Ureteroscopic laser lithotripsy for upper urinary tract calculi with active fragment extraction

2006 UroTodayAug 15 2006

In this study, the authors have changed the paradigm for ureteroscopic stone removal in several ways:

1. the concept was fragment and remove rather than the traditional fragment and let pass approach,
2. at 1 month, stone free status was judged by CT scan (albeit with 5 mm slices), and
3. patient postoperative status at 1 month was reported as stone free (i.e. no stones 2mm or larger seen on CT), 2mm- 3.9 mm fragments, and 4 mm or larger fragments.

Key to this approach is use of a holmium laser, flexible ureteroscope, and a 14F ureteral access sheath as the last greatly facilitates rapid repeated entry into the kidney; also, lower pole stones, which accounted for 33% of their study population, were dislocated into the upper pole. Among 58 patients, the average stone size was 9.4 mm; the average operative time was 45 minutes. At 1 month, on CT scan, success rates were 54%, 84%, and 95% with the criteria of stone free/< 2mm fragments, 2-3.9 mm fragments, and 4 mm or larger fragments, respectively. The key take home points in this article are clear: a ureteral access sheath facilitates ureteroscopic stone removal (as previously documented by Preminger and associates) and postoperative stone status must be determined by CT scan, as originally suggest by Pearle and colleagues)^1,2. My only concern with this article is that I would have opted for 3 mm cuts through the kidney as with 5 mm cuts, stones up to 4 mm can be missed. As Dr. Munver noted in the editorial comment, it will be interesting to follow these patients to see what the fate of ureteroscopic residual calculi are; hopefully the authors will repeat the CT scan on their patients at 3-6 months postoperative (with both 5mm and then 3 mm cuts) and provide us with this very important information.

¹ - Pearle, M. S., Watamull, L. M., and Mullican, M. A.: Sensitivity of noncontrast helical computerized tomography and plain film radiography compared to flexible nephroscopy for detecting residual fragments after percutaneous nephrostolilthomotomy. J. Urol. 162: 23, 1999.

² - L'esperance, J.O., Ekeruo, W.O., Scales, C.D. Jr., Marguet, C.G., Springhart, W.P., Maloney, M.E., Albala, D.M., and Preminger, G.M. Effect of ureteral access sheath on stone-free rates in patients undergoing ureteroscopic management of renal calculi. Urology 66:252, 2005.

J. Urology 175: 2129-2134, June 2006