Department of Urology, University of Michigan, 4432 Medical Science I, 1301 Catherine Street, Ann Arbor, MI, 48109-5330, USA.
Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.
World J Urol. 2024 Mar 26;42(1):197. doi: 10.1007/s00345-024-04896-4.
High fluid temperatures have been seen in both in vitro and in vivo studies with laser lithotripsy, yet the thermal distribution within the renal parenchyma has not been well characterized. Additionally, the heat-sink effect of vascular perfusion remains uncertain. Our objectives were twofold: first, to measure renal tissue temperatures in response to laser activation in a calyx, and second, to assess the effect of vascular perfusion on renal tissue temperatures.
Ureteroscopy was performed in three porcine subjects with a prototype ureteroscope containing a temperature sensor at its tip. A needle with four thermocouples was introduced percutaneously into a kidney with ultrasound guidance to allow temperature measurement in the renal medulla and cortex. Three trials of laser activation (40W) for 60 s were conducted with an irrigation rate of 8 ml/min at room temperature in each subject. After euthanasia, three trials were repeated without vascular perfusion in each subject.
Substantial temperature elevation was observed in the renal medulla with thermal dose in two of nine trials exceeding threshold for tissue injury. The temperature decay time (t½) of the non-perfused trials was longer than in the perfused trials. The ratio of t½ between them was greater in the cortex than the medulla.
High-power laser settings (40W) can induce potentially injurious temperatures in the in vivo porcine kidney, particularly in the medullary region adjacent to the collecting system. Additionally, the influence of vascular perfusion in mitigating thermal risk in this susceptible area appears to be limited.
激光碎石术中的体外和体内研究都观察到了较高的流体温度，但肾实质内的热分布尚未得到很好的描述。此外，血管灌注的热沉效应仍然不确定。我们的目标有两个：首先，测量激光激活肾盂时肾组织的温度；其次，评估血管灌注对肾组织温度的影响。
在三个猪模型中进行输尿管镜检查，使用包含尖端温度传感器的原型输尿管镜。在超声引导下经皮引入带有四个热电偶的针，以允许在肾髓质和皮质中进行温度测量。在每个模型中，以 8ml/min 的冲洗速度在室温下进行 3 次激光激活（40W）60s 的试验。安乐死后，每个模型中重复进行 3 次无血管灌注的试验。
在肾髓质中观察到明显的温度升高，在 9 次试验中的 2 次中，热剂量超过了组织损伤的阈值。无灌注试验的温度衰减时间（t½）比灌注试验长。它们之间 t½ 的比值在皮质中比髓质中更大。
高能激光设置（40W）可在活体猪肾中引起潜在的损伤性温度，特别是在靠近收集系统的髓质区域。此外，血管灌注在减轻该易感区域的热风险方面的影响似乎是有限的。
