Title: The Effect of Positioning on Ureteral Stone Retropulsion: “Gravity Works”

Abstract

To evaluate the potential impact of alterations in “patient” position on laser-induced ureteral stone retropulsion in an in vitro model. In this paper, a ceramic (phantom) stone was placed in a water-filled clear polymer tube and subjected to continuous laser energy until the stone had retropulsed a distance of 10cm. The trial was stopped after 60 seconds if the stone had not reached 10cm. The time and total energy needed to cause 10cm of retropulsion were recorded at an incline angle of 0°, 10°, 20°, and 40°; ten trials at each angle were completed. The study was then repeated with pure calcium phosphate brushite stones. Retropulsion decreased with increasing incline angle of the saline-filled clear polymer tube. At 0° of incline the phantom stone reached a distance of 10cm after 7.4 seconds. At 10°, 20°, and 40° the phantom stone migrated a mean maximum distance of 3.1 cm, 1.2 cm, and 0.7 cm, respectively, and the trial was stopped after 60 seconds. For the calcium phosphate stone, at 0° and 10° of incline, the stone reached 10cm after 6.9 seconds and 42.8 seconds respectively (p<0.05). At 20° and 40°, the calcium phosphate stone moved a mean maximum distance of 2.4cmmore » and 1cm, and the trial was stopped after 60 seconds. Alterations in the angle of inclination reduced stone retropulsion during ureteroscopic lithotripsy in an in vitro model to <1cm. Finally, increasing the incline angle of a patient may effectively preclude retropulsion when performing laser lithotripsy of ureteral stones.« less

Authors:

Patel, Roshan M.  ^[1];

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Walia, Arman S. ^[1]; Grohs, Evan ^[2]; Okhunov, Zhamshid  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-8294-933X"
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Landman, Jaime ^[1]; Clayman, Ralph V. ^[1]

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+ Show Author Affiliations

1. Univ. of California, Irvine, CA (United States). Dept. of Urology
2. Univ. of California, Berkeley, CA (United States). Dept. of Physics; Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Publication Date:

2018-08-10

Research Org.:

Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Sponsoring Org.:

USDOE; National Science Foundation (NSF); Heising-Simons Foundation (United States)

OSTI Identifier:

1467344

Report Number(s):

LA-UR-18-24885
Journal ID: ISSN 1464-4096

Grant/Contract Number:  

AC52-06NA25396; PHY-1630782; 2017-228

Resource Type:

Accepted Manuscript

Journal Name:

BJU International

Additional Journal Information:

Journal Volume: 123; Journal Issue: 1; Journal ID: ISSN 1464-4096

Publisher:

Wiley

Country of Publication:

United States

Language:

English

Subject:

60 APPLIED LIFE SCIENCES; nephrolithiasis, ureteroscopy, retropulsion, patient positioning, gravity