Cool-tip radiofrequency ablation for renal cell carcinoma in vitro
Chen Guangfu1, Wang Xiyou2 Liu Aijun3 Sun Shengkun1,Zhu Jie1, Chen Wenzheng1, Zhang Xu1
1Department of Urology, Chinese People's Liberation Army General Hospital, Beijing 100853, China; 2Department of Urology, The Navy General Hospital of the Chinese People's Liberation Army; 3Department of Pathology, The General Hospital of the Chinese People's Liberation Army
Abstract：Objective: To investigate the influence of radiofrequency ablation on the ablation necrosis range, form and surrounding tissue of human vitro kidney carcinoma, in order to provide theoretical basis for clinical application. Methods: 12 cases of kidney of renal cell carcinoma patients by laparoscopic retroperitoneal radical nephrectomy(the maximum diameter of tumor ≤3.2 cm), which were randomly divided into 5 min normal kidney group (group A, 12 cases / times), 5 min renal carcinoma group (group B, 6 cases / times), 12 min normal kidney group (group C, 12 cases) and 12 min renal carcinoma group (group D, 6 cases / times). After the specimens being sent to Pathology Department, we gave them radiofrequency ablations for different time, observed the state during radiofrequency ablation, ablation necrosis range of normal kidney tissue and tumor tissue and the integrity of collection system by macroscopic observation. Then made the pathological slices and observed the pathological changes of the ablation issue. Results: ①The outer surface temperature of the tissue rises during radiofrequency ablation, tissue shrinks, sinks, and there are hot bubbles overflowing along the needle track; ②The patterns of normal kidney tissue radiofrequency ablation lesion is the ellipsoidal around RF needle, long axis parallels to RF needle, the kidney tumor tissue ablation lesion less than 3.2 cm is the original shape of tumor morphology, the capsule formation obvious boundary of tumor and normal kidney tissue; ③Compared with group C, radiofrequency ablation range of group A decreased significantly (P<0.01). The ablation range of group B is not consistent, less than 2 cm in diameter of tumor ablation maximum tumor diameter, tumor ablation diameter greater than 2 cm, the ablation diameter of group D is the maximal tumor diameter; ④There are 2 cases of collection system injury, which are observed in the kidney of needle tip close to collection system of less than 5 mm. Conclusions: 5 minutes of radiofrequency ablation cannot ensure completely ablate the tumors wich are less than 3.2 cm, 12 minutes of ablation is suitable for the tumor with the maximum diameter of less than 3.2 cm; when complete capsule, forming the "pressure cooker" effect, less than 3.2 cm of the tumors can be any angle needle; when incomplete capsule, ensure the RF needle and tumor axis overlap as far as possible, such as renal ventral or central tumor, laparoscopic radiofrequency ablation may be more appropriate; when the tumor is close to collection system, it may be damaged, the collection system cold perfusion can be used to protect it; if the tumor is adjacent to the organs such as bowel, spleen, laparoscopic surgery may be safer.
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