摘要 Objective: The Holmium:yttrium-aluminum-garnet (Ho:YAG) laser is the standard lithotrite for ureteroscopy.This research is to evaluate a Ho:YAG laser with a novel effect function in vitro, which allows a real-time variation of pulse duration and pulse peak power.Methods: Two types of phantom calculi with four degrees of hardness were made for fragmentation and retropulsion experiments.Fragmentation was analysed at 5 (0.5 J/10 Hz), 10 (1 J/10 Hz), and 20 (2 J/10 Hz) W in non-floating phantom calculi, retropulsion in an ureteral model at 10 (1 J/10 Hz) and 20 (2 J/10 Hz) W using floating phantom calculi.The effect function was set to 25%, 50%, 75%, and 100% of the maximum possible effect function at each power setting.Primary outcomes: fragmentation (mm3), the distance of retropulsion (cm); ≥ 5 measurements for each trial.Results: An increase of the effect feature (25% vs.100%), i.e., an increase of pulse peak power and decrease of pulse duration, improved Ho:YAG laser fragmentation.This effect was remarkable in soft stone composition, while there was a trend for improved fragmentation with an increase of the effect feature in hard stone composition.Retropulsion increased with increasing effect function, independently of stone composition.The major limitations of the study are the use of artificial stones and the in vitro setup.Conclusion: Changes in pulse duration and pulse peak power may lead to improved stone fragmentation, most prominently in soft stones, but also lead to increased retropulsion.This new effect function may enhance Ho: YAG laser fragmentation when maximum power output is limited or retropulsion is excluded.
Abstract: Objective: The Holmium:yttrium-aluminum-garnet (Ho:YAG) laser is the standard lithotrite for ureteroscopy.This research is to evaluate a Ho:YAG laser with a novel effect function in vitro, which allows a real-time variation of pulse duration and pulse peak power.Methods: Two types of phantom calculi with four degrees of hardness were made for fragmentation and retropulsion experiments.Fragmentation was analysed at 5 (0.5 J/10 Hz), 10 (1 J/10 Hz), and 20 (2 J/10 Hz) W in non-floating phantom calculi, retropulsion in an ureteral model at 10 (1 J/10 Hz) and 20 (2 J/10 Hz) W using floating phantom calculi.The effect function was set to 25%, 50%, 75%, and 100% of the maximum possible effect function at each power setting.Primary outcomes: fragmentation (mm3), the distance of retropulsion (cm); ≥ 5 measurements for each trial.Results: An increase of the effect feature (25% vs.100%), i.e., an increase of pulse peak power and decrease of pulse duration, improved Ho:YAG laser fragmentation.This effect was remarkable in soft stone composition, while there was a trend for improved fragmentation with an increase of the effect feature in hard stone composition.Retropulsion increased with increasing effect function, independently of stone composition.The major limitations of the study are the use of artificial stones and the in vitro setup.Conclusion: Changes in pulse duration and pulse peak power may lead to improved stone fragmentation, most prominently in soft stones, but also lead to increased retropulsion.This new effect function may enhance Ho: YAG laser fragmentation when maximum power output is limited or retropulsion is excluded.
Christopher Netsch, Sophie Knipper, Christian Tiburtius, Andreas J. Gross. Systematic evaluation of a holmium: yttrium-aluminumgarnet laser lithotripsy device with variable pulse peak power and pulse duration[J]. Asian Journal of Urology, 2014, 1(1): 57-61.
Christopher Netsch, Sophie Knipper, Christian Tiburtius, Andreas J. Gross. Systematic evaluation of a holmium: yttrium-aluminumgarnet laser lithotripsy device with variable pulse peak power and pulse duration. Asian Journal of Urology, 2014, 1(1): 57-61.
Gupta PK. Is the holmium:YAG laser the best intracorporeallithotripter for the ureter? A 3-year retrospective study. J Endourol2007; 21: 305-9.
[6]
Teichman JM, Rao RD, Rogenes VJ, Harris JM. Ureteroscopicmanagement of ureteral calculi: Electrohydraulic versus holmium:YAG lithotripsy. J Urol 1997; 158: 1357-61.
[7]
Vassar GJ, Teichman JM, Glickman RD. Holmium:YAG lithotripsyefficiency varies with energy density. J Urol 1998; 160: 471-6.
[8]
Lee HJ, Box GN, Abraham JB, Deane LA, Elchico ER, EisnerBH, et al. In vitro evaluation of nitinol urological retrieval coiland ureteral occlusion device: Retropulsion and holmium laserfragmentation efficiency. J Urol 2008; 180: 969-73.
Finley DS, Petersen J, Abdelshehid C, Ahlering M, Chou D, BorinJ, et al. Effect of holmium:YAG laser pulse width on lithotripsyretropulsion in vitro. J Endourol 2005; 19:1041-4.
[11]
Wezel F, Häcker A, Gross AJ, Michel MS, Bach T. Effect of pulseenergy, frequency and length on holmium:yttrium-aluminum-garnetlaser fragmentation efficiency in non-floating artificial urinarycalculi. J Endourol 2010; 24: 1135-40.
[12]
Sea J, Jonat LM, Chew BH, Qiu J, Wang B, Hoopman J, et al.Optimal power settings for Holmium:YAG lithotripsy. J Urol 2012;187: 914-9.
[13]
Yoshida T, Fujimura K, Yamazaki T, Nogaki J, Okada K.Experimental and clinical study of a holmium: YAG laser withadjustable pulse duration. Aktuelle Urol 2003; 34: 276-8.
[14]
Michel MS, Knoll T, Ptaschnyk T, Köhrmann KU, Alken P. Flexibleureterorenoscopy for the treatment of lower pole calyx stones:influence of different lithotripsy probes and stone extraction tools onscope deflection and irrigation flow. Eur Urol 2002; 41: 312-7.
[15]
Nazif OA, Teichman JM, Glickman RD, Welch AJ. Review of laserfibers: A practical guide for urologists. J Endourol 2004; 18: 818-29.
[16]
Mues AC, Teichman JM, Knudsen BE. Evaluation of 24 holmium:YAG laser optical fibers for flexible ureteroscopy. J Urol 2009; 182:348-54.
[17]
Lee H, Ryan RT, Teichman JM, Kim J, Choi B, Arakeri NV, et al.Stone retropulsion during holmium:YAG lithotripsy. J Urol 2003;169: 881-5.
[18]
Kang HW, Lee H, Teichman JM, Oh J, Kim J, Welch AJ.Dependence of calculus retropulsion on pulse duration during Ho:YAG laser lithotripsy. Lasers Surg Med 2006; 38: 762-72.
[19]
Marguet CG, Sung JC, Springhart WP, L'Esperance JO, ZhouS, Zhong P, et al. In vitro comparison of stone retropulsion andfragmentation of the frequency doubled, double pulse nd:yag laserand the holmium:yag laser. J Urol 2005; 173: 1797-800.
Christopher Hartman, Nikhil Gupta, David Leavitt, David Hoenig, Zeph Okeke, Arthur Smith. Advances in percutaneous stone surgery[J]. Asian Journal of Urology, 2015, 2(1): 26
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