Role of paravertebral block anaesthesia during percutaneous transhepatic thermoablation.

PURPOSE: This paper discusses the technique and preliminary results of right thoracic paravertebral block (TPVB) for percutaneous thermal ablation of liver tumours. MATERIALS AND METHODS: Between October 2011 and August 2012 we treated 36 lesions (25 hepatocellular carcinoma and 11 metastases) in 30 patients aged 47-85 years (mean 67.5). Patients received ultrasound (US)-guided injection of 7 ml of naropin 0.75 % in T7, T9 and T11 levels, below the costo-vertebral ligament, until we observed an anterior displacement of the parietal pleura. For the subcapsular lesions, a cervical right phrenic nerve block was associated. The level of analgesia was evaluated during and after the percutaneous procedures with the Numerical Rating Scale. Finally, we investigated statistical correlations between pain and lesions (histological type, site, dimensions), and ablation time and technique (microwave or radiofrequency ablation). RESULTS: Technical success was achieved in all patients. Despite the correct anaesthetic diffusion during the ablation, 10 patients (33.3 %) reported medium/severe pain and intravenous sedation was required. Pain was not found to correlate with any variable. No complications were observed. CONCLUSIONS: In most cases, TPVB is a safe and effective technique for conscious anaesthesia during percutaneous thermal ablation of liver tumours. Failures probably derive from left sympathetic and parasympathetic fibre stimulation. We recommend performing a TPVB in the presence of the anaesthetist.