Radiofrequency thermal ablation of echinococcal liver cysts

Percutaneous treatment of cystic echinococcosis of the liver is increasingly being employed. However, puncture of multivesiculated cysts may be difficult and Gharbi type IV cysts are generally thought unsuitable both for medical and percutaneous treatment. Small daughter cysts may easily recur after treatment with albendazole, and they may be difficult to reach with a needle. Two groups have reported their successful experience in percutaneous treatment of type IV cysts with large-bore catheters.4, 5 Although ground-breaking, this method is still rather complex. We present an alternative simpler percutaneous method for these cysts, based on thermal ablation of the germinal layer. We used a radiofrequency ablation device (LeVeen Needle Electrode, RadioTherapeutics, Mountain View, CA), currently used for percutaneous treatment of solid neoplasms of the liver. The technique uses an insulated 14-gauge outer needle that houses ten solid retractable curved electrodes. When deployed, the electrodes assume the configuration of an umbrella 3·5 cm in diameter. Two men, aged 66 and 75 years, respectively, were selected and gave informed consent for this procedure. One had a 10 cm cyst in the right liver, and the other a 10 cm right-liver cyst and 12 cm middle-liver cyst. The two men had been treated with albendazole for at least 2 years, with incomplete solidification of their cysts and permanence of small, peripheral daughter cysts. In the presence of an anaesthesiologist, a LeVeen needle was inserted through a 15-gauge coaxial needle under ultrasonographic guidance in the cyst, by a transhepatic approach. The needle was attached to a 100 W generator operated at 480 kHz. Daughters cysts were reached and broken by deploying the electrodes; then energy was applied for 8 min at each location. The procedure was completed without complications. No scolices were seen on microscopic examination and no residual germinal membrane was found at pathological and electron microscopy examination of the material aspirated after radiofrequency. Ultrasound-guided radiofrequency of complex cysts is feasible, safe, and simpler than treatment with large-bore catheters. No dilators, hypertonic saline and contrast-medium injection, fluoroscopy, or catheters for external drainage are needed with this technique. If proven effective at longterm follow-up, it may extend the indications of percutaneous treatment to complex echinococcal cysts, carrying further the challenge to surgery.