Diode Laser Lithotripsy of Urinary Calculi Using Controlled Fragmentation Technique

One of the triggers of infectious processes developing in the kidney after contact laser lithotripsy is calculus disintegration followed by the release of bacteria and toxins from the biofilm. Prevention urgency determines the search for new mechanisms and methods of laser calculus fragmentation without scattering of fragments and microbial dissemination into the pelvicalyceal system of the kidney.

The aim of the study was to evaluate the possibilities of applying the technology of urinary calculus fragmentation with continuous-wave diode lasers of different wavelengths using fiber light guides with strongly heated distal tips for controlled fragmentation and minimization of traumatic effects on the adjacent tissues.

Materials and Methods. To fragment postoperative samples of porous urinary stones (n=58), we applied standard certified continuous-wave diode 10 W lasers with fiber output to quartz light guides, their distal tips being coated with a layer of graphite microparticles in silicone varnish. The quality of stone fragmentation using lasers with wavelengths of 0.81 (n=17), 0.97 (n=22), and 1.47 µm (n=19) and identical quartz light guides were evaluated. Control of laser-induced heating of the urinary tract tissues adjacent to the stone was carried out on the model medium with a thermocouple. Simulation of intraoperative errors (short contact with the ureteral wall as the result of the fiber slipping off the stone surface) was performed on the ureteral wall took post mortem. Tissue condition was assessed using histological sections stained with hematoxylin and eosin.

Results. The average fragmentation time depended on calculus density and cross-sectional dimension and was 12–15 s. All selected stones, including those potentially infected, with X-ray density 119 to 1735 HU were fragmented effectively both in liquid and air. Assessment of temperature regimes provided by lasers with 0.81 and 0.97 µm wavelengths showed that the stone surface temperature during fragmentation in the air reached 40 and 57°C, respectively, and it was 25 and 33°C in liquid.

The obtained morphological and thermometric data suggest safety of lasers used for controlled fragmentation of potentially infected urinary calculi.

Conclusion. The use of continuous-wave diode lasers with strongly heated distal fiber tips at 0.81 and 0.97 µm wavelengths makes it possible to successfully fragment potentially infected urinary stones into size-controlled fragments, which may become a significant factor in prevention of systemic inflammatory response in the postoperative period.

1. Koras O., Bozkurt I.H., Yonguc T., Degirmenci T., Arslan B., Gunlusoy B., Aydogdu O., Minareci S. Risk factors for postoperative infectious complications following percutaneous nephrolithotomy: a prospective clinical study. Urolithiasis 2015; 43(1): 55–60, https://doi.org/10.1007/s00240-014-0730-8.
2. Yang T., Liu S., Hu J., Wang L., Jiang H. The evaluation of risk factors for postoperative infectious complications after percutaneous nephrolithotomy. Biomed Res Int 2017; 2017: 4832051, https://doi.org/10.1155/2017/4832051.
3. Margel D., Ehrlich Y., Brown N., Lask D., Livne P.M., Lifshitz D.A. Clinical implication of routine stone culture in percutaneous nephrolithotomy — a prospective study. Urology 2006; 67(1): 26–29, https://doi.org/10.1016/j.urology.2005.08.008.
4. Palagin I.S., Sukhorukova M.V., Dekhnich A.V., Edelstein M.V., Shevelev A.N., Grinyov A.V., Perepanova T.S., Kozlov R.S., Kogan M.I. Current state of antibiotic resistance of pathogens causing community-acquired urinary tract infections in Russia: “DARMIS” study (2010–2011). Klinicheskaya mikrobiologiya i antimikrobnaya khimioterapiya 2012; 14(4): 280–302.
5. Korets R., Graversen J.A., Kates M., Mues A.C., Gupta M. Post-percutaneous nephrolithotomy systemic inflammatory response: a prospective analysis of preoperative urine, renal pelvic urine and stone cultures. J Urol 2011; 186(5): 1899–1903, https://doi.org/10.1016/j.juro.2011.06.064.
6. Didenko L.V., Tolordava E.R., Perpanova T.S., Shevlyagina N.V., Borovaya T.G., Romanova Yu.M., Cazzaniga M., Curia R., Milani M., Savoia C., Tatti F. Electron microscopy investigation of urine stones suggests how to prevent post-operation septic complications in nephrolithiasis. J Appl Med Sci 2014; 3(4): 19–34.
7. Bredikhin V.I., Bityurin N.M., Kamenskiy V.A., Smirnova L.A., Salomatina E.V., Strel’tsova O.S., Pochtin D.P. Method of contact lithotripsy. Patent RU 2604800. 2015.
8. Streltsova О.S., Grebenkin Е.V., Pochtin D.P., Bredikhin V.I., Kamensky V.А. Contact laser lithotripsy using strongly heated distal tip of optic fiber. Sovremennye tehnologii v medicine 2017; 9(4): 137–142, https://doi.org/10.17691/stm2017.9.4.17.
9. Sapogova N., Bredikhin V., Bityurin N., Kamensky V., Zhigarcov V., Yusupov V. Model for indirect laser surgery. Biomed Opt Express 2016; 8(1): 104–111, https://doi.org/10.1364/boe.8.000104.
10. Bredikhin V., Kamensky V., Sapogova N., Elagin V., Shakhova M., Snopova L., Bityurin N. Indirect laser surgery. Applied Physics A 2016; 122(3): 181, https://doi.org/10.1007/s00339-016-9734-2.
11. Boulnois J.L. Photophysical processes in recent medical laser developments: a review. Lasers in Medical Science 1986; 1(1): 47–66, https://doi.org/10.1007/bf02030737.
12. Leijte J.A., Oddens J.R., Lock T.M. Holmium laser lithotripsy for ureteral calculi: predictive factors for complications and success. J Endourol 2008; 22(2): 257–260, https://doi.org/10.1089/end.2007.0299.
13. Pierre S., Preminger G.M. Holmium laser for stone management. World J Urol 2007; 25(3): 235–239, https://doi.org/10.1007/s00345-007-0162-y.
14. Teichman J.M., Vassar G.J., Bishoff J.T., Bellman G.C. Holmium:YAG lithotripsy yields smaller fragments than lithoclast, pulsed dye laser or electrohydraulic lithotripsy. J Urol 1998; 159(1): 17–23, https://doi.org/10.1016/s0022-5347(01)63998-3.
15. Patel A.P., Knudsen B.E. Optimizing use of the holmium: YAG laser for surgical management of urinary lithiasis. Curr Urol Rep 2014; 15(4): 397, https://doi.org/10.1007/s11934-014-0397-2.
16. Santiago J.E., Hollander A.B., Soni S.D., Link R.E., Mayer W.A. To dust or not to dust: a systematic review of ureteroscopic laser lithotripsy techniques. Curr Urol Rep 2017; 18(4): 32, https://doi.org/10.1007/s11934-017-0677-8.
17. Weiss B., Shah O. Evaluation of dusting versus basketing — can new technologies improve stone-free rates? Nat Rev Urol 2016; 13(12): 726–733, https://doi.org/10.1038/nrurol.2016.172.
18. Türk C., Knoll T., Petrik A., Sarica K., Seitz C., Straub M. Guidelines on urolithiasis. European Association of Urology; 2011.
19. Kuwahara M., Kageyama S., Kurosu S., Orikasa S. Computed tomography and composition of renal calculi. Urol Res 1984; 12(2): 111–113, https://doi.org/10.1007/bf00257175.

Streltsova О.S., Grebenkin Е.V., Bredikhin V.I., Yunusova K.E., Elagin V.V., Kamensky V.A. Diode Laser Lithotripsy of Urinary Calculi Using Controlled Fragmentation Technique. Sovremennye tehnologii v medicine 2019; 11(2): 103, https://doi.org/10.17691/stm2019.11.2.15