Ultrasound-Guided Thoracic Paravertebral Block for Controlling Pain in Percutaneous Radiofrequency Ablation of Hepatic Tumors: A Prospective Case Series

Objective: Patients with hepatic tumors undergo percutaneous radiofrequency ablation (PRFA) performed under local anesthesia and intravenous sedation can experienced severe post procedural pain. This prospective case series evaluated the feasibility, efficacy and safety of ultrasound assisted thoracic paravertebral blocks (TPVB) at three levels (T5-6, T7-8 and T9-10) for post procedural pain control. Methods: 35 patients with hepatic tumors received 3 levels ultrasound guided right thoracic paravertebral blocks (TPVB) at T5-6, T7-8 and T9-10. Patients were administered with propofol bolus with continuous infusion for sedation. Pain score at post anesthesia care unit and maximum pain score during 24 hours were recorded. Results: All patients except one reported minimal pain after PRFA. Mean NRS on arrival in PACU was 0.51 (SD: 1.50; range: 0-7) at rest and 1.20 (SD: 1.95; range: 0-10) on movement. The maximum pain score during 24 hour post-procedure period was 1.31 (SD: 1.93; range: 0-10). One case reported severe pain at shoulder due to the tumor adjacent to the diaphragm. Patients can tolerate TPVB well and there were no complications associated with the blocks. Conclusion: 3 levels ultrasound guided TPVB can produce the effective post procedural pain control. The technique is promising and may also be appropriate for other interventional radiological procedures such as trans-arterial chemoembolization (TACE) of hepatic tumors and percutaneous trans-hepatic biliary drainage (PTBD).