Adjunctive hydrodissection of the bare area of liver during percutaneous thermal ablation of sub-cardiac hepatic tumours.

To report the technique of hydrodissection of the sub-diaphragmatic bare area of the liver, in order to protect the diaphragm/heart during percutaneous thermal ablation (PTA) of sub-cardiac hepatic tumours. Between January 2016 and December 2018, five patients (four female, one male; mean age 56.2 years) with five sub-cardiac liver tumours (two hepatocellular carcinoma, three metastases; mean size 39 mm) abutting the bare area (segments II/IVA) with expected ablation zones ≤ 5 mm from the myocardium were treated with PTA and adjunctive hydrodissection. Time to perform hydrodissection, distance between superior hepatic and diaphragmatic/pericardial surfaces before and after hydrodissection, ablation efficacy, complications, and local tumour progression (LTP) at last imaging follow-up were recorded. Technical feasibility was 100%, with mean hydrodissection-volume of 126 ml (range 80-200 ml) and median hydrodissection-time of 9 min (range 8-45 min). Liver-diaphragmatic and liver-pericardial distance increased, respectively, from 2.4 mm (range 0-8 mm) to 10.8 mm (range 6-19 mm) and from 4 mm (range 1-10 mm) to 12.6 mm (range 8-20 mm) post-hydrodissection. All procedures were performed at full-power with complete tumour ablation and without complications (including peri-procedural haemodynamic/electrocardiographic disturbances, pericardial effusion and diaphragmatic hernia) or evidence of LTP at mean 12.2-month (range 1-26 month) follow-up. Hydrodissection of the sub-diaphragmatic bare area of the liver is technically feasible and may potentially optimize safety PTA of sub-cardiac hepatic tumours.