Do High-Power Lasers Reduce Operative Time for Ureterorenoscopy? A Comparison of Holmium Lasers in An Australian Tertiary Centre

There is some laboratory-based evidence that high-powered laser systems destroy stones more effectively than low-power laser systems. However, whether this translates clinically is unknown, as direct clinical comparisons are absent from the literature. This study provides a direct comparison of the two laser systems. Abstract Objective: Holmium lasers are an effective endoscopic treatment for renal stones. Although laboratory studies have demonstrated reduced destruction times for high-power lasers, clinical evidence is lacking. Operative times for ureterorenoscopy (URS) were investigated by comparing high- and low power lasers in a general hospital setting. Materials and Methods: An audited review was conducted of 354 patients who underwent URS over a two-year period at two hospital sites using high- or low power laser. Operative time, stone characteristics, disposable equipment, s use of dusting, complications and stone-free rates were recorded. Linear regression was used to model the relationship between laser type and theater time. Univariate analysis was performed to determine other factors associated with increased operative time. Results: Mean operative time was 61.9 minutes. No significant difference between sites [0.40, p=0.88, confidence interval (CI) -4.9-5.8] was found, including following the exclusion of large stones (>20 mm). Stone size categories analyzed separately showed reduced operative times for larger stones when using high-power laser. Basket use (8.4, p=0.002, CI 3.06-13.65) and increasing stone size (6.9, p<0.005, CI 3.4-10.4) were associated with increased operative time. Complications and stone-free rates did not vary between sites. Conclusion: High-power laser was not associated with reduced total operative time in this cohort, although there was a trend toward this for larger renal calculi. Further delineation by surgeon expertise would be useful to determine whether high power laser is generally advantageous in the clinical setting. In training hospitals, any differences may be obscured by other factors.