Laparoscopic radiofrequency ablation of primary and metastatic liver tumors - Technical considerations

Background: Radiofrequency thermal ablation is a new technology for the loc al destruction of liver tumors. Since we first described laparoscopic radio frequency ablation (LRFA) for the treatment of liver tumors, much has been learned about patient selection, laparoscopic ultrasound (LU) guided placem ent of the ablation catheter, monitoring of the ablation process, and patie nt follow-up. Methods: Since January 1996 we have performed LRFA of 250 tumors in 67 pati ents including 85 adenocarcinomas, 107 neuroendocrine rumors, 34 sarcomas, 1 melanoma, and 11 hepatomas. We used LU to guide placement of the ablation catheter and to monitor the ablation process. Most of the patients had two trocars (camera and laparoscopic ultrasound) with the 15-gauge ablation ca theter (RITA Medical Systems, Mountain View. CA? USA) placed percutaneously . Results: The LRFA procedure was completed successfully in all patients, wit h 1 to 14 lesions per patient, ranging in size from 0.5 to 10 cm in diamete r. The entire liver could be examined by LU via light subcostal ports. Crit eria for successful ablation were 5-min ablation times at 100 degrees C wit h 1-min cool-down temperatures of 60 degrees to 70 degrees C. Outgassing of dissolved nitrogen, monitored by ultrasound, was useful in confirming the zone of ablation. Intralesional color-flow Doppler, seen before ablation, w as eliminated after ablation. Placement of the grounding pad closer to the lesion on the back rather than the thigh resulted in more efficient energy delivery to the tumor. Lesions larger than 3 cm in diameter required overla pping ablations to achieve a 1-cm margin of normal liver. Most patients req uired overnight hospitalization, with no coagulopathy or electrolyte distur bances noted. Conclusions: The LRFA procedure is a novel, minimally invasive technique fo r treatment of liver tumors that have failed conventional therapy. This stu dy documents the technical aspects of targeting lesions and performing repr oducible zones of ablation. Familiarity with these techniques should lead t o more widespread application.