Urology Service, Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
Ther Adv Urol. 2013 Jun;5(3):135-41. doi: 10.1177/1756287212465457.
To examine the effects and safety of using endoscopic spray cryotherapy (ESC) on bladder, ureteral, and renal pelvis urothelium in a live porcine model.
ESC treatments were systematically applied to urothelial sites in the bladder, ureter, and renal pelvis of eight female Yorkshire swine in a prospective trial. Freeze-thaw cycles ranged from 5 to 60 s/cycle for one to six cycles using a 7 French cryotherapy catheter. Tissue was evaluated histologically for treatment-related effects. Acute physiologic effects were evaluated with pulse oximetry, Doppler sonography, and postmortem findings.
In bladder, treatment depth was inconsistent regardless of dose, demonstrating urothelial necrosis in one, muscularis propria depth necrosis in two, and full thickness necrosis in all remaining samples. In ureter, full thickness necrosis was seen in all samples, even with the shortest spray duration (5 s/cycle for six cycles or 30 s/cycle for one cycle). Treatment to the renal pelvis was complicated by adiabatic gas expansion of liquid nitrogen to its gaseous state, resulting in high intraluminal pressures requiring venting to avoid organ perforation, even at the lowest treatment settings. At a planned dose of 5 s/cycle for six cycles of the first renal pelvis animal, treatment was interrupted by sudden and unrecoverable cardiopulmonary failure after three cycles. Repeated studies replicated this event. Ultrasound and immediate necropsy confirmed the creation of a large gaseous embolism and reproducible cardiopulmonary effects.
ESC in a porcine urothelial treatment model results in full-thickness tissue necrosis in bladder, ureter, and renal pelvis at a minimal treatment settings of 5 s/cycle for six cycles. Adiabatic gas expansion may result in fatal pyelovenous gas embolism and collateral organ injury, as seen in both animals receiving treatment to the renal pelvis in this study. These results raise safety concerns for use of ESC as a treatment modality in urothelial tissues with current device settings.
在活体猪模型中研究内镜喷雾冷冻疗法（ESC）对膀胱、输尿管和肾盂尿路上皮的作用和安全性。
在一项前瞻性试验中，将 ESC 治疗系统地应用于 8 头雌性约克夏猪的膀胱、输尿管和肾盂尿路上皮部位。每个冷冻-解冻循环的冷冻时间为 5 至 60 秒，使用 7 法国号的冷冻治疗导管进行 1 至 6 个循环。使用组织学评估治疗相关效果。通过脉搏血氧仪、多普勒超声和死后发现评估急性生理效应。
在膀胱中，无论剂量如何，治疗深度均不一致，表现为 1 例尿路上皮坏死，2 例固有肌层深度坏死，所有其余样本均为全层坏死。在输尿管中，所有样本均出现全层坏死，即使喷雾时间最短（6 个循环 5 秒/循环或 1 个循环 30 秒/循环）。由于液氮绝热膨胀至气态，肾盂治疗变得复杂，导致腔内压力升高，需要通风以避免器官穿孔，即使在最低治疗设置下也是如此。在第一例肾盂动物的计划剂量为 5 秒/循环 6 个循环时，在 3 个循环后由于心肺功能衰竭突然且无法恢复而中断治疗。重复研究复制了这一事件。超声和立即尸检证实了大的气体栓塞和可重复的心肺效应的形成。
在猪的尿路上皮治疗模型中，在最小治疗设置为 5 秒/循环 6 个循环时，膀胱、输尿管和肾盂会出现全层组织坏死。在本研究中，接受肾盂治疗的两只动物都出现了绝热气体膨胀导致的致命肾盂静脉气体栓塞和相邻器官损伤，这引起了对 ESC 作为尿路上皮组织治疗方式的安全性的关注。
