PURPOSE To evaluate the thermal effect of high-power holmium:yttrium-aluminum-garnet (Ho:YAG) laser lithotripsy in flexible/semirigid ureteroscopy (fURS/sURS) and percutaneous nephrolithotomy (PNL) in a standardized ex vivo porcine kidney model with real-time temperature assessment. METHODS The experimental setup consisted of three models designed to evaluate the thermal effects of Ho:YAG laser lithotripsy in fURS, sURS and PNL, respectively. In all setups, a postmortem porcine kidney was placed in a 37 °C water bath. Three thermocouples were inserted into the renal parenchyma while a flexible thermocouple was placed 3-4 mm proximal to the laser fiber to measure temperature variations in the collecting system. The thermal impact was evaluated in relation to laser power between 5 and 100 W and various irrigation rates (37 °C, 0-100 ml/min). RESULTS In all three experimental setups, sufficient irrigation was required to prevent potentially damaging temperatures into the renal pelvis and parenchyma. Even 5 W in fURS can lead to a potentially harming temperature rise if insufficient irrigation is applied. Particularly, high-power settings ≥ 30 W carry an elevated risk for critical temperature rises. The results allow the definition of a specific irrigation threshold for any power setting to prevent critical temperatures in the present study design. CONCLUSIONS Ho:YAG laser lithotripsy bears the risk of thermal damages to the urinary tract even at low-power settings if inadequate irrigation is applied. Sufficient irrigation is mandatory to perform safe Ho:YAG laser lithotripsy. Based on the results, we developed a formula calculating the approximate ΔT for irrigation rates ≥ 30 ml/min: ΔT = 15 K × (power [W]/irrigation [ml/min]).

中文翻译：

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Ho：YAG激光碎石术在逆行肾内手术和离体猪肾脏模型中经皮肾镜取石术中的热效应。

目的在标准的离体猪肾脏肾脏模型（具有真实的真实肾脏模型）中评估大功率：钇铝石榴石（Ho：YAG）激光碎石术在柔性/半刚性输尿管镜（fURS / sURS）和经皮肾镜取石术（PNL）中的热效应时温度评估。方法实验装置由三个模型组成，分别用于评估Ho：YAG激光碎石术在fURS，sURS和PNL中的热效应。在所有设置中，将死后猪肾置于37°C水浴中。将三个热电偶插入肾实质，同时将柔性热电偶放置在靠近激光光纤3-4 mm处，以测量收集系统中的温度变化。评估了相对于5至100 W之间的激光功率和各种冲洗速率（37°C，0-100 ml / min）的热影响。结果在所有三个实验装置中，都需要进行充分的冲洗，以防止温度损害肾盂和实质。如果不充分灌溉，即使fURS中的5 W也可能导致有害的温度上升。特别是，≥30 W的高功率设置会增加临界温度升高的风险。结果可为任何功率设置定义特定的灌溉阈值，以防止本研究设计中出现临界温度。结论Ho：YAG激光碎石术即使在低功率条件下，如果灌溉不充分，也会对尿路造成热损伤。为了执行安全的Ho：YAG激光碎石术，必须进行充分的冲洗。根据结果​​，我们开发了一个公式，计算≥30 ml / min的灌溉速度时的近似ΔT：