射频消融治疗继发性脾肿大、脾功能亢进可行性和安全性的实验研究

目的 评价射频消融(RFA)脾脏治疗继发性脾肿大和脾功能亢进的可行性和安全性。方法 14只健康杂种狗随机分为Ⅰ组(脾静脉结扎,n=4)和Ⅱ组(脾静脉结扎 RFA,n=10),通过结扎脾静脉主干和脾静脉属支引起淤血性脾肿大,3周末Ⅱ组剖腹行射频热能毁损脾脏。观察动物脾脏经RFA后的并发症,定期行CT扫描以及切取脾脏观察热毁损后脾脏病灶的影像学和组织病理学变化。结果 全组动物无死亡和并发症。CT显示脾静脉结扎后脾脏明显肿大并可持续2个月以上,RFA后脾脏病灶呈节段性毁损,包括高密度的坏死区和低密度的梗死区——后者称为“旁观者效应”;梗死区在RFA后4—6周内消失,残脾缩小;坏死区改变不明显。射频热能引起脾脏局部组织凝固性坏死和广泛的血栓性梗死形成。梗死区逐渐吸收、纤维化,血管闭塞、纤维素沉积和脾窦消失引起活性脾脏组织结构致密。结论 RFA治疗实验性脾肿大和脾亢是可行和安全的,将来可在开腹或腹腔镜下严格隔离脾脏周围器官后在临床安全实施。

The feasibility and safety of radiofrequency ablation for secondary splenomegaly and hypersplenism in dogs

Objective To assess the feasibility and safety of radiofrequency ablation (RFA) in spleen to treat secondary splenomagely and hypersplenism in dogs. Methods Fourteen healthy mongrel dogs were randomly divided into two groups: group A (n=4) and group B (n=10) Both groups underwent ligation of the splenic vein and its collateral branches to induce congestive splenomegaly. At the end of the 3rd week, radiofrequency thermal ablation of the spleen was performed in the group B via laparotomy. After splenic RFA, the procedure-related complications were observed, CT scan was performed and the spleens were obtained according to schedule. The radiofrequency (RF) thermal lesions and its histo- pathological changes of the spleen were examined regularly. Results There were no morbidity and mortality in the experimental dogs. CT findings revealed that splenomegaly could sustained over 2 months after ligation of the splenic vein. The segmental RF lesions included hyperintense zone of coagulative necrosis and more extensively peripheral hypointense infarcted zone. The latter was called as "bystander effect". The infarcted zone would be absorbed and subsequently disappeared between 4 and 6 weeks after RFA, and the size of the remnant spleen shrinked, but the lesion of coagulative necrosis hardly altered. The fundamental histopathological changes of splenic lesions caused by RF thermal energy included local coagulative necrosis and the peripheral thrombotic infarction zone. Subsequently, tissue absorption and fibrosis occurred in the zone of thrombotic infarction. Simultaneously occluded vessels, fibrin deposition, and disappearance of normal splenic sinuses resulted in the condensed structure of the viable remnant spleen, which were the pathological basis responsible for the shrinked spleen. Conclusions It is feasible and safe to perform RFA in the spleen to treat experimental splenomegaly and hypersplenism. The RFA technique could be safely performed clinically via laparotomy or laparoscopic procedure to strictly isolate the spleen from the surrounding organs.