This study aims to analyse retrospectively the feasibility, the safety, and the efficiency, of biliary or digestive protection with room air interposition for thermal ablation of central liver tumors with high iatrogenic risk.

Thermal ablation is a mini-invasive and curative treatement of liver tumors. However, it requires to be carefull about surrunding organs, such as digestive structures or central biliary tree, which can be injured if not insulated.

The technique of gas interposition to protect adjacent gut is already known and validated with carbonic gas. Nevertheless, resorption of this gas is very fast, making its use tricky to keep a correct insulation during the whole thermal ablation process.

Room air interposition is easy to use and can offer a slow resorption speed. Furthermore no datas are available concerning the use of room air whatever the organ protected, and the protection of central biliary tree whatever the gas used.

Inclusion Criteria :

• Patients with single malignant primary or secondary liver tumor
• Thermal ablation area located within 1 centimeter from central biliary tree or gut
• Thermal insulation using room air interposition
• Follow-up of at least 2 months

Patients with single malignant liver tumor with high iatrogenic risk treated by thermal ablation with biliary or digestive protection by room air interposition, in Nice CHU, between January 2013 and December 2021.