Development of an automated laser drilling algorithm to compare stone ablation patterns from different laser pulse modes

Purpose To develop a novel automated three-dimensional (3D) laser drilling algorithm to further investigate laser–stone interaction with different laser pulse modes. Comparison of post-ablative lattice architecture combined with mass of stone ablated can provide a more complete understanding of differences between pulse mode. Methods A 3D positioner (securing laser fiber) was programmed to create a 5 × 5 grid of drill holes spaced 1 mm apart on 15:5 cylindrical BegoStones. Beginning 0.5 mm above the stone surface, the laser fiber was activated and advanced 2 mm toward and into the stone for all 25 points. Four trials for each pulse mode [short pulse (SP), long pulse (LP), Moses Contact (MC), Moses Distance (MD)] were completed. Outcome measures were assessment of lattice preservation and mass of ablated stone. Results MC exhibited the greatest lattice preservation and least stone mass ablated (50.5 ± 2.2 mg). SP (69.4 ± 4.3 mg) and MD (70.0 ± 2.6 mg) had the greatest lattice destruction and stone mass ablated. The differences in stone ablated between MC and MD ( p = 0.00003), MC and SP ( p = 0.0002), and LP and MD ( p = 0.004) were statistically significant. Conclusions Consistent quantitative and qualitative differences between pulse modes were observed with a novel automated 3D laser drilling algorithm applied to BegoStone. The laser drilling algorithm developed here can be used to further enhance mechanistic understanding of laser–stone interactions and facilitate selection of appropriate laser pulse modes to balance precision and efficiency across the range of laser lithotripsy techniques.