Impact of stone density on the total laser time and other surgical outcomes in flexible ureteroscopy

Abstract

Several preoperative factors are assessed for the evaluation of operative time and fragmentation efficacy during retrograde intrarenal surgery. Due to limited energy capabilities, stone density is regarded as an important factor contributing to procedural time. This study aimed to evaluate the effect of stone density on the total laser time (TLT) in lithotripsy. A total of 52 patients who underwent flexible ureteroscopy (fURS) using the Cyber Ho 60 holmium laser system (Quanta System) from October 2017 to November 2020 were prospectively analyzed. These patients were divided into groups according to their stone attenuation values (Hounsfield units [HU]) and were followed up for 3 months to determine the success of stone clearance. Differences in the TLT, patient demographics, stone characteristics, intraoperative maneuvers, and complications were analyzed. The mean stone size and density were 14.44 mm and 1043 HU, respectively. Furthermore, the mean TLT was 26.58 min, whereas the mean operative time was 41.44 min. The TLT did not significantly differ between stones with attenuation > 1000 HU and those with attenuation < 1000 HU (p = 0.486). Stones measuring > 13 mm in size required considerably longer TLT than their smaller counterparts (p = 0.008). In conclusion, in the era of rapid laser technology and instrumental developments, our findings suggest that stone density has no value on the outcomes of fURS, including the TLT, stone-free rate, and overall complications, whereas stone size significantly influences the TLT and stone-free rate.

Laser Lithotripsy for the Management of Ureteric Calculus

“…Pain abdomen was the presenting complaint in a study done in India by Jagannath et al 9 In contrast to these, Jeevaraman et al 15 found hematuria as the most common clinical presentation of ureteric calculi. In our study, left ureteric calculus (49.2%) was more common which was similar to study done by Rashid et al 16 and Ali et al 17 Right ureteric calculi undergoing laser lithotripsy was slightly more common (60.7%, 50.3% and 51.4%) in studies done by Jagannath et al, 9 Abedi et al 4 and Koju et al 3 respectively. Bilateral calculi were only 7.6% in our study and this finding was similar to other studies.…”

“…In contrast to this, a study done in India showed that only 28.0% patients had calculus with density ≥1000 HU. 20 The mean density of the calculus was 1043 ± 335.2 HU in a study done by Rashid et al 16 which is lesser than our study.…”

“…19 Majority of the residual stone on USG was ≥10 mm with density ≥1000 HU and was located in the upper ureter. Rashid et al 16 also showed no statistical significance between stone density and other variables. Similarly, the other two studies also showed that association was statistically not significant in case of SFR and stone density.…”

“…Other studies show variation in the size of the calculus undergoing laser lithotripsy, the mean stone size ranging from 7.08 ± 1.66 mm to 14.44 ± 3.56 mm. 4,14,[16][17][18][19] Stone density also predict stone composition and different stones have different HU but success does not correlate with stone density. 20 The mean density of the calculus in our study was 1312.36 ± 324.37 and 87.3% patients had calculus with density ≥1000 HU.…”

“…The SFR of 88% to 96.0% were achieved in patients with large stones. [12][13][14][15][16] SFR of 100.0% was seen in a study done by Ali et al 17 where the mean stone size was 18.2 ± 1.5 mm. Study done in Nepal also suggest that laser lithotripsy as a better option in regards to SFR (99%).…”