Liu Min, Li Ling, Xu Zhipeng, Peng Yonghan, Wang Zeyu, Xie Fei, Gao Xiaofeng
Department of Urology, Shanghai Changhai Hospital, Shanghai, China.
Department of Urology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, China.
J Endourol. 2022 Apr;36(4):508-513. doi: 10.1089/end.2021.0651.
Stone retropulsion was shown to be impacted by pulse duration during holmium laser lithotripsy, although the whole process of retropulsion was troublesome to study. We developed a modified method to analyze retropulsion using a smartphone and video tracking software. A holmium laser system was incorporated with a short (200 μseconds) and long pulse-duration (LP) (800 μseconds), and a 272-μm core fiber was attached. A cross-sectional V-shaped rail was submerged in a tank, on which artificial stones were displaced linearly after lasering. Different combinations of pulse energy, frequency, and pulse duration were tested for at least 4 seconds. An iPhone 11 capable of high-definition videoing and video tracking software was used to analyze the stone's displacement and velocity. For most settings, the displacement-time graph resembled logarithmic growth and the velocity peaked within the first second after lasering. Higher energy or frequency translated into greater displacement, accompanied by earlier and faster velocity peaks. When the laser power was constant, the short pulse-duration at the fourth second after lasering was much larger in 0.5 J × 40 Hz than 1.0 J × 20 Hz under the short pulse-duration (SP) (13.17 ± 0.92 mm 6.90 ± 1.98 mm, < 0.05), but this discrepancy was offset by the LP. The largest stone displacement and velocity were observed in 0.5 J × 40 Hz SP. The pulse duration plays a dominant role in determining the stone retropulsion and velocity, and a long pulse decreases retropulsion and velocity. Given a constant power, the variable combination of frequency and pulse energy contributes to significantly different retropulsion with a short pulse rather than a long pulse. The modified method offers a feasible solution for the study of stone retropulsion by laser lithotripsy.
钬激光碎石术中，结石后推受脉冲持续时间的影响，尽管研究结石后推的整个过程很麻烦。我们开发了一种改进方法，使用智能手机和视频跟踪软件来分析结石后推情况。将一个钬激光系统与短脉冲持续时间（200微秒）和长脉冲持续时间（LP）（800微秒）相结合，并连接一根272微米芯径的光纤。将一个横截面为V形的轨道浸入水箱中，激光照射后人工结石在该轨道上线性移动。对脉冲能量、频率和脉冲持续时间的不同组合进行了至少4秒的测试。使用一部能够进行高清录像的iPhone 11和视频跟踪软件来分析结石的位移和速度。对于大多数设置，位移-时间图类似于对数增长，并且速度在激光照射后的第一秒内达到峰值。更高的能量或频率会导致更大的位移，同时伴随着更早、更快的速度峰值。当激光功率恒定时，在短脉冲持续时间（SP）下，激光照射后第四秒时，0.5J×40Hz的短脉冲持续时间产生的位移比1.0J×20Hz的大得多（13.17±0.92毫米对6.90±1.98毫米，P<0.05），但这种差异在长脉冲持续时间下被抵消。在0.5J×40Hz SP时观察到最大的结石位移和速度。脉冲持续时间在决定结石后推和速度方面起主导作用，长脉冲会降低后推和速度。在功率恒定的情况下，频率和脉冲能量的可变组合在短脉冲而非长脉冲时会导致明显不同的后推情况。这种改进方法为通过激光碎石术研究结石后推提供了一种可行的解决方案。
