting of large stone burden, in that they positioned the end sheath just inside the ureteropelvic junction to facilitate active irrigation of fragments during shock wave lithotripsy, with the end result being that many of the fragments washed out of the kidney during the procedure. Given the large stone burden, the stone free result in the patient were excellent. The operative time is not provided, although I imagine that the procedure was fairly tedious. I have used a similar technique during ureteroscopic treatment of large renal stones, in patients whom, for one reason or another, were not candidates for percutaneous stone extraction. In cases where active clearance of fragments is desired, a ureteral access sheath is a useful adjunct in endourological management.

Dr. J. Stuart Wolf Jr.
Associate Professor of Urology
University of Michigan
Ann Arbor, Michigan, USA