Bare naked baskets: ureteroscope deflection and flow characteristics with intact and disassembled ureteroscopic nitinol stone baskets.
OBJECTIVE
Lower pole renal access during flexible ureterorenoscopy is often limited by the active deflection capabilities of the ureteroscope. Deterioration in the deflection and flow capabilities of ureteroscopes occurs with the passage of instrumentation through the working channel. We performed in vitro evaluation of a novel technique using unsheathed nitinol baskets to minimize the deterioration in deflection and maximize the irrigant flow associated with instrument passage through the working channel during flexible ureterorenoscopy.


METHODS
Alterations in the irrigant flow and active deflection of 4 ureteroscopes from different manufacturers were evaluated. Each ureteroscope was evaluated with an empty working channel, and then with sheathed and unsheathed 2.2, 3 and 3.2Fr (Cook Urological, Inc., Indianapolis, Indiana), 2.4 and 3Fr (Microvasive Urology, Natick, Massachusetts) nitinol baskets in the working channel.


RESULTS
With all baskets tested and in all ureteroscopes the deterioration in active deflection and irrigant flow was improved with the unsheathed baskets. The disassembled basket within the working channel allowed an additional 15 to 20 degrees of active deflection. In addition, the disassembled basket allowed for a 2 to 30-fold increase in irrigant flow compared with an intact basket.


CONCLUSIONS
The combination of improved deflection and irrigant flow with this technique may improve ureteroscopic access to lower pole renal calculi.
Landman
Jaime
J
Division of Urology, Department of Radiology, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA.
Monga
Manoj
M
El-Gabry
Ehab A
EA
Rehman
Jamil
J
Lee
David I
DI
Bhayani
Sam
S
Sundaram
Chandru P
CP
Clayman
Ralph V
RV
D000497:Alloys; D004867:Equipment Design; D006801:Humans; D066298:In Vitro Techniques; D007669:Kidney Calculi / Q000628:therapy*; D012212:Rheology; D007507:Therapeutic Irrigation; D020709:Ureteroscopes; D018666:Ureteroscopy
D000497:Alloys; C013616:nitinol