The transomphalic and then the transligamentary extraperitoneal drainage imagined by D. Burlui and its multiple use in the liver and the biliary tract surgery, is well known. Concerning the hepatic hydatid cysts, the drainage of the remaining cavity by the round ligament way is possible for most of the locations of the parasite, but it is less performed in the right liver lateral segments locations, too far situated, and also in the left liver locations. On the other hand, this specific method implies to place the drainage tube using the round ligament "in situ ", normally placed and inserted. We encountered an extremely large hydatid cyst of the left hepatic lobe, adherent to the anterior and posterior abdominal wall, spleen, stomach, pancreas and large bowel, which required to extend the incision to the left and make the necessary segmentation of the round ligament at its hepatic insertion. After pericystotomy and the evacuation of the cyst, the remaining cavity drainage was performed through the same round ligament whose free end was tightly fixed to the partial pericystotomy border. This transposition allowed the exteriorisation of the drainage tube in the same way as for the transligamentary and total extraperitoneal original method.