Hoey M F, Dixon C M, Paul S
Department of Physiology and Urology, University of Minnesota, Minneapolis 55455, USA.
J Endourol. 1998 Oct;12(5):461-8. doi: 10.1089/end.1998.12.461.
An interstitial saline-electrode has been developed to couple radiofrequency (RF) energy to prostate tissue in order to produce large lesions quickly and controllably. In this study, we attempted to produce similar results using a flexible catheter introduced transurethrally via a flexible cystoscope. An insulated 4F catheter with an extendable needle electrode (26-gauge, 5-mm exposed metal tip) was introduced through a port of a flexible cystoscope into the urethra of 10 dogs via a small perineal incision (required for the canine U-shaped urethra). Under visual endoscopic guidance, the electrode was placed in the center of the prostate and the needle electrode extended at an angle into the prostate, one lobe at a time. Hypertonic saline (14.6% NaCl) was infused at 2 mL/min through the needle electrode into the tissue for 30 seconds before and during RF application. The energy (50 W, 475 kHz) was delivered for 30, 45, 60, or 90 seconds (RFT System; U.S. Surgical Corporation). Prostate and urethral temperatures were monitored using thermocouples mounted on the catheter. There was an automatic high-temperature shut-off if the urethra reached >42 degrees C or if impedance reached >300 omega during RF energy application. Prostate sizes ranged from 1.4 x 2.0 x 1.4 cm to 5.0 x 4.5 x 4.2 cm. In this group, there were no automatic shut-offs at any of the energy durations, and the lesions produced ranged from 1.3 x 1.3 x 1.1 cm (0.99 cm3) to 1.6 x 2.7 x 2.2 cm (5.03 cm3). The average ablation volumes produced were 1.76 cm3 at 30 seconds' RF application, 2.42 cm3 at 45 seconds, 3.96 cm3 at 60 seconds, and 5.03 cm3 at 90 seconds. Histologic examination revealed typical coagulation necrosis in the treatment zone without tissue desiccation. Introduction of the saline-electrode through a flexible cystoscope provides a minimally invasive procedure that quickly and controllably produces large lesions that may provide effective treatment for benign prostatic hyperplasia with less patient discomfort.
一种间质盐水电极已被研发出来，用于将射频（RF）能量耦合到前列腺组织，以便快速且可控地产生大的病灶。在本研究中，我们试图通过经柔性膀胱镜经尿道插入的柔性导管来取得类似的结果。一根带有可伸展针电极（26号，5毫米外露金属尖端）的绝缘4F导管通过柔性膀胱镜的一个端口，经一个小的会阴切口（犬类U形尿道所需）插入10只犬的尿道。在内镜可视引导下，将电极置于前列腺中央，针电极以一定角度一次伸入一个前列腺叶。在施加射频之前和期间，以2毫升/分钟的速度通过针电极向组织内注入高渗盐水（14.6%氯化钠）30秒。施加能量（50瓦，475千赫兹）30、45、60或90秒（RFT系统；美国外科公司）。使用安装在导管上的热电偶监测前列腺和尿道温度。如果在施加射频能量期间尿道温度达到>42摄氏度或阻抗达到>300欧姆，则会自动高温切断。前列腺大小从1.4×2.0×1.4厘米到5.0×4.5×4.2厘米不等。在该组中，在任何能量持续时间下均未出现自动切断情况，产生的病灶大小从1.3×1.3×1.1厘米（0.99立方厘米）到1.6×2.7×2.2厘米（5.03立方厘米）。在30秒射频施加时产生的平均消融体积为1.76立方厘米，45秒时为2.42立方厘米，60秒时为3.96立方厘米，90秒时为5.03立方厘米。组织学检查显示治疗区域有典型的凝固性坏死，无组织干燥。通过柔性膀胱镜引入盐水电极提供了一种微创程序，可快速且可控地产生大的病灶，这可能为良性前列腺增生提供有效的治疗，且患者不适感较小。
