1527 DETERMINANTS OF HO:YAG CUMULATIVE LASER ENERGY AND TIME DURING URETEROSCOPIC LASER LITHOTRIPSY

Abstract

You have accessJournal of UrologyStone Disease: SWL, Ureteroscopy or Percutaneous Stone Removal (I)1 Apr 20131527 DETERMINANTS OF HO:YAG CUMULATIVE LASER ENERGY AND TIME DURING URETEROSCOPIC LASER LITHOTRIPSY Wilson Molina, Giovanni Marchini, Alexandre Pompeo, David Sehrt, Fernando Kim, and Manoj Monga Wilson MolinaWilson Molina Denver, CO More articles by this author , Giovanni MarchiniGiovanni Marchini Cleveland, OH More articles by this author , Alexandre PompeoAlexandre Pompeo Denver, CO More articles by this author , David SehrtDavid Sehrt Denver, CO More articles by this author , Fernando KimFernando Kim Denver, CO More articles by this author , and Manoj MongaManoj Monga Cleveland, OH More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.3017AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES To investigate the relationship between preoperative non-contrast computed tomography (NCCT) stone characteristics and total Ho:YAG laser time and cumulative laser energy during ureteroscopic (URS) laser lithotripsy. METHODS We retrospectively reviewed patients with ureteral and/or renal stones who underwent URS and Ho:YAG laser lithotripsy between April/10 and May/12 at two tertiary centers. Inclusion criteria were stone size <4 mm; NCCT; operative data including laser time and energy; stone composition. Laser lithotripsy was performed using a Ho:YAG laser (200 or 365 μm fiber); laser settings were set to 0.8J and 8Hz. Fragments <5 mm were considered suitable for removal. Pearson's correlation and regression analysis were performed to evaluate associations between patient and stone characteristics and laser energy and time. Significance was set at p<0.05. RESULTS 100 patients met our inclusion criteria. After controlling for stone size, we found no significant correlation between HU and laser energy (R=0.133, p=0.20). However, the correlation of HU with laser time (R=0.262, p=0.011), and HUD with laser energy (R=0.238, p=0.021) and time (R=0.264, p=0.014) were significant. On univariate analysis, cumulative laser energy had a positive significant association only with stone volume (Fig1A). With the exception of stone composition, all parameters significantly impacted laser energy on multivariate analysis (R2=0.459; table 1). Laser time had a significant positive correlation only with stone volume on univariate analysis (fig1B). Multivariate analysis revealed a significant positive association with stone volume and HUD (R2=0.499). A second regression analysis was performed considering all calcium stone compositions separately and revealed no cumulative laser energy or total laser time difference among the distinct stone compositions. CONCLUSIONS Ho:YAG laser cumulative energy and total time are significantly affected by stone dimensions and hardness. Stone composition does not affect cumulative laser energy and time. Table 1. Univariate and Multivariate Models for cumulative laser energy and total laser time. Laser Energy Univariate Analysis Multivariate Analysis B 95% CI p-value R2 B 95% CI p-value R2 Volume (cm3) 3078.8 2056.6-4100.9 <0.001 0.280 3715.8 2715.0-4715.3 ⁎<0.001 0.459 Location (renal) 652.1 −47.2-1351.4 0.067 0.036 667.3 41.3-1293.3 ⁎0.037 HUD (HU/cm) −39.2 −101.3-23.0 0.214 0.018 65.0 10.6-119.4 ⁎0.020 Fiber (365um) 213.6 −519.2-946.4 0.564 0.004 960.0 328.8-1591.3 ⁎0.003 Calcium Stone −97.4 −1792.8-1598.0 0.909 <0.001 −188.8 −1146.9-1069.3 0.766 Univariate Analysis Multivariate Analysis B 95% CI p-value R2 B 95% CI p-value R2 Volume (cm3) 433.1 305.0-561.2 <0.001 0.329 568.5 437.8 -669.2 ⁎<0.001 0.499 Location (renal) 73.0 −18.3-164.2 0.116 0.027 42.5 −39.3-124.3 0.304 HUD (HU/cm) −1.7 −10.2-6.8 0.698 0.002 13.5 6.4-20.6 ⁎<0.001 Fiber (365um) −6.1 −101.4-89.2 0.900 <0.001 69.4 −13.1-151.9 0.098 Calcium Stone −9.8 −229.9-210.3 0.930 <0.001 1.3 −163.1-165.7 0.987 ⁎ p-value for Calcium Stones vs. Uric Acid stones © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e625-e626 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Wilson Molina Denver, CO More articles by this author Giovanni Marchini Cleveland, OH More articles by this author Alexandre Pompeo Denver, CO More articles by this author David Sehrt Denver, CO More articles by this author Fernando Kim Denver, CO More articles by this author Manoj Monga Cleveland, OH More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...